Search Results

A dual piston Variable Compression Ratio (VCR) engine has been newly developed. This compact VCR system uses the inertia force and hydraulic pressure accompanying the reciprocating motion of the piston to raise and lower the outer piston and switches the compression ratio in two stages. For the torque characteristic enhancement and the knocking prevention when the compression ratio is being switched, it is necessary to carry out engine controls based on accurate compression ratio judgment. In order to accurately judge compression ratio switching timing, a control system employing the Hidden Markov Model (HMM) was used to analyze vibration generated during the compression ratio switching. Also, in order to realize smooth torque characteristics, an ignition timing control system that separately controls each cylinder and simultaneously performs knocking control was constructed.

Bio-ethanol is used in many areas of the world as ethanol blended gasoline at low concentrations such as “E10 gasoline”. In this study, a method was examined to effectively use this small amount of ethanol within ethanol blended gasoline to improve thermal efficiency and high-load performance in a high-compression-ratio engine. Ethanol blended gasoline was separated into high-concentration ethanol fuel and gasoline using a fuel separation system employing a membrane. High-ethanol-concentration fuel was selectively used at high-load conditions to suppress knocking. In this system, a method to decrease ethanol consumption is necessary to cover the wide range of engine operation. Lower ethanol consumption could be achieved by Miller-cycle operation because decrease of the effective compression ratio suppresses knocking. However, high-load operation was limited due to the decrease in intake air volume with Miller-cycle operation.

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.

The practical application of heat recovery using thermoelectrics requires the realization of reasonable cost effectiveness. Therefore, a thermoelectric generator (TEG) structure that can compatibly increase efficiency and reduce cost was investigated with the aim of enhancing cost effectiveness. To increase efficiency, a method of using a vacuum space structure to reduce the TEG size was investigated to enable installation just after the close-coupled catalyzer, which is subject to many space restrictions. It was found that by making it possible to use high temperature exhaust heat, power generation efficiency can be increased to approximately twice that of the typical under floor installation. In addition, coupled simulation of heat transfer and power generation using FEM, 1D cost effectiveness simulations, and bench tests were performed with the aim of reducing cost.

Bioethanol is being used as an alternative fuel throughout the world based on considerations of reduction of CO2 emissions and sustainability. It is widely known that ethanol has an advantage of high anti-knock quality. In order to use the ethanol in ethanol-blended gasoline to control knocking, the research discussed in this paper sought to develop a fuel separation system that would separate ethanol-blended gasoline into a high-octane-number fuel (high-ethanol-concentration fuel) and a low-octane-number fuel (low-ethanol-concentration fuel) in the vehicle. The research developed a small fuel separation system, and employed a layout in which the system was fitted in the fuel tank based on considerations of reducing the effect on cabin space and maintaining safety in the event of a collision. The total volume of the components fitted in the fuel tank is 6.6 liters.

A highly efficient two-motor plug-in hybrid system is developed to satisfy the global demands of CO2 reduction. This system switches three operation modes, what is called “EV Drive”, “Hybrid Drive” and “Engine Drive”, to maximize fuel efficiency according to the driving condition of the vehicle. Practical plug-in EV (Electric Vehicle) capability is also realized by adding a high-power on-board charger and a high capacity Li-ion battery to the original system. The outlines of the system components including a newly developed Atkinson cycle engine, a highly efficient electric coupled CVT (Continuously Variable Transmission) with built-in motor and generator, an integrated PCU (Power Control Unit) and an exclusive battery for plug-in HEV (Hybrid Electric Vehicle) are described in this paper. In addition to the switching of three driving modes and the efficiency improvement of each device, cooperative control of the hybrid system is introduced.

The purpose of this research was to predict the amount of wear on exhaust valve seats in durability testing of gasoline engines. Through the rig wear test, a prediction formula was constructed with multiple factors as variables. In the rig test, the wear rate was measured in some cases where a number of factors of valve seat wear were within a certain range. Through these tests, sensitivity for each factor was determined from the measured wear data, and then a prediction formula for calculating the amount of wear was constructed with high sensitivity factors. Combining the wear amount calculation formula with the operation mode of the actual engine, the wear amount in that mode can be calculated. The calculated wear amount showed a high correlation with the wear amount measured in bench tests and the wear amount measured in vehicle tests.

