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The wear mechanisms of the methanol engine were studied using dynamometer tests. Formic acid from methanol combustion mixes with the lubricant oil and attacks the metal surfaces. The iso tacho prorissis method was successfully applied to analyze the formic acid content of the used oil. A large amount of condensed water is also formed by methanol combustion and accelerates the wear. Wear can be effectively reduced by shortening lubricant oil change intervals, by using a special oil and by durable surface treatment of engine parts.

For reduction of fuel consumption, a new device “Water Jacket Spacer” which improves temperature distribution of a cylinder block bore wall was developed. In the case of a conventional cylinder block, coolant flow concentrates at the bottom and middle region of the water jacket. While temperature of the upper bore wall is high (due to high-temperature combustion gas) the temperature of the lower bore wall is low, since its only function is to support the piston. When the developed spacer is inserted into a water jacket, the coolant flow concentrates at the upper part of the jacket. As a result, cooling ability to the upper bore wall was improved and temperature of lower bore wall was increased, thereby reducing fuel consumption.

Rankine bottoming system, which operates on waste heat of engine cooling, has been developped to improve the fuel economy of a passenger car. Evaporative engine cooling system is utilized to obtain high thermal efficiency and simplicity of the Rankine bottoming system. The bottoming system uses HCFC123 as a working fluid, and scroll expander as a power conversion unit. The results indicate that energy recovery, which depends on the ambient temperature, is almost 3 percent of engine output power at ambient temperature of 25°C.

Finite element aodels have been developed to analyze drive line and suspension vibration. For the analysis of booming noise, we have addressed the optimization of the differential gear carrier mounting system by using a virtual system and realization of it considering many constraints. To reduce the differential whine noise, a simulation method considering the transmitting error of the differential gear was applied. And we have approached for the subtle arrangements of many structural resonances with detail research of the drive line and suspension. For the reduction of road noise, we adopted the approach of shifting the node of the rear suspension member mode.

A prototype power control unit (PCU) was manufactured using silicon carbide (SiC) power semiconductors (diodes and transistors), which have low power loss when switching on and off. This PCU was installed in a hybrid vehicle (HV) and driven on a test course and chassis dynamometer. The test results confirmed a fuel efficiency improvement of about 5 percent.

This paper proposes a technology to reduce vehicle surge during towing that utilizes motors and shifting to help ensure comfort in a parallel HEV pickup truck. Hybridization is one way to reduce fuel consumption and help realize carbon neutrality. Parallel HEVs have advantages in the towing, hauling, and high-load operations often carried out by pickup trucks, compared to other HEV systems. Since the engine, motor, torque converter, and transmission are connected in series in a parallel HEV, vehicle surge may occur when the lockup clutch is engaged to enhance fuel efficiency, similar to conventional powertrains. Vehicle surge is a low-frequency vibration phenomenon. In general, the source is torque fluctuation caused by the engine and tires, with amplification provided by first-order torsional driveline resonance, power plant resonance, suspension resonance, and cabin resonance. This vibration is amplified more during towing.

The development of electric vehicles has been progressed, rapidly, to achieve Carbon neutrality by 2050. There have been increasing concerns about Electromagnetic Compatibility (EMC) performance due to increasing power for power trains of vehicles. Because same power train system expands to some vehicles, we have developed numerical simulations in order to predict the vehicle EMC performances. We modeled a vehicle which has inverter noises by numerical simulation to calculate electric fields based on GB/T18387. We simulated the common mode noise which flows through the shielding braid of the high voltage wire harnesses. As a result, it is confirmed a correlation between the electric fields calculated by numerical simulation and the measured one.

In-wheel motors (IWM) will be a key technology that contributes to the popularization of electric vehicles. Combining electric drive with IWM enables both good vehicle dynamics and a roomy interior. In addition, the responsiveness of IWM is also capable of raising dynamic control performance to an even higher level. IWM enable vertical body motion control as well as direct yaw control, electric skid control, and traction control. This means that IWM can replace most control actuators used in a vehicle chassis. The most important technology for IWM is to enable the motor to coexist with the brake and the suspension arms inside the wheel. The IWM drive unit described in this paper can be installed with a front double wishbone suspension, the most difficult configuration.

