Question
Calculate the RPM for an engine with the following parameters:
4 cylinders,
a stroke length of 0.66 feet,
a bore of 3.1 inches,
has an indicated mean effective pressure (IMEP) of 1100 psi per cylinder,
and operates at 5500 horsepower.
Round to 1 decimal place. Remember,
RPM
4 cylinders,
a stroke length of 0.66 feet,
a bore of 3.1 inches,
has an indicated mean effective pressure (IMEP) of 1100 psi per cylinder,
and operates at 5500 horsepower.
Round to 1 decimal place. Remember,
Ask by Graham Evans. in Canada
Dec 09,2024
Upstudy AI Solution
Tutor-Verified Answer
Answer
The RPM of the engine is approximately 1379.0.
Solution

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The Deep Dive
To calculate the RPM, we first need to find the displacement and then use the given horsepower and IMEP to find the engine speed.
-
Convert the bore and stroke to consistent units:
- Stroke = 0.66 feet = 0.66 x 12 = 7.92 inches
- Bore = 3.1 inches (no conversion needed)
-
Calculate the engine displacement for one cylinder:
-
Total displacement for 4 cylinders:
-
Calculate the work done per cycle per cylinder using IMEP and displacement:
-
Convert work done to horsepower:
The formula for horsepower can be given as:To find the work done in ft-lbs, convert the work done in psi-cubic inches: -
Relate horsepower to RPM:Substituting values and solving for N (which is RPM/2):
-
Solve for N:
-
Convert N to RPM:
After rounding, the RPM is approximately 659.8.