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An Engine Start/Stop System for Improved Fuel Economy
Abstract
During city traffic or heavily congested roads, a vehicle can consume a substantial amount of fuel idling when the vehicle is stopped. Due to regulation enforcement, auto manufacturers are developing systems to increase the mileage and reduce emissions. Turning off the engine at traffic lights and regenerative braking systems are simple ways to reduce emissions and fuel consumption. In order to develop strong manufacturer and consumer interest, this type of operation needs to be automated such that the stop/start functionality requires no driver interaction and takes place without the intervention of the vehicle operator. Valeo Electrical Systems has developed such a system that replaces the OEM engine alternator with a starter/alternator driven by a standard multi-ribbed V belt. To avoid a break and dual voltage network, this system is based on a 12V electrical system using an Enhanced Power Supply. In 2004, this system was designed for and integrated into a 2003 GMC Envoy and is capable of starting the vehicle's engine very quickly and quietly. In order to obtain smooth, transparent start/stop operation on the road, a substantial amount of integration work with the factory PCM, engine, and transmission was accomplished. During operation, the Start/Stop system can start and stop the vehicle very quickly and is able to produce acceleration from vehicle rest that feels identical to a production factory vehicle. Baseline vehicle fuel economy was measured for the OEM configuration and after installation of the start/stop system using standard chassis dynamometer fuel economy test procedures. This testing demonstrated 5.3% improvement in the city cycle and found approximately a 4.0% improvement in the highway drive cycle due to regenerative braking. Future development of the start/stop system was done using a forward looking vehicle simulation model to determine the fuel economy impact of modifying this system to operate as a mild hybrid electric system. Using the vehicle simulation software (RAPTOR), it was determined that hybridization of the start/stop system could obtain a 10% improvement in the city cycle and a 5% improvement in the highway drive cycle, based on the applied system architecture and design. This type of system can be easily integrated into a production vehicle and could provide significant fuel economy improvements with minimal cost or affect on vehicle performance.
... Some of the works are focused on the reduction of noise and vibration during the engine restart (see, for example, Reference [10] where a Pneumatic S/S system is proposed) or to guarantee a faster restart [18,19,20,21]. Other works on the S/S system address technological issues like the application of automatic transmissions with torque converter [22] or the mechanical connection between the electric machine and the engine [23,24]. ...
... The improvement in fuel economy (and consequently in CO 2 emissions) that can be achieved by using the S/S system strongly depends on the specific driving cycle. In a standard chassis dynamometer NEDC test, the use of the S/S system and regenerative braking was proved to guarantee a 5.3% improvement of fuel economy in the city cycle and about 4.0% improvement in the extra-urban part [24]. Similar results are reported in [25,26] where the NEDC is compared with the WLTC, and the estimated improvement on CO 2 emissions in the WLTC is found to be significantly less relevant due to the shorter idling period. ...
The Start/Stop (S/S) system is a technology that switches off the engine without the intervention of the driver when the vehicle is stopped. The goal of this device is to eliminate the consumption of fuel associated with the idling of the engine and, consequently, save carbon dioxide (CO 2) and pollutant emissions. However, its effectiveness is related to the percentage of the total driving time with the vehicle stopped. Moreover, even if the S/S system is installed and the vehicle is stopped, the S/S system can be inhibited by the condition of the vehicle like, for example, a too low state of charge of the battery. This investigation evaluates the actual effect of S/S on tailpipe gaseous emissions in Real Driving Emissions tests compliant with the new European Regulations (E-RDE). The investigation is based on data from on-road and on-track RDE tests performed with a Portable Emission Measurement System on a diesel sports utility vehicle (SUV). From the analysis of these data, the reduction of emission guaranteed by the S/S system was found to be quite lower than the potential in the New European Driving Cycle (NEDC) test due to the limited activation of the S/S system in real driving tests. Moreover, the analysis put into evidence that the saving associated with the S/S could be counterbalanced by the engine restart especially if the stop time is shorter than a certain threshold.
... Some of the works are focused on the reduction of noise and vibration during the engine restart (see for example reference [10] where a Pneumatic Start-Stop system is proposed) or to guarantee a faster restart [18][19][20][21]. Other works on the Start/Stop system address technological issues like the application of automatic transmissions with torque converter [22], or the mechanical connection between the electric machine and the engine [23][24]. ...
... The improvement in fuel economy (and consequently in CO2 emissions) that can be achieved by using the S/S system strongly depends on the specific driving cycle. In a standard chassis dynamometer NEDC test, the use of the Start/Stop system and regenerative braking was proved to guarantee a 5.3% improvement of fuel economy in the city cycle and about 4.0% improvement in the extra-urban part [24]. Similar results are reported in [25,26] where NEDC is compared with WLTC, and the estimated improvement on CO2 emissions in the WLTC is found to be significantly less relevant due to the shorter idling period. ...
Now accepted for publication.
Cite this as SAE Technical Paper 2022-01-5024
... Many approaches on developing driving strategies that improve fuel economy and emissions have been proposed; that include advanced traffic signal control [4], advanced vehicle technology [5], Eco Fuel [6], and vehicle operation [7]; those works were primarily focused on characteristics of the engine, power train system, and structure of the vehicle against aerodynamic drag and road surface conditions [8], [9], [10], [11]. However, recent studies have revealed that driving behavior has a potential influence on fuel consumption and emissions [12], [13], [14]. ...
... In the first step, we consider all possible recommended velocities and obtain the corresponding performance index values and crossing probability. In the next step, we calculate the expected value of the performance index considering the probability of crossing the intersection using (10). ...
Fuel consumption and travel time of a vehicle are significantly infiuenced by driving behavior especially when approaching a signalized intersection. Injudicious driving reacting to sudden changes in traffic signal can lead to additional energy consumption and increase of travel time. This paper presents a learning-based event-driven ecological (eco) driving system (EDS) that generates the optimal velocity from self-driving data of a vehicle. Currently, full autonomy of vehicles and proper infrastructure development for vehicle-to-vehicle (V2V) and infrastructure-to-vehicle (I2V) communications are not widespread; however, the proposed system can be beneficial for driving scenarios in the existing traffic environment. We design a Gaussian process model using Bayesian network for naturalistic learning from driving data and traffic signal condition to estimate the probability of a vehicle crossing the intersection within a signal phase. Based on the estimated probability, the optimal velocity is generated and the vehicle/driver will be advised to either slow down earlier (to avoid aggressive braking) at the red signal or speed up (to cross the intersection) at the green signal. Finally, microscopic simulations are performed to evaluate the performance of the proposed scheme. The results show significant performance improvement in both fuel economy and travel time.
... This can be achieved by using the Start-Stop systems, and, in some cases, by introduction of recuperative braking (Audi Technology Portal. Start-Stop System, n.d., 'Start/Stop System Operating Principle', n.d.;Bishop et al., 2007;Henein et al., 2000). ...
