Glossary “exhaust pipe” Definition:
Pipe that connects the exhaust manifold, the muffler, or catalytic converter.

Glossary “exhaust port” Definition:
Opening in the head or block that allows the burned gases to leave the engine.

Glossary “exhaust pressure” Definition:
The pressure in the cylinder at the end of its combustion stroke.

Glossary “exhaust stroke” Definition:
Upward motion of the piston forcing burned gases out the open exhaust valve.

Glossary “exhaust system” Definition:
Tubing, mufflers, and catalytic converters that direct exhaust gases from the engine to the atmosphere.

Glossary “exhaust valve” Definition:
Valve that, upon opening, allows the burned gases to leave the combustion chamber during the exhaust stroke.

Glossary “exhaust gas speed” Definition:
Speed at which exhaust gases pass through the header pipes, usually at about 200-300 feet (61-91 meters) per second at WOT.

Glossary “exhaust headers” Definition:
1). Term used for exhaust manifold. 2). A special exhaust manifold with tubes of equal length from the exhaust ports to the header of the exhaust system.

Glossary “Exhaust Heat Control Valve (EHCV)” Definition:
A valve which routes hot exhaust gases to the intake manifold heat riser during cold engine operation.

Glossary “exhaust manifold” Definition:
Component, generally of cast iron, with passages of unequal lengths that carry the exhaust gases from the exhaust ports to the header of the exhaust system.

Glossary “exhaust gas recirculation (EGR)” Definition:
Process of passing a small, measured amount of exhaust gas back into the cylinders to reduce combustion temperatures and formation of Nox.

Glossary “exhaust gas recirculation (EGR)” Definition:
Emissions control system that reduces an engine’s production of NOx by diluting the air/fuel mixture with exhaust gas so that peak combustion temperatures in the cylinders are lowered.

Glossary “exhaust gas recirculation valve (EGR valve)” Definition:
Valve, that is generally vacuum operated, to regulate the exhaust gas flow into the intake manifold.

Glossary “exhaust gas oxygen” Definition:
Amount of oxygen present in the exhaust stream, as measured by an oxygen sensor and reported to the computer in closed-loop, feedback systems to aid in the control of the air/fuel mixture.

Glossary “exhaust analyzer” Definition:
Automotive test and service device that uses a process involving infrared energy and sensors to determine and display the composition of an engine’s exhaust gases, such as: HC, CO, CO2, O2, and NOx. Some types may also measure sulpher compounds and particulates.

Glossary “exhaust back pressure” Definition:
The resistance of the free flow of gas in the exhaust system.

Glossary “exhaust back pressure testing” Definition:
Test of the exhaust system to determine the amount of exhaust restriction

Glossary “exhaust emissions” Definition:
Pollutants that are the result or by-product of combustion.

Glossary “exhaust gas” Definition:
Burned and unburned gases that remain after combustion.

Glossary “exhaust gas analyzer” Definition:
Instrument for determining the amount of HC, CO, CO2, O2, and NOx emitted into the atmosphere.