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In recent years, improvements in the fuel economy and exhaust emission performance of internal combustion engines have been increasingly required by regulatory agencies. One of the salient concerns regarding general purpose engines is the larger amount of CO emissions with which they are associated, compared with CO emissions from automobile engines. To reduce CO and other exhaust emissions while maintaining high fuel efficiency, the optimization of total engine system, including various design parameters, is essential. In the engine system optimization process, cycle simulation using 0-D and 1-D engine models are highly useful. To define an optimum design, the model used for the cycle simulation must be capable of predicting the effects of various parameters on the engine performance. In this study, a model for predicting the performance of a general purpose SI (Spark Ignited) engine is developed based on the commercially available engine simulation software, GT-POWER.

Titanium alloy for forging and pure titanium material for exhaust systems have been developed. The forging alloy will be applied to production of lightweight motorcycle frames and the pure titanium will be applied to improve engine performance. The materials have been made inexpensive by the use of off-grade sponge that includes many impurities for production of titanium ingot. Stable characteristics have been obtained by controlling oxygen equivalent after setting the volume of tolerable impurities by considering mechanical properties and production engineering. In spite of low-cost, the material provides the same design strength compared to conventional material, and enables parts production with existing equipment. A review of manufacturing and surface treatment processes indicated a reduction in the price of titanium parts produced with this new material.

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.

Manganese oxides show high catalytic activity for CO and HC oxidation without including platinum group metals (PGM). However, there are issues with both thermal stability and resistance to sulfur poisoning. We have studied perovskite-type YMnO₃ (YMO) with the aim of simultaneously achieving both activity and durability. This paper describes the oxidation activity of PGM-free Ag/i-YMO, which is silver supported on improved-YMO (i-YMO). The Ag/i-YMO was obtained by the following two methods. First, Mn⁴+ ratio and specific surface area of YMO were increased by optimizing composition and preparation method. Second, the optimum amount of silver was supported on i-YMO. In model gas tests and engine bench tests, the Ag/i-YMO catalyst showed the same level of activity as that of the conventional Pt/γ-Al₂O₃ (Pt = 3.0 g/L). In addition, there was no degradation with respect to either heat treatment (700°C, 90 h, air) or sulfur treatment (600°C to 200°C, total 60 h, 30 ppm SO₂).

Currently, two consolidated aftertreatment technologies are available for the reduction of NOx emissions from diesel engines: Urea SCR (Selective Catalytic Reduction) systems and LNT (Lean NOx Trap) systems. Urea SCR technology, which has been widely used for many years at stationary sources, is becoming nowadays an attractive alternative also for light-duty diesel applications. However, SCR systems are much more effective in NOx reduction efficiency at high load operating conditions than light load condition, characterized by lower exhaust gas temperatures.

Devices for use in control of exhaust emissions have become indispensable to motorcycles. In order to evaluate quantitatively the effect of each device, the modal analysis system has to be required. The Modal Analysis System is one that classifies any driving schedule which is used for emissions measurement into four modes: idle, acceleration, cruise, and deceleration; then measures the emissions continuously using a mini-computer which accumulates the results of the analysis by mode. Instead of CO2 tracer method, we introduced the method of diluted exhaust gas measurement. In order for the system to produce reliable measurements, the accuracy of the total installation must be ensured. This paper describes the improvements of accuracy of analysers, technique on handling delay time and the verifications on the modal analysis system.

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.

When the belt contacts a pulley in a pushing belt-type CVT, vibration is generated by frictional force due to rubbing between the individual elements that are components of the belt, which is said to increase wear and noise. The authors speculated that the source of that vibration is misalignment of the secondary pulley and primary pulley V-surfaces. To verify that phenomenon, a newly developed micro data logger was attached to an element of a mass-produced metal pushing V-belt CVT and the acceleration was measured at rotations equal to those at drive (1000 to 2500 r/m). In addition, the results of calculations using a behavior analysis model showed that changes in pulley misalignment influence element vibration, and that the magnitude of the vibration is correlated to the change in the metal pushing V-belt alignment immediately before the element contacts the pulley.

With accelerating exhaust gas regulations in recent years, not only CO / HC / NOx but also PN regulation represented by Euro 6 d, China 6 are getting stricter. PN reduction by engine combustion technology development also progresses, but considering RDE, PN reduction by after treatment technology is also indispensable. To reduce PN exhausted from the gasoline engine, it is effective to equip GPF with a filter structure. Considering the installation of GPF in limited space, we developed a system that so far replaces the second TWC with GPF for the TWC 2 bed system. In order to replace the second TWC with GPF, we chose the coated GPF with filtering and TWC functions. Since the initial pressure drop and the catalyst amount (purification performance) of coated GPF have a conflicting relationship, we developed the coated GPF that can achieve both the low initial pressure drop and high purification performance.

