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This paper shows one example of cooling system, optimized by utilizing computer simulation in the early development stage. First, a numerical simulation is conducted to obtain the air flow rate through engine compartment room by the software “STREAM”. Second, ΔTw are calculated by the software “KULI”, developed by Steyr-Daimler-Puch AG, to evaluate the original cooling system. Third, the optimization of this system is conducted by the design of experiment for cost saving and weight reduction. The test value was well matched with the calculated one and CAE was confirmed to be very helpful for saving the proto-build cost and time period.

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.

Two working groups in the JSAE Committee of Fatigue–Reliability Section1 are currently researching the issue of fatigue life by both experimental and the CAE approach. Information regarding frequent critical problems on arc–welded structures were sought from auto–manufacturers, vehicle component suppliers, and material suppliers. The method for anti–fatigue design on arc–welded structures was established not only by a database created by physical test results in accordance with the collected information but also with design procedure taking Fracture–Mechanics into consideration. This method will be applied to vehicle development as one of the virtual laboratories in the digital prototype phase. In this paper, both the database from bench–test results on arc welded structures and FEA algorithm unique to JSAE are proposed some of the analysis results associated with the latter proposal are also reported.

There are many methods for case hardening such as conventional induction hardening and newly developed electron beam hardening. Electron beam hardening has been adopted in Isuzu and the reliability of engines has been improved. The beam power of the electron beam hardening equipment used was 6 kW. Various conditions of electron beam were scanned across specimens (SCM435H) in order to investigate the influence on hardening properties. As a result, relation between case depth and beam current and relation between case depth and beam scanning time were confirmed. And when the depth exceeded 1 mm, there were cracks in surface melted area. Electron beam hardening was applied to tappets according to the above fundamental experiments, and uniformly hardened layers were obtained. Durability of engines with electron beam hardened tappets was improved twice as much as those with non-hardened tappets.

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.

Countour Induction Hardening (CIH) method is in the limelight as a new possible surface refining method for gears as it reduces quenching distortion considerably and increases compressive residual stress. Also, Double Shot Peening (DSP) method, especially its advanced technique of using extensively small shots (less than 100 m) at the secondary peening, enables increased compressive residual stress under the surface of the gears. Therefore, the new Compound Surface Refining Method of using CIH + DSP is expected to give much higher compressive residual stress than the conventional methods. On studying the application of this new method, the authors evaluated their surface-refining characteristics and the fatigue limits.