This paper describes and confirms the effect of low frequency sinusoidal steering torque input on vehicle response and steering behavior using vehicle test, analysis with equations of motion and simulations. The vehicle response by low frequency torque input is quite different to the vehicle response by low frequency steer angle input. Steering system parameters such as moment of inertia, damping, friction and power steering assist torque have an effect on low frequency torque input steering system dynamics. The dynamic response of the vehicle with electric power steering (EPS) system, which has a big moment of inertia with electric motor and friction of the reduction gear, is affected by the steering system dynamic properties. The vehicle response by low frequency torque input test has capability for contribute to vehicle evaluation such as steer feel or maneuverability of handling.

In order to reduce engine development timing and cost, a numerical calculation has been developed by Toyota Motor Company and Toyota Technical Center to evaluate valve train systems. The goal is to predict valve_bounce speed, valve displacement, hydraulic lash adjuster motion and strain in the rocker arm. The numerical procedure combines finite element model and multi-body dynamic analysis. Normally, strain calculation is a two-step process. In the first step, engineers obtain the excitation from the dynamic analysis. In the second step, engineers use the forcing function from dynamic analysis to calculate strain and stress. The new approach in this paper, using ADAMS, calculates dynamic load and recover strain simultaneously. As the flexibility of the moving part (for example rocker arm) is taken into account in the equations of motion, ADAMS will calculate the modal strain. Based on the modal strain, the strain or stress at any given node(s) can be recovered.

In order to develop the valve rocker arm material for the new type engine, we investigated various materials whose chemical compositions were selected using 30% chromium cast iron, which had shown good results in screening evaluation tests, as the basis. High chromium cast irons are well known for their abrasive wear resistance, but it has been very difficult to apply them for use as rocker arm material because their machinability is very poor, and because it is difficult for them to have a regular microstructure. In this paper, both the manufacturing method for the rocker arm which decreases the disadvantages that high chromium cast iron have and the rocker arm material best suited for this method are described.

The volatile organic compounds (VOC) from diesel engines, including formaldehyde and benzene, are concerned and remain as unregulated harmful substances. The substances are positively correlated with THC emissions, but the VOC and aldehyde compounds at light load or idling conditions are more significant than THC. When coolant temperatures are low at light loads, there are notable increases in formaldehyde and acetaldehyde, and with lower coolant temperatures the increase in aldehydes is more significant than the increase in THC. When using ultra high EGR so that the intake oxygen content decreases below 10%, formaldehyde, acetaldehyde, benzene, and 1,3-butadiene increase significantly while smokeless and ultra low Nox combustion is possible.

In order to clarify future automobile technologies and fuel qualities to improve air quality, second phase of Japan Clean Air Program (JCAPII) had been conducted from 2002 to 2007. Predicting improvement in air quality that might be attained by introducing new emission control technologies and determining fuel qualities required for the technologies is one of the main issues of this program. Unregulated material WG of JCAPII had studied unregulated emissions from gasoline and diesel engines. Eight gaseous hydrocarbons (HC), four Aldehydes and three polycyclic aromatic hydrocarbons (PAHs) were evaluated as unregulated emissions. Specifically, emissions of the following components were measured: 1,3-Butadiene, Benzene, Toluene, Xylene, Ethylbenzene, 1,3,5-Trimethyl-benzene, n-Hexane, Styrene as gaseous HCs, Formaldehyde, Acetaldehyde, Acrolein, Benzaldehyde as Aldehydes, and Benzo(a)pyrene, Benzo(b)fluoranthene, Benzo(k)fluoranthene as PAHs.

We have developed a novel engine cycle simulation program (UniDES: universal diesel engine simulator) to reproduce the diesel combustion process over a wide range of engine operating parameters, such as the amount of injected fuel, the injection timing, and the EGR ratio. The approach described in this paper employs a zoning model, where the in-cylinder region is divided into up to five zones. We also applied a probability density function (PDF) concept to each zone to consider the effect of spatial non-homogeneities, such as local equivalence ratios and temperature, on the combustion characteristics. We linked this program to the commonly used commercial GT-Power® software (UniDES+GT). As a result, we were able to reproduce transient engine behavior very accurately.

