Chunde Yao

• Ph.D
• Principal Investigator at Tianjin University

In this paper, an experimental investigation on achieving ultra-low emissions in diesel engine was carried out using intake premixed methanol and EGR technology. The influence of EGR introduction method on combustion and performances were studied comprehensively. The results show that ultra-low NOx (<0.4g/kWh) and PM (<10mg/kWh) emissions can be ac...

In this paper, an experimental investigation on achieving ultra-low raw emissions in a diesel/methanol dual fuel engine based on dual-loop EGR was carried out. The effect of dual-loop EGR (High pressure EGR and low pressure EGR) on the combustion, performance and emissions of methanol engine has been studied comprehensively. The results show that u...

The diesel methanol dual fuel (DMDF) engine is confronting with the problem of high unregulated emissions of methanol and formaldehyde. The previous studies on unregulated emissions of DMDF engine focused on the measuring methanol and formaldehyde concentrations in the exhaust without distinguishing whether emissions come from leakage during valve...

Study on EGR mode and demand were carried out to meet with the requirements of main emission limits of China VI on a diesel methanol dual fuel (DMDF) engine equipped with Hybrid exhaust gas recirculation (EGR) system coupled with back pressure valve (BPV). According to the World Harmonized Steady-State Cycle (WHSC) test cycle, the effects of EGR mo...

Four typical combustion modes were found in a diesel methanol dual fuel (DMDF) engine, which subverted the traditional viewpoint that the methanol was only ignited by diesel fuel spray. In this manuscript, the results of different combustion modes from constant volume combustion chamber (CVCC), compression ignition (CI) engine and numerical simulat...

Methanol is difficult to be ignited by compression due to its low cetane number. The strategy of diesel–methanol compound combustion (DMCC) was proposed, which starts up with pure diesel fuel and switches to the mode of diesel–methanol dual fuel after the engine fully warms up. The strategy of DMCC will substitute methanol to diesel fuel up to 40%...

The super-knock poses new challenges for further increasing the power density of spark ignition (SI) engines. The critical factors and mechanism connecting regarding the occurrence of super-knock are still unclear. Misfire is a common phenomenon in SI engines that the mixture in cylinder is not ignited normally, which is often caused by spark plug...

Diesel Methanol Dual Fuel (DMDF) could achieve high efficiency and low emissions simultaneously at part of engine conditions, but the reason of this has not been clarified. In order to find the reason behind this phenomenon, Pressure-Volume (P-V) map, equivalence ratio (φ)-temperature (T) map and three-dimensional simulation software were used to c...

In order to reduce the pollutant emission and alleviate the pressure of petroleum resources shortage and greenhouse gas emission at the same time, the use of clean and renewable alternative fuel for marine engines is a promising option. In this study, a marine diesel engine, which was modified to run in diesel methanol compound combustion (DMCC) mo...

The piston in reciprocating engine would be badly ablated under severe knock. However, the mechanism of the detonation induced thermal ablation of piston is still unclear. A detonation bomb device was used to measure the thermal load of of piston under detonation. A test specimen mounted on the detonation bomb acts as a piston to bear the detonatio...

In order to reveal the mechanism of high thermal efficiency of diesel methanol dual fuel (DMDF) engine, the exergy loss of DMDF engine under different operating parameters is investigated by using experimental and calculative methods based on the second law of thermodynamics. It has been found that DMDF has lower heat transfer exergy loss under all...

The diesel methanol dual fuel (DMDF) technology has been used in diesel engines to reduce the nitrogen oxides (NOX) and particulate matter (PM) emissions in past years. A combination of a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF) is applied on DMDF engines to meet severer emission standards in this study. The DOC was mod...

The experiments were performed to achieve a significant reduction in nitrogen oxides (NOx) and soot emissions while achieving no reduction in Brake Thermal Efficiency (BTE) for Diesel Methanol Dual Fuel (DMDF) engine at low load condition. The optimization strategies mainly include internal exhaust gas recirculation (EGR), external EGR, intake air...

The (cobalt-molybdenum)/alumina ((Co-Mo)/Al2O3) dual catalysts have an excellent performance on the selective catalytic reduction (SCR) of nitric oxide with methanol (methanol-SCR) on the synthetic gas test bench. The catalytic performance of (Co-Mo)/Al2O3 needs to be studied on the engine test bench due to the complicated emissions of engines. Tes...