... The Start-Stop system is one of the ways to solve this problem (Audi Technology Portal. Start-Stop System, n.d., "Start/Stop System Operating Principle", n.d.; Bishop et al., 2007;Henein et al., 2000). ...
... This can be achieved by using the Start-Stop systems, and, in some cases, by introduction of recuperative braking (Audi Technology Portal. Start-Stop System, n.d., 'Start/Stop System Operating Principle', n.d.;Bishop et al., 2007;Henein et al., 2000). ...
... The Start-Stop system is one of the ways to solve this problem (Audi Technology Portal. Start-Stop System, n.d., "Start/Stop System Operating Principle", n.d.; Bishop et al., 2007;Henein et al., 2000). ...
This work analyses the existing Start-Stop systems. The proposed improvements to the Start-Stop system allow increasing its efficiency. Its feature is a second generator, and, thanks to it, the increased time and power of recuperative braking; besides, the engine can be stopped in a vehicle that is running by inertia or downward; at a certain speed of the car the engine is started without a starter; the energy of recuperative braking is used for electrical heating of the coolant. The paper presents a kinematic diagram of the transmission of a car with an improved Start-Stop system. A poly-V-belt drive has been chosen as a drive of the second generator. Experimental studies of the engine start in various modes have been carried out, the graphs of the dependence of the vehicle speed on the time are presented.
... Eco-coasting, as a category of eco-driving, refers to the strategies to roll the vehicle with kinetic energy without traction force [1]. For a conventional car with a gasoline engine and automatic transmission, there are three methods to coast during the deceleration phases: setting the gear in the neutral position and turning the engine to idle [2,3]; shutting fuel injection off when no torque is requested [4,5,6]; manipulating the lock-up clutch to disconnect the engine from powertrain when the engine is off [7,8,9,10]. ...
In this paper, two different coasting strategies are proposed: one leverages fuel cut-off and another uses engine start/stop. Engine drag torque and energy-cost used for engine restart are considered in the modeling to give a fair evaluation. Then, the performance of these two coasting methods is evaluated with dynamic programming (DP) under various driving scenarios with different slope profiles. Offline simulation shows that the engine start/stop method outperforms the fuel cut-off method in terms of fuel consumption and travel time by getting rid of the engine drag torque. Furthermore, on-line performance of these two coasting methods is evaluated using Mixed Integer Model Predictive Control (MIMPC). A novel operational constraint on the minimum off steps is added in the MIMPC formulation to avoid frequent switch of the integer variables representing the fuel cut-off and the engine start/stop mechanism. Simulation results show that, for both fuel cut-off and engine start/stop coasting methods, the MPC improves fuel consumption to a level comparable to DP without sacrificing the travel time.
... Again, when traffic congestion increases from moderate to peak hour, CO2 emission increases by 16.0%, 8.5%, and 4.5% for GV, PHEV, and EV, respectively. It should be noted that EV and PHEV both have the automatic start-stop feature [66], a technology that helps to prevent idle power or fuel consumption by shutting the motor or engine off when the vehicle does not move. Therefore, this technology reduces idle power consumption considerably due to frequent stops resulting from high traffic congestions. ...
Road transports in the United States (U.S.) are heavily dependent on the production and consumption of fossil fuel. This high dependency on fossil fuels contributes significantly to carbon dioxide (CO2) emission, one of the leading Green House Gases (GHGs) responsible for global warming. Electrification of passenger vehicles could be an effective strategy to curb GHG emissions. Though Electric Vehicles (EVs) have zero tailpipe emissions, the power required to charge EV batteries may not necessarily come from carbon-free power plants. In this study, for a comprehensive comparison among EV, Plug-in Hybrid Electric Vehicle (PHEV), and Gasoline Vehicle (GV), we developed an agent-based simulation modeling framework for the entire energy pathway (Well-To-Wheel). As a case study, we estimated and compared CO2 emissions for different driving cycles for Texas utilizing 2018 electricity production mix data. Our simulation results revealed that for city driving cycles, EV performed environmentally better than GV and PHEV, but for highway driving cycles, EV underperformed compared to PHEV in all traffic conditions. For a combined driving cycle, PHEV performed better compared to EV and GV in moderate and low traffic conditions. Overall, according to the year 2018 energy mix data, PHEV is a better choice in Texas from an environmental perspective. Our sensitivity analysis showed that the environmental performance of an EV greatly depends on the percentage of renewable or clean energy in the overall grid electricity production mix. Our study will pave the way to conduct similar analyses for other states of the U.S, especially for the regions dependent highly on non-renewable energy sources. The research findings will help decision-makers design effective policies for EV and PHEV adoption to achieve maximum environmental benefits.
... In HEVs, an idle stop-start system is the main technique applied to realize the purpose of energy saving and emission reduction. For micro-HEVs, the belt-driven starter generator (BSG) system is a typical idle stop-start system and is used to substitute the traditional engine front-end accessory drive system (EFEADS) (Canova et al., 2009;Chen et al., 2020;Feng et al., 2019;Hu et al., 2020;John et al., 2007;Olatunde, 2008). Different from the traditional EFEADS, the BSG system uses a reversible motor with the function of starting motor and generating electricity to replace the traditional generator. ...
For micro-hybrid electric vehicles, the belt-driven starter generator system is a typical idle stop–start system that is used to substitute the traditional engine front-end accessory drive system. The aim of this work is to present a method to investigate steady-state and start-up transient responses of a typical belt-driven starter generator system with twin tensioner arms for micro-hybrid electric vehicles. A dynamic model of the belt-driven starter generator system is established for this scheme, where a smoothing dynamic friction model considering the velocity-weakening effect is presented to model the tensioner dry friction. Unlike some traditional dynamic models of the belt-driven starter generator system that the engine dynamics and dynamics of the belt-driven starter generator system are decoupled, an engine dynamic model, which is embedded in the dynamic model of the belt-driven starter generator system, is also established to calculate engine resistance torques at the engine starting process stage. Influences of the tensioner dry friction and stiffness on steady-state responses of the belt-driven starter generator system especially the stick–slip oscillations of the twin tensioner arms are examined. Angular oscillations and rotation speed variations of the belt-driven starter generator pulley and C/S pulley as well as the belt tension variations during the engine starting process are calculated. Influences of the tensioner dry friction and stiffness on transient dynamic performances of the belt-driven starter generator system during the engine starting process and its starting efficiency are investigated.
... Therefore, extensive studies are done on the integrated driveline to obtain the maximum efficiency band of operation for the engine, and to limit engine idle; or to switch off the engine when it isn't requireda feature the industry commonly refers to as start-stop. [13] details the testing done on a fast start stop system on a GMC Envoy from which a fuel saving improvement of 5.3% in city cycle and 4.0% improvement was demonstrated in onhighway driving purely from implementing this feature. ...
