Internal combustion engines – theory for the application of conventional and renewable fuels

• Calculate basic parameters that are important to characterize the operation of an engine and analyze the effect of varying them on the performance and fuel economy
• Calculate the needed engine size of a road vehicle reaching a given top speed and the effect of engine layout on vehicle fuel consumption per distance.
• Determine stoichiometric ratio for regular and advanced fuels and evaluate the heating value of such mixtures.
• Extract the engine specific emissions based on exhaust concentration measurements.
• Assess the differences in specific performance (IMEP) and efficiency of ideal thermodynamic cycles like the Otto-cycle, Diesel-Cycle, Seiliger (pressure limited) cycle and Rankine-cycle.
• Elaborate on the interaction between in-cylinder flow and combustion.
• Use simple models to describe the combustion processes with conventional and sustainable fuels in Spark Ignition and Compression ignition engines.
• Explain the principle of exhaust aftertreatment systems used for SI and CI engines.
• Discuss the use of major parameters that govern the gas exchange process in two- and four-stroke engines.
• Develop a simple mode for tuning of inlet and exhaust systems for two and four-stroke engines to maximize volumetric efficiency.
• Assess the synergy of engine and turbos for optimum performance and efficiency.

Parameters used to rate the performance of the engine in terms of specific power, efficiency and emissions are discussed. The link between engine performance and the need of a vehicle is exemplified. The fundamentals of combustion is followed by thermodynamic cycles utilizing the heat extracted from the combustion. Ideal Otto and Diesel cycles are followed by a realistic example. The resulting output torque is derived together with a discussion on engine mechanical balance. The fluid flow in the cylinder and the turbulence generated is discussed before combustion in Spark Ignition, SI, engine is explained in some detail. The uncontrolled combustion, knock, is also explained. Engine out emissions from SI engines are explained before the introduction of exhaust aftertreatment systems. The combustion with Compression Ignition (Diesel) is explained. Exhaust emissions and aftertreatment of the CI engine is introduced. The gas exchange system of two and four stroke engines is introduced. The usage of mechanical compressors and turbos is also explained.
There will be experiments with a diesel engine in a test cell to evaluate the performance, efficiency and emissions. A basic engine simulation software will also be developed by the students.

• 36 – 49 (Mon 13-17)

41401/41045/62604

Lectures, Laboratory experiments, computer simulation and problems