Comparative analysis of methods for diagnosing and regulating fuel equipment of automobile and tractor diesel engines

Abstract

Practice shows that in most cases the main cause of diesel engine malfunctions is misadjusted fuel equipment. Under “field” conditions this cannot be detected due to the lack of simple devices necessary for diagnosing fuel equipment. Another serious drawback of the current stationary method of diagnosing and regulating fuel equipment is the significant difference between the adjustment conditions and the conditions for its operation on a diesel engine. An improved operational method for fuel equipment adjustment was proposed by the Bashkir State Agricultural University. It is based on using the diesel engine itself as an adjustment stand when operating it on part of the cylinders with missed fuel injections. At the same time, in contrast to the known methods, the diesel engine operates not only at nominal speeds, but also at nominal fuel supplies, and sections of the fuel equipment of non-working cylinders are adjusted without removing them from the diesel engine. The preservation of the adjusted values of the cyclic feeds of the sections of the fuel equipment and the uniformity of the fuel supply when operating on a diesel engine is ensured by adjustment with its own fuel lines and injectors, the use of fuel heated by the operating diesel engine, and the creation of back pressure close to that of the cylinder. Due to all this, the method turns out to be an efficient one, and the conditions for the fuel equipment adjustment are close to those when operating it on a diesel engine. It is equally important that at idle speed of a diesel engine, the same qualities of mixture formation and fuel combustion are achieved as in the nominal operating mode and, as a result, it becomes possible to calculate the mechanical efficiency of a diesel engine based on hourly fuel consumption.