🔍 Key Concepts

• Purpose of a cylinder relief (safety) valve on a diesel engine • Effect of liquid vs. gas being compressed in a cylinder • Conditions that cause abnormally high peak pressure in a cylinder

💭 Think About

• Think about what happens to pressure in a cylinder when something that does not compress easily is present during the compression stroke. • Ask yourself which option would most directly cause a sudden dangerous rise in cylinder pressure, enough to lift a safety/relief valve. • Consider how each choice (low compression, high exhaust temperature, poor fuel penetration) would actually affect maximum cylinder pressure during operation.

✅ Before You Answer

• Identify which option involves something essentially incompressible inside the cylinder. • Check which conditions normally cause excessively high cylinder pressure, not low pressure or just high temperature. • Eliminate any choices that mainly affect combustion quality or temperature rather than directly causing a sharp spike in cylinder pressure.