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ABOVE: Hino trucks, manufactured by Toyota, were the first to use common rail technology in series production decades ago. BELOW: Toyota was one of the first manufacturers to adopt fuel injection. In the late 1980s, it was the first to bring an affordable car to market sporting this technology in the form of the Corolla Conquest RSi Twin-Cam 16. It revolutionised the small-car segment and was instrumental in creating the hot-hatch segment. Among its credentials were power output of 86kW/136Nm and consumption of just six litres/100km. IN A DIESEL In a diesel engine, compression ratios as high as 20:1 are necessary to get the fuel to ignite, as diesel engines do not use spark plugs. This created special problems for any injection system. The first diesel engines, dating from 1897, employed a blast of compressed air to force the fuel into the combustion chamber. The associated compressor and air storage tanks meant that engine layouts were extremely bulky and heavy. The system changed only in 1925 when a fuel injector was invented that utilised mechanical compression of the fuel. The resulting diminished size of such an engine meant that trucks and tractors could now be fitted with diesel engines, and the first such vehicles soon followed. The system utilised an assembly HOWSTUFFWORKS of small plungers operated by a camshaft. It was mounted on the side of the cylinder block and driven by a gear or chain from the engine. Various mechanical devices were employed to adjust the amount of fuel being delivered. Under the same motoring conditions, each cylinder received the same amount of fuel, but at slightly varying pressure, because the delivery pipes from the plunger block were not all the same length. The delivery pressure inevitably increased with pump speed 79


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