An Empirical Formula for Computing the Pressure Rise Delay of a Fuel from Its Cetane Number and from the Relevant Parameters of Direct-Injection Diesel Engines

The evaluation of test results from the development of a large number of direct-injection (DI) diesel engines of different design and a great variety of cylinder dimensions enabled an empirical formula to be derived which allows the effect of the fuel, the engine parameters and the ambient conditions on the pressure rise delay to be assessed.

Application of the formula indicates the possibilities and limitations of minimising the pressure rise delay in naturally-aspirated (NA) and turbocharged (TC) diesel engines when operating on diesel fuel as well as on fuels of lower or higher ignition quality.