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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.

There has been strong public demand for reduced hazardous exhaust gas emissions and improved fuel economy for automobile engines. In recent years, a number of innovative solutions that lead to a reduction in fuel consumption rate have been developed, including in-cylinder direct injection and lean burn combustion technologies, as well as an engine utilizing a large volume of exhaust gas recirculation (EGR). Furthermore, a homogeneous charge compression ignition (HCCI) engine is under development for actual application. However, one of the issues common to these technologies is less stable combustion, which causes difficulty in engine management. Additionally, it is now mandatory to provide an onboard diagnosis (OBD) system. This requires manufacturers to develop a technology that allows onboard monitoring and control of the combustion state. This paper reports on an innovative combustion diagnostic method using an in-cylinder pressure sensor.

The Honda Accord is the world's first automobile meeting the SULEV category criteria in the LEV-II exhaust emissions standards. An improved accuracy engine control system and catalyst account for the automobile's extremely low emissions. The accuracy engine control system includes double adaptive air-fuel ratio feedback loops composed of STR (Self-Tuning Regulator), for primary air-fuel ratio control, and PRISM (Prediction and Identification Sliding Mode Control), for secondary O2 feedback. The basic algorithm of the latter was presented at SAE 20001). However, two issues required further PRISM algorithm improvements in order to apply the double adaptive loops to an actual vehicle. One such achievement is both the compensation for engine dynamic characteristics by PRISM and the avoidance of the reciprocal interference with two adaptive loops.

In order to further reduce exhaust gas emissions, an investigation was carried out with premixed charge compression ignition (PCCI) combustion mode using conventional diesel fuel. Past research was carried out with early injection into shallow-dish piston bowl, combined with a narrow nozzle angle setting. Early injection significantly reduced NOX emissions, but some of the fuel spray adhered to the piston bowl surface creating a fuel wall-film which was a major cause in increasing soot, HC and CO emissions and fuel consumption [1]. As a possible solution to this issue, PCCI combustion mode operation on a direct injection diesel engine was investigated with fuel injection timing set close to top dead center (TDC). As a result, regardless of the fuel injection timing, increasing EGR reduced NOx emissions. In terms of fuel consumption, soot, HC and CO, however, fuel injection timing close to TDC was superior to earlier injection, due to the reduction in the fuel wall-film formation.

In order to further reduce exhaust gas emissions, an investigation was carried out concerning premixed charge compression ignition (PCCI) combustion, which is achieved by the early injection of conventional diesel fuel to the combustion chamber. The engine used for the experiments was a single cylinder version of a modern passenger car type common rail engine with a displacement of 550(cm3). An injector with a narrower corn angle was used to prevent interaction of the spray and the cylinder liner. Also, the compression ratio was decreased in order to avoid an excessively advanced ignition situation. Additionally, a large degree of cooled exhaust gas recirculation (EGR) was applied. These measures led to a significantly reduction in NOX emissions. However, a fuel wall-film, which was formed on the surface of the piston bowl wall, caused increases in soot, HC and CO emissions.

Recently, emission regulations have been strict in many countries, and it is very difficult technical issue to reduce emissions of diesel cars. In order to reduce the emissions, various combustion technologies such as Massive EGR, PCCI, Rich combustion, etc. have been researched. The combustion technologies require precise control of the states of in-cylinder gas (air mass flow, EGR rate etc.). However, a conventional controller such as PID controller could not provide sufficient control accuracy of the states of in-cylinder gas because the air-pass system controlled by an EGR valve, a throttle valve, a variable nozzle turbo, etc. is a multi-input, multi-output (MIMO) coupled system. Model predictive control (MPC) is well known as the advanced MIMO control method for industrial process. Generally, the sampling period of industrial process is rather long so there is enough time to carry out the optimization calculation for MPC.

