Experimental investigation on a low heat rejection engine

摘要

In a normal diesel engine, about thirty percent of the total energy is rejected to the coolant. The low heat rejection concept is based on suppressing this heat rejection to the coolant and recovering the energy in the form of useful work. The purpose of this project is to increase the performance of the engine and improved the fuel economy resulting from coating those using partially stabilized zirconia (PSZ) thermal barrier coating for the performance in the diesel engine application. PSZ over the combustion chamber increases the temperature over the inside the combustion chamber and reduces the heat rejection to the atmosphere. Also an experimental investigation performed using a thermally insulated single cylinder direct injection water cooled diesel engine to evaluate the effect of coating on the cylinder head, piston top surface and the valve seats using PSZ to study the heat release, performance and emission characteristics. Studies are conducted for the engine with insulated head and piston and are compared with the base line engine. Based on the experimental studies it is concluded that a thermally insulated engine reduces the fuel consumption, improves the fuel efficiency. Also the emissions of HC and CO are reduced to a great extent while the emissions of NOX are increased due to higher combustion temperature. Various method of reducing NOX emissions will be adopted. Such as retarding the fuel injection timing, lowering the intake temperature, lower compression ratio. Thus, the LHR engine was tested for two different injection timings at Crank angle before top dead centre (BTDC), with the same engine Speeds and load conditions. The results showed that the BSFC and NOx emissions were reduced respectively by retarding the Injection timing.