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In the automobile industries, weight reduction has been investigated to improve fuel efficiency together with reduction of CO2 emission. In such circumstance, it becomes necessity to make an electric power steering (EPS) more compact and lightweight. In this study, we aimed to have a smaller and lighter EPS gear size by focusing on an impact load caused at steering end. In order to increase the shock absorption energy without increase of stopper bush size, we propose new theory of impact energy absorption by not only spring function but also friction, and a new stopper bush was designed on the basis of the theory. The profile of the new stopper bush is cylinder form with wedge-shaped grooves, and when the new stopper bush is compressed by the end of rack and the gear housing at steering end, it enables to expand the external diameter and produce friction. In this study, we considered the durability in the proposed profile.

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.

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.

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.

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.

Bio-ethanol is one of the candidates for automotive alternative fuels. For reduction of carbon dioxide emissions, it is important to investigate its optimum combustion procedure. This study has explored effect of ethanol fuels on HCCI-SI hybrid combustion using dual fuel injection (DFI). Steady and transient characteristics of the HCCI-SI hybrid combustion were evaluated using a single cylinder engine and a four-cylinder engine equipped with two port injectors and a direct injector. The experimental results indicated that DFI has the potential for optimizing ignition timing of HCCI combustion and for suppressing knock in SI combustion under fixed compression ratio. The HCCI-SI hybrid combustion using DFI achieved increasing efficiency compared to conventional SI combustion.

In PCCI diesel engine, the fuel is injected much earlier than the injection timing of conventional diesel engines. Exhaust-emission improvements are attained by the lean-premixed combustion. It is expected that fuel properties influence mixture formation and combustion characteristics. In this research, experiments were carried out using a single-cylinder PCCI diesel engine operating on pure fuels with different volatilities. The injection timing and overall equivalence ratio of the premixed spray were varied. The results showed that the maximum heat release rate was smaller for lower-volatility fuel while ISFC was maintained smaller. So the combustion of a lower-volatility fuel would moderately make progress.

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.

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.

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.

Just as CO2 reduction is required of four wheeled vehicles for environmental protection, similar environmental concerns drive the development of motorcycle oil technology. Zinc dialkyldithiophosphate (Zn-DTP) type additives are widely used for engine oil formulations. However, phosphorus compounds are environmental load materials. The reduction of the quantity of phosphorus compounds in engine oils is required to reduce poisoning of three-way catalysts used to purify exhaust gases from internal combustion engines. Mr. Ito and his co-authors1) reported that they developed a sulfur-based additive as a substitute for Zn-DTP. Their non-phosphorus engine oil formulation for four-wheeled vehicles with a sulfur-based additive was examined to evaluate its anti-wear performance using the following test methods:JASO M328 for gasoline engines (KA24E) and JASO M354 for Diesel engine (4D34T4).

With a growing demand for high-power diesel engines, a key issue in engine development is to create efficient methods for developing highly durable cylinder heads, without having to repeat trial-and-error testing. Especially, it was difficult to accurately predict the occurrence and origin of cracks on the surfaces of cylinder heads in hot and cold cycle engine operation. This paper describes a thermal fatigue evaluation method developed by analyzing areas around the glow plug hole where cracks often occur during hot and cold cycle engine operation. To reveal the conditions of edges from which cracks were formed under engine durability tests, we used two procedures. One was estimating local temperature of edge areas based on material hardness determination, in order to compensate for the accuracy of the thermal analysis. The other was analyzing the strain amplitudes on the cylinder head surface using computer simulation.

Multiple injections that are necessary to reduce emissions, noise, and vibration of diesel engine have been accomplished by common-rail fuel injection system. Especially a fuel amount of each injection has to be tightly controlled, but actually there is a difference between an actual amount and a target one. Injection period will be determined according to a map in that the relation between injected amount and injection period is stated. But in the case of multiple injections, pressure wave caused by previous injections remain in a common-rail system at the time an injection second or later starts. Therefore, actual amounts injected will be different from target ones. In order to compensate the difference, the method that the influence of pressure wave on fuel amount injected is also investigated and injection period will be corrected is realized in an actual engine control system. Meanwhile, pressure wave propagation in common-rail has been studied.

In an attempt to decrease the amount of CO2 emitted by engines and yet improve engine output power, various approaches to the development of variable valve-lift mechanisms and the application of direct fuel injection and supercharger mechanisms are rapidly gaining popularity. In the case of the swing motion which takes place in variable valve-lift mechanisms, the relative speed between the two components reaches zero at the location where the load is high and the oil film tends to break, thereby leading to wear. Furthermore, the use of a supercharger and a direct injection device generates soot, which promotes further wear. Therefore establishing a reliable method for estimating wear has become a pressing issue. Wear problems caused by the swing motion occur during boundary lubrication, and we have devised a solution for them.

This study examined a high-speed, high-powered diesel engine featuring a pent-roof combustion chamber and straight ports, with the objective of improving the specific power of the engine while minimizing any increase in the maximum cylinder pressure (Pmax). The market and contemporary society expect improvements in the driving performance of diesel-powered automobiles, and increased specific power so that engine displacement can be reduced, which will lessen CO2 emissions. When specific power is increased through conventional methods accompanied with a considerable increase in Pmax, the engine weight is increased and friction worsens. Therefore, the authors examined new technologies that would allow to minimize any increase in Pmax by raising the rated speed from the 4000 rpm of the baseline engine to 5000 rpm, while maintaining the BMEP of the baseline engine.

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.

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 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 reduction of NOx and soot emission with conventional diesel diffusion combustion, the authors focused on enhancement of the rate of injection (hereafter referred to as RoI) to improve air availability, thus enhancing the fuel distribution and atomization. In order to increase opening ramp of the RoI (hereafter referred to as fast injection rate), a hydraulic circuit was improved and nozzle geometries were optimized to make the greatest use of the advantages of the hydraulic circuit. Two different common rail injectors were prepared for this research. One is a mass production-type injector with piezo actuator that achieved the EURO-V exhaust gas emission standards, and the other is a prototype injector equipped with the new hydraulic circuit. The nozzle needle of the prototype injector is directly actuated by high-pressure fuel from common rail to improve the RoI.

It is important to take action regarding environmental issues on a global scale, and automakers are adding downsized turbocharged engines to their line-ups as a means of reducing CO2 emissions, particularly in Europe. Honda has recently announced a next-generation powertrain series that realizes a good balance between environmental performance and driving pleasure. As part of this series, the company has developed a downsized and turbocharged 2.0L gasoline direct injection engine. This is a high-powered sports car engine positioned in the European “hot hatch” category. The development balanced engine power with good environmental performance.