Search Results

Gasoline-related factors that affect low-speed pre-ignition (LSPI) include the distillation properties of gasoline, manganese (Mn), ethanol, diesel fuel, detergent for aftermarket, and iron (Fe). The combined effect of Mn with ethanol or high calcium engine oil (high-Ca oil) has not been sufficiently clarified. Therefore, appropriate countermeasures for LSPI have not yet been implemented. To clarify the effect of the gasoline properties and additives on LSPI, engine tests were conducted using gasoline with different “PM Index” values, an indicator of distillation properties, different concentrations of Mn, ethanol, diesel fuel, detergent, Fe, and high-Ca oil. The results showed that the LSPI frequency tended to increase with the PM Index, Mn up to 60 ppm, diesel fuel up to 2 vol.%, and detergent up to three times the standard amount.

Electrification is the well-accepted solution to address carbon emissions and modernize vehicle controls. Batteries play a critical in the journey of electrification and modernization with battery voltage prediction as the foundation for safe and efficient operation. Due to its strong dependency on prior information, battery voltage was estimated with recurrent neural network methods in the recent literatures exploring a variety of deep learning techniques to estimate battery behaviors. In these studies, standard recurrent neural networks, gated recurrent units, and long-short term memory are popular neural network architectures under review. However, in most cases, each neural network architecture is individually assessed and therefore the knowledge about comparative study among three neural network architecture is limited. In addition, many literatures only studied either the dynamic voltage response or the voltage relaxation.

The SAE J300 classification was expanded to 0W-12 and 0W-8 viscosity grades in 2015, and lower viscosity engine oils have been studied in the industry. ILSAC GF-6B that will be introduced in 2020 will specify a 0W-16 requirement, but 0W-12 and 0W-8 grades are not considered. Because engine oil equal to or higher than the 0W-20 grade is recommended for almost all engines globally, suitable engine tests for 0W-12 and 0W-8 do not exist. Therefore, the Japan Automobile Manufacturers Association, Petroleum Association of Japan and Society of Automotive Engineers of Japan decided to establish new 0W-12 and 0W-8 low viscosity engine oil specifications. It is referred to as JASO GLV-1, and together with a new fuel economy engine test procedure, these engine oils for better fuel economy will be put on the Japanese market in 2019. Motoring friction torque tests are widely used to ascertain the friction reduction effect of fuel-economy engine oils.

Aiming at the high altitude operation problems for piston-type aero-engines and to improve the practical ceiling and high altitude dynamic performance, this thesis analyzes a controllable three-stage composite supercharging system, using a two-stage turbocharger coupled supercharger method. The GT-Power simulation model of a four-cylinder boxer engine was established, and the control strategy of variable flight height was obtained. The simulation research of engine performance from 0 to 20,000 meters above sea level has been carried out, which shows that the engine power is at the same level as the plain condition, and it could still maintain 85.28 percent of power even at the height of 20,000 meters, which meets the flight requirements of the aircraft.

The spray structure and vaporization processes of flash-boiling sprays in a constant volume chamber under a wide range of superheated conditions were experimentally investigated by a high speed imaging technique. The Engine Combustion Network’s Spray G injector was used. Four fuels including gasoline, ethanol, and gasoline-ethanol blends E30 and E50 were investigated. Spray penetration length and spray width were correlated to the degree of the superheated degree, which is the ratio of the ambient pressure to saturated vapor pressure (pa/ps). It is found that parameter pa/ps is critical in describing the spray transformation under flash-boiling conditions. Three distinct stages namely the slight flash-boiling, the transition flash-boiling, and the flare flash-boiling are identified to describe the transformation of spray structures.

This research examined the focused design, elastic design, energy decoupling, and torque roll axis (TRA) decoupling methods for mount optimization design. Requiring some assumptions, these methods are invalid for some load conditions and constraints. The linearity assumption is advantageous and simplifies both design and optimization analysis, facilitating engineering applications. However, the linearity is rarely seen in real-world applications, and there is no practical method to directly measure the reaction forces in the three locally orthogonal directions, preventing validation of existing methods by experimental results. For nonlinear system identification, there are additional challenges such as unobservable internal variables and the uncertainty of measured data.

Light-duty China-6, which is among the most stringent vehicle exhaust emission standards globally, mandates the monitoring and reporting of real driving emissions (RDE) from July, 2023. In the process of regulation promulgation and verification, more than 300 RDE tests have been performed on over 50 China-5 and China-6 certified models. This technical paper endeavors to summarize the experience of RDE practice in China, and discuss the impacts of some boundary conditions (including vehicle dynamic parameters, data processing methods, hybrid propulsion and testing altitude) on the result of RDE measurement. In general, gasoline passenger cars confront few challenges to meet the upcoming RDE NOx requirement, but some China-5 certified samples, even powered by naturally-aspirated engines may have PN issues. PN emissions from some GDI-hybrid powertrain systems also need further reduction to meet China-6 RDE requirements.

