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When evaluating the wear properties of slide bearings for car engines, it is a common practice to conduct long-term physical test using a bearing tester for screening purposes according to the revolution speed of the shaft, supply oil temperature and bearing pressure experienced in the actual use of engines. The loading waveform applied depends on the capability of the tester that is loaded, and it is often difficult to apply a loading waveform equivalent to that of actual engines. To design an engine that is more compact or lighter, it is necessary to reduce the dimensions of slide bearings and the distance between bearings. This requires loading tests on a newly designed engine by applying a loading waveform equivalent to that of actual engines to slide bearings and their vicinity before conducting a firing test. We therefore conducted an engine firing test by attaching thin-film sensors to the slide bearing part of the engine and measured the actual load distribution.

A new motor has been developed that combines the goals of greater compactness, increased power and a quiet drive. This motor is an interior permanent magnet synchronous motor (IPM motor) that combines an interior permanent magnet rotor and a stator with concentrated windings. In addition, development of the motor focused on the slot combination, the shape of the magnetic circuits and the control method all designed to reduce motor noise and vibration. An 8-pole rotor, 12-slot stator combination was employed, and a gradually enlarged air gap configuration was used in the magnetic circuits. The gradually enlarged air gap brings the centers of the rotor and the stator out of alignment, changing the curvature, and continually changing the amount of air gap as the rotor rotates. The use of the gradually enlarged air gap brings torque degradation to a minimum, and significantly reduces torque fluctuation and iron loss of rotor and stator.

Water management is one of the key factors to ensure high performance, cold start and durability of polymer electrolyte fuel cells (PEFCs), and it is important to understand the behavior of liquid water in PEFCs. X-ray computed tomography (X-ray CT) imaging and the two-phase lattice Boltzmann method (two-phase LBM) are applied to analyze the mechanism of water transport in the gas diffusion layers (GDLs) and the gas channels in generating PEFCs. The results of the two-phase LBM are compared with those of X-ray CT imaging, and are found to agree qualitatively in that water is discharged along the hydrophilic channel wall and accumulated in the GDL, especially under the rib. The effects of the wettability of the GDLs, and of the gas channels, the diameter of the carbon fibers, and the porosity of the GDLs on water discharge from the GDLs and gas channels are also investigated.

There are strong demands for reduced production costs of ordinary bolts, of which a large number are used throughout automobiles. In addition, there are continued demands for higher performance and lower weight in automobiles. For this reason, there is an increasing trend to develop steel for high strength bolts or to adopt the plastic region tightening method. At present, the principal materials used in high strength bolts of class 10.9 are medium carbon alloy steel. When a low carbon boron steel bolt is used as a class 10.9 bolt under high stress, delayed fracture may occur, so that these cannot always be used for the body and chassis applications. The authors have developed a new low carbon boron steel with increased delayed fracture strength on the same order as that of JIS-SCM435 (equivalent to SAE4135) medium carbon alloy steel. Attention was focused principally on decreasing the amounts of phosphorus and sulfur in the steel.

A second-generation power control unit (PCU) for a two-motor hybrid system is proposed. An optimally designed power module, which is a key component of the PCU, is applied to increase heat-resistant temperature, while the basic structure of the first generation is retained and the power semiconductor chip is directly cooled from the single side. In addition to the optimum design, by decreasing the power loss as well as increasing the heat-resistant temperature of the power semiconductors (IGBT: Insulated Gate Bipolar Transistor and FWD: Free Wheeling Diode), the proposed PCU has attained 25% higher power density and 23% smaller size compared to first-generation units, maintaining PCU efficiency (fuel economy). To achieve a high yield rate in the power module assembly process, a new screening technology is adopted at the initial stage of power module manufacturing.

A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept.

Honda announced an independent right and left rear toe control system (first generation) in 2013 and presented it as the world's first. As stated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has achieved a balance between an enjoyable driving experience in which handling is performed at the driver's will (“INOMAMA” handling) and stable driving performance.(1) This first generation is optimally designed to the vehicle specifications such as suspension axial force and steering gear ratio of the vehicle to which the system is applied. For more widespread application of independent rear toe control technology, a next generation system (second generation) has been developed, which achieves both cost reduction and flexible system performance which can be adapted to a variety of vehicles. The system development began by setting the required target performance with consideration for adaptation to various car models.

