Development of Two New High Specific Output 3 Cylinder Engines for the Global Market with Capacities of 1.2l and 1.5l

Abstract

MAHLE Powertrain has developed an industrialized version of its 3-cylinder downsizing engine as a low cost, high specific output engine, for the global automotive market. The engine has been developed in both 1.2 and 1.5 liter capacities, with the maximum commonality being maintained between the two variants. Through careful design, the engines are capable of delivering exceptionally high-specific torque and power outputs whilst utilizing only simple low-cost technology. At the same time the engines have also been engineered to meet the requirements of the latest Euro 6c and China 6a emissions standards. This was demonstrated very early in the project through use of a representative development vehicle. The 1.2 and 1.5 liter engines are rated at 30bar Brake Mean Effective Pressure (BMEP) and 100 kW/l and 28 bar BMEP and 94 kW/l respectively and are both capable of achieving these outputs whilst operating on 92 RON gasoline. The engines provide the capability of delivering competitive real-world fuel economy, which has been achieved through a combination of low friction design and reduced pumping losses, enabled by the downsizing effect, together with optimized thermal management and combustion systems. This also allows over 70 kW/l to be produced under stoichiometric operating conditions. The engines have been specifically designed to have compact external dimensions, for their respective power outputs, and to be able to be manufactured using well understood processes in local markets using their supply base. This paper discusses some of the key design features that have been implemented and the performance attributes of these two new high-specific output 3-cylinder gasoline engines.