The study of vehicle state estimation performance especially on the aspect of observer-based control for improving vehicle ride comfort and road handling is a challenging task for vehicle industry. Since vehicle roll behavior with various road excitations act an important part of driving safety, how to accurately obtain vehicle state under various driving scenes are of great concern. However, previous researches seldom consider coupling relation between vehicle vertical and lateral response with steering input under various road excitation. To address this issue, comprehension analyses on vehicle roll state estimation with coupled input are present in this paper. A full-car nonlinear Takagi-Sugeno (T-S) fuzzy model is first created to describe vehicle lateral and vertical coupling dynamics.

The advanced Pedestrian Legform Impactor (aPLI) incorporates a number of enhancements for improved lower limb injury prediction capability with respect to its predecessor, the FlexPLI. The aPLI also incorporates a simplified upper body part (SUBP), connected to the lower limb via a mechanical hip joint, that expands the impactor’s applicability to evaluate pedestrian’s lower limb injury risk also in high-bumper cars.As the aPLI has been developed to be used in standardized testing, further considerations on the impactor’s manufacturability, robustness, durability, usability, and repeatability need to be accounted for.. The aim of this study is to define and verify, by means of numerical analysis, a battery of design modifications that may simplify the manufacturing and use of physical aPLIs, without reducing the impactors’ biofidelity. Eight candidate parameters were investigated in a two-step numerical analysis.

Particulate matter emissions are becoming a big issue for GDI engines as the emission regulations being more stringent. Methanol has been considered to be an important alternative fuel to reduce soot emissions. To understand the effect of methanol addition on soot and polycyclic aromatic hydrocarbons (PAHs) formation, the 2-D distributions of soot volume fraction and different size PAHs relative concentrations in methanol/gasoline laminar diffusion flames were measured by TC-LII and PLIF techniques. The effect of methanol was investigated under the conditions of the same carbon flow and the same flame height. The methanol volume fraction was set as M0/20/40/60/80. The results showed that the natural luminescent flame lift-off height and soot lift-off height increases consistently with the increasing methanol content due to the increase of outlet velocity of fuel vapor.

In the urea SCR system, urea solution is injected by injector installed in the front stage of the SCR catalyst, and NOx can be purified on the SCR catalyst by using NH3 generated by the chemical reaction of urea. NH3 is produced by thermolysis of urea and hydrolysis of isocyanic acid after evaporation of water in the urea solution. But, biuret and cyanuric acid which may cause deposit are sometimes generated by the chemical reactions without generating NH3. Spray behavior and chemical reaction of urea solution injected into the tail-pipe are complicated. The purpose of this study is to reveal the spray behavior and NH3 generation process in the tail-pipe, and to construct the model capable of predicting those accurately. In this report, the impingement spray behavior is clarified by scattered light method in high temperature flow field. Liquid film adhering to the wall and deposit generated after evaporation of water from the liquid film are photographed by the digital camera.

Soot emission, known as PM (particulate matter), is becoming a big issue for GDI engines as the emission regulations being increasingly stricter. It is found that ethanol, as an oxygenated bio-fuel, can reduce the soot emission when added to gasoline. In order to fully understand the effect of ethanol on soot reducing, the soot characteristics of ethanol/gasoline blends were studied on laminar diffusion flames. In this experiment, the blending ratio of ethanol/gasoline was set as E0/20/40/60/80. Considering the carbon content decreasing due to ethanol addition, carbon mass flow rate was remained constant. The two-dimensional distributions of soot volume fraction were measured quantitatively by using two-color laser induced incandescence technique. The results showed that ethanol is able to decrease the soot significantly, but the effect of ethanol on soot reduction is weakened with the increasing ethanol ratio.

The Opposed Piston Two-Stroke (OPTS) engine has many advantages on power density, fuel tolerance, fuel flexibility and package space. A type of self-balanced opposed-piston folded-crank train two-stroke engine for Unmanned Aerial Vehicle (UAV) was studied in this paper. AVL BOOST was used for the thermodynamic simulation. It was a quasi-steady, filling-and-emptying flow analysis -- no intake or exhaust dynamics were simulated. The results were validated against experimental data. The effects of high altitude environment on engine performance have been investigated. Moreover, the matching between the engine and turbocharger was designed and optimized for different altitude levels. The results indicated that, while the altitude is above 6000m, a multi-stage turbocharged engine system need to be considered and optimized for the UAV.

