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Variable-valve-actuation mechanism is considered to be one of the most suitable solutions to realize the compatibility between higher power output and performances in the practical speed range. A new variable-valve-actuation mechanism named “Shuttle Cam” was designed and studied. In this mechanism which was applied to a conventional motorcycle engine with rocker arms and gear-train-driven valve system, the cam gears move along the idler gear. And cam shafts simultaneously slide along the rocker-arm slipper surfaces which are concentric with the idler gear. Consequently valve lift varies continuously in accordance with the alteration in the rocker-arm lever ratio and the cam phasing changes simultaneously in accordance with the cam gear rotation. Result of the experiments has confirmed that the mechanism functions accurately even at high speeds up to 10,000 rpm and some improvements were achieved in power output, fuel consumption, idling quality, and exhaust-noise level.

The tires are one of the most important parts of the vehicle chassis, as they significantly influence aspects such as vehicle's directional stability, braking performance, ride comfort, NVH, and fuel consumption. The tires are also a part whose size affects the vehicle's essential specifications such as wheelbase and track width. The size of the tires should therefore be determined in the initial stage of vehicle development, taking into account whether the size allows the vehicle to achieve the targeted overall performance. In estimations of vehicle performance, computer simulation plays more of an important role, and simulated tire models are designed to reproduce the measured tire characteristics of existing tires. But to estimate the chassis performance with various tire sizes or with tires of uncommon sizes, the prevailing modeling approach, “individual models for individual tires,” would not function well because of limited ability to expand tire models to unfamiliar sizes.

To enable non-throttling operation of gasoline S.I. engine, we have manufactured engines equipped with a newly developed Hydraulic Variable-valve Train (HVT), which can vary its intake-valve closing-timing freely. The air-intake control ability of HVT engine is equivalent to conventional throttling engines. Combustion becomes unstable, however, under non-throttling operation at idling. For the countermeasure, newly designed combustion chamber has been developed. The reduction of pumping loss by the HVT depends on engine speed rather than load, and amounts to about 80 % maximum. A conventional engine-management system is not applicable for non-throttling operation. Therefore, new management system has been developed for load control.

Honda diesel engine vehicles that go on the market in 2018 will be equipped with a newly developed silver (Ag)-type catalyzed diesel particulate filter (cDPF). Ag has high particulate matter (PM) oxidation performance, but conventional catalyst-carrying methods cause weak contact property between PM and Ag; therefore, the newly Ag-type cDPF was developed on the concept of enhancing the property of contact between PM and the catalyst to realize contact property enhancement at the macro, meso, and nano scales. As a result, the newly developed catalyst showed an enhancement of T90 performance by a factor of approximately 2 relative to the conventional Ag-type catalyst in fresh condition. Durability in the environment of an automobile in use was examined through hydrothermal aging, lean-rich (L/R) aging, sulfur (S) poisoning, and ash deposition. The results have confirmed that hydrothermal aging is the greatest factor in deterioration.

This paper reports on DaimlerChrysler's participation in the Ad Hoc Diesel Fuels Test Program. This program was initiated by the U.S. Department of Energy and included major U.S. auto makers, major U.S. oil companies, and the Department of Energy. The purpose of this program was to identify diesel fuels and fuel properties that could facilitate the successful use of compression ignition engines in passenger cars and light-duty trucks in the United States at Tier 2 and LEV II tailpipe emissions standards. This portion of the program focused on minimizing engine-out particulates and NOx by using selected fuels, (not a matrix of fuel properties,) in steady state dynamometer tests on a modern, direct injection, common rail diesel engine.

An electric servo brake system applied for use on electric vehicles was applied for use on plug-in hybrid vehicles in order to achieve fuel-savings together with good brake feel and enhanced operability for plug-in hybrid vehicles. The electric servo brake system is made up of highly accurate braking pressure control that functions cooperatively with regenerative brakes together with a structure in which pedal force is not influenced by braking pressure control. The configuration of these components enabled good braking feel even when the power train was being switched from one drive mode to another. Automated pressurization functions that are intended for plug-in hybrid vehicles and that operate with electric servo brake systems were also developed. These developed functions include stall cooperative control that functions cooperatively with the power train, regenerative coordinate adaptive cruise control, and hill-start assist.

Variable Valve Actuation (VVA) technology provides high potential in achieving high performance, low fuel consumption and pollutant reduction. However, more degrees of freedom impose a big challenge for engine characterization and calibration. In this study, a simulation based approach and optimization framework is proposed to optimize the setpoints of multiple independent control variables. Since solving an optimization problem typically requires hundreds of function evaluations, a direct use of the high-fidelity simulation tool leads to the unbearably long computational time. Hence, the Artificial Neural Networks (ANN) are trained with high-fidelity simulation results and used as surrogate models, representing engine's response to different control variable combinations with greatly reduced computational time. To demonstrate the proposed methodology, the cam-phasing strategy at Wide Open Throttle (WOT) is optimized for a dual-independent Variable Valve Timing (VVT) engine.

