الفهرس 
ARABIC SUMMARY
Ideal fuel-air constant volune cycleOnly 14 pages are availabe for public view
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Abstract
The effect of the exhaust gases left in the clearance space of a reciprocating spark ignition engine on both the ideal fuel-air cycle and that engine did not receive suitable attention in published work. However, in the present investigation this matter has been thoroughly studied. This was carried out through:
1- The theoretical fuel-air cycle calculations which were made according to the charts of Starkman and al’s to determine the effect of the variable exhaust back pressure on the state points variables and performance of this cycle.
2- The chemical equilibrium concept which was followed to obtain the combustion products at different state points of the cycle. This included components containing Hydrogen, carbon, oxygen or Nitrogen.
3- An experimental work which was carried on a single cylinder variable compression spark ignition engine under different conditions of speed, compression ratio fuel-air ratio, spark advance, load, ... etc. The engine was fitted with a vacuum pump to vary the exhaust back pressure from 1.0 atm. to 0.5 atm. The Actual pressure-time and pressure-volume diagrams were taken under various operating conditions.
Analysis of both the theoretical performance of the fuel-air cycle, the components of combvustion products from chemical equilibrium and of the actual diagrams from the engine have proved that considerable gain and improvements o the engine specific fuel consumption and indicated thermal efficiency had been achieved by the operation using different exhaust back pressure. The combustion characteristics ehich exist under this new operation of the engine have been clearly shown and discussed. For the first time, comprehensive analysis of the actual combustion time-loss, expansion heat loss and the fluid or oumping loss had been given. The present work gives both theoretical and experimental support for the application of a vacuum pump which is to be integrated with the exhaust system of the spark ignition engine.