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A multi-tube EGR cooler was developed to have high heat exchanger efficiency with high reliability for heavy-duty diesel engine application. Using three-dimensional numerical analyses as well as several laboratory experiments on both a test rig and a diesel engine, the authors determined the most critical factors for developing such an EGR cooler with low production costs. Technology development focused on achieving a high heat transfer coefficient on the gas side in a tube for increased heat exchanger efficiency and uniform coolant flow distribution in the shell for effective cooling of all tubes in the shell. The tube's inside wall was designed with a spiral configuration both for improved gas flow and heat transfer characteristics. Both the layout of the coolant inlet and outlet on the shell and the arrangement of tubes in the shell were optimized for the best results.

This paper describes some of the advanced technologies designed for low fuel consumption in the new P11C in-line 6-cylinder, heavy duty diesel engine which has two power ratings of 239kW at 2100rpm and 221kW at 2150rpm. The new engine's displacement has been increased from 8.8 liters of the base engines (EP100, P09C) to 10.5 liters without an increase in either engine weight or overall dimensions. The turbocharger has a mixed-flow turbine which improves the fuel consumption by improving the turbine efficiency. The piston, made from ductile cast iron, improves the fuel consumption and reduces the exhaust emissions by heat insulation of the combustion chamber (i.e. the ductile cast iron has a lower thermal conductivity than the previous piston's aluminum alloy). Additionally, this engine achieves lower friction loss by an intake air system with low air flow resistance and by roller cam followers.

Considerable amount of research work on hydrogen fueled engines has been conducted for 17 years in Musashi Institute of Technology. The primary purpose of the research has been to develop a hydrogen powered autmobile, and in order to realized it, various innovations have been applied and tested. The newest outcome of this 17 years research was Musashi-7 Track, which demonstrated its performance in Innovation vehicle Design Competition held in Vancouver in July 1986. Musashi-7 Track was a modified medium duty truck, which was originally made by Hino Motors, and had a hydrogen powered engine. The track was equipped with 150 ℓ liquid hydrogen (LH2) tank and 8 MPa high pressure LH2 pump. The pump delivered 8 MPa high pressure hydrogen gas to the engine and the fuel was injected to a hot surface igniter in DI combustion chamber. This type of hydrogen enigne has following advantages. Firstly, fuel corrier weight and volume can be much smaller than those of metal-hydrides (MH).

A hydrogen powered vehicle system consisted of LH2 tank high pressure LH2 -pump, a device to inject hydrogen onto the hot surface, and ignitor in turbo-engine of CR 12:1 had been developed by Musashi Institute of Technology- Recently the authors applied this system to a medium duty truck produced by Hino Motors Ltd. Then following improvement were required. (1) Gas tightness and endurance of hydrogen injector were improved by the selection of material, size, finishing and by suppling a small amount of lubricating oil. (2) Mixture formation of the injected hydrogen with the compressed air was improved by tuning up the size and number of the nozzle holes and injection timing with the hydraulic pump and valve. (3) A small amount of hydrogen was supplied into the intake manifold. It reduced the combustion noise and also it recovered the evaporation loss in the LH2 -tank.

A current unmodified and modified engines with different amounts of thermal insulation have been used to generate data from which changes in bsfc, cooling loss, emissions, exhaust loss were determined. Since legislative requirement exists for allowable emission of NOx, fuel injection timing and other controllable factors were adjusted to maintain constant NOx emission except a test of influence on NOx emission according to the rate of heat insulation (adiabaticity). The effect of higher combustion temperature on the combustion phenomena is discussed.