What is Torque?

is a torque force for rotating an object occurs. The torque of the engine refers to an engine output torque from the crankshaft end. It is inversely proportional relationship with the engine speed, the faster the speed the smaller the torque in the fixed condition of the power, the greater the contrary, it reflects the car load capacity within a certain range.

1. Torque Glossary

Physics torque is the torque magnitude equal to the product of force and moment arm, is the international unit Nm Nm, can also be seen in addition kgm, lb such units -ft torque, since G = mg, when g = 9.8 when the weight is 1kg 9.8N, so 1kgm = 9.8Nm, and lb-ft lb-ft of torque units are imperial, 1lb = 0.4536kg; 1ft = 0.3048m, can be calculated 1lb-ft = 0.13826kgm. In everyday expression, the torque is often referred to as torque (in physics this is two different concepts). For example: 8 Civic 1.8 Generation of torque 173.5Nm@4300rpm, the presentation engine 4300 r / time output torque 173.5Nm, that 173.5N of force how to make more than one ton of cars run up it? In fact, the engine torque is sent to the amplified (the price is at the same time the speed is reduced) It is up to the gearbox, the final pass and tires. Engine torque is released through the first transmission for “tunable” amplifying torque (or reduction ratio at ultra speeds) and then spread to the final pass (end banquet) was further amplified (while further reducing the rotational speed), and finally through the tire the driving force is released. 1 as a car speed gear ratio (the gear ratio of the gear, the gear ratio of the radius of essentially) is 3, 4 year-end party, the tire radius of 0.3 m, then the original torque is 200Nm, and finally becomes torsion axle 200 part × 3 × 4 = 2400Nm (100 set the transmission efficiency percentage) divided by the tire radius of 0.3 m, the friction of the tire with the ground there 2400Nm / 0.3m = 8000N, i.e., the driving force of 800 kilograms force, which is sufficient to drive car.

2. Detailed engine torque


is a torque force for rotating an object occurs. The torque of the engine refers to an engine output torque from the crankshaft end. It is inversely proportional relationship with the engine speed, the faster the speed the smaller the torque in the fixed condition of the power, the greater the contrary, it reflects the car load capacity within a certain range.

In some cases the car can really reflect the “nature”, such as when starting or driving in the mountains, the higher the torque reaction of the car will run better. To do the same type of comparison engine car, the greater the load greater the amount of torque output, better acceleration performance, stronger climbing force, the more the number of shiftLess wear and tear on the car will be relatively reduced. Especially when the car starts zero speed, but also shows a high torque by lifting fast advantages.

● representation

of torque representation

Nm is an engine (N.m). The same power, as described generally in the maximum engine output torque is also marked revolutions per minute (r / min). Generally appear in the maximum torque, the low speed range of the engine, as the speed increases, but decreases torque.

● physical principles

torque and power, is one of the major automobile engine index, which reflects the performance in the car, including acceleration, climbing ability and the like. Its precise definition is: piston reciprocates in the cylinder, back and forth once will do some work, its international standard unit is the joule (J). In the work done per unit distance is the torque. Popular speak, a car engine torque is a measure of the quality of an important criterion, power is proportional to the size of a car engine torque.

For popular example, play a very appropriate analogy, like the human body as in motion, power is like the body’s durability, while torque is the body of the explosive. For the family car, the acceleration torque is higher the better; the greater the greater the degree of climbing for off-road vehicles, the torque; for trucks, the larger the torque the greater the weight of broaching. The torque is higher the better car, when traveling in the same way, in the case of the same displacement, the engine torque is higher the better. While driving the car will feel anything, to accelerate can be accelerated, “posted back a sense of” very good. Torque is one of the main parameter for evaluating the performance of a car. Now there is an important evaluation of a car data, the car is the acceleration time from 0 to 100 km / h. And this torque acceleration time depends on the car engine.

In general, the highest index of the torque can be achieved at relatively low engine speeds, the engine will be described preferred process of the car, power or. Some cars about speed 5000 / min to reach the highest index of torque the car indicating that “power” is not a director of this car. It can be said that we pursue driving pleasure mainly from the torque, the so-called “push back” if the maximum torque of the engine of a car appeared in the rev range we often use, then thisThe car can definitely bring you extraordinary driving pleasure. For the family car, the perfect engine maximum torque should occur at a very low speed, and maximum power occurs at a relatively high speed. .

Equation 3 calculates the engine torque

Overall, the driving force of the car is calculated by the following formula:


[123 ] = torque of a driving force transmission gear ratio × × ÷ final gear ratio × tire radius mechanical efficiency (unit: m)

Summary: 1kgm = 9.8Nm1lb-ft = 0.13826kgm1lb-ft = 1.355Nm

in certain circumstances displacement, small bore, the stroke length of the cylinder the torque more emphasis on play, the rotational speed will not be too high, applied to a vehicle requiring a large load. And a large bore, short stroke cylinder more emphasis on output power, typically high speed, the race is applied to a vehicle. Briefly: power is proportional to the rotational speed × torque.


why the engine power can be calculated by the torque out?

Power P = power W ÷ time t work W = force F × Distance s therefore, P = F × s / t = F × velocity v

v here is the linear velocity, and in the engines, the line speed of the crankshaft = angular velocity ω × crank radius r of the crankshaft into the above equation obtained: P = power force F × r × radius the angular velocity [omega]; the force F × radius r = torque

stars: power P = [omega] the angular speed × torque so that the power from the engineTorque and rotational speed calculated

of the angular velocity in radians / sec, a representative of π radians in 180 degrees. .

4 intrinsic factors related factors yield strength

Effect of the yield strength are: a bond, organization, structure, atomic nature.

The yield strength of the metal and the ceramic, polymeric materials can be seen in comparison affect bond is fundamental. Effect from the organizational structure point of view, there are four kinds of strengthening mechanisms may influence the yield strength of the metal material, which is:

● solid solution strengthening;

● deformation strengthening;

[123 ] ● precipitation strengthening and dispersion strengthening;

● grain and sub-grain strengthening. Precipitation strengthening and fine grain strengthening means is the most common industrial material yield strength alloy improved. In these types of strengthening mechanisms, the other three mechanisms while improving the strength of the material, but also reduces the ductility, grain and sub grain refinement only, and can not only improve the strength of the plastic increases. External factors

Effect of the yield strength are: temperature, strain rate, stress state.

As the strain rate decrease the temperature increased, the yield strength of the material increases, especially in body centered cubic metals are particularly sensitive to temperature and strain rate, which results in a low-temperature embrittlement of steel. The effect of stress state is also very important. Although the yield strength is an essential indicator to reflect the intrinsic properties of the material, but with different state of stress, the yield strength values ​​are different. We usually yield strength of said material generally refers to the yield strength of the uniaxial stretching.

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