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The multi-body dynamics simulation and physical iteration were carried out based on the 4-channel road simulation bench, the solution of fatigue test bench which was suitable for cab with frame and suspension was designed. Large load and displacement above the suspension can be loaded on the test bench, and the same weak position of cab exposed on the road test can be assessed well on the fatigue test bench. The effectiveness of the bench test solution was verified though comparative study. And it has important reference for the same type of cab assembly with suspension in the fatigue bench test. According to the durability specifications of cab assembly, a multi-body dynamics model with a satisfactory accuracy was built. And the fixture check and virtual iteration analysis were used to verify the effectiveness of the solution. According to the road load signal analysis and multi-body dynamics analysis results, the test bench with linear guide and spherical joint was built.

The nonlinear characteristics impact of multi-staged stiffness clutch damper on the vehicle creeping is investigated by using the lumped-parameter modeling method as a certain mass-production passenger sedan is taken as the research subject. Firstly, a quasi-transient engine model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is acquired and as the input excitation to the driveline system. Secondly, a 12-DOF (Degree of Freedom) nonlinear and branched powertrain system and vehicle longitudinal dynamics model is established. The differential mechanism characteristics and dynamic tire property based on the LuGre tire model are considered. Then, for a traditional two-staged stiffness clutch damper in consideration of hysteresis characteristics, vehicle powertrain system responses in both the time and frequency domain are obtained.

Hydrogen energy is a kind of secondary energy with an abundant source, wide application, green, and is low-carbon, which is important for building a clean, low-carbon, safe, and efficient energy system and achieving the goal of carbon peaking and being carbon neutral. In this paper, the effect of nozzle position, hydrogen injection timing, and ignition timing on the in-cylinder combustion characteristics is investigated separately with the 13E hydrogen engine as the simulation object. The test results show that when the nozzle position is set in the middle of the intake and exhaust tracts (L2 and L3), the peak in-cylinder pressure is slightly higher than that of L1, but when the nozzle position is L2, the cylinder pressure curve is the smoothest, the peak exothermic rate is the lowest, and the peak cylinder temperature is the lowest.

The present work discusses a novel oxy-fuel combustion cycle utilized in compression ignition internal combustion engine. The most prominent feature of this cycle is that the air intake is replaced by oxygen; therefore nitric oxide (NOX) emission is eliminated. The enrichment of oxygen leads to higher flame speed and mass fraction consumption rate; on the other hand, the high concentration of oxygen presented during combustion will result in intense pressure rise rate which may cause severe damage to engine hardware. As water injection is already utilized in gasoline engine to control knocking, the utilization of water injection in optimizing oxy-fuel combustion process has been tested in this study. To understand the relationship between water injection strategy and cycle efficiency, computational fluid dynamics (CFD) simulations were carried out. The model was carefully calibrated with the experimental results; the errors were controlled within 3%.

Ultra-lean combustion of GDI engine could achieve higher thermal efficiency and lower NOx emissions, but it also faces challenges such as ignition difficulties and low-speed flame propagation. In this paper, the sparked-spray is proposed as a novel ignition method, which employs the spark to ignite the fuel spray by the cooperative timing control of in-cylinder fuel injection and spark ignition and form a jet flame. Then the jet flame fronts propagate in the ultra-lean premixed mixture in the cylinder. This combustion mode is named Sparked-Spray Induced Combustion (SSIC) in this paper. Based on a 3-cylinder 1.0L GDI engine, a 3D simulation model is established in the CONVERGE to study the effects of ignition strategy, compression ratio, and injection timing on SSIC with a global equivalence ratio of 0.50. The results show it is easier to form the jet flame when sparking at the spray front because the fuel has better atomization and lower turbulent kinetic energy at the spray front.

In order to study the fast filling problem of large-capacity on-board hydrogen storage tank for highway passenger cars, a computational fluid dynamics (CFD) simulation model of 134L large-capacity hydrogen storage tank was established. By simulating different pre-cooling temperatures and mass flow rates, the temperature distribution and thermal transmission in the tank were observed. Due to the large ratio of length to diameter of the hydrogen tank, the temperature distribution is extremely uneven during the whole filling process, and the high temperature area is mainly concentrated in the tank tail. And the heat transfer between the gas and the tank wall is not obvious under the low and constant mass flow rate. The temperature rise process during the whole filling process under different mass flow conditions was simulated to satisfy the highest safe temperature limit.

Regulated gaseous and particulate matter (PM) emissions in the exhaust from a heavy duty diesel engine with biodiesel fuel were studied, and the emission characteristics of PM and polycyclic aromatic hydrocarbons (PAHs) emissions in PM were highlighted. In the experiment, pure diesel fuel and B10 (a blend of diesel and biodiesel fuels with the volume ratio of 9 to 1) fuel were chosen. The study shows that, compared to the pure diesel, the emissions of PM, soluble organic fractions (SOF) and PAHs from the heavy duty diesel engine decrease when the engine burns B10 fuel, and the nitrogen oxides (NOx) emission slightly increases, while the unburned hydrocarbon (HC) and carbon monoxide (CO) emissions also decline. Among the detected 12 kinds of PAHs, emission concentrations of 10 kinds of PAHs from the engine with B10 descend. Especially Benzo(a)pyrene equivalent toxicity (BEQ) analysis results show that the BEQ of B10 fuel decreases by 15.2% compared to pure diesel.

