Abstract:
The quest for increasing the efficiency of an internal combustion engine has been going on ever since the invention of this reliable workhorse of the automotive world. Recently, much attention has been focused on achieving this goal by reducing energy lost to the coolant during the power stroke of the cycle. Ceramic coatings have a significant effect in the reduction of wear and abrasion failure in reciprocating and rotary engines for transportation and stationary power. As operating temperatures are pushed higher to improve efficiency in these engines, the wear/abrasion problem becomes more challenging because lubrication in the high temperature locations becomes increasingly problematic. Ceramic coatings also have applications as thermal barriers to improve the efficiency of the engines, by reducing energy loss and cooling requirements. The main aim of this study is to evaluate the effects of ceramic coating on diesel engines' effective efficiency at different engine loads and speeds. Experiments were conducted with six cylinders, directly injected, turbocharged, intercooled diesel engine. First, this engine was tested at different speed and load conditions without coating. Then, combustion chamber surfaces cylinder head, valves and piston crown faces were coated with ceramic materials. Ceramic layers were made of CaZrO3 and MgZrO3, by using plasma-coating method onto the base of the NiCrAl bond coat. The ceramic-coated research engine was tested at the same conditions as the standard (without coating) engine. The results showed a reduction in heat loss to the coolant and an increase in effective efficiency. (c) 2005 Elsevier B.V. All rights reserved.
