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The problem of cracks in cylinder heads due to low cycle fatigue (thermal fatigue) is well known for engines with high specific power output. However it is still difficult to predict the lifetime of a new cylinder head due to the number of influencing parameters and the complexity of material behavior. Better understanding of cylinder head fatigue can improve the development process of a new engine concerning CAE as well as mechanical testing efficiency. Therefore a CAE tool which can calculate strains and stresses as a function of time for a defined operating cycle of the engine was developed. In parallel a measuring technique was developed which allows to measure strains on the surface of the combustion chamber side of the cylinder head during fired engine operation. For different Aluminum-Silicon casting alloys the material behavior was described in the Finite Element Program ABAQUS by a nonlinear kinematic / isotropic hardening model.

The CO2 reduction request for automotive industry promotes the efforts on the engine thermal efficiency improvement. The goal of this research is to improve the thermal efficiency on an extremely downsized 3-cylinder 1.0 L turbocharged gasoline direct injection engine. Effects of compression ratio, exhaust gas recirculation (EGR), valve timing and viscosity of oil on fuel economy were studied. The results show that increasing compression ratio, from 9.6 to 12, can improve fuel economy at relative low load (below 12 bar BMEP), but has a negative effect at high load due to increased knock intensity. EGR can significantly reduce the pumping loss at low load, optimize combustion phase and reduce exhaust gas temperature. Therefore, the fuel consumption is reduced at all test points. The average brake thermal efficiency (BTE) benefit percentage is 3.47% with 9.6 compression ratio and 5.33 % with 12 compression ratio.

The existence of the cyclic variation of the flow inside an cylinder affects the performance of the engine. Developing methods to understand and control in-cylinder flow has been a goal of engine designers for nearly 100 years. In this paper, passive control of the intake flow of a 3.5-liter DaimlerChrysler engine was examined using a unique optical diagnostic technique: Molecular Tagging Velocimetry (MTV), which has been developed at Michigan State University. Probability density functions (PDFs) of the normalized circulation are calculated from instantaneous planar velocity measurements to quantify gas motion within a cylinder. Emphasis of this work is examination of methods that quantify the cyclic variability of the flow. In addition, the turbulent kinetic energy (TKE) of the flow on the tumble and swirl plane is calculated and compared to the PDF circulation results.

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.

Under China’s “3060” target of carbon peak and carbon neutrality, heavy commercial vehicles are a key breakthrough point to promote the automobile industry to achieve carbon peaking and carbon neutrality goals. Green methanol, as a clean alternative fuel, are an effective technical route for heavy commercial vehicles to achieve energy conservation and emission reduction. Based on a 13L methanol engine, this study fully considers the methanol combustion characteristics, the ω shape combustion system of the base engine is redesigned as a pent-roof combustion chamber. The intake port is changed from a swirl port to a high-tumble port, and the piston crown is also adjusted adaptively. At the same time, the cam profile, cooling water jacket, intake and exhaust system are redesigned, and the turbocharger is re-matched according to the physical properties of methanol. CAE tools and means are used to optimize and determine the design proposal.

Gasoline Direct Injection (GDI) engines show advantages in reducing fuel consumption and gaseous pollution emissions when compared to Port Fuel Injection (PFI) engines. However, particulate matter emissions are an essential issue for GDI engine development due to increasingly stringent worldwide emission regulations. Previous studies have shown that gasoline fuel compositions, as well as deposits formed in GDI fuel injectors, can affect emissions in the GDI engine. In this work, the impact of gasoline fuel properties on forming injector deposits and the resulting effect on particulate emissions were investigated using a modern Chinese GDI engine. Six test fuels with different properties involving changes in olefins, aromatics, heavy (C9/C9+) aromatics, T90 and deposit control additive (DCA) were prepared based on the gasoline survey results from the Chinese gasoline fuel market and the China 6 gasoline fuel standard limits.