The Computer and Improvement of the Engine Carburetion System
Published January 1, 1974 by Societe des Ingenieurs de l'Automobile in France
Attempts are now being made to solve the problem of adapting spark-ignition engines and fuels by using varied concepts such as Research, Motor and Road Octane Numbers, Engine Severity, Lead Bonus, etc. All these open the way to statistical analysis rather than an interpretation of phenomena. The only reason these concepts have been developed is because of the fineness of the multiple and complex interactions of the phenomena involved, all of which have made theoretical methods unusable.
The aim of this paper is to show that the reaearch done by I.F.P. and partially sponsored by G.I.M.T. make it possible to build models for the overall engine/fuel behavior in the range of light knocking. The basic parameters for such models are: spark timing, compression ratio, volumetric efficiency for the engine and equivalence ratio, ignition delay for the air fuel mixture.
After demonstrating that it is possible to go from the pressure-temperature history to the delay properties:
τ= A exp (B/T) p-n in which A,B and n, are properties of the air fuel mixture
we demonstrate that high and low running conditions knocking can be explained by the same formula.
As an example, it is shown that the model can be used to simulate the important effect of volumetric efficiency on knock. The mini-computer system developed to store and process digitalized pressure values is then described.
The paper concludes with an examination of the possibilities offered by such a method for both engine and petroleum industries.