How to apply more torque to increase speed from steady-state

In summary: In a car with an automatic transmission, the gearbox will buffer the power so that when you put your foot down on the accelerator, the engine will start to turn faster but the car will still be in the same gear.
  • #1
jjolla
1
0
If I am traveling along at a steady 60 kph in top gear ... and say my tacho is showing 2000rpm,
then my "torque curve" says for this rpm the engine is outputting a specific torque - as I understand it, this is what is needed to zero out the forces from wind resistance and other frictional forces. Thus the net force will be zero and i maintain a steady speed.

Great ... now, how do i accelerate to increase speed? Put my foot further down on the accelerator ... but how does the car experience a higher torque at my starting 2000rpm? (assuming i stay in the same gear). Remember, at 2000rpm, the Torque curve tells me I have a specific torque value .. so in order for me to have more torque, i need more rpm ... but this means i need more speed. (this is a chicken/egg scenario)

I am assuming one of two explanations:

(a) the Torque curve actually represents the Max torque at Full throttle ... so anything less than full throttle means you get smaller torque (than the graphs we see) at any given rpm ; or

(b) the gearbox has some buffering/damping ... so when I put my foot down the revs go up even athought the speed of the wheels follow more slowly behind.

Of course, new cars have auto self-adjusting everything (valves, continuous transmission ratios, etc) ... but let's answer the question assuming I have a stick-shift jalopy from the 60's ... so which is it? (a) or (b) or (c) both or (d) something else?
 
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  • #2
jjolla said:
...
Great ... now, how do i accelerate to increase speed? Put my foot further down on the accelerator ...
Hint: Think "throttle" instead of "accelerator".
 
  • #3
It's a. Power curves as seen from a dyno are typically at wide open throttle.
Part throttle will give some value less than this.
 
  • #4
jjolla said:
(a) the Torque curve actually represents the Max torque at Full throttle ... so anything less than full throttle means you get smaller torque (than the graphs we see) at any given rpm ;

This is the correct explanation.
 

1. How does torque affect speed?

Torque is a force that causes an object to rotate around an axis. In the case of applying torque to increase speed from steady-state, it is the force that is responsible for accelerating the object and increasing its speed.

2. What factors influence the amount of torque required to increase speed?

The amount of torque required to increase speed from steady-state is influenced by several factors, including the mass of the object, the distance from the axis of rotation, and the frictional forces present.

3. How can I increase the torque applied to an object?

To increase the torque applied to an object, you can either increase the force being applied or increase the distance from the axis of rotation at which the force is being applied. This will result in a greater torque being exerted on the object, causing it to accelerate and increase in speed.

4. What are some ways to increase the speed of an object using torque?

One way to increase the speed of an object using torque is by using a gear system. By increasing the gear ratio, you can increase the torque applied to the object, resulting in a higher speed. Another way is by reducing the friction between the object and its surroundings, allowing for a greater transfer of torque and an increase in speed.

5. Can too much torque be applied to an object?

Yes, too much torque can be applied to an object, which can result in damage or failure of the object. It is important to consider the limitations and capabilities of the object when applying torque to increase speed. It is also important to ensure that the object is properly supported and that the torque is being applied in a safe and controlled manner.

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