CORDUNUM PISTONS INCREASE DIESEL ENGINE ECONOMY AND RELIABILITY

Abstract

Taking into account the oil resources depletion the requirements to fuel consumption of internal combustion
engines are now increasing as well as to their reliability and durability. With the continual increase in the number
of internal combustion engines in operation, along with the problem of parts of the cylinder piston group wearing
out has caused exhaust from such engines to be one of the main source of harmful pollutant emissions in cities.
Therefore, environmental requirements have in turn increased dramatically. The engine resource and its
efficiency largely depend on the process of fuel combustion in the combustion chamber. Experimental studies
aimed to improve the working process on diesel engines by piston insulation have shown an effective decrease
in fuel consumption by reducing heat loss and more complete fuel combustion. When oxide ceramic coatings
were used on the piston and cylinder head, the maximum power increased and the specific fuel consumption
decreased. However ceramic coatings are not widely used due to their peeling. We have developed a technology
for the galvanic plasma treatment of pistons, which made it possible to obtain on the pistons surface made of
aluminum alloys a ceramic corundum layer with high adhesion to the base metal that does not peel and has
electret properties. In 1993, pistons with a corundum surface layer were installed in a shunting diesel locomotive
and life-time running tests were conducted. Such pistons increased wear resistance, reduced the wear of cylinder
liners, increased the strength of the annular jumpers, and were not prone to burnouts and scuffing. They
provided an increase in the resource of the cylinder-piston group of the diesel engine by more than 125 thousand
engine hours. The paper provides an analysis of the effect of corundum pistons thermal insulation on significant
increasing the, engine power and fuel consumption reduction. Basing on experimental bench studies
of a gasoline engine, a tractor diesel engine and long-term operational life tests of diesel engines, an attempt
had been made to explain the reasons for the improvement in the engines’ efficiency.