Development of 2-Cylinder Diesel Engine for European Quadricycle in Compliance with EURO4

The EURO4 standard has been enforced since the year 2017 for European quadricycle. The vehicles are regulated upper limit of unladen weight and engine displacement, in addition to the exhaust emissions and the net power. In order to meet those regulations, the engine for European quadricycle is demanded low exhaust emissions and light weight. Further, it is required to be achieved good drivability, low fuel consumption, low noise and more compact. We introduce technologies to meet demand for European quadricycle in compliance with EURO4. The limit values of exhaust emissions have been strengthened in EURO4 standard compared to the previous one. As devices to improve the exhaust emissions, the exhaust-after-treatment devices and the common rail injection system are well known, whereas those devices make engine systems heavier. In addition, to satisfy high torque at low speed for better drivability, larger displacement is effective. However the engines of larger displacement have higher friction loss than smaller one, therefore countermeasures to reduce fuel consumption are necessary. In order to achieve to be lower emissions without additional devices, we improved the in-direct injection system engine. We optimized the shape of the combustion chamber to meet EURO4. To achieve low fuel consumption keeping better drivability with large displacement, we developed the new piston to be lower friction. We optimized the shape of the coating pattern to improve lubrication between piston skirt and cylinder wall. As the result, we attained to meet the requirements of European quadricycle with developing new technologies in compliance with EURO4.