Environmental concerns and energy efficiency have been driving the transportation innovation in the past decades. In this framework, hybrid city transport has been receiving the attention of the industry. The challenges for this application are the required high-power density, lower maintenance cost and the high-temperature environment due to the integration with the internal combustion engine. A multiport converter is proposed to realise the requirements of the automotive industry to achieve greater performance in driveline electrification. The platform suggests the combination of previously discrete power electronics converter modules into one physical package commonising parts such as the microcontroller, heatsink and busbars. This paper provides an overview of design considerations for engine start-stop within a series-parallel topology and how it is achieved using the multiport converter. Finally, a comparison between the multiport and discrete converter approach is compared and findings presented, highlighting the advantages of the integrated solution.
... The off-grid hybrids recharge their batteries exclusively from the combustion engine's alternator, and the lowest level of hybridization is the start-stop system that shuts down the engine when it is not necessary, acting only at the start of the vehicle (Ehsani et al. 2010). However, in cities such as São Paulo, where vehicles remain standstill for long periods of time, such a system has great potential for reducing both fuel consumption and pollutant emissions (Bishop et al. 2007;Fonseca et al. 2011). ...
This book focuses on climate change and sustainable development, showcasing examples of research, projects and other initiatives aimed at educating various target groups. Helping readers gain a better understanding of the water, energy and food nexus challenges in the context of climate change, and featuring valuable insights that can be implemented in other areas, it will appeal to researchers and students as well as practitioners.
... There is a rich existing literature focusing on the optimal predictive scheduling of vehicle gear shifting for objectives such as fuel consumption minimization. The work in this literature uses a variety of optimization algorithms, including dynamic programming [42,43,44,45], Pontryagin methods [45], model predictive control [46], and fuzzy logic [47]. Studies consistently show that optimal gear shifting can reduce fuel consumption significantly, both in simulation and experimentally. ...
This paper examines the degree to which connectivity and automation can potentially reduce the overall fuel consumption of on-road vehicles. The paper begins with a simulation study highlighting the tradeoff between: (i) the fuel that a vehicle can save through speed trajectory shaping, versus (ii) the additional inter-vehicle spacing needed for this trajectory shaping to be feasible. This study shows that connectivity and automation are essential, rather than merely useful, for substantial reductions in the fuel consumed by fixed on-road vehicle powertrain/chassis configurations in traffic. Motivated by this insight, we survey the literature on the fuel savings achievable through different connected/automated vehicle technologies. This includes optimal vehicle routing, eco-arrival/departure at intersections, platooning, speed trajectory optimization, predictive driveline disengagement, predictive gear shifting, and predictive powertrain accessory control. This survey shows that the ability to shape vehicle speed trajectories collaboratively plays a dominant role in reducing urban/suburban fuel consumption, while platooning plays a dominant role in influencing the attainable fuel savings on the highway. Moreover, the survey shows that the degree to which connectivity/automation can reduce on-road vehicle fuel consumption, in both urban/suburban and highway settings, depends critically on the integration of powertrain- and chassis-level control.
... Multiple start of the engine can be realized with the help of the heavy-duty starter motor, reversing generator (starter-generator), hydraulic starter, fuel injection in the cylinders and ignition of the mixture [24][25][26][27]. ...
Improving the method of regenerative braking of a car with a start-stop system by installing an additional generator isoffered. An option of the optimal control of the brake torque of an additional generator is offered. The regenerativebraking under consideration required an appropriate method of calculation. This technique makes possible to obtain thedependence of the braking moment on the angular velocity of the generator in various modes, the dependence of theallowable maximum generator power on the speed and load, the dependence of efficiency and the braking moment on thespeed. Redistribution of energy generated by an additional generator for charging the battery and heating the enginecoolant has been introduced. The brake torque of the electric machine G290 is calculated in the mode of regenerativebraking. The obtained results are of practical importance for the transport industry. Calculated N at which the current 150А is reached. According to factory data the ultimate current is reached at 1450 rpm (discrepancy of less than 3%). So, thereis a good coincidence of calculated data. This method does not require a great number of experimental points. Theobtained results are of practical importance for the transport industry.
... There are different physical factors, e.g., characteristics (type and size) of the engine and its power train system, relationship between vehicle structure and aerodynamic drag, road surface and weather conditions that affect the energy consumption and emissions of a vehicle [7,8]. Hence, various technologies have been developed, such as hybrid vehicles, lightweight automobile, efficient power train systems, and advanced engine control systems [9,10]. However, recent studies have shown that energy consumption of a vehicle is highly influenced by driving behavior [11][12][13]. ...
Driving behavior is one of the main reasons that causes bottleneck on the freeway or restricts the capacity of signalized intersections. This paper proposes a car-following scheme in a model predictive control (MPC) framework to improve the traffic flow behavior, particularly in stopping and speeding up of individual vehicles in dense urban traffic under a connected vehicle (CV) environment. Using information received through vehicle-to-vehicle (V2V) communication, the scheme predicts the future states of the preceding vehicle and computes the control input by solving a constrained optimization problem considering a finite future horizon. The objective function is to minimize the weighted costs due to speed deviation, control input, and unsafe gaps. The scheme shares the planned driving information with the following vehicles so that they can make better cooperative driving decision. The proposed car-following scheme is simulated in a typical driving scenario with multiple vehicles in dense traffic that has to stop at red signals in multiple intersections. The speeding up or queue clearing and stopping characteristics of the traffic using the proposed scheme is compared with the existing car-following scheme through numerical simulation.
... Recently, in order to obtain a good energy-saving and emission reduction performance, the start-stop system is gradually applied by engine manufacturer. 2,3 This system automatically powers off the engine when the car is stopped and then restarts the engine when the car is needed to start. The fuel consumption during the idling stage of traditional engines can be saved and this system seems to have great potential in urban traffic. ...
For main bearings of internal combustion engines, most of the wear occurs during the start-ups and stops. The popularity of the start–stop system in automobile engines, which is used to save fuel consumption during idling stage, makes the working condition of main bearings severer because more frequent starts and stops will be generated. Changes in the bearing surface caused by wear will directly affect the bearing’s working performance. So in this study a transient mixed lubrication model and a wear model are coupled to analyze the influence of numerous start-ups and stops on the tribological performance evolution of engine main bearings. Starved lubrication of bearings before the oil supply is considered. The wear process is studied on the scale of surface topography and geometry. A main bearing in a four-stroke four-cylinder gasoline engine is studied under engine start–stop cycle conditions. The effects of temperature and lubricant grade on the transient tribodynamic behavior during the start-ups and stops are first investigated. Then the evolutions of surface characteristics and tribological performance of main bearings after numerous engine start-ups and stops are simulated. Results show that the temperature and lubricant grade can significantly affect the friction and wear of bearings. Hot start–stop condition leads to more serious asperity contact friction in the early stage of start-up, while cold start–stop condition generates more friction loss. The wear process of bearing surface is faster when applying oil with lower viscosity. And the impacts of engine start-ups and stops on bearing working performance are mainly seen in contact friction.
