Calculating Cycles Per Second for a Four Stroke Diesel Engine

Understanding how engine speed relates to the number of power cycles completed is fundamental in engine mechanics. For a four-stroke engine, the crankshaft completes two full revolutions for every one power cycle (Intake, Compression, Power, Exhaust).

The question asks for the number of cycles completed per second for a four-stroke diesel engine running at a specific speed given in revolutions per minute (rpm). To find the cycles per second, we first need to convert the engine speed from rpm to revolutions per second (rps).

Step-by-Step Calculation

The engine speed is given as 6000 rpm. To convert this to revolutions per second, we divide by the number of seconds in a minute, which is 60.

Step 1: Convert RPM to Revolutions Per Second (RPS)

\[ \text{Engine Speed in RPS} = \frac{\text{Engine Speed in RPM}}{60} \]

\[ \text{Engine Speed in RPS} = \frac{6000 \text{ rpm}}{60 \text{ seconds/minute}} \]

\[ \text{Engine Speed in RPS} = 100 \text{ rps} \]

So, the engine crankshaft makes 100 revolutions every second.

Step 2: Determine Cycles Per Second for a Four-Stroke Engine

As mentioned, a four-stroke engine completes one full power cycle for every two revolutions of the crankshaft.

\[ \text{Cycles per Revolution} = \frac{1 \text{ cycle}}{2 \text{ revolutions}} \]

To find the number of cycles completed per second, we multiply the revolutions per second by the cycles per revolution:

\[ \text{Cycles per Second} = \text{Engine Speed in RPS} \times \text{Cycles per Revolution} \]

\[ \text{Cycles per Second} = 100 \text{ rps} \times \frac{1 \text{ cycle}}{2 \text{ revolutions}} \]

\[ \text{Cycles per Second} = \frac{100}{2} \text{ cycles/second} \]

\[ \text{Cycles per Second} = 50 \text{ cycles/second} \]

Therefore, for a four-stroke diesel engine running at 6000 rpm, 50 cycles are completed every second.

Summary of the Result

Engine Speed = 6000 rpm

Conversion to RPS = \( \frac{6000}{60} = 100 \) rps

Cycles per second for four-stroke engine = \( \frac{\text{RPS}}{2} \)

Cycles per second = \( \frac{100}{2} = 50 \)

The number of cycles completed per second for a four stroke diesel engine running at 6000 rpm is 50.