Wind noise becomes the foremost noise source when a car runs at high speeds. High frequency characteristics of wind noise source and effective performance of seal rubbers for insulating leakage noise make research on the Transmission Loss (TL) of automotive door sealing systems significant. The improvement of TL of automotive door sealing system could effectively decrease the interior noise due to wind noise for vehicles at high speeds. In this study, compression simulation of seal rubbers for an automotive door is performed through a Finite Element (FE) tool firstly. Compressed geometries of the seal rubbers are obtained. Then, based on the final compressed geometries and pre-stress modes of the automotive door seal rubbers, the TL of the whole door sealing system is acquired by hybrid Finite Element - Statistic Energy Analysis (FE-SEA) method. The fluctuating surface pressure on a car body was captured by a Computational Fluid Dynamics (CFD) tool.

Jet-wake flow and secondary flows are undesirable in torque converters as they are responsible for flow losses and flow nonuniformity; that is, jet-wake flow and secondary flows negatively affect the torque converter performance. Therefore, it is very important to investigate and minimize the undesirable flows to decrease flow losses in torque converter. However, the existing studies are limited to employ geometry design parameter modifications rather than focusing on the actual causes and intrinsic physical mechanism that generate the flows to reduce the flow losses. In this paper, Calculation model of a torque converter is presented first and a three dimensional CFD code was used to simulate the internal flow field of a torque converter. The simulation results coincide with experimental measurements, which verifies the validity of the method. Based on flow field calculation results, the internal flow field of impeller, turbine and stator were analyzed, respectively.

The effect of jet geometry on flow, heat transfer and defrosting characteristics was numerically investigated for elliptic and rectangular impinging jets on an automobile windshield. Initially, various turbulence models within the commercial computational fluid dynamics (CFD) package FLUENT were employed and validated for a single jet, and the results indicated that the impinging jet heat transfer was more accurately predicted by the SST k -ω turbulence model, which was then utilized for this study. The aspect ratios (AR) of elliptic and rectangular jets were respectively 0.5, 1.0, and 2.0, with jet-to-target spacing h/d=2, 4 and jet-to-jet spacing c/d=4, and all those situations were numerically analyzed with the same air mass flow and jet open area. It was observed that the heat transfer coefficient and defrosting performance of the inclined windshield were significantly affected by the shape of the jet, and the best results were obtained with the elliptic jet arrangements.

Ammonia is employed as the carbon-free fuel in the future engine, which is consistent with the requirements of the current national dual-carbon policy. However, the great amount of NOx and unburned NH3/H2 in the exhaust emissions is produced from combustion of ammonia and is one kind of the most strictly controlled pollutants in the emission regulation. This paper aims to investigate the NOx and unburned NH3/H2 generative process and emission characteristics by CFD simulation during the engine combustion. The results show that the unburned ammonia and hydrogen emissions increase with an increase of equivalence ratio and hydrogen blending ratio. In contrast, the emission concentrations of NOx, NO, and NO2 decrease with the increasing of equivalence ratio, but increase with hydrogen blending ratio rising. The emission concentration of N2O is highly sensitive to the O/H group and temperature, and it is precisely opposite to that of NO and NO2.

Aerodynamic noise transmits through automotive window, causing great adverse influence on comfortability and noise-vibration-harshness (NVH) performance. However, the complicated external turbulent air flow, as well as the internal metal-rubber nonlinear sealing constraint, makes the mechanism of aerodynamic noise generation and transmission very difficult. Regarding the complex exterior aerodynamics-induced load and nonlinear metal-rubber interaction and constraint, an efficient two-step numerical prediction method is presented in order to study the mechanism of its generation and transmission. The first step uses the commercial ANSYS-Fluent computational fluid dynamics (CFD) analysis based on the shear stress transport (SST) - turbulence kinetic energy (k) - the rate of dissipation of turbulence kinetic energy ε (epsilon) model and Lighthill’s noise source theory.

Numerical analysis of thermal efficiency improvement up to 45% of an 1.8-liter turbocharged direct-injection (DI) gasoline engine was conducted in this study in response to the need of improving vehicle fuel economy. 1D thermodynamics simulations and 3D computational fluid dynamics (CFD) modeling were carried out to investigate the technical approaches for improving engine thermal efficiency. Effects of various technologies on the improvement in the engine performance were evaluated, and then the technical routes to achieve 41% and 45% brake thermal efficiency were summarized, respectively. It is concluded that 41% thermal efficiency can be reached under stoichiometric combustion conditions, while it is expected lean burn technology is needed for the target of 45% thermal efficiency. The effects of high tumble intake flow on accelerating burning speed and of high compression ratio on intensifying knocking were analyzed.

