Wheel Torque To Crank Calculator

Crank Torque Formula:

\[ T_{crank} = \frac{T_{wheel}}{(gear\_ratio \times final\_drive \times efficiency)} \]

Wheel Torque (T_wheel):

Gear Ratio:

dimensionless

Final Drive:

dimensionless

Efficiency:

dimensionless

Crank Torque (T_crank):

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1. What is the Crank Torque Calculation?

The crank torque calculation determines the torque at the engine crankshaft based on wheel torque, gear ratio, final drive ratio, and drivetrain efficiency. This helps engineers understand the actual torque requirements at the engine level.

2. How Does the Calculator Work?

The calculator uses the crank torque formula:

\[ T_{crank} = \frac{T_{wheel}}{(gear\_ratio \times final\_drive \times efficiency)} \]

Where:

\( T_{wheel} \) — Wheel torque (Nm)
\( gear\_ratio \) — Current gear ratio (dimensionless)
\( final\_drive \) — Final drive ratio (dimensionless)
\( efficiency \) — Drivetrain efficiency (0-1, dimensionless)

Explanation: The formula accounts for torque multiplication through the transmission and final drive, while considering energy losses in the drivetrain system.

3. Importance of Crank Torque Calculation

Details: Accurate crank torque calculation is essential for engine design, performance optimization, transmission selection, and ensuring proper power delivery throughout the vehicle's operating range.

4. Using the Calculator

Tips: Enter wheel torque in Nm, gear ratio, final drive ratio, and efficiency (0-1). All values must be positive numbers with efficiency between 0 and 1.

5. Frequently Asked Questions (FAQ)

Q1: What is typical drivetrain efficiency?
A: Most modern vehicles have drivetrain efficiencies between 0.85-0.95 (85-95%), depending on the type of transmission and number of driven wheels.

Q2: How does gear ratio affect crank torque?
A: Higher gear ratios (numerically larger) require less crank torque to achieve the same wheel torque, as the transmission multiplies the engine torque.

Q3: Why is final drive ratio included separately?
A: The final drive is a fixed ratio in the differential that provides additional torque multiplication beyond the selected gear ratio.

Q4: Can this calculation be used for electric vehicles?
A: Yes, the same principle applies to electric vehicles, though their transmission systems may be simpler with fewer gear ratios.

Q5: How accurate is this calculation for real-world applications?
A: This provides a good theoretical estimate, but actual results may vary due to factors like tire slip, temperature effects, and varying efficiency under different load conditions.