Power Sports and Electronic Fuel Injection Glossary
DIRT BIKE
Motorcycles that are designed to be ridden on rough terrain. They are known as dirt bikes or trail bikes. Dirt bikes will typically have suspension with more travel than a street bike, higher ground clearance, and a small (less than 500cc) engine. Related to dirt bikes are dual-sport bikes which are street-legal versions of dirt bikes with more suspension travel than a standard bike, but having all the other equipment usually found on street bikes.
DUAL OVER HEAD CAMS (DOHC)
Two camshafts found in the head or top of the engine that open and close the valves. Two cams allow more precise control than one.
DRIVING CYCLES
To ensure that tests remain mutually comparable, the speeds used on the dynamometer must accurately reflect actual highway operation . Testing is based on a standardized driving cycle in which shift points, breaking maneuvers, idling and stationary phases have all been selected to reflect the traffic conditions typically encountered in large urban areas. Seven different test cycles are in use at the international level.
DUAL-SENSOR LAMBDA CLOSED-LOOP CONTROL
Installing the Lambda oxygen sensor downstream of the catalytic converter provides better protection against contamination from the exhaust gas. This type of backup sensor can provide a second control signal to augment the one from the main sensor upstream of the converter. The second signal is super-imposed on the first to provide stable mixture composition over an extended period.
DUCATI
A brand of motorcycle produced in Italy.
DWELL-ANGLE CLOSED-LOOP CONTROL
High-performance ignition systems operate with ignition coils which charge very rapidly. For this purpose, the ohmic resistance of the primary winding is reduced to less than 1(omega). The information content of the signal of a hall vane switch in the ignition distributor corresponds to the signal of an ignition contact breaker. In one case, the swell angle is determined by the distributor cam and in the other the pulse duty factor is determined by the rotor vane. A rapidly chargeable ignition coil cannot operate with a fixed dwell angle. This is why two measures must be taken to protect the ignition coil: a primary-current regulation system and a dwell-angle closed-loop control system.
DYNAMOMETER
An instrument for measuring force or power; especially, the power developed by a motor.