Based on the first law of thermodynamics, this paper presents the experimental results of parameter study on energy balance of a diesel methanol dual fuel (DMDF) engine including load characteristic tests for both pure diesel (D) mode and DMDF mode and comparison of energy flow conversion under different load ratios. The results show that replaceme...

At high loads, Diesel-Methanol Dual Fuel (DMDF) engines strongly rely on high methanol substitution for diesel proportion (MSP) to achieve high efficiency combustion and reduce nitrogen oxides (NOx) and soot emissions. However, high MSP is limited by the probability of methanol auto-ignition. The experimental study was conducted to investigate into...

The experimental research on effects of diesel pilot injection strategy, including pilot injection timing (t2) and mass (mdp), on the combustion of diesel in a premixed methanol-air mixture atmosphere were conducted in a newly developed constant volume combustion chamber (CVCC), where both methanol and diesel fuel were injected directly into the ch...

The late-injection strategy (close after main-injection) of common-rail diesel engine is capable of enhancing combustion turbulence and reducing particulate matter (PM) emissions. In this work, experimental study was performed to investigate the effect of diesel late-injection on combustion and emissions characteristics of diesel/methanol dual fuel...

Experiments were conducted on a common-rail heavy-duty diesel/methanol compound combustion (DMCC) engine to investigate the effect of pilot injection quantity on regulated and unregulated emission characteristics. The regulated and unregulated emissions were measured by Horiba MEXA-7100DEGR and MEXA-6000FT, respectively. The results show that the p...

Shock wave formed in internal combustion engines under severe knock will reflect and converge in close space, causing severe damage to combustion chamber parts. However, the research on the failure of piston has not yet gone deeper. In order to reveal such a convergence mechanism and its destruction effects in cone-roof close space, a constant volu...

To extend the maximum of methanol substitution percent(MMSP)under high loads, the effects of MMSP enhanced by injection timing and exhaust back pressure on combustion and emissions were investigated. These experiments were carried out on a diesel/methanol compound combustion(DMCC)engine modified from a turbocharged intercooled electronic-unit-pump...

Experiments were conducted to extend the operation range of Diesel/Methanol Compound Combustion (DMCC), as to further reduce the emissions of Diesel Methanol Dual Fuel (DMDF) engine at full load. The engine was operated under 100% of full engine load at three different speeds of 1660 r/min (speed A), 2090 r/min (speed B), and 2520 r/min (speed C),...

In internal combustion engines, severe knock is a destructive phenomenon that would converge the energy released by fuel burning to damage the piston so that the engine can't work anymore, which should be avoided. The destruction mechanism have been revealed in previous researches in which the focusing of shock waves is considered as a main reason...

Non-contact method is adopted to measure the current and inlet pressure signals of high-pressure common-rail high-speed solenoid injector and the process of injection is synchronously recorded by video camera. Test results show that there is a high correlation between the opening and closing delays of solenoid in electromagnetic injector and coil c...

This paper explored the reason that the amount of methanol consumed is much lower than that of its theoretical value in terms of calorific value in diesel methanol dual fuel (DMDF) combustion by the means of engine bench test and modeling analysis. The results from experiments show that, the DMDF has much higher combustion rate than that of the cor...

Based on European Steady-state Cycle (ESC) test procedure, an engine test was carried out to meet the demand of Euro V legislation with diesel methanol compound combustion (DMCC) technology on a common-rail, turbocharged, inter-cooling heavy-duty and high pressure exhaust gas recirculation (HP EGR) diesel engine with meeting the requirements of Eur...

The experiments on the ignition and combustion characteristics of diesel in air atmosphere (AA) and premixed methanol/air mixture atmosphere (MAA) were conducted in a constant volume combustion chamber (CVCC) equipped with a high pressure common-rail injection system. The ignition and combustion processes were recorded by a high-speed camera and a...

Under severe knock of IC (internal combustion) engines, engine parts like pistons are vulnerable to be damaged rapidly, the mechanism of which remains unsolved. Especially how the chemical energy released from fuel burning is transformed into the force damaging the material of pistons is still unclear. In order to reveal the in-cylinder energy tran...

An experiment was carried out in a direct injection spark ignition (DISI) engine to research the effect of aromatics, especially the heavy aromatics (aromatics with c ≥ 9) content on the characteristics of in-cylinder combustion and engine-out ultrafine particle. The results show that total aromatics and heavy aromatics content all have a limited e...

