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A blowoff valve is designed to release pressure in the intake system when the throttle is closed. A "recirculating" type blowoff valve releases the pressurised air back into the non-pressurized section of the intake (i.e. upstream of the turbocharger), while an "atmospheric venting" type blowoff valve dumps the air directly into the atmosphere.
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.
Advancements in fuel modelling—HCCI combustion is driven mainly by chemical kinetics rather than turbulent mixing or injection, reducing the complexity of simulating the chemistry, which results in fuel oxidation and emissions formation. This has led to increasing interest and development of chemical kinetics that describe hydrocarbon oxidation.
Just before the piston reaches TDC, ignition begins. In the case of a SI engine, the spark plug receives a high voltage pulse that generates the spark which gives it its name and ignites the charge. In the case of a CI engine, the fuel injector quickly injects fuel into the combustion chamber as a spray; the fuel ignites due to the high ...
This is due to the fact that the fuel hits the intake valves on the way to the combustion chamber, allowing the detergents in the fuel to keep them clean. However, carbon build-up on intake valves is a problem for engines with direct injection only, as the fuel is injected directly into the combustion chamber.
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 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 ...
Typical airflow in a four-stroke engine: In stroke #1, the pistons suck in (aspirate) air to the combustion chamber through the opened inlet valve.. A naturally aspirated engine, also known as a normally aspirated engine, and abbreviated to N/A or NA, is an internal combustion engine in which air intake depends solely on atmospheric pressure and does not have forced induction through a ...