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Based on the TurboDISI engine presented earlier [1], [2], a new Spray Guided Turbo (SGT) concept with enhanced engine performance was developed. The turbocharged engine was modified towards utilizing a spray-guided combustion system with a central piezo injector location. Higher specific power and torque levels were achieved by applying specific design and cooling solutions. The engine was developed utilizing a state-of-the-art newly developed charge motion design (CMD) process in combination with single cylinder investigations. The engine control unit has a modular basis and is realized using rapid prototyping hardware. Additional fuel consumption potentials can be achieved with high load EGR, use of alternative fuels and a hybrid powertrain. The CO2 targets of the EU (120 g/km by 2012 in the NEDC) can be obtained with a mid-size vehicle applying the technologies presented within this paper.

The challenge to reduce fuel consumption in S.I. engines is leading to the application of new series production technologies: including direct injection and, recently, the variable valve train, both aiming at unthrottled engine operation. In addition to these technologies, turbo- or mechanical supercharging is of increasing interest because, in principle, it offers a significant potential for improved fuel economy. However, a fixed compression ratio normally leads to a compromise, in that the charged engine is more of a performance enhancement than an improver of fuel economy. Fuel efficient downsizing concepts can be realized through the application of variable compression ratio. In this paper, a variable compression ratio design solution featuring eccentric movement of the crankshaft is described. Special attention is given to the integration of this solution into the base engine.