Increasing the compression ratio of a diesel...

Question 1 of 270705eccefa1bacbc34ba4d47359

Increasing the compression ratio of a diesel engine while maintaining the designed rate of fuel flow will result in __________.

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Question 1 of 27070

Increasing the compression ratio of a diesel engine while maintaining the designed rate of fuel flow will result in __________.

🔍 Key Concepts

• compression ratio and how it affects peak temperature and pressure in the cylinder • basic diesel cycle / thermal efficiency relationship to compression ratio • what happens to heat losses and cylinder pressure when compression ratio changes

💭 Think About

• If the same amount of fuel is injected but the air is compressed to a higher pressure and temperature before injection, what happens to the combustion temperature and pressure? • How does increasing compression ratio generally affect the efficiency of an ideal diesel (or Otto) cycle? Think in terms of work output vs. heat input. • Would higher compression normally cause more or less heat to be rejected to the exhaust and cooling water, for the same fuel flow?

✅ Before You Answer

• Recall that in a diesel engine, ignition is caused by compression heating the air – what does more compression imply? • Consider whether cylinder peak pressure would be higher or lower with increased compression, all else equal. • Think about whether a higher compression ratio makes the engine convert a greater fraction of fuel energy into work or into waste heat.