MEC403

MEC403 1 TURN OVER

DEPARTMENT OF MECHANICAL ENGINEERING – Autumn Semester 2009-2010 RECIPROCATING ENGINES 1 Hour Answer all questions. Symbols not defined have their usual meanings.

State all assumptions in your answer.

MEC403

MEC403 2

1. Whilst the reduction of CO2 emission is presently the primary task in automotive engine design, NOx, CO, soot and hydrocarbon emissions have to be within legislative limits. (a) What are the main production mechanisms of NOx, CO, soot and hydrocarbons in SI and CI engines? [16 Marks] (b) What methods are used to limit the emissions of NOx, CO, soot and hydrocarbons in SI and CI engines? [12 Marks] (c) Have the strategies used to control NOx, CO, soot and hydrocarbons had any impact on CO2 emissions? [2 marks]

2. The volumetric efficiency is reduced by fuel, frictional, charge heating,

choking, ram and reverse flow effects. Briefly describe each and sketch how volumetric efficiency is modified with engine speed. [14 marks]

3. How is the RON of a fuel measured? [6 marks]

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