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In order to correspond to the exhaust emissions regulations that become severe every year, more advanced engine control becomes necessary. Engine engineers are concerned about the Hydrocarbons (HCs) that flow through the air-intake ports and that are difficult to precisely control. The main sources of the HCs are, the canister purge, PCV, back-flow gas through the intake valves, and Air / Fuel ratio (A/F) may be aggravated when they flow into the combustion chambers. The influences HCs give on the A/F may also grow even greater, which is due to the increasingly stringent EVAP emission regulations, by more effective ventilation in the crankcase, and also by the growth of the VVT-operated angle and timing, respectively. In order to control the A/F more correctly, it is important to estimate the amount of HCs that are difficult to manage, and seek for suitable controls over fuel injection and so on.

A multi-dimensional numerical method for predicting the warm-up characteristic of automobile catalytic converter systems was developed to effectively design catalytic converter systems which achieve low tail pipe emissions with satisfactory packagebility. The features of the method are; (1) consideration of the governing phenomena such as gas flow, heat transfer, and chemical reactions (2) capability of predicting warm-up characteristic for not only the catalytic converters but also the system as a whole during emission test modes such as the USA LA-4 mode. The description of the method is presented. The experimental verifications of the method were conducted to assure the accuracy of it. The effect of design parameters such as electrically heated catalyst (EHC), high loading of noble metal and thin honeycomb wall on warm-up characteristic of the catalyst are analyzed in the paper.

Over the last few decades, in-cylinder visualization using optically accessible engines has been an important tool in the detailed analysis of the in-cylinder phenomena of internal combustion engines. However, most current optically accessible engines are recognized as being limited in terms of their speed and load, because of the fragility of certain components such as the elongated pistons and transparent windows. To overcome these speed and load limits, we developed a new generation of optically accessible engines which extends the operating range up to speeds of 6000 rpm for the SI engine version, and up to in-cylinder pressures of 20 MPa for the CI engine version. The main reason for the speed limitation is the vibration caused by the inertia force arising from the heavy elongated piston, which increases with the square of the engine speed.

In SI engines with port injection system, fuel behavior both in the intake port and in the cylinder has significant influence on the transient A/F characteristics and HC emissions [1]. Therefore, to improve the engine performance, it is very important to understand fuel behavior in the intake port and in the cylinder [2, 3]. This paper describes the following three unique methods to analyze fuel behavior in port injected SI engines and some test results. (1) Observation of fuel behavior in the intake port, using a transparent intake air tube and a strobe synchronized TV-photographic system. (2) Observation of fuel behavior in the cylinder, using a glass cylinder and fluorescent fuel. (3) Measurement of fuel wall wetting in the intake port and in the cylinder, using the engine with electronically controlled hydraulically driven in-take/exhaust valves.

To meet the requirements for higher horsepower and torque as well as lower fuel consumption and emissions, we have developed a new “Intelligent Variable Valve Timing (VV-i)” system. It gives continuously variable intake cam phasing by up to 60 degrees crank angle (CA) . This system not only increases WOT output by optimizing intake valve closing timing but also reduces fuel consumption and NOx/ HC emissions under part load by increasing intake and exhaust valve overlap on 4 stroke Spark Ignited engines. VVT-i has been applied to optimize a new 3-liter inline 6 engine for higher torque and at the same time better fuel economy with continuous and wide-range cam phasing.

A laboratory scale simulation test method was developed to evaluate deterioration of radial lip seals of fluoroelastomer (FKM) compounds for engine crankshafts. The investigation of the collected radial lip seals of FKM compounds from the field with service up to 450,000km indicated that the only symptom of deterioration is a decrease of lip interference. This deterioration was not duplicated under conventional test conditions using an oil seal test machine because sludge build up at the seal lip caused oil leakage. However, revised test conditions make it possible to duplicate the deterioration experienced in the field. An immersion test using a radial lip seal assembled with the mating shaft was newly developed. This test method was found to be useful to evaluate deterioration of radial lip seals using FKM compounds. Oil additives affect the deterioration of lip seal materials significantly. Therefore, immersion tests of four different oils were conducted to evaluate this effect.

