STRATIFIED CHARGE ENGINE
● The principle of stratified charge applies to direct injection petrol engines.
● It involves concentrating spraying of the fuel close to the spark plug rather than throughout the whole of the combustion chamber.
● This method of operation delivers a reduction in fuel consumption that can reach 40% when the engine is running at very low charge.
The principle of the stratified charge engine is to deliver a mixture that is sufficiently rich for combustion in the immediate vicinity of the spark plug and in the remainder of the cylinder, a very lean mixture that is so low in fuel that it could not be used in a traditional engine. On an engine with stratified charge, the delivered power is no longer controlled by the quantity of admitted air, but by the quantity of petrol injected, as with a diesel engine.
Homogeneous Charge Compression Ignition (HCCI)
● HCCI is an alternative piston-engine combustion process that can provide efficiencies as high as compression-ignition, direct-injection (CIDI) engines (an advanced version of the commonly known diesel engine) while, unlike CIDI engines, producing ultra-low oxides of nitrogen (NOx) and particulate matter (PM) emissions.