About
53
Publications
10,695
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,705
Citations
Introduction
Current institution
Publications
Publications (53)
Hyperloop systems, where a pod travels at high speed within a tube under rarefied conditions, have a maximum speed limit due to the Kantrowitz effect. One solution to overcome this limit is to include a circuit with a fan that can also assist the pod's propulsion through a nozzle at the vehicle's rear. This paper focuses on analyzing the propulsive...
Featured Application
hyperloop powertrain.
Abstract
The current environmental concern has led both the industry and researchers to look for alternate means of transport. Amongst them, the hyperloop has become a quite promising idea. In order to overcome some of its limitations, including a compressor in its propulsive system has been investigated....
The utilization of automotive engine components for the development of a reverse Brayton cycle is shown in this study. The well-known characteristics of turbochargers and electrical centrifugal compressors commonly used in the automotive industry is a starting point for developing an experimental cycle configuration of a reverse Brayton refrigerati...
The utilization of automotive engine components for the development of a reverse Brayton cycle is shown in this study. The well-known characteristics of turbochargers and electrical centrifugal compressors commonly used in the automotive industry is a starting point for developing an experimental cycle configuration of a reverse Brayton refrigerati...
The increased concern for environmental problems has boosted the electrification of passenger cars to remove air pollutant emissions from urban areas. Automotive manufacturers have predominantly opted for hybrid powertrains with advanced gasoline engines, because of the current limitations of battery electric vehicles and the higher costs of diesel...
This paper presents the results of a computational investigation of the aerodynamic choking mechanism in a variable geometry turbine, which is widely used in automotive turbocharging. RANS and URANS numerical simulations were carried out for two stator vane positions, 10% and 30% opening at different speeds and several other operating conditions to...
The present paper shows a numerical research about the influence of different thermal storage capacities and thermal power consumption strategies in a solar-driven air-conditioning system operating with refrigerant R1234yf. The computational model is fed with hourly climatic data (solar irradiance and ambient temperature) of the typical meteorologi...
The aftertreatment systems used in internal combustion engines need high temperatures for reaching its maximum efficiency. By this reason, during the engine cold start period or engine restart operation, excessive pollutant emissions levels are emitted to the atmosphere. This paper evaluates the impact of using a new cylinder deactivation strategy...
Internal combustion engines working at cold conditions lead to the production of excessive pollutant emissions levels. The use of the exhaust gas recirculation could be necessary to reduce the nitrogen oxides emissions, even at these conditions. This paper evaluates the impact of using the high-pressure exhaust gas recirculation strategy while the...
In the present paper, the mid-term performance of two different architectures of a solar-driven jet-ejector refrigeration system is numerically compared: The first one is fitted with a fixed-geometry jet-ejector while the second one is equipped with an adjustable spindle that modifies the jet-ejector area ratio. The jet-ejector behavior has been pr...
The low efficiency of the after-treatment systems during the cold start period of the internal combustion engines leads to excessive pollutant emissions levels. To reduce the nitrogen oxide emissions at these conditions, it could be necessary to use the high- and low-pressure exhaust gas recirculation strategies, even operating at low temperatures....
In the present paper, a numerical investigation of a jet ejector is carried out using R1234yf real gas model. The prototype under investigation works with specific operating conditions of a jet-ejector refrigeration system intended for waste heat recovery in an internal combustion engine. In the first instance, the geometry optimization involving n...
The present paper evaluates numerically the feasibility of a solar jet-ejector refrigeration system from an efficiency maximization perspective with three low environmental impact refrigerants, namely, R1234yf, R1234ze and R600a. Special emphasis is given to the jet-ejector internal geometry optimization as a mechanism to improve the overall cycle...
To fulfill the future NOx emission regulations, the use of exhaust gas recirculation could be necessary for the engine starting at cold conditions. In this context, condensation inside the exhaust gas recirculation line could appear, affecting in several ways the engine components and their life span. In this article, a mathematical model is develo...
The present paper evaluates a jet ejector refrigeration system intended to cool down diesel engine intake below ambient conditions. Performance is assessed by means of 1D thermodynamic model of the cycle fed with ejector maps obtained with CFD code using R134a as working fluid. In the first study, no particular ejector geometry is fixed thus allowi...
Recent investigations demonstrated that real-world emissions usually exceed the levels achieved in the laboratory based type approval processes. By means of on-board emissions measurements, it has been shown that nitrogen oxides emitted by diesel engines substantially exceed the limit imposed by the Euro 6 regulation. Thus, with the aim of compleme...
In order to comply with the legislation, car manufacturers are looking for a way to lower the CO2 emission by improving engine efficiency. About one third of the fuel combustion energy is wasted through exhaust gasses. Waste Heat Recovery (WHR) could improve engine efficiency by recovering a part of exhaust gasses energy. In this study, the potenti...
According to the International Council on Clean Transportation, the target for CO2 emissions in passenger cars was reduced until 2007 an average of 1% per year, however from 2008 more restrictive targets were imposed with an average of 4% per year. In 2020 the target of CO2 emissions for passenger cars and light-commercial vehicles will be reduced...
With the tightening of on-board diagnostics requirements, accuracy of sensors is essential to monitor the efficiency and ensure a proper control of the after-treatment systems. Temperature sensors are commonly used in the exhaust line at the diesel oxidation catalyst-inlet of turbocharged diesel engines for control and diagnosis of the after-treatm...
This paper presents a mathematical model of a bottoming Organic Rankine Cycle coupled to a 2 l turbocharged gasoline engine to optimize the cycle from a thermo-economic and sizing point of view. These criteria were optimized with different cycle values. Therefore, a methodology to optimize the ORC coupled to Waste Heat Recovery systems in vehicle a...
This paper deals with the thermodynamic analysis of an Absorption Refrigeration Cycle used to cool down the temperature of the intake air in an Internal Combustion Engine using as a heat source the exhaust gas of the engine. The solution of ammonia-water has been selected due to the stability for a wide range of operating temperatures and pressures...
This paper deals with the experimental testing of a bottoming Organic Rankine Cycle (ORC) integrate in a
2 l turbocharged gasoline engine using ethanol as working fluid. The main components of the cycle are a
boiler, a condenser, a pump and a swash-plate expander. Both steady and transient tests were performed
in three engine operating points to un...
This paper deals with the evaluation and analysis of a bottoming ORC cycle coupled to an IC engine by
means of conventional and advanced exergy analysis. Using experimental data of an ORC coupled to a
2 l turbocharged engine, both conventional and advanced exergy analysis are carried out. Splitting the
exergy in the advanced exergy analysis into un...
Waste heat recovery (WHR) in exhaust gas flow of automotive engines has proved to be a useful path to increase the overall efficiency of internal combustion engines (ICE). Recovery potentials of up to 7% are shown in several works in the literature. However, most of them are theoretical estimations. Some present results from prototypes fed by stead...
In this paper, an experimental facility is implemented with the aim of improving the performance of internal combustion engines working at low ambient temperatures. Pollutant emissions and fuel consumption are one of the major issues that automotive engineers have to face. Cold engine start and warming up analysis have become important topics for r...
Waste Heat Recovery in exhaust gas flow of automotive engines has proved to be a path to increase the overall efficiency of automotive vehicles. Recovery potential of up to 7% are shown in several works in the literature. However, most of them are theoretical estimations. Some of them presents results from prototypes fed by steady flow generated in...
This paper deals with the experimental testing of an Organic Rankine Cycle (ORC) integrate in a 2 liter turbocharged gasoline engine using ethanol as working fluid. The main components of the cycle are a boiler, a condenser, a pump and a swash-plate expander. Five engine operating points have been tested, they correspond to a nominal heat input int...
An average passenger car engine effectively uses about one-third of the fuel combustion energy, while the two-thirds are wasted through exhaust gases and engine cooling. It is of great interest to automotive industry to recover some of this wasted energy, thus increasing the engine efficiency and lowering fuel consumption and contamination. Waste h...
This work describes a technique for measuring the precession movement of the shaft of small automotive turbochargers. The main novelty is that the technique is based on infrared light diode sensors. With presented technique it is possible to perform secure mounting of electronics and also to measure, with good accuracy, far enough from the turbocha...
A specific study of the uncertainties of turbine power output measured in turbocharger test benches is presented using the law of uncertainty propagation and the influence of the different terms that contribute to it is shown. Then, non-linear mixed integer mathematical programming algorithms used with the turbine power uncertainty expression becom...
