ic engines notes on non conventional engines

5
HCCI Engine What Is HCCI? HCCI is a combustion process. HCCI is not an engine concept. HCCI must be incorporated in an engine concept. HCCI is a low temperature chemically controlled (flameless) combustion process. HCCI can be considered as a hybrid form between the diesel and Otto combustion process. However combustion process is different. So there is neither

Transcript of ic engines notes on non conventional engines

Page 1: ic engines notes on non conventional engines

HCCI Engine

What Is HCCI?

HCCI is a combustion process. HCCI is not an

engine concept. HCCI must be incorporated in

an engine concept.

HCCI is a low temperature chemically controlled

(flameless) combustion process.

HCCI can be considered as a hybrid form

between the diesel and Otto combustion

process.

However combustion process is different. So

there is neither Diffusion flame (as in a diesel

engine) nor a flame front traveling through a

premixed charge ( as in SI engine).

Page 2: ic engines notes on non conventional engines

WORKING PRINCIPLE OF HCCI

Homogenous charge is drawn in to the cylinder during suction and

compress to high enough temperature to achieve spontaneous ignition

of the charge.

Combustion starts in almost whole volume of C.C Two degree before

TDC

After Combustion initiation the temperature rapidly increases and

whole fuel burn simultaneously As whole mixture burns simultaneously

and no flame propagation , combustion temperature can be controlled

less than 700 deg Centigrade and thus NOx formation is avoided.

Page 3: ic engines notes on non conventional engines

LEAN BURN ENGINE

Combustion is considered “lean”when excess air is

introduced into the engine along with the fuel

Advantages Of Burning Leaner Overall Fuel-Air Mixtures

1. Higher thermodynamic efficiency.2. Reduced airpollution

A relatively rich mixture was formed at the spark plug by an auxiliary spray while

another spray injecting fuel along the major axis of the combustion chamber

formed a leaner mixture

Page 4: ic engines notes on non conventional engines