We had developed Electric Servo Brake System, which can control brake pressure accurately with a DC motor according to brake pedal force. Therefore, the system attains quality brake feeling while reflecting intentions of a driver. By the way, “Build-up” is characteristics that brake effectiveness increases in accordance with the deceleration of the vehicle, which is recognized as brake feeling with a sense of relief as not to elongate an expected braking distance at a downhill road due to large-capacity brake pad such as sports car and large vehicles. Then, we have applied the optical characteristic control to every car with Electric Servo Brake System by means of brake pressure control but not brake pad. Hereby, we confirmed that the control gives a driver the sense of relief and the reduction of pedal load on the further stepping-on of the pedal. In this paper, we describe the development of brake feel based on the control overview.

Car engine piston cooling is an important technology for improving the compression ratio and suppressing the deformation of pistons. It is well known that thermal conductivity improves dramatically through the use of heat pipes in computers and air conditioners. However, the heat pipes in general use have not been used for the cooling of engines because the flow of gas and liquid is disturbed by vibration and the thermal conductivity becomes excessively low. We therefore developed an original heat pipe and conducted an experiment to determine its heat transfer coefficient using a high-speed reciprocation testing apparatus. Although the test was based on a single heat pipe unit, we succeeded in improving the heat transfer coefficient during high-speed reciprocation by a factor of 1.6 compared to the heat transfer coefficient at standstill. This report describes the observed characteristics and the method of verification.

In recent years, increasing attention has been paid to a non-throttling technology that is expected to contribute to a reduction in fuel consumption. This paper describes a study on the technology behind the electromagnetic variable valve timing mechanism (electromagnetic valve mechanism). The electromagnetic valve mechanism ensures highly efficient and stable valve opening/closing control. The detailed information and findings will be described in the main body. In addition, the advantages of the mechanism's application to a homogeneous charge compression ignition engine (HCCI engine) will also be described.

In recent years, emission regulations have become more stringent as a result of increased environmental awareness in each region of the world. For lean-burn diesel engines, since it is not possible to use three-way catalytic converters, reducing NOX emissions is a difficult technical challenge. To respond to these strict regulations, an exhaust gas aftertreatment system was developed, featuring a lean NOX catalyst (LNC) that uses a new chemical reaction mechanism to reduce NOX. The feature of the new LNC is the way it reduces NOX through an NH3-selective catalytic reduction (SCR), in which NOX adsorbed in the lean mixture condition is converted to NH3 in the rich mixture condition and reduced in the following lean mixture condition. Thus, the new system allows more efficient reduction of NOX than its conventional counterparts. However, an appropriate switching control between lean and rich mixture conditions along with compensation for catalyst deterioration was necessary.

As technologies for simultaneously maintaining the current high thermal efficiency of diesel engines and reducing particulate matter (PM) and nitrogen oxide (NOX) emissions, many new combustion concepts have been proposed, including premixed charge compression ignition (PCCI) and low-temperature combustion[1]. However, it is well known that since such new combustion techniques precisely control combustion temperatures and local air-fuel ratios by varying the amount of air, the exhaust gas recirculation (EGR) ratio and the fuel injection timing, they have the issues of being less stable than conventional combustion techniques and of performance that is subject to variance in the fuel and driving conditions. This study concerns a system that addresses these issues by detecting the ignition timing with in-cylinder pressure sensors and by controlling the fuel injection timing and the amount of EGR for optimum combustion onboard.

In recent years, emission regulations have become more stringent as a result of increased environmental awareness in each region of the world. For diesel engines, reducing NOX emissions is a difficult technical challenge.[1],[2],[3],[4]. To respond to these strict regulations, an exhaust gas aftertreatment system was developed, featuring a lean NOX catalyst (LNC) that uses a new chemical reaction mechanism to reduce NOX. The feature of the new LNC is the way it reduces NOX through an NH3-selective catalytic reduction (SCR), in which NOX adsorbed in the lean mixture condition is converted to NH3 in the rich mixture condition and reduced in the following lean mixture condition. Thus, the new system allows the effective reduction of NOX. However, in order to realize cleaner emission gases, precise engine control in response to the state of the exhaust aftertreatment system is essential.

We have developed a bench test method to assess driver distraction caused by the load of using infotainment systems. In a previous study, we found that this method can be used to assess the task loads of both visual-manual tasks and auditory-vocal tasks. The task loads are assessed using the performances of both pedal tracking task (PT) and detection response task (DRT) while performing secondary tasks. We can perform this method using simple equipment such as game pedals and a PC. The aim of this study is to verify the reproducibility of the PT-DRT. Experiments were conducted in three test environments in which test regions, experimenters and participants differed from each other in the US, and the test procedures were almost the same. We set two types of visual-manual tasks and two types of auditory-vocal tasks as secondary tasks and set two difficulties for each task type to vary the level of task load.

