AUTOMOTIVE EMISSIONS: Describes the different types of fumes expelled into the atmosphere (exhaust gas, fuel fumes, crankcase fumes) from an internal combustion engine.
BACKFIRE: Caused by the passage of unburned fuel mixture into the exhaust system where it ignites and causes a minor explosion (backfire) prematurely.
BACK PRESSURE: Describes the resistance to the flow of exhaust gases through the exhaust system. By rerouting the exhaust gases for noise suppression, a muffler causes back pressure, but a straight pipe alone causes only minimal backpressure. Some engines require backpressure, meaning that removing the exhaust system will cause internal damage.
BLOWDOWN: Describes the escape of gases between the opening of the exhaust valve and the piston reaching bottom dead centre, or in a two-stroke engine between exhaust port opening and transfer port opening.
CARBON MONOXIDE (CO): Describes the deadly, colourless, odourless, and tasteless gas found in the engine exhaust, formed by incomplete burning of hydrocarbons. Toxic even in relatively small concentrations.
CATALYST CONVERTOR: Describes an emissions control device used in vehicles to reduce the harmful pollutants present in the exhaust gases before they are released into the atmosphere.
CLOSED CRANKCASE VENTILATION: Describes a system in which crankcase vapours are discharged into the engine intake system through the intake manifold and pass through the engine cylinders rather than being released into the atmosphere.
COLD-CONDENSATE CORROSION: Describes the corrosion of the inside of an exhaust system caused by direct chemical attack condensing from the exhaust gas at relatively low temperatures and collecting at the cooler rear portions of the exhaust system.
COLD MANIFOLD: Describes a type of intake manifold not heated by exhaust gas
CONSTANT-VOLUME SAMPLING: Describes an exhaust-emissions measuring technique in which the exhaust gases produced by a vehicle's engine are collected as it is driven through a test sequence of accelerations, decelerations, and cruise modes on a chassis dynamometer.
CONVERSION RATE: Denotes the rate at which a given catalytic converter purifies the exhaust gas stream, governed by various operating conditions and converter design parameters.
DIVERTER VALVE: Describes a valve used in an air injection system to channel airflow to the exhaust manifold.
DOWNPIPE: Describes the pipe that joins the entire exhaust system to the exhaust manifold.
UB5