Question

compression ratios beyond ____ generally will result in a decrease of engine efficiency
25 to 1
18 to 1
20 to 1
23 to 1
8 multiple choice 1 point
the camshaft and crankshaft within a four - stroke cycle engine are timed or synchronized to rotate together, how many times must a technician rotate the crankshaft to complete one full rotation of the synchronized camshaft?
1 rotation
3 rotation
4 rotation
2 rotation
9 multiple choice 1 point
the two - cycle diesel engine delivers a power stroke every ____ of crankshaft rotation.
360°
90°
120°
180°

Explanation:

1. In engines, a compression ratio beyond 18 to 1 generally leads to a decrease in engine efficiency due to factors like pre - ignition and increased heat losses.
2. In a four - stroke cycle engine, the camshaft rotates at half the speed of the crankshaft. So, to complete one full rotation of the synchronized camshaft, the technician must rotate the crankshaft 2 times.
3. In a two - cycle diesel engine, a power stroke occurs every 360° of crankshaft rotation.

Answer:

1. B. 18 to 1
2. D. 2 rotation
3. A. 360°