Assessment of the impact of the number and the arrangement of cylinders of the KAMAZ disel engines on their fuel efficiency

Abstract

Most of the natural aspirated truck diesel engines had an eight-cylinder V-twin (V8) configuration. Modern turbocharged diesel engines have a six-cylinder in-line configuration (L6), although some V8 diesel engines continue to be produced. A comparison was made of the performance of the KAMAZ-740 (V8) diesel engine with two turbochargers and KAMAZ-910 (L6) diesel engines with one turbocharger, having almost the same displacement with the same pattern of torque along the full load characteristic. The AVL BOOST software and experimental compressor and turbine maps were used. The factors influencing fuel efficiency were analyzed: indicated efficiency, friction and gas exchange losses, turbocharger efficiency. The L6 diesel engine had a uniform pressure pulsation in the exhaust manifold and at the turbine inlet. In the V8 diesel engine, the pulsations were uneven and had higher amplitude, which led to higher gas exchange losses and a decrease in turbine efficiency. The L6 diesel engine had a higher indicated efficiency but also higher friction losses. On average, the brake specific fuel consumption of the L6 diesel engine was by 5.5 % lower than that of the V8 diesel engine. Keywords V8 and P6 diesel engines; modeling in AVL BOOST; pressure pulsations in the exhaust system; turbocharger efficiency; friction and gas exchange losses