... From a fuel economy perspective, restarting the engine has a cost, that is generally lower than the cost of a cold start, but may be higher than the cost of idling for a short time. Still, in favorable conditions and with a sufficiently long preview of the upcoming driving profile, fuel savings between 5 and 10 % were reported [68,69]. ...
Autonomous driving technology pledges safety, convenience, and energy efficiency. Challenges include the unknown intentions of other road users: communication between vehicles and with the road infrastructure is a possible approach to enhance awareness and enable cooperation. Connected and automated vehicles (CAVs) have the potential to disrupt mobility, extending what is possible with driving automation and connectivity alone. Applications include real-time control and planning with increased awareness, routing with micro-scale traffic information, coordinated platooning using traffic signals information, eco-mobility on demand with guaranteed parking. This paper introduces a control and planning architecture for CAVs, and surveys the state of the art on each functional block therein; the main focus is on techniques to improve energy efficiency. We provide an overview of existing algorithms and their mutual interactions, we present promising optimization-based approaches to CAVs control and identify future challenges.
... Fuel consumption benefits were found to improve within the range of 2.8-35.0 % depending on the technology, method and vehicle used [6][7][8][9]. Hypothetically, the amount of fuel consumption benefit from a start-stop is proportional to the amount of time the engine spends in the stop-mode [10]. ...
The engine start-stop technology is gaining acceptance as a key technology adopted by manufacturers to improve the fuel economy of passenger cars. This technology shuts the engine off when a vehicle is at a stop. The inherent issue with the implementation of the start-stop technology in hot climates is the requirement for the air-conditioning system to be in constant operation which reduces the duration of engine shut-off during vehicle stops, and consequently, nullifying the benefit of the system. The aim of this study is to evaluate the potential fuel consumption improvements on a spark ignition engine when using the start-stop technology in real conditions of the Malaysian tropical climate, with consideration towards cabin comfort temperature. The result provides useful insight and enables vehicle manufacturers to assess whether such technology is feasible for implementation in tropical climates. A 1.6 litre spark ignition engine was modelled along with an air-conditioning system model using a commercial one-dimensional engine simulation gas dynamic software. A vehicle driving profile of engine speed and engine torque obtained from real driving on Malaysian roads was captured and used as the boundary conditions for the simulation. Iterations of the start-stop strategy were simulated to further explore the possible impacts on fuel consumption. The result of this study showed that the duration of engine shut-off during vehicle stops becomes shorter due to the necessity of the air-conditioning system to operate in maintaining the cabin’s comfort temperature. With the shorter duration of engine shut-off, the fuel consumption improvement stemming from the start-stop technology is reduced from the average of 20.7 % to 11.0 %, therefore, addressing the concerns on the application of the start-stop technology in hot climate countries and the opportunity to further optimise fuel consumption.
... The system can be easily integrated into a production vehicle and could provide significant fuel economy improvements with minimal cost or affect on vehicle performance. And the simulation results demonstrated start-stop system can improve vehicle fuel economy 5.3% in city cycle, 4.0% on the highway cycle and 4.8% combined [4]. Fonseca N et al. presents measurements of CO 2 emission and efficiency of stop-start technology on a diesel vehicle in urban traffic. ...
In order to reduce the fuel consumption of idling, lots of vehicles are equipped with idle start–stop system. In the actual traffic situation, heavy traffic result in frequent short time idle stop, which causes two major problems with the existing start–stop system, frequent starting and stopping and invalid stopping. That not only exacerbates component wear but also makes fuel efficiency worse. Aiming at this problem, an improved Markov model for idle time prediction based on spatiotemporal learning is proposed. Based on original Markov model, related training subset for training model is determined according time and space information, which could increase prediction accuracy by reducing the redundant noisy data. Experiments conducted on real urban dataset demonstrate that our proposed model could get better performance, the F1-measure increased by 8.0%. Start–stop strategy using the prediction method can make invalid idling reduced by 35.1%, which can effectively avoid invalid idling and obtain a reduction of frequent starting and stopping.
... 60% of new cars sold in Europe have stop-start technology (Gross, 2015). It is thought to deliver fuel savings of between 3 and 5%, making any potential benefit within the natural variability of PEMS measurements (Bishop et al., 2007), and therefore not an explicit consideration explicitly in this study. ...
In this study CO2 and NOx emissions from 149 Euro 5 and 6 diesel, gasoline and hybrid passenger cars were compared using a Portable Emissions Measurement System (PEMS). The models sampled accounted for 56% of all passenger cars sold in Europe in 2016. We found gasoline vehicles had CO2 emissions 13-66% higher than diesel. During urban driving, the average CO2 emission factor was 210.5 (sd. 47) gkm-1 for gasoline and 170.2 (sd. 34) gkm-1 for diesel. Half the gasoline vehicles tested were Gasoline Direct Injection (GDI). Euro 6 GDI engines <1.4ℓ delivered ~17% CO2 reduction compared to Port Fuel Injection (PFI). Gasoline vehicles delivered an 86-96% reduction in NOx emissions compared to diesel cars. The average urban NOx emission from Euro 6 diesel vehicles 0.44 (sd. 0.44) gkm-1 was 11 times higher than for gasoline 0.04 (sd. 0.04) gkm-1. We also analysed two gasoline-electric hybrids which out-performed both gasoline and diesel for NOx and CO2. We conclude action is required to mitigate the public health risk created by excessive NOx emissions from modern diesel vehicles. Replacing diesel with gasoline would incur a substantial CO2 penalty, however greater uptake of hybrid vehicles would likely reduce both CO2 and NOx emissions. Discrimination of vehicles on the basis of Euro standard is arbitrary and incentives should promote vehicles with the lowest real-world emissions of both NOx and CO2.
... BL and ML are especially important for hybrid vehicles, whose engines start and stop each time the drive train switches to and from battery power. Also, many new vehicles implement 'start-stop' systems, which reduce fuel consumption by automatically shutting the engine off when the vehicle is motionless [10]. Overall, lubricant design for modern engine systems must give due consideration to the frequent occurrence of BL and ML conditions [11]. ...
