This is a GOOD read. If you want to understand Torque and Horsepower, read it.

In short:
Torque and work measurements tell us how much has been accomplished, but provides no clue how fast a given amount of work (or torque) is done. That’s the job of power, an expression of the rate or speed at which work is performed. The more power that is generated, the more work is done in a given time-period.

Torque Explained:
Torque is about how much the WORK is done.
Work = D (distance moved) x F (force applied)
For example:
You pushes (with a force of 20 pounds) a table to move forward 10 meters. Then the work done is: work = 10 meters * 20 pounds.
Engine’s torque is 320 NM, Newton*Meter (force*distance).
BUT the problem here is: Torque is only about how much work is done – 10 meters movement of table forwards with a power of 20 pounds. But it does NOT tell us about HOW FAST the work is done – how fast you move the table forwards.

Horsepower Explained:
Torque and work measurements tell us how much has been accomplished, but provides no clue how fast a given amount of work (or torque) is done. That’s the job of power, an expression of the rate or speed at which work is performed. The more power that is generated, the more work is done in a given time-period.

Suppose it takes a constant 100 lb-ft of torque to spin a nut onto a bolt one complete revolution. Your girlfriend takes 10 seconds to do this. You, being a real stud (pun intended), take only 5 seconds to perform the same task. You would be twice as powerful, because you performed the same work in half the time.

In the U.S. system, power is expressed as “horsepower” (hp). One hp is the amount of power it takes to perform 33,000 ft-lb of work in 1 minute.

ENGINE SPEE: RPM*1000

最大马力

马力是发动机功率大小的单位;最大马力指发动机在某一转速所能发出的最大功率。

扭矩是发动机输出端力矩,大小单位是牛顿.米。

它们的关系是:
发动机功率(马力或千瓦)=发动机扭矩(牛顿.米)×发动机转速(转/分钟)
马力和千瓦都是发动机功率的单位,1千瓦=1.35马力。

在油门开度相同的情况下,随着发动机转速的变化,扭矩和功率也随之发生变化,这就是厂家提供发动机功率和扭矩特性图。一般车辆的最大扭矩出现在3000~4000转/分钟的时候,然后下降;但由于“功率=扭矩×转速”,所以功率还会随着转速继续上升,大约在6000转/分钟的时候达到最大值。最大扭矩以后车辆一般还有一定的加速能力,因为只要发动机的扭矩能够克服路面阻力和空气阻力,车辆就能够有正的加速度,直到二者平衡;而是随着挡位的不同,这个转速也不是固定的。其实,马力大最高极速(Max Speed)就大;扭力大,瞬间加速的力道就大,简单来说,起步或突然加速时会比较快。

怎么看发动机工况图

汽车发动机工况图既发动机的特性曲线图,是表明发动机在不同转速下输出功率和扭矩的大小,从上可看出发动机的性能表现如何,发动机特性曲线图的横坐标为发动机的转速(转/分,或rpm),纵坐标为发动机的功率和扭矩,图中曲线为发动机在不同转速下功率和扭矩数值变化的轨迹。

发动机的特性曲线一般有两条,一条为功率曲线d,另一条为扭矩曲线e.

  功率曲线比较陡,这表明发动机的功率随着转速的提高而急剧上升,其峰顶对应的功率数值即为发动机技术参数中标注的“最大功率”。最大功率越大,汽车可能达到的最高车速也越高。

扭矩曲线的两端比较底,中间突起,并比较平缓。实际上中间突起越高和越平缓,表示发动机的扭矩特性越好,这种发动机的操纵性越好,汽车越好驾驭。如果在低速时便拥有较大的扭矩,表明汽车的起步性能要好;如果在中高速时才拥有较大扭矩,那它可能是一台高速性能的发动机,在高速行驶时性能较佳。


The graph is for a 9-3SS Aero 2.0T MY2007.

The max power (224.2HP) is achieved at 5004 rpm, which is relatively early.
The max torque is 329.8Nm at 3005 rpm.