Chapter 16 PowerPoint

Define these Technical Terms using the textbook:

1. brake horsepower

2. chassis dynamometer (dyno)

3. compression gauge

4. compression pressure

5. compression ratio

6. cubic centimeters(cc)

7. cubic inch displacement (CID)

8. engine torque

9. horsepower

10. volumetric efficiency

Answer these discussion questions using the textbook:

1. Explain engine compression ratio and how it affects engine performance.

Read the chapter summary below:

■ Engine size is determined by cylinder diameter, amount of piston travel on each stroke, and number of cylinders.

■ Cylinder bore is the diameter of the engine cylinder.

■ Piston stroke is the distance the piston moves from TDC to BDC.

■ Piston displacement is the volume the piston displaces (moves) from BDC to TDC.

■ Engine displacement, or engine size, equals piston displacement times the number of engine cylinders.

■ Force is a pushing or pulling action.

■ Work is done when force causes movement.

■ Power is the rate, or speed, at which work is done.

■ Engine compression ratio compares cylinder volumes with the piston at TDC and BDC.

■ Compression pressure is the amount of pressure produced in the engine cylinder on the compression stroke.

■ Torque is a turning, or twisting, force.

■ Engine torque is a rating of the turning force at the engine crankshaft.

■ Horsepower (hp) is a measure of an engine’s ability to perform work.

■ Brake horsepower (bhp) measures the usable power at the engine crankshaft.

■ An engine dynamometer (dyno) is used to measure brake horsepower.

■ A chassis dynamometer measures the horsepower delivered to the drive wheels.

■ Volumetric efficiency is the ratio of actual air drawn into the cylinder and the maximum possible amount of air that could enter the cylinder.

■ Mechanical efficiency compares brake and indicated horsepowers. It is a measurement of mechanical friction.

■ Thermal efficiency is heat efficiency found by comparing fuel burned and horsepower output.