During which stroke of the engine cycle are nitrogen oxides produced in the highest amount?
Power stroke
Oxides of nitrogen form when the nitrogen and oxygen already present in the cylinder charge are forced to combine, and this reaction only proceeds strongly when the gas temperature climbs very high.
Because the reaction is driven by heat, the stroke that produces the greatest quantity of NOx will be the one carrying the highest flame temperature and pressure.
Combustion is completed near the top of the cycle, and the peak temperature is reached just after ignition as the burning gases expand and drive the piston down during the power stroke.
At that instant the trapped gases are at their hottest, so nitrogen and oxygen react most vigorously and NOx production peaks.
The intake stroke only draws in fresh cool charge, and the compression stroke, though it heats the mixture, has not yet ignited it, so neither reaches the flame temperature required.
By the exhaust stroke the gases have already expanded and cooled, so little further NOx is created then.
Hence, the answer is Power stroke.
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Important Questions from Fuels and Combustion
Identify the non - renewable source of energy from the following.
The pour point of any specific fuel is defined as -
A heat engine utilizes the
_________ involves breaking of fuel into fine particles.
Losses caused due to leakage of combustion products past the cylinder onto the crank case are termed as:
