and Already Passed Solutions 2025-
2026 Updated.
1. Which of the following accurately describes engine displacement?!
a. Total piston swept volume
b. Mean effective pressure
c. Peak horsepower
d. Peak torque - Answer a. Total piston swept volume
2. Engine breathing in the two-stroke cycle is usually referred to as?!
a. Inertial
b. Scavenging
c. Exhaust displacement - Answer b. Scavenging
3. The tendency of an object in motion to want to stay in motion is known as?!
a. Kinetic energy
b. Dynamic friction
c. Inertia
d. Mechanical force - Answer c. Inertia
4. When a modern diesel engine is running at optimum efficiency, the percentage of rejected
heat
would typically be?!
a. 20%
b. 40%
c. 60%
d. 80% - Answer c. 60%
5. What percentage of the potential heat energy of the fuel does the modern diesel engine
convert to
kinetic energy when it is operating close to optimum efficiency?!
a. 20%
b. 40%
c. 60%
,d. 80% - Answer b. 40%
6. In which of the four strokes of the cycle is the cylinder pressure at its highest in a running
diesel
engine?!
a. Intake
b. Compression
c. Power
d. Exhaust - Answer c. Power
7. Where does scavenging take place on a four-stroke cycle diesel engine?!
a. BDC after the power stroke
b. TDC after the compression stroke
c. Valve overlap
d. 10 to 20 degrees ATDC on the power stroke - Answer c. Valve overlap
8. Ideally, where should peak cylinder pressure occur during the power stroke?!
a. TDC
b. 10 to 20 degrees ATDC
c. 90 degrees ATDC
d. At gas blowdown - Answer b. 10 to 20 degrees ATDC
9. Which of the seven subcircuits of the engine deals with the camshaft, valvetrains, and
mechanical
actuation of injectors and fuel pumping apparatus?!
a. Powertrain
b. Feedback assembly
c. Lubrication circuit
d. Engine housing circuit - Answer b. Feedback assembly
10. When running an engine at idle speed, which would typically be the optimum location to
peak the
cylinder pressure?!
a. 20 degrees BTDC
b. 10 degrees BTDC
c. TDC
, d. 15 degrees ATDC - Answer d. 15 degrees ATDC
11. When running an engine at rated speed and load, which would typically be the optimum
location to
peak the cylinder pressure?!
a. 30 degrees BTDC
b. 15 degrees BTDC
c. TDC
d. 15 degrees ATDC - Answer b. 15 degrees BTDC
12. At which point in the engine cycle does the crank throw leverage peak?!
a. TDC
b. Around 15 degrees ATDC
c. Just before 90 degrees ATDC
d. BTDC - Answer c. Just before 90 degrees ATDC
13. Which law states that all energy forms are convertible?!
a. The first law of thermodynamics
b. The second law of thermodynamics
c. Boyle's law
d. Charles's law - Answer a. The first law of thermodynamics
14. The energy of motion is known as?!
a. Inertia
b. Kinetic
c. Thermal
d. Potential - Answer b. Kinetic
15. Which of the following is required to produce peak torque in a diesel engine?!
a. Peak brake power
b. Peak cylinder pressure
c. Peak volumetric efficiency
d. Peak mechanical efficiency - Answer b. Peak cylinder pressure