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Cam. A disk-like piece attached to a shaft, a portion of which is circular, the remainder (the УnoseФ) protruding beyond this circle. Cams are used to impart a desired motion to poppet valves.
Camshaft. The shaft which carries the various cams required for the operation of inlet, exhaust, fuel, and starting-air valves.
Cam follower. That part of the push rod that is in contact with the cam.
Carbon. One of the chemical elements which is the main constituent of liquid and solid fuels. Also the residual substance deposited in the combustion space and exhaust system of diesel engines when combustion of fuel oil is not complete.
Carbon dioxide. Gas composed of molecules made of one atom of carbon and two atoms of oxygen.
Carbon monoxide. Gas composed of molecules made up of one atom of carbon and one of oxygen. It is formed when combustion is not complete because of the absence of sufficient air.
Carbon residue. The carbon remaining after evaporating off the volatile portion of a fuel or lubricating oil by heating it in the absence of air under controlled test conditions. It is an indication of the amount of carbon that may be deposited in a diesel engine.
Centrifugal force. The force acting on all parts of a rotating body that tends to pull thorn away from time axis of rotation.
Cetane. A hydrocarbon used in testing the ignition quality of diesel fuels.
Cetane number. A percentage indicating the ignition quality of diesel fuels.
Cetene. A hydrocarbon used formerly infesting the ignition quality of diesel fuels.
Chamfer. A beveled corner.
Charge efficiency. The ratio of the weight of the charge actually taken in to the weight of the air at standard conditions corresponding to the piston displacement.
Check valve. A valve that permits the passage of a liquid or gas in one direction only. It stops, or checks, reverse flow.
Clearance. The space between a moving and a stationary part. Clearance must be provided between two surfaces to allow for lubrication and for expansion and contraction with a change of temperature.
Clearance volume. The volume of air or liquid remaining in the cylinder of an air compressor or a pump when the piston is nearest to the cylinder head.
Coefficient. A ratio; a factor or quantity that remains constant.
Combustion. The rapid oxidation, or combination, of a combustible such as carbon, hydrogen, or sulfur, with oxygen of air.
Combustion chamber. The space above the piston in which the fuel-air mixture starts to burn.
Common rail. A pipe or header from which branch lines lead to each of the fuel valves in the different cylinder heads of a diesel engine and in which fuel is carried at high pressure, ready for delivery to each separate cylinder when the fuel valve is opened by a cam.
Compression. The act or result of pressing a substance into a smaller space. One of the events of a combustion-engine cycle.
Compression ignition. Ignition of a fuel charge by the heat of the air in a cylinder, generated by compression of the air, as in the diesel engine.
Compression pressure. The pressure of the air charge at the end of the compression stroke.
Compression ratio. The ratio of the volume of the charge in the engine cylinder at the beginning of the compression stroke to that at the end of the stroke.
Compression relief. A device to reduce the compression in a cylinder and thus to make cranking easier.
Compression rings. Piston rings placed in the upper part of a piston to seal against loss of compression pressure and against gas blowing.
Compression stroke. The stroke of the piston during which the air charge in the cylinder is compressed by the piston movement.
Compressor. The air УpumpФ which furnishes compressed air for starting the engine, or for time injection of the fuel in an airЧinjection diesel engine.
Concentric. Having a common center.
Condensation. The process by which a substance changes from vapor to the liquid state.
Connecting rod. The engine part which connects the piston to the crankshaft. It changes reciprocating motion of the piston into rotary motion of the crankshaft or vice versa.
Connecting rod bearing. The bearing located in the large end of the connecting rod by which it is attached to the crankshaft.
Constant. A value or figure in a formula or equation which does not change, remains constant.
Constant-pressure combustion. Combustion of fuel in a cylinder at so slow a rate that there is no rise in cylinder pressure. The slow-speed airinjection diesel engine is a constant-pressure combustion engine.
Constant-volume combustion. Combustion in a cylinder so fast that there is no change in volume. Many high-speed diesel engines have practically constant-volume combustion.
Contraction. Becoming smaller in size. In metals and fluids a result of cooling or a lowering of temperature.
Cooling water. Water which is circulated through the jacket space of cylinders and cylinder heads to prevent excessive heating of these parts.
Crank. That part of the crankshaft, which is in the form of a crank and crank pin.
Crankcase. The middle part of the engine structure surrounding the working parts.
Crankcase subbase. The lower portion of the engine structure; the BEDPLATE.
Crankpin. That part of the crank to which the connecting rod is attached.
Crankshaft. That part of the engine which transmits the reciprocating motion of the pistons to the driven unit in the form of rotary motion. That part to which the connecting rods are attached.
Crankshaft cheek. The part J the crankshaft that connects the crankpin to the main crankshaft journal.
Crankshaft journal. The part of the crankshaft which rotates in the main bearings and transmits the torque developed by the engine.
Crankshaft web. The crankshaft cheek.
Critical speed. Speed at which the natural period of vibration of a shaft or her machine part is in synchronism with the power impulses.
Crosshead. The part of an engine to which are attached the piston pin with the connecting rod and the piston rod and which is supported on guides.
Crown. The top of an engine piston.
Crush. The amount by which a precision bearing is compressed to ensure good contact between the back of the bearing and the bore holding it.
Cycle. A series of events, operations, or movements that repeat themselves in a regular sequence
Cylinder. The cylindrical part of the engine in which the piston moves, and in which combustion takes place.
Cylinder block. A number of cylinders cast in one piece.
Cylinder bore. The inside diameter of an engine cylinder. Also the surface of the cylinder in which the piston slides or moves.
Cylinder head. The part which covers and seals the end of the cylinder and usually contains the valves.
Cylinder - head stud. Threaded round steel rod, one end of which screws into the cylinder block, the other being threaded to take a nut which holds the cylinder head in correct position.
Cylinder liner. A cylindrical lining that is inserted into the cylinder jacket or cylinder block and in which the piston slides.

Internal-combustion engine glossary

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