Problems in the turbocharger lubrication system can cause serious deterioration in their overall performance and even their complete destruction. The paper describes several tests with different critical lubrication conditions, in order to determine the thresholds at which the operation may be appropriate. In an IC engine, these problems can be pro...
Active control turbocharger (ACT) has been proposed as a way to improve turbocharger performance under highly pulsating exhaust flows. This technique implies that the variable geometry mechanism in the turbine is used to optimize its position as a function of the instantaneous mass flow during the engine cycle. Tests presented in the literature sho...
In the present paper, a methodology to calculate the heat fluxes inside a turbocharger from diesel passenger car is presented. The heat transfer phenomenon is solved by using a one dimensional lumped model that takes into account both the heat fluxes between the different turbocharger elements, as well as the heat fluxes between the working fluids...
This article describes a methodology for the optimization of a bottoming cycle as a waste heat recovering system in vehicles. The methodology is applied to two particular cases in order to evaluate the preliminary energetic and technical feasibility of the implementation of a bottoming cycle in a heavy duty diesel (HDD) engine considering two diffe...
This paper presents a novel non-invasive technique to estimate the
turbocharger shaft whirl motion. The aim of this article is to present a
system for monitoring the shaft motion of a turbocharger, which will be
used in turbocharger destructive testing. To achieve this, a camera and
a light source were installed in a turbocharger test bench with a...
An Organic Rankine Cycle (ORC) is considered as one of the most environmental-friendly ways to convert different kinds of low temperature energies, i.e. solar, geothermal, biomass and thermal energy of exhaust gases into electrical energy. Two important facts about the ORC must be considered: An organic fluid is selected as the working fluid and a...
A theoretical investigation has been performed on the feasibility of introducing a waste heat recovery (WHR) system in a two-stage turbocharged HDD engine. The WHR is attained by introducing a Rankine cycle, which uses an organic substance or directly water as a working fluid depending on energetic performance considerations. A previous research wa...
This paper describes the study of different bottoming Rankine cycles with water-steam and/or ORC configurations in classical and innovative setups such as a waste heat recovery system in a Heavy Duty Diesel (HDD) Engine. This work has been divided in two parts. This first part describes the model of the studied HDD engine and the available waste en...
Air mass flow determination is needed for the control of current internal combustion engines. Current methods are based on specific sensors (as hot wire anemometers) or indirect estimation through manifold pressure. With the availability of cylinder pressure sensors for engine control, methods based on them can be used for replacing or complementin...
This article describes a theoretical study on the performance optimisation of a high speed direct injection turbocharged diesel engine equipped with an electro-hydraulic variable valve actuation 'camless' system. This system provides extremely fast valve opening and closing slopes. Thus, its potential for recovering part of the energy lost in the v...
Compliance with oncoming emission directives demands a great effort from researchers on the development of effective procedures and tools to cope with the technological exigencies. The first aim of this work focuses on the development of methodologies and tools related to the combustion characterisation in turbocharged diesel engines with EGR syste...
The paper presents a model of fixed and variable geometry turbines. The aim of this model is to provide an efficient boundary condition to model turbocharged internal combustion engines with zero- and one-dimensional gas dynamic codes.The model is based from its very conception on the measured characteristics of the turbine. Nevertheless, it is cap...
This article presents a two-stage turbocharged heavy-duty diesel (HDD) engine designed to fulfil the US2007 anti-pollution
directive. This directive imposes very restrictive limits on the NOx and particle emissions of HDD engines. In this work,
the possibility of combining particle traps in the exhaust line to reduce soot emissions with very high E...
This paper describes a heat transfer model to be implemented in a global engine 1-D gas-dynamic code to calculate reciprocating internal combustion engine performance in steady and transient operations. A trade off between simplicity and accuracy has been looked for, in order to fit with the stated objective. To validate the model, the temperature...
In this paper a study to analyse the influence of exhaust gases thermal energy saving and reduction of pressure pulses interference on engine dynamic performance during the load transient of high speed direct injection turbocharged diesel engines is described. The analysis has been performed thanks to the use of a dual walled air gap exhaust manifo...
