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A separate cam on the camshaft (as seen in Fig. 5 and on the two-cylinder Johann-Weitzer-engine on the right) would activate the injection valve so the compressed air would then press the fuel into the combustion chamber. Before the injection valve opens, neither fuel nor compressed air can enter the combustion chamber. [16]
The term fuel injection is vague and comprises various distinct systems with fundamentally different functional principles. The only thing all fuel injection systems have in common is the absence of carburetion. There are two main functional principles of mixture formation systems for internal combustion engines: internal and external.
In piston engines, the valves are grouped into 'inlet valves' which admit the entrance of fuel and air and 'outlet valves' which allow the exhaust gases to escape. Each valve opens once per cycle and the ones that are subject to extreme accelerations are held closed by springs that are typically opened by rods running on a camshaft rotating ...
In a naturally aspirated engine, air for combustion (Diesel cycle in a diesel engine or specific types of Otto cycle in petrol engines, namely petrol direct injection) or an air/fuel mixture (traditional Otto cycle petrol engines), is drawn into the engine's cylinders by atmospheric pressure acting against a partial vacuum that occurs as the piston travels downwards toward bottom dead centre ...
An example of an HMU, although called a Constant All Speed Control (CASC), was the Rolls-Royce/Lucas fuel control used on the Rolls-Royce Spey. It performed all the above functions as well as maintaining the HP shaft speed (being the basic control parameter) selected by the pilot for most subsequent flight conditions, the LP shaft speed was ...
The system increases the engine's power output by allowing fuel to be burned at a higher-than-normal rate, because of the higher partial pressure of oxygen injected with the fuel mixture. [1] Nitrous injection systems may be "dry", where the nitrous oxide is injected separately from fuel, or "wet" in which additional fuel is carried into the ...
The power stroke begins at TDC ([0°]; injection of fuel leads TDC by 4° [356°], such that injection of fuel will be completed by TDC or very shortly thereafter; [citation needed] the fuel ignites as fast as it is injected), after the power stroke the exhaust valves are opened, thereby greatly reducing combustion gas pressure and temperature ...
Injection phase Partway through the pump stroke, the solenoid is energized, which closes the spill valve. The fuel is forced into the cylinder through the spray tip. Pressure reduction phase Toward the end of the pump stroke, the spill valve is re-opened, allowing the fuel to recirculate again and ending the injection phase.