Multidimensional engine starting characteristics

The difficulties in obtaining the start of piston combustion engines increase at low temperature conditions. Lowering abilities of a diesel engine to undertake the independent operating, at low temperature, result from its influence on exploitation materials, engine systems properties, and directly from low ering the temperature of sucked-up into the engine cylinders air. The successful engine start-up depends on three independent parameters: engine (and ambient) temperature, engine crankshaft rotational speed extorted by starting system and the time period at which this system is operating. An individual engine starting abilities measure can be the time of starter motor operating at aparticular temperature or its start-up limit temperature determined according to a specified research standard. The dependence of start-up time or start-up limit temperature on any particular factor is the engine starting characteristic. The combustion engine is a very complex object in respect of its starting abilities. If the engine constructionai adjustment and exploitation parameters are changed, the start-up characteristic (function) is a multi-dimensional function. Formally, from mathematical point of view, it is a surface in a multidimensional space. It is possible to obtain any engine starting characteristic by multidimensional starting surface intersection. In the paper there are presented examples of one- and multi- dimensional diesel engine starting characteristics as results of long-lasting starting tests of many engines.