Recently, the use of ethanol blended fuel is growing worldwide. Therefore, there is increasing needs for addressing issues relating to ethanol blended fuel use in gasoline engine fuel supply systems. In this paper, we focused on one of such issues, which is the reduced life of a multi-layered fuel filter used at inlet side of a fuel pump when it is used with ethanol blended fuel. In this study, we clarified that ethanol blended fuel tends to disperse dust particles contained in fuel to a greater extent than gasoline, and that it has a mechanism to accelerate clogging by concentrating the clogging only on the finest layer of the multi-layered filter. Also, in the process of clarifying this principle, we confirmed that dust particles dispersed by ethanol are coagulated when passing through the filter layers.

Intake manifold is a part of an engine that supplies fuel/air mixture to the cylinder heads. Recently, silicone FIPG has been used for the two part design of the intake manifold. It is known that a small, but significant, amount of gasoline fuel can penetrate through silicone FIPG layer due to the flexible nature of the siloxane backbone. Since gasoline permeation is becoming more important because of more severe regulations, it is found that a new polyacrylate based FIPG dramatically reduces the gasoline fuel permeation. This study compares this new technology, polyacrylate FIPG sealant with silicone FIPG sealant used today for vehicle powertrain gasketing applications. Adhesion investigation on both aluminum and magnesium alloys, and oil resistance are also discussed in this study.

Various plant-derived alternative fuels have been proposed in recent years as ways to curb the global warming that occurs from the CO2 that is emitted by internal combustion engines. One such fuel is bioethanol. In Brazil, flexible fuel vehicles (FFV) are used that can run on blends from 100% hydrous ethanol (E100) to gasoline containing 22% ethanol (E22). This research addresses the optimal specifications of a FFV engine. FFV engines use E100 and E22 in any ratio. E100 has a very high RON of approximately 110, while that of E22 is low at approximately 95. The researchers considered these characteristics when selecting a compression ratio capable of providing good performance at any ethanol blend ratio. Additionally, ethanol is a single-component fuel without low-boiling-point components, so it has poor combustion at low temperatures. In general, FFV engines are often built with one intake valve to enhance product usability at low temperatures.

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.

Formula One engines, which are the pursuit of the ultimate in performance, tend to be comparatively vulnerable to durability issues. These engines sometimes run under a state of unstable combustion as compensation for improved fuel economy. To cope with these issues, there have been strong demands in the racing field for a technology that will allow constant monitoring and prompt action to be carried out on system malfunctions and failures, as well as unstable combustion. The research program described in this paper deals with an onboard technology for monitoring combustion under all the operational conditions using ionic current measurement. The technology will possibly be applied to engine management and car-to-pit communications via telemetering. The scope of the control it offers includes; detection of misfire and hesitation, detection and management of detonation, and management of lean-burn combustion.

In order to reduce CO2 emissions from automobiles, a highly fuel-efficient hybrid vehicle, the “Insight”, has been developed at Honda. Life cycle CO2 emissions are compared for the aluminum-bodied Insight, a simulated steel-bodied Insight, and a conventional gasoline vehicle. Life cycle CO2 emission is still dominated by the in-use fuel consumption. However, the contribution of CO2 emission from material use and processing could increase when the vehicle fuel consumption is greatly reduced. The use of recycled aluminum reduces CO2 emission from the aluminum-bodied Insight.

For the purpose of developing onboard gasoline reforming technology for higher octane number fuel on demand, octane number enhancement of gasoline surrogate by aerobic oxidation using N-hydroxyphthalimide catalyst was investigated. At first, octane numbers of the oxygen-containing products from alkane and aromatic compound were estimated using a fuel ignition analyzer. As a result, not only alcohol but also ketones and aldehydes have higher octane numbers than the original alkanes and aromatic compound. Next, gasoline surrogate was oxidized aerobically with N-hydroxyphthalimide derivative catalyst and cobalt catalyst at conditions below 100 °C. As a result, fuel molecules were oxidized to produce alcohols, ketones, aldehydes, and carboxylic acids. N-hydroxyphthalimide derivative catalyst with higher solubility in gasoline surrogate has higher oxidation ability. Furthermore, the estimated octane number of the oxidized gasoline surrogate improves 17 RON.

