Chapter 8 Multiple choice questions

. Section 8.2 describes the petrol or spark ignition engine. Box 8.1 and Figure 8.2 describe the combustion process in a four-stroke internal combustion engine. What happens on the induction stroke?

. Box 8.2 on pages 273-274 describes power and speed. A cyclist on a flat road is travelling at 5 metres per second (11 mph). He weighs 80 kg and his bicycle another 20 kg. If he has to stop within 5 seconds, what will be the rate at which the cycle's brakes must dissipate heat?

. What does the 'octane rating' of petrol indicate?

. Section 8.3 describes the diesel engine. Those in cars typically rotate at up to 4000 revolutions per minute (r.p.m). How fast do the diesel engines in the largest container ships rotate?

. Section 8.4 describes reducing pollution from petrol and diesel engines. The nitrogen in the combustion air in an engine can be oxidized to the acid gas nitrogen oxide. This reaction only takes place above what temperature?

. Which of the following is a method of reducing the NOx emissions of diesel engines, requiring the injection of ammonia into the exhaust gas stream?

. Section 8.5 describes the gas turbine. Box 8.4 describes the principles of the turbojet engine. The turbine blades must be capable of surviving high temperatures. What are they coated with to enable this?

. Jet engines propel an aircraft forwards by producing a stream of fast-moving gas moving backwards. The phrase 'for every action there is an equal and opposite reaction' is which law of physics?

. In a jet engine a large mass flow at a low velocity can produce more useful thrust than a smaller flow at a higher velocity. What component of a modern jet engine is used to achieve this?

. Section 8.6 describes the Stirling engine, which can be almost silent. Between 1937 and 1946 the Dutch Philips company developed a small portable Stirling engine generator. What was its intended use?

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