A new test machine has been developed which can evaluate vibration due to stick-slip using an actual full-scale clutch pack. Using this machine, a static breakaway friction coefficient measurement test method and a stick-slip test method have been established. Both methods have been shown to provide results which correlate with the results from both a full-scale assembly test and a vehicle shudder evaluation test. The evaluation of the frictional properties of commercial oils using these test methods showed that the static breakaway friction coefficient and the stick-slip properties have generally contradictory performance to each other for automatic transmission. The study of the frictional properties for typical additives and an analysis of the surface of the steel plates with ESCA (Electron Spectroscopy for Chemical Analysis) showed that the frictional properties are significantly affected by the additives adsorbed on the clutch plate sliding surface.

Recently,four-wheel drive vehicle (hereinafter abbreviated as 4WD vehicle) chassis dynamometer has been developed and in the course of practical use for many kinds of test. The 4WD chassis dynamometer technology, however, involves many new requirements and advanced techniques which were not required for conventional chassis dynamometers. This study has described a generation mechanism for driving force distribution through construction of a dynamic model for the resolution of unsolved issues in composite dynamic systems of 4WD vehicle and 4WD chassis dynamometer. Additionally, we have clarified the reasons why driving force distribution on-the-road is different from that on the chassis dynamometer, and clarified that the work value of driving shaft depends upon the combination of chassis dynamometer types and 4WD vehicles types. The micro-slip theory (hereinafter abbreviated as MS theory) utilized for the analysis is the basic theory that can explain that inclinations.

To avoid knocking phenomena, a special crank mechanism for gasoline engine that allowed the piston to move rapidly near TDC (Top Dead Center) was developed and experimentally demonstrated in the previous study. As a result, knocking was successfully mitigated and indicated thermal efficiency was improved [1],[2],[3],[4]. However, performance of the proposed system was evaluated at only limited operating conditions. In the present study, to investigate the effect of piston movement near TDC on combustion characteristics and indicated thermal efficiency and to clarify the knock mitigation mechanism of the proposed method, experimental studies were carried out using a single cylinder engine with a compression ratio of 13.7 at various engine speeds and loads. The special crank mechanism, which allows piston to move rapidly near TDC developed in the previous study, was applied to the test engine with some modification of tooling accuracy.

It is well known and a common experience among drivers that controllability and stability of a car-trailer combination is affected when an articulated Heavy Goods Vehicle overtakes. In this paper, aerodynamic effects to a car-trailer combination when it is overtaken by an articulated HGV, have been analyzed experimentally using 1/20 scale models in wind tunnel, and a method to suppress this phenomenon has been investigated. The dynamic behaivor of a car-trailer combination is simulated by a simple mathematical model. The result shows that a car-trailer combination can be stable following the addittion of aerodynamic devices to each side of the vehicle. This simulated result is verified by the on-read test.

Technologies of 4WD chassis dynamometers (CHDY hereinafter) have advanced dramatically over the past several years, enabling 4WD vehicles to be tested without modifying their drive-train into 2WD. These advances have opened the use of 4WD-CHDY in all fuel economy and emission evaluation tests. In this paper, factors that influence the accuracy of fuel economy tests on 4WD CHDY are discussed. Fuel economy tests were conducted on 4WD CHDY and we found that most of the vehicle mechanical loss is the tire loss and that stabilizing the tire loss of the test vehicle is essential for the test reproducibility.

A newly-developed time resolved exhaust gas analysis system was utilized in this study. The hydrocarbon compositions upstream and downstream of the catalytic converter were investigated during cold start and warm up of the Federal Test Procedure(FTP), with three fuels of different aromatic contents. Although engine-out hydrocarbon emissions had high concentrations right after cold start, the specific reactivity was low. This can be explained by the selective adsorption of the high boiling point components which had a high Maximum Incremental Reactivity (MIR) in the intake manifold and engine-oil films. Thereafter, the high boiling point components were desorbed rapidly and consequently specific reactivity increased. Hydrocarbon adsorption of high boiling point components and hydrocarbon conversion of low boiling point components occurred simultaneously on the catalyst during warm up.

A communication system that uses roadside beacons to broadcast road and traffic information and private messages to vehicles has been developed. The system, called Road/Automobile Communication System (RACS), was the result of a joint research project involving the Public Works Research Institute and 25 private-sector corporations. This paper contains an outline of RACS and of an onboard system developed by TOYOTA and presents the results of field tests conducted in the Tokyo area. The results not only verify the capability of the RACS system and the effectiveness of the in-vehicle equipment but also indicate the potential of such a beacon based network to improve traffic jam and driving safety whilst providing enhanced communication facilities without increasing radio-wave congestion.

