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A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.

As electric technique develops fast, steering system changes from conventional mechanic steering system to Hydraulic Power Steering (HPS). Flowing HPS, Electrically Controlled Steering (ECS) system, including Electric Power Steering (EPS) system, Active Front Steering (AFS) system and Steer-by-Wire (SBW) system. ECS makes it easy for a driver to control a steering wheel using a less torque at a low speed, which is usually called steering portability Besides, ECS could also help a driver steer a vehicle stably at a high speed, which is usually called steering stability ECS provides an optional method to solve the contradiction between steering portability and steering stability. [1] [2] The study of ECS involves mechanic design, detection of electric components, software design and so on. Researches of ECS need a lot of trials and errors. By now, the development of ECS mostly depends on experiments on Hardware-in-the- Loop (HIL) and real vehicles.

Vehicle dynamic performance on snow-covered roads is one aspect of performance that is influenced by tire performance. Much research concerning a vehicle's performance on snow-covered roads has focused on being directed to vehicle control technology that increases control when the tire-slip ratio is larger, such as anti-lock braking systems (ABS) and electronic stability control (ESC). There has been little research, regarding performance when the slip ratio on a snow- covered road is smaller. We studied the friction performance of tires on snow-covered roads to predict vehicle performance within the grip range. We propose a technology for predicting vehicle performance within the small slipangle range and also verify its effectiveness. We established the tire characteristics that assure the grip range on a snow-covered road using performance indicators.

One of the passive methods to reduce drag on the unshielded underbody of a passenger road vehicle is to use a vertical deflectors commonly called air dams or chin spoilers. These deflectors reduce the flow rate through the non-streamlined underbody and thus reduce the drag caused by underbody components protruding in to the high speed underbody flow. Air dams or chin spoilers have traditionally been manufactured from hard plastics which could break upon impact with a curb or any solid object on the road. To alleviate this failure mode vehicle manufacturers are resorting to using soft plastics which deflect and deform under aerodynamic loading or when hit against a solid object without breaking in most cases. This report is on predicting the deflection of soft chin spoiler under aerodynamic loads. The aerodynamic loads deflect the chin spoiler and the deflected chin spoiler changes the fluid pressure field resulting in a drag change.

It is considered that door mirror drag is composed of not only profile drag but also interference drag that is generated by the mixing of airflow streamlines between door mirrors and vehicle body. However, the generation mechanism of interference drag remained unexplained, so elucidating mechanism for countermeasures reducing drag have been needed. In this study, the prediction formulas for door mirror drag expressed by functions in relation to velocities around the vehicle body were derived and verified by wind tunnel test. The predicted values calculated by formulas were compared with the measured values and an excellent agreement was found. In summary, new prediction formulas made it possible to examine low drag mirror including profile and interference drag.

The study presented in this paper aims to evaluate the performance of a new conceptual combined power system composed of a turbocharged engine and an inverted Brayton cycle (IBC). A validated 1D model of a downsized SI engine has been built in GT-power as the baseline model to quantify the performance improvement due to introducing the inverted Brayton cycle. The results show that a system performance improvement caused by adopting IBC is expected depended on the engine load, IBC turbomachinery efficiency and the bottoming expansion ratio. The maximum thermal efficiency of the combined system is achieved when both the wastegates of turbocharger and IBC turbines are closed, which is up to 6.15 percent point.

Pilot ignited natural gas diesel engine (PINGDE) was demonstrated to achieve low NOx emission, high fuel economy and low fuel cost. Despite of that, PINGDE is still confronted with problems such as high mechanical and thermal stress under heavy load, high CO and THC emission under small load and a trade-off relationship between NOx emission and fuel efficiency for whole operating points. In this study, tests were conducted to explore how three main variables including pilot injection timing, pilot diesel substitution rate and two kinds of pilot injection strategies influence the performance and emission of the modified WP10 engine. Two pilot injection strategies including pilot diesel injected once and twice were proposed and potential of promoting fuel economy and saving fuel cost was demonstrated. Moreover, a numerical engine model is established to optimize engine performance and emission with the help of MBC toolkit through limited experiments.