The aim of this research is to develop the diesel combustion simulation (UniDES: Universal Diesel Engine Simulator) that incorporates multiple-injection strategies and in-cylinder composition changes due to exhaust gas recirculation (EGR), and that is capable of high speed calculation. The model is based on a zero-dimensional (0D) cycle simulation, and represents a multiple-injection strategy using a multi-zone model and inhomogeneity using a probability density function (PDF) model. Therefore, the 0D cycle simulation also enables both high accuracy and high speed. This research considers application to actual development. To expand the applicability of the simulation, a model that accurately estimates nozzle sac pressure with various injection quantities and common rail pressures, a model that accounts for the effects of adjacent spray interaction, and a model that considers the NOx reduction phenomenon under high load conditions were added.

A phosphor thermometry, for measurements of two-dimensional gas-phase temperature was examined in turbulent combustion in an engine. The reasonable temperature deviation and the agreement with calculated data within 5% precision were achieved by single-shot images in the ignition process of compression ignition engine. Focusing on the local flame kernel, the flame structure could be quantitatively given by the temperature. It became evident that the HCCI flame kernels had 1-3 mm diameter and the isolated island structures. Subsequently, the HTR zone consisted of the combined flame kernels near TDC.

Phosphor thermometry was used during fuel injection in an optical engine with the glass piston of reentrant type. SiO2 coated phosphor particle was used for the gas-phase temperature measurements, which gave much less background signal. The measurements were performed in motored mode, in combustion mode with injection of n-heptane and in non-combustion mode with injection of iso-octane. In the beginning of injection period, the mean temperature of each injection cases was lower than that of the motored case, and temperature of iso-octane injection cases was even lower than that of n-heptane injection cases. This indicates, even if vaporization effect seemed to be the same at both injection cases, the effect of temperature decrease changed due to the chemical reaction effect for the n-heptane cases. Chemical reaction seems to be initiated outside of the fuel liquid spray and the position was moving towards the fuel rich area as the time proceeds.

High fuel efficiency and low emission technologies, such as Direct Injection (DI) gasoline and diesel engines and hybrid powertrains, have been developed to resolve environmental and energy resource issues. The hybrid powertrain system has achieved superior power performance as well as higher system efficiency and is expected to be a core powertrain technology because it is compatible with various power sources including fuel cells. It becomes important to control complicated hybrid systems that consist of not only a powertrain but also vehicle systems such as regenerative braking. Model-based control and calibration enables both control strategy optimization and control system development efficiency improvement.

An accurate prediction of internal nozzle flow in fuel injector offers the potential to improve predictions of spray computational fluid dynamics (CFD) in an engine, providing a coupled internal-external calculation or by defining better rate of injection (ROI) profile and spray angle information for Lagrangian parcel computations. Previous research has addressed experiments and computations in transparent nozzles, but less is known about realistic multi-hole diesel injectors compared to single axial-hole fuel injectors. In this study, the transient injector opening and closing is characterized using a transparent multi-hole diesel injector, and compared to that of a single axial hole nozzle (ECN Spray D shape). A real-size five-hole acrylic transparent nozzle was mounted in a high-pressure, constant-flow chamber. Internal nozzle phenomena such as cavitation and gas exchange were visualized by high-speed long-distance microscopy.

The running direction of a vehicle can be controlled by not only wheel steer but also torque steer. This paper introduces the tractive torque steer effect produced by a newly developed electropneumatic control system, the limited-slip differential for large-sized vehicles. This system enhances the vehicle's running stability and controllability by controlling the tractive force of the drive axle. The tractive force maintains a stable running course against disturbances such as road roughness and wind gusts, thereby enhancing the steering response and providing a better feeling of handling to the driver. The system also improves mobility. especially on low-μ roads. It is expected that a single axle equipped with this system will exhibit good performance comparable to that of tandem axle.