The authors have developed an instrument that measures the CO2 concentration in engine combustion chambers using the infrared absorption method. The characteristics of this technology are as follows: 1 Measuring can be carried out while the engine is running at 600r/min to more than 3000r/min, full load operation. (Applicable to all EGR conditions) 2 Quick response; 2ms 3 High linearity; ±1% Full Scale and under (FS: 10%) 4 No aggravation is caused to the intake/exhaust performance of engines This technology contributes to the improvement of the in-cylinder EGR system using, for instance, a variable valve-timing mechanism that is now expanding in number of applications, and also the conventional EGR system.

In recent years Road Departure Mitigation Systems (RDMS) is introduced to the market for avoiding roadway departure collisions. To support the performance testing of the RDMS, the most commonly seen road edge, grass, is studied in this paper for the development of standard surrogate grass. This paper proposes a method for defining the resembling grass color and height features due to significant variations of grass appearances in different seasons, temperatures and environments. Randomly selected Google Street View images with grass road edges are gathered and analyzed. Image processing techniques are deployed to obtain the grass color distributions. The height of the grass is determined by referencing the gathered images with measured grass heights. The representative colors and heights of grass are derived as the specifications of surrogate grass for the standard evaluation of RDMS.

In recent years, enhancing engine thermal efficiency is strongly required. Since the maximum engine thermal efficiency is especially important for HVs, the technologies for improving engine thermal efficiency have been developed. The current gasoline engines for hybrid vehicles have Atkinson cycle with high expansion ratio and cooled exhaust gas recirculation (EGR) system. These technologies contribute to raise the brake engine thermal efficiency to more than 38%.In the near future the consumers demand will push the limit to 40% thermal efficiency. To enhance engine thermal efficiency, it is essential to improve the engine anti-knock quality and to decrease the engine cooling heat loss. To comply with improving the anti-knock quality and decreasing the cooling heat loss, it is known that the cooled EGR is an effective way.

The flow around a simplified vehicle-like body was computed. The aerodynamic characteristics of this body depended on the afterbody geometry, especially the rear slant angle. In order to examine reliability of computation, the computations were performed for various rear slant angles. Regarding the computational method, two kinds of methods were applied: a Navier-Stokes solver that employs a k- ε turbulence model and a quasi-direct simulation with a third-order upwind difference scheme. Comparing the results with a wind tunnel test data of the flow fields and aerodynamic forces, it was found that, the k- ε model had potential for prediction of flow field and the quasi-direct simulation for prediction of aerodynamic forces.

Wind noise is becoming a higher priority in the automotive industry. Several past studies investigated whether Statistical Energy Analysis (SEA) can be utilized to predict wind noise. Because wind noise analysis requires both radiation and transmission modeling in a wide frequency band, turbulent-structure-acoustic-coupled-SEA is being used. Past research investigated coupled-SEA’s benefit, but the model is usually simplified to enable easier consideration on the input side. However, the vehicle is composed of multiple interior parts and possible interior countermeasure consideration is needed. To enable this, at first, a more detailed coupled-SEA model is built from the acoustic-SEA model which has a larger number of degrees of freedom for the interior side. Then, the model is modified to account for sound radiation effects induced by turbulent and acoustic pressure.

Piston ring moving zone in the cylinder is one of the most critical lubrication regimes in diesel engines. This area is susceptible to combustion substances. In particular, abnormal wear is occasionally detected due to Exhaust Gas Recirculation (EGR) system equipment. In Japan, NOx emission requirements for passenger car diesels have become more stringent effective October 1, 1986. OEMs tend to apply EGR systems to reduce NOx in exhaust gas. In order to identify the phenomenon of abnormal cylinder wear of EGR equipped engine, engine bench tests were conducted under varied conditions in EGR equipment, cooling water temperature and fuel sulfur content. The test results suggest that wear caused at low temperature is mainly corrosive wear attributable to sulfuric acid formed by reaction with fuel sulfur and condensed water.

A lean burn engine is effective in reducing fuel consumption. NOX storage-reduction catalysts (NSR catalyst) have been developed for these engines. In order to improve the performance of NSR catalysts, suppression of sulfur poisoning, which is one of the main causes of NSR catalyst deactivation, must be improved. In this paper, the sulfur desorption phenomenon has been analyzed from a novel point of view. Based on these results, an NSR catalyst with improved sulfur resistance has been developed by incorporation of highly dispersed titania, and use of a heat resistant zirconia with enhanced basicity.