This paper summarizes the piston pin noise mechanism and show the way to reduce noise level of semi-floating system. A mechanism of piston pin noise of semi-floating system was clarified by measurement of piston and piston pin behavior and visualization of engine oil mist around piston and piston pin. Piston and piston pin behavior was measured by accelerometer and eddy current type gap sensor with linkage system at the actual engine running condition. Engine oil behavior was visualized and measured its flow vector by Particle Tracking Velocimetry (PTV). For PTV, engine oil mist particle image was taken by high speed camera with fiber scope attached to linkage system. From themeasurement, it was cleared that engine oil doesn't reach to piston hole from undersurface of piston land and come rushing out from piston broach via groove. The result shows that lacking of engine oil between piston and piston pin makes noise larger.

Attempts were made to measure knocking phenomenon by an optical method, which is free from influences of mechanical noises and is allowing an easy installation to an engine. Using a newly developed high durability optical probe, the light intensity of hydroxyl radical component, which is diffracted from the emitted light from combustion, was measured. The intensity of this emission component was measured at each crank angle and the maximum intensity in a cycle was identified. After that, the angular range in which the measured intensity exceeded 85% of this maximum intensity was defined as “CA85”. When a knocking was purposely induced by changing the conditions of the engine operation, there appeared the engine cycles that included CA85 less than a crank angle of 4 degrees. The frequency of occurrence of CA85 equal to or less than 4 degrees within a predetermined number of engine cycles, which can be interpreted as a knocking occurrence ratio, was denoted as “CA85-4”.

The use of electric vehicles (EV) is becoming more widespread as a response to global warming. The major issues associated with EV are the annoyance represented by charging the vehicles and their limited cruising range. In an attempt to remove the restrictions on the cruising range of EV, the research discussed in this paper developed a dynamic charging EV and low-cost infrastructure that would make it possible for the vehicles to charge by receiving power directly from infrastructure while in motion. Based on considerations of the effect of electromagnetic waves, charging power, and the amount of power able to be supplied by the system, this development focused on a contact-type charging system. The use of a wireless charging system would produce concerns over danger due to the infiltration of foreign matter into the primary and secondary coils and the health effects of leakage flux.

Owing to its combustion characteristics and chemical composition, natural gas features cleaner emissions and lower CO2 compared to gasoline under equal thermal efficiency. Natural gas can be a promising alternative energy source to respond to crude oil exhaustion and global warming issues. Focusing on the utility of natural gas, a feasibility study on CNG (Compressed Natural Gas) -fueled two-wheeled vehicles has been conducted. A proto-type two-wheeled vehicle was made based on a 125 cm3 class gasoline-fueled scooter. To adapt the engine to the use of CNG fuel, an electronically controlled gas injection system was applied to the fuel supply system. To provide abrasion resistance of engine valves and valve seats, the specific matter of gas-fuel was improved. Furthermore, a lubricant circulation passage was added to maintain the temperature of the pressure reducing valve.

The properties sought in a multi-layer steel cylinder head gasket include cylinder pressure sealing and fatigue strength in order for there to be no damage while the engine is in operation. Diesel engines, in particular, have high cylinder pressure and a high axial tension by the cylinder head bolt demanding severe environment to the gaskets. As engine performance is enhanced, there are cases when cracks develop in the gasket plate, necessitating countermeasures. The cause of cracking in a flat center plate, in particular, has not yet been explained, and no method for evaluation had previously existed. Three-dimensional non-linear finite element calculation was therefore performed to verify the cause. First, a static pressurization rig test was used and the amount of strain was measured to confirm the validity of the calculations. Then the same method of calculation was used to verify the distribution of strain, with a focus on the plate position.

Conventionally, the Ni-based superalloys NCF3015 (30Ni-15Cr) and the high nickel content NCF440 (70Ni-19Cr) (with its outstanding wear resistance and corrosion resistance), have been used as engine exhaust valve materials. In recent years, automobile exhaust gases have become hotter because of exhaust gas regulations and enhanced fuel consumption efficiency. Resource conservation and cost reductions also factor into global environmental challenges. To meet these requirements, NCF5015 (50Ni-15Cr), a new resource-conserving, low-cost Ni-based heat-resistant alloy with similar high-temperature strength and wear resistance as NCF440, has been developed. NCF5015's ability to simultaneously provide wear resistance, corrosion resistance and strength when NCF5015 is used with diesel engines was verified and the material was then used in exhaust valves.