Terms Starting with D
Data Link-A device in an automobile computer system to send and receive digital signals.
Decibel-A unit of sound measurement. Usually 90 to 100 decibels experienced for a long time can cause hearing damage.
Deep cycle battery-A battery that is designed to withstand continuous cycling, or discharging and charging.
Deflection angle-The angle at which the oil is deflected inside the torque converter during operation. The greater the angle of deflection, the greater the torque applied to the output shaft.
Desiccant-A material that absorbs moisture from a gas or liquid. A desiccant substance is used in an air-conditioning system to remove moisture from the refrigerant.
Detonation sensor-A sensor used on computerized ignition systems which is able to measure if the engine is producing a “knock.” The sensor is able to pick up small, high-frequency vibrations produced from engine knock.
Dial indicator-A measuring tool used to check small clearances up to 0.001 inch. The clearance is read on a dial.
Diaphragm-A partition separating one cavity from another. A mechanical fuel pump uses a diaphragm to separate two cavities inside the pump. A diaphragm is usually made of a rubber and fiber material.
Differential-A gear assembly that transmits power from the drive shaft to the wheels. It also allows two opposite wheels to turn at different speeds for cornering and traction.
Digital signal-A computer signal that has either an on or off condition.
Diode-A type of semiconductor in an electrical circuit to allow electrical current to flow in only one direction.
Dispersant-A chemical added to engine motor oil to disperse or keep the particles of dirt from sticking together.
Displacement-The volume the piston displaces from BDC to TDC.
Distributor cam-Cams on older engines on the distributor shafts used to open and close the breaker points used on mechanical ignition systems. There is one cam for each cylinder of the engine.
Distributor-less ignition-An ignition system that uses a computer to distribute the electrical spark, rather than a rotor and distributor cap.
Drive lines-Components on the street rod that transmits the engine power to the wheels.
Drive shaft-A metal tube or shaft with U joints or CV joints at each end, used to transmit power from a transmission to the wheels or differential.
Dual camshaft-A type of engine that has two camshafts for opening and closing additional intake and exhaust valves.
Duty cycle-The timing cycle of on and off of a particular engine component, such as the on and off sequence of fuel injectors.
DVOM-A digital volt-ohm-ammeter, or a meter that reads voltage and resistance in ohms, that uses a digital readout rather than an analog readout using a pointer on a scale.
Dwell-The length of time in degrees of distributor shaft rotation that the conventional ignition points remain closed.
Dynamic balancing-Equal distribution of weight on each side of a centerline of a wheel. Dynamic means moving or action, and dynamic balancing is done with the wheel moving or spinning.
Dynamometer-A device attached to a street rod or just the engine used to brake or absorb mechanical power produced from the engine for testing purposes in a laboratory situation. Often street rods are put on dynamometer stands and tested to see how much horsepower a certain engine can produce.
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Data Link-A device in an automobile computer system to send and receive digital signals.
Decibel-A unit of sound measurement. Usually 90 to 100 decibels experienced for a long time can cause hearing damage.
Deep cycle battery-A battery that is designed to withstand continuous cycling, or discharging and charging.
Deflection angle-The angle at which the oil is deflected inside the torque converter during operation. The greater the angle of deflection, the greater the torque applied to the output shaft.
Desiccant-A material that absorbs moisture from a gas or liquid. A desiccant substance is used in an air-conditioning system to remove moisture from the refrigerant.
Detonation sensor-A sensor used on computerized ignition systems which is able to measure if the engine is producing a “knock.” The sensor is able to pick up small, high-frequency vibrations produced from engine knock.
Dial indicator-A measuring tool used to check small clearances up to 0.001 inch. The clearance is read on a dial.
Diaphragm-A partition separating one cavity from another. A mechanical fuel pump uses a diaphragm to separate two cavities inside the pump. A diaphragm is usually made of a rubber and fiber material.
Differential-A gear assembly that transmits power from the drive shaft to the wheels. It also allows two opposite wheels to turn at different speeds for cornering and traction.
Digital signal-A computer signal that has either an on or off condition.
Diode-A type of semiconductor in an electrical circuit to allow electrical current to flow in only one direction.
Dispersant-A chemical added to engine motor oil to disperse or keep the particles of dirt from sticking together.
Displacement-The volume the piston displaces from BDC to TDC.
Distributor cam-Cams on older engines on the distributor shafts used to open and close the breaker points used on mechanical ignition systems. There is one cam for each cylinder of the engine.
Distributor-less ignition-An ignition system that uses a computer to distribute the electrical spark, rather than a rotor and distributor cap.
Drive lines-Components on the street rod that transmits the engine power to the wheels.
Drive shaft-A metal tube or shaft with U joints or CV joints at each end, used to transmit power from a transmission to the wheels or differential.
Dual camshaft-A type of engine that has two camshafts for opening and closing additional intake and exhaust valves.
Duty cycle-The timing cycle of on and off of a particular engine component, such as the on and off sequence of fuel injectors.
DVOM-A digital volt-ohm-ammeter, or a meter that reads voltage and resistance in ohms, that uses a digital readout rather than an analog readout using a pointer on a scale.
Dwell-The length of time in degrees of distributor shaft rotation that the conventional ignition points remain closed.
Dynamic balancing-Equal distribution of weight on each side of a centerline of a wheel. Dynamic means moving or action, and dynamic balancing is done with the wheel moving or spinning.
Dynamometer-A device attached to a street rod or just the engine used to brake or absorb mechanical power produced from the engine for testing purposes in a laboratory situation. Often street rods are put on dynamometer stands and tested to see how much horsepower a certain engine can produce.
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