In this research, a material model was developed that has orthotropic properties with respect to in-plane damage to support finite element strength analysis of components manufactured from a randomly oriented long-fiber thermoplastic composite. This is a composite material with randomly oriented bundles of carbon fibers that are approximately one inch in length. A macroscopic characteristic of the material is isotropic in in-plane terms, but there are differences in the tension and compression damage properties. In consideration of these characteristics, a material model was developed in which the damage evolution rate is correlated with thermodynamic force and stress triaxiality. In-plane damage was assumed to be isotropic with respect to the elements. In order to validate this material model, the results from simulation and three-point bending tests of closed-hat-section beams were compared and found to present a close correlation.

In recent years along with stringent the regulations, vehicles equipped with gasoline particulate filter (GPF) have started to launch. Compared to bare GPF, coated GPF (cGPF) requires not only PN filtration efficiency, low pressure drop, but also purification performance. In the wall flow type cGPF having a complicated the pore shape, the pore structure further irregularly changes depending on the coated state of the catalyst, so it is difficult to understand the matter of in-wall. In order to advance of cGPF function, it was researched that revealing the relevance between pore structure change in the wall and GPF function. Therefore, to understand the catalyst coated state difference, cGPF of several coating methods were prepared, and their properties were evaluated by various analyses, and performance was tested.

Turbine housings in car engine turbochargers, which use costly stainless steel castings, account for nearly 50% of the parts cost of a turbocharger. They are also the component which controls the competitiveness of the turbocharger, in terms of both function and cost. In this research, focusing on thermal fatigue resistance which is one of the main functions demanded of a turbine housing, achieving reduction in wall thickness while securing sufficient thermal fatigue resistance, it is possible to reduce the amount of material used in the turbine housing and aimed for cost reduction. Therefore, we built a method to quantitatively predict, using 3D FEM, the lifespan from the initiation of thermal fatigue cracking to the formation of a penetrating crack which leads to gas leakage.

The suitability of FM radio receivers for automobiles has conventionally been rated by evaluating reception characteristics for broadcast waves in repeated driving tests in specific test environments. The evaluation of sound quality has relied on the auditory judgment due to difficulties to conduct quantitative evaluations by experiments. Thus the method had issues in terms of the reproducibility and objectivity of the evaluations. To address these issues, a two-stage method generating a virtual radio wave environment on a PC was developed. The research further defined the multipath distortion rate, MDr, as an index for the sound quality evaluation of FM receivers, and the findings concerning the suitability of the evaluation of FM terminals for automobiles were reported at the 2015 SAE World Congress.

There are a couple of ways to manufacture aluminum cylinder blocks that have a good balance between productivity and abrasion resistance. One of them is the insert-molding of a sleeve made of PMC (Powder Metal Composite) by the HPDC (High Pressure Die Casting) method. However, in this method, cracks are apt to occur on the surface when the PMC sleeve is extruded and that has been a restriction factor against higher extrusion speed. The authors attempted to raise this extrusion temperature by eliminating the Cu additive process from the aluminum alloy powder in order to raise its melting point by approximately 50 °C. This enabled the wall of the extruded sleeve to be thinner and the extrusion speed to be higher compared to those of a conventional production method while avoiding the occurrence of surface cracks.

There are several all-aluminum cylinder blocks. A typical example is a mono-block cylinder of alusil alloy produced by low pressure die casting. This material's resistance to abrasion and seizure, however, is not satisfactory for motorcycle; in addition, long processing time is another disadvantage. To cope with these problems, the authors developed a light and highly productive all-aluminum cylinder block with a cast-in liner through die casting. The liner is made from powder metallurgy composite (PMC) with 3 to 5 % alumina and 0.5 to 3 % of graphite additives. The PMC reconciles abrasion resistance and machinability. The hardness deterioration of the composite due to the heat at die casting is avoided by using heat-resistant rapidly-solidified powders, made from an aluminum-silecon-iron alloy, for the matrix.

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.

The cooling performance and the heat resistance performance of commercial vehicle are balanced with aerodynamic performance, output power of powertrain, styling, cost and many other parameters. Therefore, it is desired to predict the cooling performance and the heat resistance performance with high accuracy at the early stage of development. Among the three basic forms of heat transfer (conduction, convection and radiation), solving thermal conduction accurately is difficult, because modeling of “correct shape” and setting of coefficient of thermal conductivity for each material need many of time and efforts at the early stage of development. Correct shape means that each part should be attached correctly to generate the solid mesh with high quality. Therefore, it is more efficient and realistic method to predict the air temperature distribution around the rubber/resin part instead of using the surface temperature at the preliminary design stage.

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.

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.

Into the early-part of the next century, automotive emission standards are becoming stricter around the world. The electrically-heated catalyst (EHC) is well known as an effective technology for the reduction of cold-start hydrocarbon emissions without a significant increase in back pressure. Our extruded, alternator powered EHC (APEHC) manufactured with a unique canning method and equipped with a reliable, water proof electrode has demonstrated excellent durability and reliability, as stated in our previous SAE paper (#960340). The APEHC system discussed in this paper has achieved the Ultra-Low-Emission Vehicle (ULEV) standards, after 100,000 miles of fleet testing, without any failure. This is the final milestone in addressing the EHC as a realistic-production technology for ULEV. With the ability to meet ULEV/Stage III emission targets without a significant increase in back pressure, the EHC will be applied to an especially high performance vehicle with a large displacement engine.