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rrowe

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- TL;DR Summary
- While trying to simulate the physics of a Toyota Camry, my values for torque during acceleration seem to be nigh impossible when compared to the car's specified maximum torque.

I'm trying to simulate the physics of a Toyota Camry during acceleration with a time granularity of 100ms. My simulated conditions are as follows:

m = 1590 kg

v = 17 m/s

a = 1.5 m/s

η (transmission efficiency) = 0.85

r

F

F

F

F

The car is in 4th gear with a ratio of 1.46 and a total differential gear ratio of 2.8. This yields a combined effective gear ratio G = 1.46 × 2.8 = 4.088.

I've been operating under the assumption of perfect road traction, yielding the equation:

ω

I've been using many of the equations from the Engineering Toolbox. Specifically, here I'm using equation (3) from Car - Required Power and Torque. Rewritten using my naming conventions and solving for torque:

τ

Given the relationship between angular velocity above, I know ω

τ

When I solve for torque given the conditions stated, I get:

τ

The specifications list the maximum torque output of the Camry as 184 lb ft ≈ 250 N⋅m. How is it possible that I'm exceeding the maximum torque for this vehicle while accelerating at such a relatively leisurely rate?

m = 1590 kg

v = 17 m/s

a = 1.5 m/s

^{2}η (transmission efficiency) = 0.85

r

_{wheel}= 0.35 mF

_{drag}= 100 NF

_{friction}= 260 NF

_{accel}= 1590 kg × 1.5 m/s^{2}= 2400 NF

_{total}= 100 N + 260 N + 2400 N = 2760 NThe car is in 4th gear with a ratio of 1.46 and a total differential gear ratio of 2.8. This yields a combined effective gear ratio G = 1.46 × 2.8 = 4.088.

I've been operating under the assumption of perfect road traction, yielding the equation:

ω

_{engine}= Gω_{wheel}I've been using many of the equations from the Engineering Toolbox. Specifically, here I'm using equation (3) from Car - Required Power and Torque. Rewritten using my naming conventions and solving for torque:

τ

_{engine}= F_{t}r_{w}ω_{w}/ω_{e}ηGiven the relationship between angular velocity above, I know ω

_{w}/ω_{e}= 1/G. This then yields:τ

_{e}= F_{t}r_{w}/GηWhen I solve for torque given the conditions stated, I get:

τ

_{e}= 2760 N × 0.35 m / (4.088 × 0.85) = 278 N⋅mThe specifications list the maximum torque output of the Camry as 184 lb ft ≈ 250 N⋅m. How is it possible that I'm exceeding the maximum torque for this vehicle while accelerating at such a relatively leisurely rate?