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 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 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 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 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 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.