Based on a 125cm3 single cylinder SI engine, the designated idle speed was controlled by adjusting of cycle ignition advance angle. By analyzing the effects of different idle speed and throttle open position on three way catalyst (TWC) light-off time and conversion efficiency of HC and CO emissions, combined with the corresponding total HC and CO emissions level, the optimum idle speed and throttle open position at engine's warm-up phase were found by the matching optimum. The present method for engine control strategy is helpful to optimize the warm-up phase emission levels in SI engine with LPG fuel.

In order to meet the ever more stringent demands on the CO2 emission reduction, downsized modern gasoline engine with highly boosted turbo charger meets new challenges such as super knock and pre-ignition, which will influence the engine combustion efficiency, smooth operation and even cause mechanical failure. A spark plug type ion current detection sensor was used in a 1.8L turbo charged gasoline engine. The ion-current wave signal differed greatly under different engine operating conditions such as without knock, with knock of different knock intensities. The frequency spectrum of ion-current was also studied, by the method of discrete Fourier transform (DFT). In knocking cycles, there were fluctuations of frequency 8-13 kHz both in the combustion pressure signal and in the ion current signal, proving the existence of knock information.

The Linear Internal Combustion Engine-Linear Generator Integrated System (LICELGIS) is different from conventional crank-based engine for reducing frictional losses by eliminating the crankshaft. Thus, the LICELGIS piston stroke is not constrained geometrically and the system compression ratio is variable. During steady-state operation, the LICELGIS converts the fuel chemical energy into electric power with piston assembly reciprocating motion, which can be used as a range-extender in hybrid electric vehicles. The LICELGIS scavenging process is prerequisite and key for the system steady-state operation, which has remarkable influence on mixture gas and, eventually, on engine combustion performance. In order to achieve high scavenging performance, a LICELGIS is investigated in this paper. The LICELGIS motion characteristics and scavenging process were analyzed.

The roof sensor system is an indispensable part of intelligent vehicles to observe the environment, however, it deteriorates the aerodynamic and noise performance of the vehicle. In this paper, large eddy simulation and the acoustic perturbation equation are combined to simulate the flow and sound fields of the intelligent vehicle. Firstly, test and simulation differences of aerodynamic drag and pressure coefficients on the roof and rear of the intelligent vehicle without roof sensor system are discussed. It is found that the difference in aerodynamic drag coefficient is 5.5%, and the pressure coefficients’ differences at 21 out of 24 measurement points are less than 0.05. On this basis, under the influence of the sensor system, the aerodynamic drag coefficient of the intelligent vehicle is increased by 23.4%.

Gas distribution of proton exchange membrane fuel cells (PEMFCs) is mainly decided by flow field of bipolar plate. The improper design of distributing channel, nonuniform gas flow distribution and current density distribution among different straight channels are the leading factors that could tremendously undermine the performance and life expectancy of the cell. However, there is lack of research focusing on distributing channel in straight-parallel flow field. In this work, a three-dimensional numerical model of PEMFC cathode flow field is developed with CFD method to investigate the effects of configuration type and width of the distributing channel on pressure distribution in distributing channel and on reactant flow distribution, pressure drop and concentration distribution in multiple straight channel. Effects of electrochemical reaction and formation of water on the flow distribution are taken into consideration.

A segment of steel tube with the inner diameter of 60 mm and length of 100 mm was fixed between the intake manifold and cylinder head in a direct injection natural aspirated diesel engine. The surface of the tube could be heated to be above 400 °C by the heater enwrapped outside within several minutes under the power less than 600 W. The tip of an injector traditionally used for in-cylinder diesel direct injection was extended to the axis of the tube. The diesel sprays could impinge onto the hot inner surface of the tube and atomize quickly if the temperature of the tube was high enough. Then the fuel-air mixture would be sucked into the cylinder, and HCCI combustion could be fulfilled. The vaporization ratio of the impinged diesel sprays was estimated by fuel consumption, intake air flux and excess air coefficient (λ) calculated from the volumetric concentration of O2, CO2 and CO emissions. The NOx emission was always very low.

Previous studies have indicated that longer torque increase time benefits the reduction of emissions during transient process for a diesel engine. However, quantitative conclusions on reduction of emissions and effects on fuel economy have not been made clear so far. The aim of this study was to evaluate the transient process of diesel engine under different torque increase time, and to find the quantitative statement between torque increase time, fuel economy and engine-out emissions. To do this, experiment was carried out on a 7L common rail diesel engine used for commercial vehicles. Three engine speeds (1100r·min−1, 1300r·min−1 and 1500r·min−1) were chosen to represent an engine working range. For each speed, the engine torque is increased within different time (0.5s, 1s, 2s and 5s). It was shown that, in the transient process mentioned above, engine torque increase time effects fuel economy, smoke opacity and CO emission.