Cam-phasing is increasingly considered as a feasible Variable Valve Timing (VVT) technology for production engines. Additional independent control variables in a dual-independent VVT engine increase the complexity of the system, and achieving its full benefit depends critically on devising an optimum control strategy. A traditional approach relying on hardware experiments to generate set-point maps for all independent control variables leads to an exponential increase in the number of required tests and prohibitive cost. Instead, this work formulates the task of defining actuator set-points as an optimization problem. In our previous study, an optimization framework was developed and demonstrated with the objective of maximizing torque at full load. This study extends the technique and uses the optimization framework to minimize fuel consumption of a VVT engine at part load.

An electronically controlled belt-type CVT (Continuously Variable Transmission) has been developed for scooter type two-wheeled vehicles. Related to two-wheeled vehicles, the electronically controlled belt-type CVT has advantages over the conventional belt-type CVT, such as more compact and lighter weight. This was achieved by developing a new rubber belt-type. The new rubber belt-type CVT uses a rubber belt with high friction coefficient and pulleys made of aluminum. To obtain good shifting characteristics, the desired speed ratio related to throttle opening and drive speed is calculated. When moving, the actual speed ratio automatically adjusts to the desired value. For the shift modes, three shift modes, two automatic modes and one manual mode with six-speeds were prepared. The electronically controlled CVT increased the range of usable engine speeds compared to the conventional belt-type CVT. Therefore good drivability is maintained.

One primary concern with applying an AWD system to a front wheel drive (FWD) vehicle architecture is the additional weight and drag associated with the AWD drivetrain components, resulting in an increase in fuel consumption compared to FWD-only models. Therefore, Honda recently developed a next-generation integrated AWD unit that reduces weight and drag loss, and increases the SH-AWD cornering performance while maintaining the performance requirements of the previous rear drive unit. These targets were achieved primarily through the application of hydraulically-actuated clutches and an increase in the “speed-increasing ratio”. This paper describes the development, system validation and future technology implications of this recent advancement.

An electronically controlled fuel injection system for controlling the air/fuel (A/F) ratio has been looked forward as a means for improving drivability, output characteristics, and fuel consumption of two-stroke cycle motorcycle racer engines. However, actual installation of such a system on a high output two-stroke cycle engine (which utilizes exhaust gas pressure pulsation effects) has been considered difficult for the following reasons. Fluctuation in the delivery ratio (L) during firing and misfiring becomes great due to effects from the exhaust pipe. Applying the control method used for conventional four-stroke cycle engines (by which the delivery ratio (L) is measured) would necessitate a large and heavy system. The authors have eliminated such problems by developing an electronically controlled fuel injection system, the PGM-FI (Programmed-Fuel Injection) system, which employs basic intake air flow data according to engine speed (NE) and throttle opening (θTH).

The development of the lightweight and compact EU1000i generator with a maximum output of 1kVA is presented. The technology applied to achieve the required levels of exhaust emission, fuel consumption and noise, and to provide a stable electrical power supply with low waveform distortion is described. The technology comprises of four elements: a high-speed, multi-pole, external rotor type alternator, a microcomputer-controlled sine wave inverter, a compact high-speed 4-stroke engine with electronic speed governing, and a lightweight frame with a two-level noise-damping system. Combination of these four elements of technology has achieved 50% less weight, 25-30% lower fuel consumption, and 7-9dB(A) less noise than the previous model. The emission levels of CO and of NOx + HC are also 30% and 65% lower than the 2000 CARB regulations.

In order to contribute to the resolution of global environmental problems and to respond to the issue of diminishing resources, the Civic Hybrid, a hybrid passenger automobile has been developed to achieve both low emissions and low fuel consumption. The hybrid system takes the conventional Honda IMA (Integrated Motor Assist) system as its foundation. 4-cylinder, 1.3L SOHC, 2-plug engine i-DSI (DSI: Dual and Sequential Ignition) has been selected and modified for lean burn combustion. In addition, a cylinder idling system to increase the amount of electrical energy regenerated during deceleration has been adopted, among other technology. The ultra-thin DC brushless motor has been modified with its magnetic circuit to improve maximum regenerative torque by approximately 30%. Thanks to a new power train that improves CVT transfer efficiency, low fuel consumption of 48mpg in the city and 47mpg on the highway (the 5MT vehicle is 46mpg in the city and 51mpg on the highway) is achieved.