The experimental research on reducing unregulated emissions (included unburned methanol, formaldehyde, formic acid, 1,3-butadiene, benzene and toluene) of diesel/methanol dual fuel (DMDF) engine with different after-treatment devices was carried out on a turbocharged inter-cooling diesel engine. The DMDF engine was operated under 25%, 50%, 75% and...

In order to understand the interaction between fuels of different ignition properties, the ignition and combustion characteristics of diesel injected in either methanol or methane mixture were researched in a constant volume combustion chamber coupled with high pressure common rail system by using high speed camera optical system. The premixed atmo...

The expanding energy demand, surging oil prices, depleting oil reserves, environmental pollution and climate change problems associated with the utilization of fossil fuels have revived interest to find out clean alternative fuels. Methanol is one of the most competitive alternative fuels due to its liquid nature, high oxygen contents, and high oct...

The basic principles, analytical method and problems regarding the conventional response displacement method are described. The formulas of formation spring stiffness are given with the assumption of both a slip and noslip contact surface, and a generalized response displacement method is put forward based on the formation-structure model. As for t...

Experiments about the ignition and combustion processes and soot formation characteristic of diesel fuel in air atmosphere(AA) and premixed methane/air mixture atmosphere(MAA) respectively, were conducted in an optical constant volume combustion chamber at different injection pressures. It is shown that, the test results in AA and MAA have the same...

An electronic system was installed at the intake pipeline of a turbocharged, inter-cooling electronic unit pump diesel engine, which makes it possible to run in diesel/methanol dual-fuel (DMDF) mode. Experiments were conducted to investigate the effects of nano-TiO2 concentration in methanol and the quantity of methanol injection for constant TiO2...

The effects of diesel fuel injection pressure on the combustion and emissions of a diesel/methanol dual fuel(DMDF) engine were studied on a turbocharged intercooled electronic-controlled common rail diesel engine. The results show that at lower diesel injection pressure, the cylinder pressure at the end of compression stroke in DMDF mode is lower t...

In order to reduce particulate matter emissions, the effects of injection timing on PM emissions from a diesel/methanol compound combustion (DMCC) engine modified from a turbocharged intercooled common-rail fuel injection diesel were investigated. Testing condition was chosen at 50% of load and 1340 r·min⁻¹ of speed, which is mostly used by heavy d...

This study was performed on a four-cylinder diesel engine with a turbocharged intercooled electronic unit pump. The bench test was conducted in the engine, which was modified for diesel/methanol dual fuel (DMDF) operation. The effects of the substitution ratio of methanol as well as different posttreatment combinations on the emissions of harmful g...

Under severe knocks of internal combustion engines, parts like pistons and spark plugs are vulnerable to be damaged by energy convergence of shock waves. Furthermore, the damaged positions and failure modes have a significant regularity. In order to reveal the mechanism and avoid such damage, numerical simulations combined with detonation bomb expe...

Experimental study was conducted on a compression ignition engine to investigate into the effects of methanol substitution percent (MSP), injection timing, intake air temperature (Ti), exhaust gas recirculation (EGR) and other parameters on the ultrafine particle emitted from the engine. The testing engine was run on the mode of Diesel/methanol dua...

Methanol fumigation strategy in multi-cylinder diesel engine has received great attentions in recent years. Experimental work was conducted in a turbocharged inline 4-cylinder diesel engine fueled with diesel methanol dual fuel (DMDF). Three different methanol injection positions were chosen to investigate into their effect on cylinder-to-cylinder...

Experiments were conducted in a 4-cylinder, turbocharged DI diesel engine fueled with diesel/methanol dual fuel(DMDF), the unevenness degree among cylinders and the COV of peak pressure within cylinders were investigated.The results show that the unevenness degree of engine increases with the increase of methanol substitution percentage.The COV of...

The ignition characteristics of diesel in premixed methane-air and methanol-air mixture atmospheres (MeAA and MoAA) at low temperature were studied respectively in a constant volume combustion chamber equipped with a high-speed camera. Using the reduced reaction mechanism of n-heptane/methane fuel blends and the skeletal reaction mechanism of n-hep...

An experiment study on the dynamic response of a high speed solenoid injector for GDI engine was carried out using a high-speed microphotography and synchronous current-pressure collection system. The results show that there is a high correlation between the delay time and the solenoid current. When the fuel injection starts the current rate of cha...