Extreme pressure (EP) lubricant additives form protective tribofilms at the site of contact using the heat and pressure of contact and relative motion. Common EP additives contain undesirable elements such as phosphorus and sulfur. A novel EP lubricant additive, which contains no phosphorus and sulfur, is presented for generating lubricious carbon films. The additive consists of a surface-active molecule with a metastable cycloalkane ring, which dissociates readily during tribological contact to form lubricious carbon films. Friction and wear performance of PAO4 with this additive under a range of loads and speeds were shown to be superior to that without the additive. Optical and scanning electron microscopy and Raman spectroscopy were used to analyze the tribofilms formed on post-test contact surfaces, providing direct evidence for the formation of carbon films. Quantitative kinetics for the carbon tribofilm formation was analyzed as a function of temperature and stress, from which the activation energy for carbon tribofilm formation was obtained.
... Attempts at mitigating the environmental effects of road traffic congestion can already be seen. The development of systems such as start-stop [3] are one example of this. The aim of start-stop is to reduce fuel consumption and emissions by disabling the internal combustion engine when a vehicle comes to a stop. ...
Despite the significant research efforts and resources spent to alleviate the impact of road traffic congestion on economy, environment and road safety, it is still one of the major unsolved problems of the 21st century. The emergence of smart self-driving vehicles promises a dramatic change in the way road traffic congestion is controlled and mitigated. This can be achieved by enabling efficient communication between these vehicles and modern road infrastructure such as smart traffic lights controllers. This paper, therefore, proposes a simple yet efficient mechanism named (TRADER: TRaffic Light Phases Aware Driving for REduced tRaffic Congestion) in order to reduce the overall vehicles' travel time in smart cities. TRADER has been implemented and extensively evaluated under several scenarios using SUMO and TraCI. The obtained simulation results, using a set of typical road networks, have demonstrated the effectiveness of TRADER in terms of the significant reduction of travel time, up to 31.44% in a random road network topology.
... Because they stop during idle and it takes much longer time for the oil to warm up [3]. Also, many new commercial vehicles implement 'start-stop' systems, which reduce fuel consumption by automatically shutting the engine off when the vehicle is motionless [7]. In addition, lubrication technology is also crucial in the reliability and lifetime of vehicles, and can even reduce the toxicity of engine exhaust [8]. ...
The purpose of this work was expanded the applications of molybdenum disulfide (MoS2) nanosheet additives by investigating their effectiveness and advantages for lubricating line contacts between bearing steel and medium carbon steel surfaces. The friction and wear effects of MoS2 nanosheet additives were investigated using block-on-ring tests, and compared with those from zinc dialkyldithiphosphates (ZDDP). Both additives were combined with ISO VG 32 white oil as base fluid. Results suggest 0.25 wt% MoS2 nanosheets exhibited similar friction coefficient, oil temperature and wear scar width with those of ZDDP at low loads; while the reductions of friction coefficient and wear scar width were 28.6 % and 34.3 %, respectively, compared to the behavior of ZDDP at high load (459 N). Furthermore, the wear scar widths of the ZDDP containing oil significantly increased in 2 hours tests, while they remained constant with a smaller size for 0.25 wt% additives of MoS2 nanosheets at a load of 326 N. Scanning electron microscope observations showed some pits on the wear scar lubricated with ZDDP, compared with spalls for 0.06 wt% MoS2 nanosheets. The wear scar was smooth and had a patched film for tests using 0.25 wt% MoS2 nanosheets. Energy-dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy analysis revealed that the patched surface film was composed of MoS2 and phosphate, and that film reduced friction coefficient and wear. The results highlight how high concentration MoS2 nanosheets exhibit significant advantages over ZDDP in reducing friction and wear in high load in line contact.
... The start-stop system is one of the most likely to be widely used to reduce the fuel consumption, especially for urban traffic. 3,4 The start-stop system automatically powers off the engine when the car is stopped and then restarts the engine when the car is needed to start. By the start-stop system, the fuel consumption during idling stage of traditional engines can be saved, as in the case of stops at traffic lights or jams. ...
The starting-up process of internal combustion engines presents a great challenge to the tribodynamic performance of the crankshaft-main bearing system. In this study, a transient mixed elastohydrodynamic lubrication model is presented to investigate the transient process. In the model, the average Reynolds equation is adopted with considering the influences of surface deformation and starting temperature. Then the oil film and friction loss of the system and the journal center trajectory during engines starting up are analyzed. The results at different starting temperatures show that the asperity contact under the hot start-up condition is more serious. However, during the engine run-up and transition to idling phases, more viscous friction loss is generated under the cold start-up condition.
... For the first time, students in Shell Eco-Marathon competition proposed Start-Stop technique. Pure stop-start system, that are sometimes called micro hybrid or reinforced starter hybrid system is a system that stops engine when the vehicle comes to a halt such as stationary condition at stop light [18][19]. This system can typically provide 5-7 percent improvement in fuel economy in standard driving cycles such as NEDC [20]. ...
... Artificial intelligence techniques have seen extensive use in automative applications (Prokhorov 2008), for example in predicting engine power and torque for automated tuning (Vong, Wong, and Li 2006), learning to diagnose faults (Murphey et al. 2006), learning driver models for adaptive cruise control (Rosenfeld et al. 2012), and improving vehicle power management by estimating road time and traffic congestion conditions (Park et al. 2009). However, although a great deal of effort has gone into the design of the electrical and mechanical aspects of start-stop systems (Bishop et al. 2007;Furushou et al. 2012), reinforcement learning has not (to the best of our knowledge) been applied to optimizing the software start-stop controller prior to our work. However, machine learning has wide applicability to the broader class of energy conservation problems. ...
We applied a policy search algorithm to the problem of optimizing a start-stop controller-a controller used in a car to turn off the vehicle's engine, and thus save energy, when the vehicle comes to a temporary halt. We were able to improve the existing policy by approximately 12% using real driver trace data. We also experimented with using multiple policies, and found that doing so could lead to a further 8% improvement if we could determine which policy to apply at each stop. The driver's behaviors before stopping were found to be un- correlated with the policy that performed best; however, further experimentation showed that the driver's behavior during the stop may be more useful, suggesting a useful direction for adding complexity to the underlying start-stop policy. Copyright © 2014, Association for the Advancement of Artificial Intelligence (www.aaai.org). All rights reserved.
... Theoretically, solar-powered air ventilators help to decrease cabin temperature by removing hot air from the cabin and replacing it with cooler fresh air. This method is capable of reducing the ambient cabin air temperature at the windshield and the dashboard by up to 8.3°C on average (Bishop et al., 2007;Henein, Taraza, Chalhoub, Lai, & Bryzik, 2000). Research into the use of sunshades during sunshine has been conducted by Manning & Ewing (2009) and Al-Kayiem et al. (2010), and the effect of sunshades has proved to be significant. ...
