4.12.3.b Inlet valve
However, on the way to the ideal improving of the operation of the internal combustion engine, the intake valve was still installed - additional resistance in the path of the air-fuel mixture. It was decided to inject fuel directly into the cylinder in order to obtain the desired characteristics of the internal combustion engine. The designers were faced with an acute question of how to implement this, since the fuel, which is injected onto the valves during multipoint injection, had time to thoroughly mix with air, which was not the case with direct injection. The solution of this situation was found in the complex shape of the piston, or rather its top. However, in recent years, engine developers have made great strides in the design of direct injection gasoline engines. At first, nothing good came of it. They managed to obtain low fuel consumption, high power and consistently high torque, but at the same time, the requirements for fuel quality increased. The last moment became a limiting factor in the development of this technology in the CIS countries.
The direct fuel injection system uses the same sensors as the multiport fuel injection system. The difference lies in the fuel injectors, which must withstand higher operating temperatures, pressures and shock loads. The fuel metering accuracy in these injectors is almost an order of magnitude higher than in distributed injection injectors.
Note
It is worth mentioning that attempts to create a gasoline engine with direct fuel injection have been made more than once. The most striking example of use of such an engine in history is the 1954 Mercedes 500 SL. Direct injection system provided excellent power and torque characteristics with acceptable fuel consumption. However, the injection was mechanical. All the engine parts had to be precisely machined. As a result of this they were very expensive due to the technological level that was 60 years ago.
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