🔍 Key Concepts

• Air charge density in diesel engines and how temperature affects it (cold vs warm air) • Relationship between intake air temperature, oxygen available, and combustion efficiency • How changes in air density influence power output and mean effective pressure

💭 Think About

• If you cool the intake air, what happens to its volume and density for the same mass of air going into the cylinder? • How does a denser air charge affect the amount of fuel you can burn efficiently in each cycle of a diesel engine? • Looking at the choices, which ones describe effects that would logically result from having more oxygen per unit volume in the cylinder?

✅ Before You Answer

• Recall that cooler air is denser than warmer air at the same pressure. • Think about whether compression ratio is a fixed geometric property of the engine or something that easily changes with air temperature. • Check which choices would be consistent with more mass of air (and oxygen) per cylinder charge, and eliminate any that describe the opposite.