The Influence of the Exhaust Back Pressure of a Piston Engine on Air Consumption, Performance, and Emissions

730195

02/01/1973

Event
1973 International Automotive Engineering Congress and Exposition
Authors Abstract
Content
The theoretical relationship between engine air consumption and exhaust back pressure is derived for an idealized, 4-stroke-cycle engine inlet process, and compared to results obtained by testing a typical automobile engine. The exhaust back pressure of a 1971 Ford 351-W, V8 engine was varied 0.5-1.5 atm, under a wide range of engine speeds and loads. The results show that engine air consumption responds to variation of the ratio of absolute exhaust back pressure to absolute inlet manifold pressure in a manner approximating that indicated by theory, with a strong dependence on engine speed. These data can be useful in the design of speed-density fuel injection systems for automobiles.
Data are also presented concerning the effect of exhaust back pressure on performance and exhaust emissions. Increase in exhaust back pressure decreases nitric oxide, due to the increased exhaust gas remaining in the cylinder, as has also been demonstrated by others. Hydrocarbon emissions are also reduced as exhaust back pressure is increased, since the last exhaust gas to leave the cylinder has a higher hydrocarbon concentration.
Meta TagsDetails
DOI
https://doi.org/10.4271/730195
Pages
12
Citation
Bolt, J., Bergin, S., and Vesper, F., "The Influence of the Exhaust Back Pressure of a Piston Engine on Air Consumption, Performance, and Emissions," SAE Technical Paper 730195, 1973, https://doi.org/10.4271/730195.
Additional Details
Publisher
Published
Feb 1, 1973
Product Code
730195
Content Type
Technical Paper
Language
English