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Beside the traditional prediction of stresses and verification by mechanical testing the optimization of cylinder liner bore distortion is one of today's most important topics in crankcase structure development. Low bore distortion opens up potentials for optimizing the piston group. As the piston rings achieve better sealing characteristics in a low deformation cylinder liner, oil consumption and blow-by are reduced. For unchanged oil consumption and blow-by demands, engine friction and subsequently, fuel consumption could be reduced by decreasing the pre-tension of the piston rings. From the acoustical point of view an optimization of piston-slap noise is often based on an optimized bore distortion behavior. Apart from basics to the behavior of liner bore distortion the paper presents advanced analytical and empirical methods for detailed prediction, verification and optimization of bore distortion taking into account the effective engine operation conditions.

Like all technical fluids, lubricants are able to solve gases. While solved gas is a neutral part of the lubricant, dissolved gas has an influence especially on the compressibility behavior. The effects of oil aeration on engine drive causes malfunctions of several components. A successful optimization of the oil circulation concerning the oil aeration presupposes a safe and reproducible measuring procedure. The FEV has developed a measurement apparatus according to the principle of the volume measurement which allows a simple but efficient oil aeration measurement.

In recent years, more attention has been focused on environment pollution and energy source issues. As a result, increasingly stringent fuel consumption and emission legislations have been implemented all over the world. For automakers, enhancing engine’s efficiency as a must contributes to lower vehicle fuel consumption. To reach this goal, Geely auto started the development of a 3-cylinder 1.0L turbocharged direct injection (TGDI) gasoline engine to achieve a challenging fuel economy target while maintaining fun-to-drive and NVH performance. Demanding development targets for performance (specific torque 205Nm/L and specific power 100kW/L) and excellent part-load BSFC were defined, which lead to a major challenge for the design of the combustion system. Considering air/fuel mixture, fuel wall impingement and even future potential for lean burn combustion, a symmetrical layout and a central position for the injector with 200bar injection pressure was determined.

Modern passenger car engines are designed to operate at increasingly higher rated engine speeds with higher thermal loads. To reduce engine weight and length, the engines are usually siamesed without a cooling path between the cylinder liners. This leads to high temperatures in the siamesed area and to an increase in liner deformation. The distortion of the cylinder liners of internal combustion engines has a significant affect on engine operation. It can affect the oil consumption, the blow-by, the wear behavior and, due to friction, the fuel consumption. In order to achieve future requirements regarding exhaust emissions and fuel consumption, the development of low distortion engine blocks will play a significant role.

The connecting rod big-end bearing is one of the most heavily loaded components of the lubrication system of high speed combustion engines. The bearing's oil supply has to be designed consciantious in order to ensure an immaculate reliability in operation. The supply oil flow has to pass the main bearing and the rotating crankshaft before entering the connecting rod bearing. It is common knowledge that the centrifugal forces due to the crankshaft rotation influence the oil flow through the also rotating supply bore. The centrifugal forces effect a parabolic pressure profile along the supply bore. The oil pump has to ensure a certain pressure level in the main oil gallery (depending on the engine speed and the spherical positioning of the rotating bore) to overcome these centrifugal forces. If the oil pressure is lower than this certain level the bearing's oil supply will be interrupted - bearing damage is the consequence.

Fuel consumption of a modern combustion engine is significantly influenced by the mechanical friction losses. Particularly in typical city driving, the reduction of the engine friction losses offers a remarkable potential in emission and fuel consumption reduction. The analysis of the engine friction distribution of modern engines shows that the piston group has a high share at total engine friction. This offers a high potential to optimize piston group friction. The paper presents results of recent research and development work in the field of the tribological system piston/piston ring/cylinder bore.

The fuel consumption and the emissions of modern passenger cars are highly affected by the fluid and material temperatures of the engine. Unfortunately, the high thermal efficiencies of Direct Injection (DI) Diesel and Spark Ignition (SI) engines cause in many driving situations low heat transfer to the engine components and especially to the oil and the coolant. In these conditions the normal operating temperatures are not achieved. Especially at low ambient temperatures and low engine loads the requirement of a comfortable cabin heating and a fast warm-up of engine oil and coolant cannot be satisfied simultaneously. To reach the required warm-up performance, an Exhaust Heat Recovery System (EHRS) will be demonstrated. Further design and optimization processes for modern cooling systems in fuel-efficient engines require numerical and experimental investigations of supplemental heater systems to meet all requirements under all circumstances.