Current engine development processes typically involve extensive steady-state and simple transient testing in order to characterize the engine's fuel consumption, emissions, and performance based on several controllable inputs such as throttle, spark advance, and EGR. Steady-state and simple transient testing using idealistic load conditions alone, however, is no longer sufficient to meet powertrain development schedule requirements. Mapping and calibration of an engine under transient operation has become critically important. And, independent engine development utilizing accelerated techniques is becoming more attractive. In order to thoroughly calibrate new engines in accelerated fashion and under realistic transient conditions, more advanced testing is necessary.

We studied a simple and cost effective controlled auto ignition (CAI) combustion engine in order to achieve simultaneous reduction of NOx and soot, which are issues in diffusion combustion. The engine type was a uniflow scavenging 2-stroke engine, and the fuel used was diesel, as is common in diesel engines. We examined the position of the injector that effectively forms the premixture and realized stable operation with diesel fuel by the low pressure fuel injection device for port fuel injection (PFI), and it was found that the CAI combustion ignition timing can be controlled through setting the air/fuel ratio that obtains the optimal ignition timing per operation conditions.

Improvement of engine cycle thermal efficiency is an effective way to increase engine torque and to reduce fuel consumption simultaneously. However, the extent of the improvement is limited by engine knock, which is more evident at low engine speeds when combustion flame propagation is relatively slow. To prevent engine damage due to knock, the spark ignition timing of a gasoline engine is usually controlled by a knock sensor. Therefore, an engine's ignition timing cannot be set freely to achieve best engine performance and fuel economy. Whether ignition timings for a multi-cylinder engine are the same or can be set differently for each cylinder, it is not desirable for each cylinder has big deviation from the median with respect to knock tendency. It is apparent that effective measures to improve engine knock toughness should address both uniformity of all cylinders of a multi-cylinder engine and improvement of median knock toughness.

A simulation tool has been developed that can be used to estimate a fuel economy while driving in a mode test of a motorcycle equipped with a continuously variable transmission (CVT) at an early stage of development. For a precise estimation of a mode fuel economy, it is necessary to accurately estimate the CVT ratio, the engine speed, and the crankshaft torque during driving in a mode. To achieve this, this study has generalized the transmission efficiency of a CVT system. This study has also derived developed balance equations that can take into account the transmission efficiency of CVT and the slippage that occurs when the centrifugal clutch is about to be engaged. In the proposed method, the pulley ratio of CVT, the engine speed, and the torque at the crankshaft were obtained first by solving the developed balance equations at discrete times during driving in a mode.

Predicting fuel consumption and performance of an outboard motor for a high speed small planing boat are numerically challenging. The propeller is one of the most popular propulsion systems used for outboard motors. We focused our attention on the fact that the thrust performance of a propeller has a major impact on cruising fuel consumption and performance. We believe that we can numerically predict cruising fuel consumption, which has conventionally been estimated through experiential means, using accurate thrust performance measurements via CFD simulation without cavitations model. This study aims to develop a simulator that could quantitatively predict cruising fuel consumption and performance of an outboard motor used for a high speed small planing boat. After comparing the CFD simulation of propellers against the results of model tests, the simulated results are in good agreement with the experimental results.

With the interest in global environmental issues growing in recent years, the demand for the reduction of exhaust gas emission and improvement in fuel consumption for small motorcycles has increased greatly. Recently, small motorcycles have been marketed equipped with an electronically controlled fuel injection system effective in reducing emissions and enhancing fuel consumption by accurately controlling the air-fuel ratio. The small motorcycles' market comprises mainly ASEAN countries, and the majority of the motorcycles consist of reasonably priced models with air-cooled engines. Fuel injection systems have already been adopted for motorcycles equipped with water-cooled engines in the markets of advanced countries, mostly in EU. Given the above situation, two issues must be addressed to adopt a successful fuel injection system for air-cooled, low-priced small motorcycles.

The “RA168E”, a turbo-charged V-6 1.5-liter engine, was developed by Honda Motor Co., Ltd. for the 1988 Formula One Championship Race events. Despite boost restrictions (2.5bar), the engine boasts a maximum power of 504 kw (685 ps), which is equivalent to 336 kw/ℓ (457 ps/ℓ). The development of improvements on the fuel consumption of this engine allowed the achievement of a minimum brake specific fuel consumption of 272 g/kwh (200 g/Psh). This paper Introduces major specifications, along with power output and fuel consumption characteristics of the RA168E racing engine. In addition, the effects of intake air temperature, boost, air-fuel ratio, fuel temperature and fuel ingredients on fuel efficiency and power output are presented.