Particulate matter (PM) emissions from a turbocharged GDI gasoline engine operating on two kinds of fuels with different amount of aromatics were examined and compared. The results indicated that, under the normal operation condition, the proportion of number concentration of particles in nucleation mode increased and became dominant with increasin...

Diesel/ natural gas dual fuel (DNDF) and diesel/ methanol dual fuel (DMDF) are both very potential alternative energy technologies for internal combustion engine. In this work, a comparative study was done to better understand ignition characteristics of dual fuel combustion. Firstly, apparent ignition characteristics of them were studied experimen...

Three different fuels, gasoline, M15 and M45, were tested on an electronically controlled multi-point port injection gasoline engine which met the China (3) standards. A DMS 500 fast particulate spectrometer was employed to reveal the effect of different fuels on particle size distribution. The results show that compared with pure gasoline, the fue...

Experiments were conducted on YC4D140 electronic unit pump turbo-charged, inter-cooling diesel engine which was modified to run in the mode of diesel/methanol compound combustion (DMCC). By using AVL 415S smoke meter and DMS 500, the effect of different post-processors on the PM emission of DMCC engine was investigated. The results showed that eith...

The irregular exhaust emissions were generated by a turbocharged, inter-cooled, electronically controlled unit injection pump diesel engine with diesel/methanol dual fuel. Emissions were measured by FTIR. The results showed that compared with those from pure diesel mode, the irregular emissions including formaldehyde, unburned methanol, 1, 3-butadi...

In internal combustion engines, different combustion technologiescan result in different knocks, such as the conventional knock of gasoline engines, the super knock and the knock of HCCI engines. Though they are all caused by the auto-ignition of unburned mixture which leads to the oscillation burning, the rising rate and the oscillation amplitude...

In the present work, the effects of diesel-methanol compound combustion (DMCC) and diesel oxidation catalyst coupled with a particulate oxidation catalyst (DOC+POC) on unregulated emissions was studied. A 4-cylinder, turbo-charged, electronic unit pump diesel engine equipped with a methanol injection system was used in the experiment. The results s...

Diesel engine performance and emissions are closely related to fuel atomization and spray processes, which in turn are strongly influenced by nozzle geometry. In this study, five kinds of single-hole cylindrical injectors which have different orifice diameters (0.13–0.23 mm) and lengths (0.7–1.0 mm) were employed to research the effects of the nozz...

An energy balance model was built based on the YC4 D120-30 diesel engine, which has been reformed to run in either pure diesel (D) mode or diesel methanol dual-fuel (DMDF) mode. Thermal balance analysis was conducted at 1660 r/min, 420 N·m and 1660 r/min, 105 N·m operating points. Results show that the methanol replacement ratio is lower than its t...

Methanol has drawn increasing attention in recent years as an alternative fuel due to its potential to reduce NOX and soot emissions. In this work, the combustion characteristic of diesel in air atmosphere (AA) and premixed methanol–air mixture atmosphere (MAA) were studied in an optical constant volume chamber under different in-cylinder temperatu...

In a constant volume combustion chamber combined with high pressure common rail system, the ignition, combustion and soot formation characteristics of diesel were studied at different injection pressures keeping injection pulse width or fuel injection volume constant. The change range of injection pressure was 40~160 MPa, which was commonly used in...

To explore the effect of nozzle geometry on spray of a high pressure common rail injector, the droplet size distribution of different nozzle geometries was measured under high injection pressure condition using the phase Doppler particle analyzer (PDPA). Droplet size distribution shows that the Sauter mean diameter (SMD) in the central axis is larg...

For internal combustion engines, the knock of Homogeneous Charge Compression Ignition engines, the conventional knock of gasoline engines and the super knock are all caused by the auto-ignition of unburned mixture which leads to the oscillation burning, but their Maximal Pressure Oscillation Amplitude (MPOA) and Maximum Pressure Rising Rate (MPRR)...

This paper presented the analytical results for the energy balance of a diesel methanol dual-fuel (DMDF) engine. A methanol injection system was fixed on a diesel engine and let the engine to alternate to run in either the pure diesel (D) mode or DMDF mode. Primary application of the thermal balance analysis was to investigate the cause of methanol...

The direct relation graph(DRG) method and the sensitivity analysis(SA) method were used to reduce the diesel/methanol high-temperature oxidation mechanism, which contains 261 species and 1, 338 reactions. A mechanism reduction program for laminar premixed flame was developed based on the DRG theory. By setting the threshold to 0.01 in the program,...

