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Blended fuels of turpentine oil and castor oil, palm oil, and sunflower oil have been used as alternative fuels in compression ignition, pre-combustion chamber CI engines. The effect of these blended fuels on engine performance, exhaust emissions, and combustion process have also been investigated. Here, the effect of higher injection valve opening pressures with blended fuels was investigated, and the behavior of the fuel spray at the higher injection valve opening pressure were observed by a Liquid-Liquid Injection Technique. The fuel injection rate at the higher injection valve opening pressure was measured by the Bosch method.

The engine performance, combustion characteristics and the effect of injection timing differences of a prechamber-type diesel engine operated by Diesel-fuel and methanol were investigated. When the Diesel-fuel is used as a pilot fuel, the ignition lag was mainly controlled by the Diesel-fuel. The maximum thermal efficiency occurs with the optimum main methanol injection timing. The optimum methanol injection timing is about 2 to 3 degrees crank angle before the ignition, as methanol vapor is required for smooth combustion. This was determined from results showing that the methanol combustion was initiated by flame propagation from the combustion of Diesel-fuel. It is advantageous that parts of the Diesel-fuel and methanol sprays be mixed.

A direct fuel-injection two-stroke cycle engine operated with neat methanol was investigated. The engine performance, combustion and exhaust-gas characteristics were analyzed experimentally and compared for operation with a carburetor, EFI injection at the intake manifold, and EFI injection at the scavenging port. The power and the brake thermal efficiency of the direct fuel-injection engine were higher than those of engines operated with a carburetor and either of the two EFI methods. The exhausted unburnt fuel of the direct fuel-injection engine was lower than that for operation with a carburetor, and formaldehyde and the CO concentration were of the same level as for operation with the carburetor and EFI methods. The NOx concentration of the direct fuel-injection was half the level of the result of carburetor operation.

If the water/gas-oil-emulsion fuel is to be used in a compression ignition engine, it is necessary not only to carry out directly engine experiment but also to determine the characteristics of so-called mixture formation process, including those of fluidity, spray mode, injection rate and evaporation in high-temperature environment and on high-temperature wall as well as the influence of these characteristics on engine performance. In this report, the authors have experimentally investigated on the physical properties and injection characteristics of water/gas oil-emulsion fuel (W/O).