In the past few years many fatalities have been reported as the result of internal car heat. Problems arise when the temperature in a car cabin is too hot when parked under direct sunlight. The trapped and accumulated heat causes the temperature inside a car to reach up to 36°C and even up to 50°C. The objectives of this paper are to study and analyze the behavior of car cabin temperature influenced by ventilation under direct sun exposure. The performance of the proposed mathematical modelling was compared to data collected in real time from the car cabin. The simulation model was used to study the behavior of cabin temperature by investigating the ventilation mass flow rate as its parameter. An experimental result was obtained from measurements on a salon car parked in the direct sun. It is hoped that this study will be able to provide beneficial information for car interior design and material selection in order to improve comfort levels in cars.
The idle start-go (ISG) system has been widely used, but there have been few relevant studies of its effect on emissions. This paper investigates fuel economy, total hydrocarbon (THC), carbon monoxide (CO), nitrogen oxides (NO x ), particulate mass (PM), and particle number (PN) emissions from China VI gasoline direct injection (GDI) vehicles with and without ISG. Three test cycles were performed under hot start conditions, that is, the worldwide harmonized light vehicle test cycle (WLTC), the China light-duty vehicle test cycle (CLTC), and the USA federal test procedure-75 (FTP-75). About 28 idling phases were selected to specifically analyze the influence of ISG system. The results reveal that ISG system helps decrease fuel consumption, THC and CO emissions but aggravates NO x and solid PN emissions. Also, ISG system increases the proportions of sub-23 nm and nucleation-mode particle emission. Idling time plays a role in fuel economy, THC and CO emissions, while accelerated speed affects the emissions of THC, CO, NO x , and PN.
Advanced fuel economy strategies are expected to reduce the fuel consumption of vehicles. An internal combustion engine (ICE) driving vehicle equipped with free-wheeling turns off the fuel injection and decouples the engine from the drivetrain when the driving force is not required. This paper proposes a method to reduce the fuel consumption of a vehicle equipped with free-wheeling. First, an optimization problem is formulated to minimize the fuel consumption of a vehicle with free-wheeling when the traveling distance, the initial and final speed are specified and the vehicle needs to glide before arriving at the end point for fuel economy. The speed profile of the vehicle, engine operating point, and engine on/off timing are obtained as the results of the optimization. The analytical and numerical analyses results demonstrate the effectiveness and the fuel-saving mechanism of the obtained speed profile. The main finding of the analyses is that rather than starting a gliding stage immediately after an acceleration or a constant speed stage, adding a pre-acceleration stage before the gliding stage is more fuel-economic under some conditions independent of the complexity of the vehicle model. The obtained speed profile including a pre-acceleration stage is applied to a driving scenario including traffic congestions. The results demonstrate the effectiveness of the pre-acceleration stage in reducing fuel consumption for a vehicle equipped with free-wheeling.
Improving the engine starting strategy is of great significance for enhancing its combustion and emission performances. Compared with conventional start-stop systems, the direct-start process has been widely considered an efficient, viable, and low-cost solution for gasoline direct injection (GDI) engines to guarantee frequent startups. This paper proposes a novel direct-start process by introducing multistage and split injection strategies to improve the fuel–air mixture preparation, in which the effects of injection numbers and split injection timings on combustion, motion, and hydrocarbon (HC) emission characteristics are experimentally investigated. Results show that both multistage and split injection strategies achieve better starting performances than the traditional single injection approach, with the significantly advanced start points of heat release and cylinder pressure, increased peak heat release rate (HRR), enhanced accumulative heat release, shortened CA50, and promoted start combustion efficiency. The faster and more complete combustion leads to a lower bottom point of the piston. Meanwhile, the HC emissions decrease, especially under equivalence ratios of 0.6–0.8. Comparing the two strategies, the direct-start process with a three-stage injection possesses an earlier start point of heat release, while that with a split injection timing of 1 ms holds a shorter CA50 (18.91 ms), higher peak HRR (∼200 J/ms), and higher start combustion efficiency (52.16%). Moreover, under the optimal equivalence ratio range of 0.6–0.8, the engine with the split injection timing of 1 ms has better motion and HC emission characteristics.
Greenhouse gas (GHG) emissions released into the atmosphere cause climate change and air pollution. One of the main causes of GHG emissions is the transportation sector. The use of fossil fuels in internal combustion engine vehicles leads to the release of these harmful gases. For this reason, since 1992, several standards have been introduced to limit emissions from vehicles. Technologies such as reducing engine sizes, advanced compression-ignition or start/stop, and fuel cut-off have been developed to reduce fuel consumption and emissions. In this study, the contribution of deceleration fuel cut-off and start/stop technologies to fuel economy has been examined considering the New European Driving Cycle. Therefore, the fuel consumption values were calculated by creating a longitudinal vehicle model for a light commercial vehicle with a diesel engine. At the end of the study, by using the two strategies together, fuel economies of 17.5% in the urban driving cycle, 3.7% in the extra-urban cycle, and 10% in total were achieved. CO 2 emissions decreased in parallel with fuel consumption, by 10.1% in total.
The Brazilian transportation sector accounts for almost half of the carbon dioxide emissions in the country, and more than 90% of these emissions come from ground transportation. In 2017, Brazil had approximately 97 million vehicles, with 7.8 million in the city of São Paulo, the majority of which were powered by internal combustion engines. Due to CO2 reduction emission goals, many countries have plans to extinguish combustion vehicles by 2040. The start-stop system, a cheaper technology, became a trend in the hybrid vehicle market with the purpose of reducing fuel consumption and thereby reducing pollutant emissions. The São Paulo Traffic Engineering Company (CET) annually publishes the Volume and Speed Report that presents the characteristics of the São Paulo city traffic. The São Paulo State Environment Company (CETESB) publishes annually the Fleet Vehicle Emissions Report and its data. Using these public data, the present work performed a bottom-up analysis to evaluate the reduction potential of pollutant emissions for the city of São Paulo by changing the lightweight vehicle fleet to include start-stop system vehicles. This study obtained a reduction potential factor of total emissions between 12.3% and 13.8%, and a CO2 emission reduction potential for São Paulo of 1,338,341 annual tons.
Today we live in an era where environmental awareness is increasing day by day, at the same time the gradual increase of gasoline prices is also a major issue [2]. Automobile industries are making efforts to address this problem and they are trying to find new methods to increase the mileage of vehicles and reduce environmental pollution caused by vehicles. Hybrid Electric Vehicles (HEV) are one of the ways by which this goal can be achieved. This paper proposes a Start/Stop strategy for a vehicle consisting of P2 hybrid electric powertrain. In the vehicle with P2 hybrid electric powertrain, the clutch is present in between the engine and motor/generator. S/S strategy automatically turn off the engine when the vehicle is at rest and eliminate idle emissions. When the driver presses the clutch to select the 1st gear, S/S strategy restarts the engine automatically. In this system when a vehicle stops at a particular place for more than 10 s the vehicle will stop automatically and it will start as soon as the clutch is pressed. This strategy can be implemented in normal vehicles by converting them into P2 hybrid electric powertrain by means of very minor modifications. We have used LSM Amesim software to develop the P2 vehicle model and MATLAB Simulink to implement the Start/Stop control strategy. From experimentation, it is found that the fuel economy has improved by 5%–6% with limitation of start/stop frequency of 2 stops/km [9].
