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The challenges of ever increasing combustion engine complexity coupled with the introduction of new and ever more stringent emissions regulations place a unique strain on the time available during the base engine hardware development and calibration phase of the product development cycle. Considering state of the art gasoline engine architecture (dual variable valve timing, direct injection with turbocharger) it is common to have at least 12 degrees of freedom as system inputs. The understanding of interactions and inter-dependencies of these inputs is therefore key in optimising the performance of the engine. MAHLE Powertrain has developed a process using a global Design of Experiment (DoE) technique based on Gaussian processes that can be used to accurately model and optimise many aspects of an engine’s performance.

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.

Emissions legislation, fleet CO₂ targets and customer demands are driving the requirements for reducing fuel consumption. This is being achieved in the gasoline market in the near term through the adoption of engine downsizing. In order to reduce fuel consumption further and in the wider real-world operating region complimentary technologies are being investigated and applied to an extreme downsized engine. In this paper future gasoline engine technologies are applied and experimentally assessed in terms of fuel consumption improvement whilst the impact of subsequent loadings on the thermal management system have been simulated, both over drive cycle and using real-world drive data.