The prediction of temperature distribution and variation of oil-cooled sliding disk pair is essential for the design of wet clutches and brakes in a vehicle transmission system. A two-phase coupled heat transfer model is established in the study and some fluid-solid coupled heat transfer simulations are performed to investigate the thermal behaviors of wet clutch during sliding by CFD method. Both cooling liquid and grooved solid disks are contained in the heat transfer model and the heat convection due to the cooling liquid in the radial grooves is also considered by fluid-solid coupled transient heat transfer simulations. The temperature distribution and variation of the grooved disk are discussed and analyzed in detail. The results indicate that the temperature distribution on the grooved disk is nonuniform. The temperature within the middle radius area is higher than that in the inner and outer radius area.

In this paper, a novel driver model is proposed to track vehicle speed in MIL (Model-in-the-Loop) test system, which has structural consistency with HIL (Hardware-in-the-Loop) test system. First, the MIL test system which contains models of driver, vehicle and test bench is established. Second, according to the connections of the established models in Matlab/Simulink environment, the vehicle speed is calculated in vehicle model. Emphatically, through the deviation between driving cycle speed and calculated vehicle speed, PI controller in driver model adjusts the vehicle speed to ideal point through sending the torque command to drive motor, the ILC (Iterative Learning Control) controller modifies and stores P value of PI controller. Then, in order to obtain the better modification of PI controller, iterative learning control algorithm is deeply researched in term of types and parameters.

For applying ISO 26262 to motorcycles, controllability classification (C class evaluation) by expert riders is considered an appropriate technique. Expert riders have evaluated commercial product development for years and can appropriately conduct vehicle tests while observing safety restrictions (such as avoiding the risk of falling). Moreover, expert riders can ride safely and can stably evaluate motorcycle performance even if the test conditions are close to the limits of vehicle performance. This study aims to construct a motorcycle C class evaluation method based on an expert rider’s subjective evaluation. On the premise that expert riders can rate the C class, we improved a test procedure that used a subjective evaluation sheet as the concrete C class evaluation method for an actual hazardous event.

Along with the booming expansion of private car preservation, many Chinese cities are now struggling with hazy weather and ground-level ozone contamination. Although central government has stepped up efforts to purify skies above China, counter-strategies to curb ground-level ozone is comparatively weak. By using maximum incremental reactivity (MIR) method, this paper estimated the ozone forming potential for twenty-five Euro-3 to Euro-5 passenger cars burning conventional gasoline, methanol-gasoline, ethanol-gasoline, neat methanol and compressed natural gas (CNG). The results showed that, for all the fuel tested, VOC/NOx ratios and SR values decreased with the upgrading of emission standard. Except for Euro-3 M100 and Euro-4 M85, SR values for alternative fuel were to different degrees smaller than those for gasoline. When the emission standard was shifted from Euro-4 to Euro-5, OFP values estimated for gasoline vehicle decreased.

Within the hydraulic shifting circuit of power-shift steering transmission, the performance of filter is generally characterized by the theoretical filtration ratio. However in practical work, the actual filtration ratio is far less than the theoretical ratio. On the basis of investigation on the structural characteristics, the oil flowing distribution and the filter mechanisms, the re-filtering rate ω and recontaminative rate θ are defined to simulate the actual filtering process. Therefore, the dynamic filtration ratio is modelled and simulated in MATLAB/Simulink to investigate that how the filtering rate ω and θ influence the dynamic filtration ratio and the deviation between the dynamic ratio and theoretical ratio. Afterwards, the variation of dynamic filtration ratio is tested through a filtration experiment under the circumstances of various flow rate, temperature and pressure.

ISO 26262, a functional safety standard for motor vehicles, was published in November 2011. Although motorcycles are not included in the scope of application of the current edition of ISO 26262, it is expected that motorcycles will be included in the next revision. However, it is not appropriate to directly apply automotive safety integrity levels (ASILs) to motorcycles because the situation of usage in practice presumably differs between motorcycles and motor vehicles. In our previous study, we newly defined safety integrity levels for motorcycles (MSILs) and proposed that the levels of MSILs should correspond to levels one step lower than those of ASILs; however, we did not investigate the validity of their connections. Accordingly, in this research, we validated the connections. We defined the difference of levels of SILs between motorcycles and motor vehicles as the difference of target values of random hardware failure rates specified in ISO 26262-5.

Computer programs and models are playing an increasing role in simulating vehicle crashworthiness, dynamic, and fuel efficiency. To maximize the effectiveness of these models, the validity and predictive capabilities of these models need to be assessed quantitatively. For a successful implementation of Computer Aided Engineering (CAE) models as an integrated part of the current vehicle development process, it is necessary to develop objective validation metric that has the desirable metric properties to quantify the discrepancy between multiple tests and simulation results. However, most of the outputs of dynamic systems are multiple functional responses, such as time history series. This calls for the development of an objective metric that can evaluate the differences of the multiple time histories as well as the key features under uncertainty.