A 1.5 L downsizing turbocharged engine was developed to achieve both driving and environmental performance. The engine is intended to replace 1.8 - 2.4 L class NA engines. In downsizing turbocharged engines, mixture homogeneity is important for suppressing knocking and emission reduction. Particularly under high load, creating rapid combustion and a homogeneous mixture are key technologies. The authors used a long-stroke direct injection engine, which has outstanding rapid combustion and thermal efficiency, as a base engine meeting these requirements. They combined this with a high-tumble port and shallow-dish piston intended to support tumble flow. The combination enhanced flow within the cylinder. The combustion system was built to include a sodium-filled exhaust valve to reduce knocking and a multi-hole injector (six holes) for mixture homogeneity and to reduce the fuel wall wetting.

The study of 10% ethanol blended gasoline (E10 gasoline) utilization has been conducted in the Japan Auto-Oil Program (JATOP). In order to clarify the impact of E10 gasoline on vehicle performances, exhaust emissions, evaporative emissions, driveability and material compatibility have been investigated by using domestic gasoline vehicles including mini motor vehicles which are particular to Japan. The test results reveal that E10 gasoline has no impact on exhaust emissions, engine startup time and acceleration period under the hot start condition, but a slight deterioration is observed in some test cases under the cold start condition using E10 gasolines with 50% distillation temperature (T50) level set to the upper limit of Japanese Industrial Standards (JIS) K 2202. Regarding evaporative emissions, the tested vehicles shows no remarkable increase in the hot soak loss (HSL), diurnal breathing loss (DBL) and running loss (RL) testing with E10 gasolines.

Gasoline includes various kinds of chemical species. Thus, the reaction model of gasoline components that includes the low-temperature oxidation and ignition reaction is necessary to investigate the method to control the combustion process of the gasoline engine. In this study, a gasoline combustion reaction model including n-paraffin, iso-paraffin, olefin, naphthene, alcohol, ether, and aromatic compound was developed. KUCRS (Knowledge-basing Utilities for Complex Reaction Systems) [1] was modified to produce paraffin, olefin, naphthene, alcohol automatically. Also, the toluene reactions of gasoline surrogate model developed by Sakai et al. [2] including toluene, PRF (Primary Reference Fuel), ethanol, and ETBE (Ethyl-tert-butyl-ether) were modified. The universal rule of the reaction mechanisms and rate constants were clarified by using quantum chemical calculation.

Clarifying the impact of ETBE 8% blended fuel on current Japanese gasoline vehicles, under the Japan Clean Air Program II (JCAPII) we conducted exhaust emission tests, evaporative emission tests, durability tests on the exhaust after-treatment system, cold starting tests, and material immersion tests. ETBE 17% blended fuel was also investigated as a reference. The regulated exhaust emissions (CO, HC, and NOx) didn't increase with any increase of ETBE content in the fuel. In durability tests, no noticeable increase of exhaust emission after 40,000km was observed. In evaporative emissions tests, HSL (Hot Soak Loss) and DBL (Diurnal Breathing Loss) didn't increase. In cold starting tests, duration of cranking using ETBE 8% fuel was similar to that of ETBE 0%. In the material immersion tests, no influence of ETBE on these material properties was observed.

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.

A method was designed to predict the gasket surface pressure in consideration of creep which occurs on the surface of the gasket side of the cylinder head in air-cooled engines. Creep caused by heat can cause major deformation on the gasket side of the cylinder head in air-cooled engines, which may result in combustion gas leaking from between the cylinder and cylinder head. Until now, there have been no reports of methods to accurately predict phenomena relating to this deformation in the initial stage of engine design. This study combined values of strain and temperature occurring on the gasket side of the cylinder head, obtained through FEM analysis of steady heat transfer and thermal stress, with unit test results showing the domains in which the influence of the creep is critical or not. This information was used to design a method to determine whether or not an engine's specifications fell into a domain in which creep would have an effect, and predict surface pressure.