Question

A two stroke cycle gives ____________ the number of power strokes as compared to four stroke cycle engine at the same engine speed.

• A. Half
• B. Same
• C. Double
• D. Four times

Hint:

Think about how many crankshaft revolutions each cycle needs to complete one power stroke.

Answer 1

The Correct Option is C

Step 1: In a four stroke engine, one power stroke occurs once every two revolutions of the crankshaft, since the four strokes (intake, compression, power, exhaust) together take 2 revolutions and only one of them is the power stroke.

Step 2: In a two stroke engine, one power stroke occurs once every single revolution of the crankshaft, because the whole cycle is completed in just 2 strokes, that is 1 revolution.

Step 3: So at the same engine speed, the two stroke engine fires once every revolution while the four stroke engine fires once every second revolution. This means the two stroke engine gives double the number of power strokes in the same time.

The correct option is 3, Double.