A new Variable Valve Event and Lift (VVEL) system has been developed as an effective technology for reconciling environmental performance such as lowering the fuel consumption and exhaust emissions with driving performance. This system can continuously vary both the intake valve lift and event angle (valve opening duration) over a wide operating range to flexibly control the valve timing and lift for a substantial improvement in engine performance. In developing the variable valve lift control system, the essential merit is based on the fundmental configuration of multiple-link mechanism. However, it is required to resolve tribological issues for the specific mechnism. This paper describes the structure of the VVEL system and its operating and motion conversion principles. It also explains the mechanism analysis, dynamic stress analysis and lubrication simulation techniques used in developing the VVEL system, the materials adopted and the surface treatment techniques applied.

The new 2.0L gasoline engine for ACCORD Plug-in Hybrid was developed as a next-generation Honda engine series. This engine's features are low fuel consumption and good emission performance. Variable valve Timing and Electric Control (VTEC) system is applied to this engine, so we can have two characteristic cams, output cam and fuel economy (FE) cam. Output cam is narrow duration, used for power and engine starting. FE cam is wide duration, so it can get Atkinson cycle effect by late intake valve close timing (IVC). Cooled exhaust gas recirculation (Cooled-EGR) is applied to this engine. Low fuel consumption is achieved by combining VTEC and cooled EGR. We made the improvement of control systems. First is the new control which can secure the pressure difference before and behind the EGR valve. As a result, EGR flow control performance is improved. Second is improvement of torque control. It can predict an engine torque decrease when ignition retard is carried out.

A compact, low-cost fuel pump module has been developed for use in motorcycles with a small-displacement engine. Various considerations are given to make the module as compact as possible. The pump motor, which is one of the major component parts, is down-sized specifically for applications to small-displacement engines. The pressure regulator uses a simple construction consisting only of a ball and a spring without a diaphragm. Especially noteworthy is that with the volume reduced by approximately 40% from the conventional pressure regulator while using the construction that reduces self-excited vibrations caused by fuel pressure pulsations, the pressure regulator contributes significantly to the down-sizing and cost reduction of the module. Furthermore, the down-sized module remarkably reduces the size of fuel pump mount surface, allowing a modification from the flat-surface sealing to the radial sealing.

Reducing friction in the crankshaft main bearings is an effective means of improving the fuel efficiency of reciprocating internal combustion engines. To realize these improvements, it is necessary to understand the lubricating conditions, in particular the oil film pressure distributions between crankshaft and bearings. In this study, we developed a thin-film pressure sensor and applied it to the measurement of engine main bearing oil film pressure in a 4-cylinder, 2.5 L gasoline engine. This thin-film sensor is applied directly to the bearing surface by sputtering, allowing for measurement of oil film pressure without changing the shape and rigidity of the bearing. Moreover, the sensor material and shape were optimized to minimize influence from strain and temperature on the oil film pressure measurement. Measurements were performed at the No. 2 and 5 main bearings.

A continuously variable valve event and lift (VEL) system, actuated by oscillating cams, can provide optimum lift and event angles matching the engine operating conditions, thereby improving fuel economy, exhaust emission performance and power output. The VEL system allows small lift and event angles even in the engine operating region where the required intake air volume is small and the influence of valvetrain friction is substantial, such as during idling. Therefore, the system can reduce friction to lower levels than conventional valvetrains, which works to improve fuel economy. On the other hand, a distinct feature of oscillating cams is that their sliding velocity is zero at the time of peak lift, which differs from the behavior of conventional rotating cams. For that reason, it is assumed that the friction and lubrication characteristics of oscillating cams may differ from those of conventional cams.

Research is under way on an engine system [1] that achieves a variable compression ratio using a multiple-link mechanism between the crankshaft and pistons for the dual purpose of improving fuel economy and power output. At present, there is no database that allows direct judgment of the feasibility of the specific sliding parts in this mechanism. In this paper, the feasibility was examined by making a comparison with the sliding characteristics and material properties of conventional engine parts, for which databases exist, and using evaluation parameters based on mixed elasto-hydrodynamic (EHD) lubrication calculations. In addition, the innovations made to the mixed EHD calculation method used in this study to facilitate calculations under various lubrication conditions are also explained, including the treatment of surface roughness, wear progress and stiffness around the bearings.