The new 2GR-FKS / FXS engines were developed to achieve stringent fuel economy and emission targets and respond to recent innovations in the field. The major parts of the 2GR-FKS/FXS engines were re-designed based on the well-received dynamic performance and fuel economy aspects of the 2GR-FE engine. The aims of this development were as follows. 1 Best-in-class power performance 2 Environmental performance that maximizes thermal efficiency and complies with fuel economy and emission regulations in each country by a wide margin 3 Engine response typical of V6 engines through drastic weight reduction of moving parts To achieve these conflicting aims, the developed engines use a modified version of the D-4S fuel injection system, which enables selective use of direct and port injection, in addition to advanced technologies such as variable valve technology (VVT) with a mid-position lock system and an exhaust port cooling system.

Engine downsizing of the spark ignition gasoline engine is recognized as one of the most effective approaches to improve the fuel economy of a passenger car. However, further engine downsizing beyond 50% in a 4-stroke gasoline engine is limited by the occurrence of abnormal combustion events as well as much greater thermal and mechanical loads. In order to achieve aggressive engine downsizing, a boosted uniflow scavenged direct injection gasoline (BUSDIG) engine concept has been proposed and researched by means of CFD simulation and demonstration in a single cylinder engine. In this paper, the intake port design on the in-cylinder flow field and gas exchange characteristics of the uniflow 2-stroke cycle was investigated by computational fluid dynamics (CFD). In particular, the port orientation on the in-cylinder swirl, the trapping efficiency, charging efficiency and scavenging efficiency was analyzed in details.

In this paper a turbocharged aftercooled NG SI engine was experimentally investigated at Sharif University turbocharging lab at WOT. The engine torque, boost pressure, air consumption and volumetric efficiency were assessed experimentally at WOT in view point of waste-gate. Waste-gate opening effects on turbine and compressor characteristics were also evaluated experimentally at Sharif University turbocharger lab. The engine was also experimentally investigated at four different waste-gate opening pressure thresholds under ECE-R49 test cycle. It is also experimentally found that changing waste-gate opening pressure threshold from 165 mmHg to 200 and 265 mmHg decreases total bsNOx at a rate of 6% and 12% respectively. Increase of the pressure threshold to 323 mmHg augmented total bsNOx. Therefore, to minimize the bsNOx, the threshold of 265 mmHg was the optimum pressure threshold.

A supercharger system which boosts the engine via a direct drive from the engine crankshaft has been identified as a possible solution to improve low-end torque and transient response for a conventional turbocharged SI engine. However, the engine equipped with a fixed-ratio supercharger is not as fuel-efficient especially at high load and low speed due to the fact that a large portion of the intake mass air flow has to recirculate through a bypass valve causing inevitable mechanical and flow losses. In addition, the fixed drive ratio of the supercharger which is mainly determined by the full-load requirements might not be able to provide sufficient over-boost during a transient. The fact that a clutch may be necessary for high engine speed operation on the fixed-ratio supercharger system is another issue from the perspective of cost and NVH performance.

2-Butanone (C4H8O) is a promising alternative fuel candidate as a pure as well as a blend component for substitution in standard gasoline fuels. It can be produced by the dehydrogenation of 2-butanol. To describe 2-butanone's basic combustion behaviour, it is important to investigate key physical properties such as the laminar burning velocity. The laminar burning velocity serves on the one hand side as a parameter to validate detailed chemical kinetic models. On the other hand, especially for engine simulations, various combustion models have been introduced, which rely on the laminar burning velocity as the physical quantity describing the progress of chemical reactions, diffusion, and heat conduction. Hence, well validated models for the prediction of laminar burning velocities are needed. New experimental laminar burning velocity data, acquired in a high pressure spherical combustion vessel, are presented for 1 atm and 5 bar at temperatures of 373 K and 423 K.

On-board hydrogen generation technology using a fuel reforming catalyst is an effective way to improve the fuel efficiency of automotive internal combustion engines. The main issue to be addressed in developing such a catalyst is to suppress catalyst deterioration caused by carbon deposition on the catalyst surface due to sulfur adsorption. Enhancing the hydrocarbon and water activation capabilities of the catalyst is important in improving catalyst durability. It was found that the use of a rare earth element is effective in improving the water activation capability of the catalyst. Controlling the hydrocarbon activation capability of the catalyst for a good balance with water activation was also found to be effective in improving catalyst durability.

Bio-ethanol is used worldwide in fuel mixtures such as E10 gasoline. In this study, an onboard fuel system employing a pervaporation membrane was investigated to separate E10 into high-octane-number fuel (high-concentration ethanol fuel) and low-octane-number fuel (low-concentration ethanol fuel). The optimal operation conditions and size of the membrane unit for the separation system were determined in consideration of the separation rate and vehicle installation. This system can supply separated ethanol with sufficient speed and quantity to improve engine performance under practical driving conditions. In addition, the study was conducted to confirm that separated fuels have properties sufficient for use in automobiles. This separation rate enabled 5-cycle-mode driving without temporary shortage of permeated fuel.

