Diesel engine exhaust emissions

Patent Granted Diesel exhaust is produced inside diesel engines, where conditions differ considerably from spark-ignition engines. Diesel engine power is directly controlled by the fuel supply, not by controlling the air supply as in conventional gasoline engines. When the engine runs at idle, enough oxygen is present to burn the fuel completely. Diesel engines only make significant amounts of smoke when running without enough oxygen. This is usually mitigated in a turbocharged diesel engine.