Start-stop technology is an affordable pathway to reduce fuel con-sumption and emissions in automotive propulsion systems. We present two novel mechatronic starters. The first concept uses a two-speed starting device to crank the engine to a higher rpm prior to ignition. It is comprised of an arrangement of gears and clutches that changes the overall cranking gear ratio during the course of the start event. This allows the engine to reach nearly twice its rated pre-igni-tion rpm, making for ultra-smooth starts. The second concept is a mechatronic starter that can switch between geared and belted operation. This integrated starter with selectable geared and belted connections to the crankshaft enables a very fast, smooth start in belt-mode compared to a conventional 12V starter.
This work includes an original approach that combines on-road experimental fuel use and emission maps and a numerical analysis to assess the impacts of fuel efficiency and NO x emission reduction technologies on a light-duty passenger vehicle. The solutions analyzed include Stop/ Start, vehicle mass reduction up to 100 kg, drag coefficient reduction, as well as SCR and Lean NO x Trap systems. For this purpose, a reference EURO 6 diesel vehicle was monitored under real-world driving conditions with a PEMS and the experimental data obtained allowed building engine maps of fuel use and NO x emission to be used on AVL Cruise software. The results obtained with Cruise were firstly validated with the experimental data (with errors up to 10,6% on fuel and 17,5% on NOx) and then the solutions implemented were tested individually and simulated on 48 real-world driving cycles. The results pointed to Stop/Start, mass reduction of 100 kg and SCR as the most effective solutions in reducing fuel consumption and NO x emission up to 14,6% and 57,5%, respectively, depending on driving context. The combination of these technologies was tested and the results showed maximum fuel savings of 17% on urban context and a maximum reduction of 58% on NO x on combined driving cycles. Despite all the efforts, real-world driving presents NO x emissions not yet compliant with standards, indicating the need for new strategies in order to face the environmental challenges.
The design of top compression rings is an important issue that opens research possibilities for reducing friction in the field of tribology in Internal Combustion (IC) engines. Recent studies show that there is an increasing interest in top compression rings’ tribological performance. It is widely known that the piston assembly is a major contributor to parasitic losses (up to 40%) and that there is a need to understand its lubrication performance and friction mechanisms. In brief, the top compression rings suffer from higher friction and wear due to rapidly changing loads and close contact in cylinder liners (the sealing function). Because the friction and wear issues affect the efficiency of compression rings, it is necessary to investigate the surface topography of the ring-cylinder surfaces and lubrication conditions.
The current thesis supports that goal. Compression rings’ tribological characteristics, such as their pressure distribution, lubricant film, friction, power losses and lubricant flow rate, were derived and presented for different engine conditions. We used numerical models to calculate the ring balance, and we considered the fluid flow effects in terms of the Navier-Stokes equations. To include the cavitation, the Half-Sommerfeld condition and Rayleigh-Plesset volume fraction were considered based on a case study. The variation of the lubricant rheological properties due to the pressure and temperature have also been taken into account in the overall modelling. Particularly, for the non-Newtonian lubricant behaviour, we combined the Navier-Stokes approach with the power law model. The interaction of the lubricant film and the ring domain within a piston groove was modelled, and this model is called the Fluid-Structure Interaction (FSI) model. This proposed method allows complete static solutions of the 2D ring-liner lubrication problem involving complex geometries. The effects of the ring face geometry and the lubricant properties were introduced for this analysis. Moreover, CFD models were built, including Navier-Stokes, vapour transport (Rayleigh-Plesset equation), asperity interaction (Greenwood-Tripp contact model) and thermal effects (comprising ring coating properties). The results obtained from the developed 2D models were found to be in good agreement with the experimental and analytical data obtained in previous investigations.
The experimental investigations accomplished within this thesis will permit a proper understanding of the piston assembly and compression ring tribodynamics. A test method was constructed in a single-cylinder four-stroke motorbike engine using a foil strain gauge. To measure the engine friction, a challenging technique is developed in this thesis, and its limitations and robustness are fully described. The friction and noise results from the test-rig demonstrate that the contribution of the thin top compression ring to the ring pack friction was dominant. This finding shows that the thin nature of the top compression ring combined with the lubrication conditions of the ring-pack can lead to high total friction, which would induce increased frictional losses and contact wear during cold NEDC conditions.
Therefore, a proposal of artificial surface topography on the ring face width is presented and discussed in the present thesis. In practical terms, current challenges for improving the tribological behaviour in compression rings require surface topographies that are effective in different regimes of lubrication to reduce the friction and wear. To solve this problem, we have focused on square-shaped pockets in the ring face-width as the main strategy for minimizing the frictional power losses and wear of sliding surfaces; the goal is to improve the performance of automotive engines. Several different inlets and densities of square pocketed surfaces were analysed using a block on a ring test rig. The findings showed that the denser pocketed surface was responsible for controlling the lubricant film and wear in line contact during mixed lubrication conditions.
Based on the results from the experiments with textures, we have made a design proposal, and it includes the specifications of a texture design in full scale. Suggestions for future work include the development of a 3D full simulation framework to support a more detailed ring design process, optimization of measurement techniques (e.g., the strain gauge method), and square-shaped geometry.
When confronting the situation of temporary short stops such as waiting for traffic lights, the application of automatic start-stop function not only peels off the engine idle mode from start-and-stop mode, but also reduces fuel consumption. A control strategy of start-and-stop system of hybrid electric vehicle is proposed and analyzed in this paper. The modified engine model with start-stop control strategy is established. Simulations and the relevant data analysis show that under certain conditions, the proposed start-stop control strategy can control the start and stop of the vehicle according tobased on the need and requirement of the driver and it is especially good performs well at distinguishing from a transient and continuous parking from idling. Data analysis also demonstrates that the vehicle with the modified engine can could save 4% to 5% fuel consumption.
This paper has developed a start-stop control system on a GDI engine, studied effects on the rate of ignition for expansion cylinder and the start-stop performance without a starter. The experimental results showed a total rate of a successful ignition of the expansion cylinder beyond 70% when the lambda value ranges from 0.6 to 0.7. A multiple fuel injection could improve the rate of ignition with the case of single injection compared, the rate of ignition can be increased by averaged 4% for two times fuel injection, a four times fuel injection can increase the rate of ignition by averaged 5%. When the exhaust valve opening timing was retarded to 160 °CA ATDC increased success rate of engine starting. It will be 0.62 s for engine start by a start-stop starter, however 0.39 s by direct injection start-stop.
When it comes to GDI ‘start-stop’ technology, the control of final stop crank angle can never be neglected. The probability distribution of this final angle could be obtained via repetitious engine stop experimental method, the principle of which however, could not. As a result it seems impossible to get a concise control on the engine stop process. Dynamic model ‘engine stop’ has been established, simplified and modified in order to identify the key factors that have an effect on engine stop. The model was verified by related experiment to address the simulation demands. The analysis on simulation results provide us several essential conclusions that the factors, specifically heat transfer and leakage as well as the initial speed in compression top dead center of final stroke, will cause a strongly different piston final position. The engine final position will be relatively located in the range 0–10°CA, 60–90°CA ATDC.
The idle stop technology is one mean to implement zero emissions and zero fuel consumption. Based on the Gasoline Direct Injection engine (GDI) as the research object, the starting physical mechanism is analyzed and the engine starting model is established. The torque, speed and inlet pressure characteristics of engine starting process are analyzed. The influence of the piston stop position and the injection pulse width with injection timing and ignition timing on the engine start speed is researched. The results show that the torque is fluctuation and tends to be stable. The amplitude reaches the maximum, and then it gradually decays to stability. The starting speed in the first stroke injection and ignition is the fastest. And there is a small misfire region when the fuel injection quantity is less and the injection time is advanced.
Based on modified natural gas direct injection engine, we studied the impacts of ignition timing and jet timing on natural gas engine start process in this paper. The results shows that: when the first jet ignition occurs in the first compression stroke, the engine reaches idle speed 400rpm fastest; as the jet timing is delayed, emissions during engine start is gradually reduced, but when the jet late, HC surge occurs, the emissions deteriorates; with the ignition advance angle increasing, the engine speed growth accelerates, the peak moves forward; with the ignition advance angle increasing, HC emissions peak increases, the peak moves forward.
This paper investigates the control strategy of engine smart start/stop system, and develops the simulation model of the micro car equipped with smart start/stop system in Matlab/Simulink environment. The schematic and the starting process dynamics of the engine smart start/stop system are analyzed. The simulation results of the fuel economy between the baseline vehicle and the vehicle after installation of smart start/stop system are discussed using Matlab and ADVISOR software co-simulation in the NEDC driving cycle. Finally the test of engine start and the emissions test of the micro car equipped with smart start/stop system are conducted using standard chassis dynamometer. The results indicate that the engine of the micro car can be automatically shut off as it meets the conditions of engine automatic stop. The 100-kilometer fuel consumption of the micro car equipped with start/stop system decreases by 3.63% compared to that of the baseline vehicle, and the test result of the fuel saving ratio is consistent with the simulation result. The HC, CO and NOx emission results of the micro car equipped with smart Start/Stop system are 0.047 g/km, 0.542 g/km and 0.035 g/km, respectively. And the emissions are much lower than those of the Euro IV emission limits.
In this paper, we propose a driving assistant that makes recommendations in order to reduce the fuel consumption. The solution only requires a smartphone and an OBD/Bluetooth device. Eco-driving advices try to avoid situations that cause an increase in the fuel consumption such as inappropriate speed or slow reaction to the detection of traffic signs and traffic incidents. The main contribution of this paper is the use of artificial intelligence techniques in order to issue the eco-driving tips that are best adapted to the user profile, the characteristics of the vehicle, and the road state conditions. This is very important because the driver may lose the interest due to the high requirements that tend to be provided by general use eco-driving assistants. In order to properly assess and validate the proposed solution, it has been implemented on several Android mobile devices and has been validated using a dataset of 2,250 driving tests using three different models of vehicles with 25 different drivers on three distinct routes. The results show that the system reduces the fuel consumption by 11.04 percent on average and even, in certain cases, the fuel saving is greater than 15 percent.
To combat gas emissions produced by idling motorcycles at red lights, Taiwan government passed an “idle-stop (IS)” bill that requires manufacturers from year 2015 to equip 10% of newly-manufactured motorcycles with a microchip enabling the idling engines to be automatically off. Along with the safety concerns over the new but controversial technology, the additional charge would influence riders’ decisions to adopt the system. This paper, specifically studies this matter by using a survey that investigated the contributory factors to motorcyclists’ adoption of the system. Probabilistic models were estimated using data gathered from 3673 motorcyclists in Taoyuan City, Taiwan. Three separate models (by no incentive, purchase support, and annual tax rebate) with mixed logit formulation were estimated to investigate the effects of the variables on respondents’ three levels of IS-adoption (low, medium, high) and capture potential heterogeneity. Several variables (e.g., female riders) appear to have heterogeneous effects, lending support to the use of mixed logit models in idle-stop research. Annual tax rebate appears to be the most tempting incentive although it has limited effect on heavy motorcycle users, OAPs (old age pensioner) and those having safety concerns – suggesting that promotional activities (e.g., demonstrations, field operational tests) to enhance market penetration of the technology may be directed toward these groups. Other variables found to be significant determinants of the IS-adoption include, for example, gender, motorcycle engine size, red-light duration, and when the gasoline price was rising. The policy implications of the results are finally discussed.
Hybrid vehicles, which have a higher fuel economy and system efficiency than conventional gas only vehicles, has been attracting worldwide attention for its various advantages. These advantages include low emissions of greenhouse gases which mitigates direct or indirect effects on the ozone layer. LPI HEV recently developed by HMC performs with the same output level, torque and fuel economy as conventional gasoline hybrid vehicles by employing the world's first liquid-state-injection system for exclusive use of LPG. In particular, the improved fuel economy of the vehicle is expected to help cope with future regulations relating to environmental protection from exhaust fumes.
Engine ECU testing requires sophisticated sensor simulation and event capture equipment. FPGAs are the ideal devices to address these requirements. Their high performance and high flexibility are perfectly suited to the rapidly changing test needs of today's advanced ECUs. FPGAs offer significant advantages such as parallel processing, design scalability, ultra-fast pin-to-pin response time, design portability, and lifetime upgradability. All of these benefits are highly valuable when validating constantly bigger embedded software in shorter duration. This paper discusses the collaboration between Valeo and NI to define, implement, and deploy a graphical, open-source, FPGA-based engine simulation library for ECU verification.
We studied the shutdown state of natural gas engine on a modified GW4B13 direct injection engine. The result shows that when the engine is cold, high speed hold a dominant factor, causing the engine spends longer time shutting down than the time under the hot engine situation; stop position of the engine is normal distribution, and the majority of the stop position is located before the top dead center between 70° to 90°; when the stop position before the top dead center 90° and 120 ° , the engine spends shortest time, less than 0.3s, reaching the target speed, i.e. the idle speed 400rpm.
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