In order to understand the effect of the organometallic antiknock additive MMT (methylcyclopentadienyl manganese tricarbonyl) on PM (particulate matter) mass and number concentrations from GDI (gasoline direct injection) and PFI (port fuel injection) gasoline engine, PM emissions were measured from a turbocharged GDI gasoline engine and a naturally...

The failure process of interlayered rocks at different confining pressures was numerical simulated. A modified rigid body spring method(RBSM) was proposed to simulate the initiation and propagation of micro cracks. Both tensile and shear failures were considered with a failure criterion combining Mohr-Coulumb criterion and the tensile strength crit...

The effect of fuel and ambient temperature on low pressure methanol spray characteristics was investigated using a high speed camera in constant volume vessel. And the diameter of droplet was also measured using 3D laser doppler technology under various methanol temperature. Fuel and ambient temperature range from 15 ℃ to 80 ℃ and 20 ℃ to 60 ℃ resp...

Particulate matter (PM) emissions from a PFI gasoline engine with the catalysts operating on conventional gasoline fuel were examined and compared with those from the fuel blending with the organometallic antiknock additive methylcyclopentadienyl manganese tricarbonyl (MMT). The conversion efficiency of the three-way catalyst (TWC) on PM was analyz...

Premixed methanol diesel dual fuel (PMDDF) is a combustion mode in which methanol is injected from the intake port and then ignited by the direct injected diesel in the cylinder. Many studies have shown that PMDDF mode has the potential to reduce NOx and PM emissions simultaneously. In this study, investigation on realizing national phase IV emissi...

In order to improve the nutritional value and edible quality, broadening the adoption in food industry, the white sorghum was tested to germinate in different culture parameters. Its proximate composition and sensory quality have been investigated. The results of experiment by single factor experiment and response surface analysis showed that the r...

Experiments was performed on a locomotive medium speed diesel engine, fueled with intake-manifold-injected methanol and direct-injected diesel fuel, to investigate its combustion characteristic under different speeds and loads. The results show that with the increase of methanol injection, the ignition delay is extended and the combustion duration...

Particle matter (PM) emissions from a PFI gasoline engine operating on conventional gasoline fuel and the fuel blending with the organometallic antiknock additive methylcyclopentadienyl manganese tricarbonyl (MMT) were examined and compared. The testing results indicated that, with the increase of the concentration of MMT, both number and mass conc...

To provide some new experience for application and popularization of diesel/methanol dual fuel (DMDF) vehicles, and reduce the consumption of diesel, a common-rail diesel engine with a methanol injection system, which could operate on DMDF mode with intake pre-mixed methanol method, was mounted on a heavy-duty truck with full load to analyze field...

Compared to the extensive experimental studies, numerical studies of diesel/methanol dual fuel (DMDF) engine are very limited. In this work, an improved KIVA-3V code was coupled with the CHEMKIN solver to model combustion and emission of DMDF engine. Firstly, a chemical reaction mechanism including 65 reactions and 43 species was developed and vali...

A methanol mixture auto-ignition test is conducted on the first cylinder of a turbocharged intercooled diesel engine to analyze the pressure oscillation characteristics of methanol auto-ignition and study the forming law of destructive pressure wave in super knock. The results show that the probability of methanol auto-ignition tends to increase wi...

Effect of intake air temperature on combustion and soot emission of a compression ignition engine operated on diesel-methanol dual fuel(DMDF) was investigated. The results show that increasing the intake air temperature would increase peak pressure and shorten the ignition delay. The centre of the premixed heat release curve was closer to the top-d...

As an alternative energy technology for internal combustion engines, dual fuel combustion, such as natural gas/diesel, LPG/diesel and alcohols/diesel, has been widely used. In order to understand deeply the inhibition effects of the ignited fuel on the low-temperature ignition of diesel, this study investigated low-temperature ignition characterist...

In order to measure the electronic controlled injector needle valve movement accurately, the injector of PFI gasoline engine is used as a research object, the hall sensor is introduced to measure the solenoid current, and synchronous high-speed camera is chosen to record the spray process. The high-speed camera system results are compared with curr...

It has been found in previous experimental studies that the ignition of diesel is delayed by methane addition. Firstly, a zero-dimensional model was used to analyze the impact of oxygen partial pressure, specific heat and chemical kinetic reactions caused by methane addition on the ignition delay of n-heptane. Results show that the change of kineti...