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Using skirt-liner clearance and cylinder pressure measurements provided by Isuzu Motors, Ltd. of a production type gasoline automotive engine, a validation study was done of Ricardo's PISDYN code, which predicts the secondary motions and skirt liner elastohydrodynamic lubrication of pistons. Predictions using the computer code of the skirt liner clearance at two locations on the skirt were compared with measured results. Using the code, parametric studies were done. Very good qualitative and quantitative agreement was found for the baseline cases. In the parametric studies using the code only, the following were found: The predicted clearances were very sensitive to variation in cold minimum clearance. The effect of cylinder induced pressure deformation was significant, especially near the point of peak cylinder pressure. Increasing the cylinder pressure increased the peak clearances. Changing the asperity roughness height affected the clearances near a point of asperity contact only.

This paper offers a brief explanation of Isuzu Transport Auto Control (I-TAC), a system used to accurately collect and control information in-transit. I-TAC was developed as a means to meet needs for transportation by truck.

Supercharging system is obviously a necessary technology for heavy duty vehicular diesel to meet future stringent emission regulation as well as to improve fuel consumption characteristics. Although the conventional exhaust turbocharger system improves fuel consumption, there are some problems such as having a difficulty in improving starting acceleration and smoke emission characteristic because the response of an exhaust supercharger is not enough. On the other hand, the conventional mechanical supercharging system seems to be a quite effective aid for acceleration ability. However, it does not satisfy demand for low fuel consumption characteristic.

The growing need for improved fuel economy is a global challenge due to continuously tightening environmental regulations targeting lower CO2 emission levels via reduced fuel consumption in vehicles. In order to reach these fuel efficiency targets, it necessitates improvements in vehicle transmission hardware components by applying advanced technologies in design, materials and surface treatments etc., as well as matching lubricant formulations with appropriate additive chemistry. Axle lubricants have a considerable impact on fuel economy. More importantly, they can be tailored to deliver maximum operational efficiency over specific or wide ranges of operating conditions. The proper lubricant technology with well-balanced chemistries can simultaneously realize both fuel economy and hardware protection, which are perceived to have a trade-off relationship.

Every year the trucking industry demands lighter weight and lower cost truck components. But it is very difficult to achieve both these targets. This paper describes the example of a suspension system design which was conducted by computer simulation, so called CAE. The computer simulation by FEM was used completely to decide the detailed shape of each part. This paper also introduces a casting method to strengthen the aluminum alloy cast using high pressure during casting. By using this method, products have a precise metallographic structure. As a result, both the development cost and period were reduced by over the half the time required of the current system and lighter and strong parts were created.

When a heavy duty truck with 2 rear axles is turning a curve at slow speed, a large side bending force to the chassis frame occurres as vehicle turning radius becomes smaller. In the past, the stress produced by side bending forces was little analyzed. By our research work of FEM, side bending stress of heavy duty truck could be analyzed accurately.

To check sharply increasing traffic accident casualties, activities have been underway to analyze accidents and develop safety equipment Automobile makers have placed a great emphasis on improving safety in collision. In this situation, a new side impact standard was introduced in FMVSS 214 in October 1990 and will be applied to passenger cars in 1993 model year. The standard requires an additional full scale dynamic test in which an aluminum honeycomb moving deformable barrier (MDB) simulating the front end of a car is crashed at 33.5 mph into the side of a standstill car at an angle of 27 degrees. The Side impact Dummy's (SID) Thoracic Trauma index (TTI(d)), which is the average of the maximum rib acceleration and the maximum lower spine acceleration, is limited to 90 g's for a 2-door passenger car and 85 g's for a 4-door car. The dummy's pelvic maximum acceleration must remain no greater than 130 g's for both types of cars.