During an injection process, a fluid undergoes a sudden pressure drop across the nozzle. If the pressure downstream the injector is below the saturation value of the fluid, superheated conditions are reached and thermodynamic instabilities realized. In internal combustion engines, flashing conditions greatly influence atomization and vaporization processes of a fuel as well as the mixture formation and combustion. This paper reports imaging behavior of a fuel under both flash boiling and non-flash boiling conditions. A GDI injector, eight-hole, 15.0 cc/s @ 10 MPa static flow, injected a single-component fluid (iso-octane), generating the spray. Experiments were carried out in an optically-accessible constant-volume quiescent vessel by Mie-scattering technique. A C-Mos high-speed camera was used to acquire cycle-resolved images of the spray evolving in the chamber filled with N2 which pressure ranged between 0.05 and 0.3 MPa.

Effects of n-butanol on the combustion process in a direct injection spark ignition engine were investigated through flame visualization and spectroscopy. An optically accessible engine was equipped for the trials with a commercial cylinder head and wall guided injection system. Injection pressure (100 bar) and engine speed (2000 rpm) were fixed while injection timing and duration were changed to realise stoichiometric and lean fuelling in homogenous charge conditions. Specifically, UV-visible digital imaging was applied in order to study the flame front inception and propagation with particular interest in the early combustion stages. UV-visible natural emission spectroscopy was applied to investigate the formation and the evolution of the main chemical compounds characterizing the spark ignition and combustion processes. Detailed image processing allowed to correlate the morphology and the local flame front curvature with thermodynamic data.

Investigation of both intake valve deposit (IVD) formation tendency and the effect of surrounding conditions (e.g. atmospheric temperature) on IVD formation was conducted using poly aromatics-rich gasoline in a port fuel injected (PFI) engine. The IVD mostly consisted of carbonaceous deposit and this was shown to be derived from the heavier poly aromatic fuel molecules and engine oil. Analysis also indicated that some metals in the deposit structure came from additives of lubricating oil and the wear and/or corrosion within the engine. In this engine test, there was a significant effect of room temperature where higher room temperatures correlated with higher levels of IVDs. These results illustrate the importance of the surrounding condition in order to understand the IVD issues, higher IVDs weights will result under hotter driving (e.g. in summer) condition.

Hydrogen can be produced by electrolyzation with renewable electricity and reduce the combustion products from hydrogen mixture don't include CO, CO2 and unburned hydrocarbon components. We focused on these characteristics of hydrogen and high thermal efficiency of diesel engine and acquired the performance of hydrogen diesel dual fuel (DDF) engine. We changed proportion of hydrogen to total input energy and studied basic combustion and exhaust gas emission performance of hydrogen DDF operation. In addition, we studied the effects of advancement of diesel fuel injection timing and EGR on combustion behavior and improvement of NOx emission. Especially, EGR improved NOx emission from hydrogen DDF operation drastically without a decrease in thermal efficiency. Under hydrogen DDF operation with EGR, diesel fuel injection timing was advanced for stable combustion and it inhibited the degradation of thermal efficiency.

The large eddy simulation (LES) with Volume of Fluid (VOF) interface tracking method in Ansys-FLUENT has been used to study the effects of nozzle hole geometrical parameters on gasoline direct injection (GDI) fuel injectors, namely the effect of inner hole length/diameter (L/D) ratio and counter-bore diameters on near field spray characteristics. Using iso-octane as a model fuel at the fuel injection pressure of 200 bar, the results showed that the L/D ratio variation of the inner hole has a more significant influence on the spray characteristics than the counter-bore diameter variation. Reducing the L/D ratio effectively increases the mass flow rate, velocity, spray angle and reduces the droplet size and breakup length. The increased spray angle results in wall impingements inside the counter-bore cavity, particularly for L/D=1 which can potentially lead to increased deposit accumulation inside fuel injectors.

This paper explores the use of rate of injection (ROI) and rate of momentum (ROM) to characterize the internal flow of an ECN gasoline direct injector. Rate of momentum has been successfully used in diesel injectors with this objective and for the first time, the measurements have been made on a GDi injector. The paper focuses on the experimental setup used and the different uncertainties and difficulties to translate the typically measured diesel technique to a gasoline injector.