Glossary: Engine Blocks and Cylinder Heads

A control circuit taking its name from the arrangement of its four transistors that switch the polarity current applied to a load. It is often used to change the direction of DC electric motors or to rapidly open and close injector solenoids.

A sensor commonly used to measure the rotational speed of a shaft; it has the advantage of producing a square waveform digital signal and has strong signal strength at low shaft rotational speeds.

A vibration that sends pressure waves moving back and forth along the axis of a shaft, particularly the crankshaft.

Strategy used to increase exhaust temperatures in an effort to slowly remove HC accumulations under controlled conditions.

A system of tubes and fins circulating coolant that transfers heat from coolant to the atmosphere.

Systems that transfer heat from coolant into the atmosphere.

The transfer of heat into the cooling system from the combustion chamber.

The equivalent of the LD OBD-II system for HD vehicles.

A software program inside the MCM used to run monitors and make decisions concerning the OBD system.

A tool used by technicians to adjust the plunger travel of a unit injector for Detroit Diesel N2 injectors.