IMPORTANT TERMS OF INTERNAL COMBUSTION ENGINES

1.)AFTER COOLER – A device used on turbocharged engines to cool air which has undergone compression.

2.)ATDC – After TDC, After top dead centre.

3.)AIR CLEANER – A device mounted on the intake manifold for filtering out unwanted solid impurities such as dirt and dust from air that is being drawn into the engine cylinder through the inlet manifold.

4.)AIR COOLED ENGINE – An engine that is cooled by passage of air around the cylinder, not by passage of a liquid through water jackets.

5.)AIR STANDARD CYCLE – A standard cycle of reference by which the performance of the different internal combustion engines may be compared, and their relative efficiencies calculated.

6.)AKROYD ENGINE – The first compression ignition engine, patented by Akroyd Staurt in 1890.

7.)ALUMINIUM CYLINDER BLOCK – An engine cylinder block cast from aluminium or aluminium alloy, and which usually has cast iron sleeves installed for use as cylinder bores.

8.)ANTIFREEZE – A chemical, added to the coolant (usually ethylene glycol) to lower its freezing point and thereby prevent the coolant from freezing in cold weather.

9.)ANTI ICING SYSTEM – A carburettor unit designed to prevent formation of ice on a surface or in a passage.

10.)ARTICULATED CONNECTING ROD – The auxiliary connecting rods of a radial engine, which work on pins carried by the master rod instead of on the main crankpin. Also called LINK RODS.

11.)BACK PRESSURE – A pressure exerted by a fluid contrary to the pressure producing the main flow. For example, pressure in the exhaust manifold, the higher the back pressure, greater is the resistance to flow of exhaust gases through the exhaust system. This lowers volumetric efficiency.

12.)CLEARANCE VOLUME – The volume remaining above the piston when the piston is at TDC.

13.)COMBUSTION CHAMBER – The space at the top of the cylinder and in the cylinder head or piston or both, in which combustion of fuel and charge takes place. The space enclosed by the piston, when the piston is at TDC.

14.)COMPRESSION RATIO – The ratio between the total volume of the cylinder when the piston is at BDC and the volume when the piston is at TDC.

15.)CONNECTING ROD – The rod made of steel or aluminium alloy usually having an I beam cross-section. A piston pin connects the connecting rod and the piston.