A numerical analysis method is developed for predicting the pressure fluctuations on the front side window surface, aiming at the elucidation of the external aerodynamic flow structure about the front pillar of a road vehicle. The simulated results are assessed by comparison with the acoustic theory and reveal fairly well the dependence of the predicted surface pressure fluctuations upon the vehicle cruising speed with the sixth power law. The features of three dimensional vortical flow are clarified from the analysis of the simulated results, indicating the strong relationship between the vortical formation and the external pressure fluctuations on the front side window surface. The external pressure fluctuations seem to be strongly related to the vortex breakdown during its interaction with the front side window and the roof-side window junction.

GVW 20 ton class cargo trucks were mainly powerd by L6 turbocharged engines ISUZU 6SD1TC and ISUZU 6RB1TC, and this time new 6WA1TC turbocharged engine with intercooler as a successor to 6RB1TC went into production in July 1992. In the recent cargo vehicle market in Japan, demand is increasing for higher out-put power, light weight, long service life, high reliability and low fuel consumption. Under such circumstances special engineering attention was paid to exhaust emissions and noise regulations which are expected to become even stricter in future. The basic engine structure consists of an OHC 4-valve type cylinder head and a ladder frame type cylinder block which satisfies the requirements for the high out-put power, low fuel consumption and light weight. Also, adopted are various variable structures such as a high pressure fuel injection pump with a variable injection timing and rate control device, variable swirl system and variable geometry turbocharger.

There is ever an increasing need for weight reduction and high performance of engine (clean smoke and improving fuel economy) To achieve this, recently aluminum castings are used for engine parts such as cylinder heads that construct combustion chamber and are required thermal resistance. This paper describes thermal fatigue tests of aluminum castings that are made under various conditions of cooling rate during solidification, heat treatment, and chemical compositions. It further investigates the influence of material (such as cooling rate, chemical conmposition and heat treatment) and mechanical properties (such as σB, δ, E ) on thermal fatigue life of aluminum castings.

Application of alternate fuels to diesel engine is much desired. A new and unique dual-fuel injection system has been developed for high speed automotive diesel engines. This system has two features. One is that alternate fuels such as methanol, ethanol and biomass, are directly inducted into the fuel injection pipe through one-way check valve under pressure, and blended fuels are simultaneously injected into the combustion chamber. The other is that various kinds of fuel can be easily adapted to this system not dependent upon the fuel properties such as viscosity. Using a single cylinder direct injection diesel engine and ethanol as an alternate fuel, injection characteristics and exhaust gas emissions were investigated. The results showed that ethanol could replace up to 50% of diesel fuel while keeping the normal engine operating stability. A better fuel economy was also obtained by applying both higher compression ratio and advanced injection timing.

The P’UP has been on the markets worldwide since 1972, both in Japan and overseas, including for the U.S., in which case, with model designation as the Chevrolet LUV. In 1980, for the first time since its market introduction, it was fully remodelled with detail improvements reflected thereon in every aspect. This new model continues to be on the U.S. market as the Chevrolet LUV as it has been, but, beginning from spring of 1981, the similar model has been introduced to the market by the American Isuzu Motors Inc. (AIM) as the Isuzu P’UP. Taking this opportunity, a diesel version has been added to its model lineup. The diesel engine mounted on this version features its 20 to 30% better fuel efficiency over its gasoline counterpart. In the first half of this paper, the engineering concepts of its full remodelling and their onvehicle reflection will be introduced.

In order to meet the demands for reduced emissions and improved fuel consumption, a subport-type variable swirl system (Isuzu Variable Electronic Economy Swirl, or IVES) was developed by Isuzu for medium- and heavy-duty direct-injection-type diesel engines. The main characteristics of IVES are: (1) It is simple in structure and only minor changes to the cylinder head are required. (2) Modular design is possible for three different swept volume engines due to the use of a common actuator and sensor. (3) The problem of air flow coefficient drop when swirl is varied has been successfully eliminated.

In fleet uses, heavy-duty trucks with turbo, inter-cooled engines are popular in Japan. These trucks usually experience congested traffic and/or frequent road grade change in expressways. As a result, frequent vehicle speed and engine load fluctuations are observed. This paper describes the typical, on road driving data from the field and presents one sample of engine control optimization for better fuel economy in actual road conditions.