What is engine torque?
When motorists choose a car, read the characteristics of new products in various editions, then first of all they are interested in how many “horses” fit in the novelty under the hood, what are the engine appetites, what is its maximum speed. But about one important parameter is forgotten by almost everyone, even experienced motorists. This is the engine torque. This parameter can tell about the characteristics of the motors much more. Why? Let's find out.
Moment - not power
The capabilities of the power units were rated in power from the very moment when the first self-propelled mechanisms appeared. But power allows only a partial characterization of the thrust force of a motor.This is easily noticeable on the ICE of one class. So, on different cars you can observe that the dynamic characteristics may vary. That is, one car behaves quite briskly already at low revs, and on the other, to achieve the same effect, it is necessary to spin the flywheel to almost maximum revolutions.
What is car engine torque?
If we talk about science, it is a physical quantity. This is the product of a force that is applied to a lever 1 m long and the distance from the axis in which this lever rotates to the point where the force is applied.
In the school course of physics, this quantity was called the "moment of force", and in the courses of mechanics - the "torque." This force is measured by the number of Newtons per meter.
The engine torque is a quantity that indicates the thrust force of the unit. The greater the value of torque from the engine to the wheels, the better and the more weight this engine can move, and the more acceleration will be able to develop this car. So, trucks, tractors, various bulldozers, sports cars really need high torque motors.
But this force, which comes from the motor to the wheels, no longer depends not even on the characteristics of the engine. In a greater degree of dependence here is observed on the transmission ratios. So, the higher the gear ratios, the greater the moment will be given to the wheels at the engine speed. This machine will have a higher dynamic performance.
Where and how is the moment born?
In order to find out where this phenomenon is formed from, we need to recall the principle of the internal combustion engine. You do not need to consider the whole process, consider the cylinders.
At the beginning of the cycle fuel is injected into the cylinder cavity. Then the piston rises, and the mixture of air and fuel is compressed. After that, the spark plug comes into play. With the aid of a spark, the mixture is ignited and then expanded. At the same time the piston goes down and makes the crankshaft rotate.
When the driver presses the accelerator pedal, the volume of the injected mixture increases, the piston will move faster. Naturally, the crankshaft will also rotate at higher revs. So there is a torque of the engine.
What depends on the amount of torque?
The maximum speed depends on the dynamic characteristics. If the engine gives the best dynamics, then it can reach maximum speed faster. The process of acceleration is influenced mostly by power only. This is a constant force, it can be regulated by turns. More momentum - more power. How fast the car will gain momentum depends on the number of these revolutions.
But the speed with which the unit will pick up speed, is completely dependent on the torque. And the engine torque itself depends on the number of revolutions.
How to calculate this value?
For these purposes, there is a formula from the physics course. This is Mc = F * L, where F is the force with which the crankshaft rotates, and L is the shoulder length.
But to perform accurate calculations using this formula is quite difficult. The crankshaft rotational force is variable. When the piston is directed downwards, an empty seat appears in the cylinder, and the force that acts on the piston loses power.
Therefore, in order to calculate the engine torque, the formula gives only approximate values. Moment easier to determine the number of revolutions of the engine. But do not think that it will be constant along with turns. This force tends to grow with increasing speed, and when the speed reaches the peak threshold, the torque decreases. This can be easily noticed if you overclock a car.
Each driver noticed that at the start the car goes to accelerate more slowly, but after a while the speed with which the car accelerates grows. Then after a time, it decreases again.
Power and torque
Power is measured in horsepower. However, in most average cars all power will be used only at the maximum speed. In the city at about 2000 about. the engine will only be able to use half of the herd. The unit will show itself in full force only when overtaking at high revs. Moreover, the more the moment grows, the faster the turnovers increase. There is a relationship between the moment and the length of the connecting rod. Longer connecting rod - stronger moment.
When the engine gives maximum power to 6000 rpm, it is necessary to increase the rpm from 2000 rpm to accelerate. It takes some time, which is very important when performing overtaking. In the case of a high-torque motor, the maximum power may appear as early as 2000 vol.
These engines can be ranked most with low volumes. Also higher than that of a gasoline engine, the torque of a diesel engine, even at lower power and low revs.
It is those who own such cars, write on the forums that the power is far from power, but in the moment.
The moment of 200 Nm at low revs will be much better than the same time at 4000 rpm. The best option is a motor, in which the torque values will be practically peak throughout the entire rev range. But it is very expensive.
Diesel or petrol?
Knowing what the engine torque is, you can compare the gasoline engine and diesel. So, the moment in the internal combustion engine on gasoline is small, and it can be reached at 3000 rpm. However, these motors are easily gaining maximum speed.
Diesel engines do not like high speed, often there is a maximum - 5000 rpm. But the moment of diesel engines is much higher, and you can even use it at idle.
For example, you can take two 2-liter units. The first - a diesel engine in 140 hp. and 320 Nm of torque and an injection engine of 150 hp. The rated torque of the engine is 200 Nm. Even without testing, there is a difference in the moment with a minimum number of revolutions.
If you test both units, the diesel is already at 1-4 thousand. will show power up 40 hp This is a big difference.
No need to trust high power. The moment is also important when choosing a car. High torque is high dynamic performance. Also, high torque at low revs saves fuel.
For example, the torque of the engines of VAZ is achieved at medium speed, and allows these cars to feel confident in the conditions of the city.
Since we have touched on the topic of torque, then we need to talk about this characteristic. Elasticity - the ability to gain momentum in the loaded state.
This is expressed, for example, in acceleration from 60 to 100 km in fourth gear. Sometimes it happens that modern high-tech engines with high torque at low revs allow you to feel good dynamics in the city, but on the track it will be worse than any average aggregate.
How to increase the moment?
If you need to improve the dynamics of the car, you can apply several ways. This increase in volume, installation of supercharging, as well as changes in gas dynamics.
Engine displacement can be increased by replacing a crankshaft with a large eccentric or with the help of boring cylinders. Replacing the crankshaft often requires certain costs, and the desired model is very difficult to find.
It is much more profitable to grind the cylinders. The walls fully admit such an event. You can even do with serial pistons. However, not the fact that such a replacement would be cheaper than replacing a crankshaft.
Additional boost can be applied only where there is already a turbine.This method requires additional changes. You can change the charge by raising the bar to release pressure. Also, along with this, it will be necessary to further improve the combustion chambers, change the cooling system, radiators, air intakes.
You can do less radical chip tuning. So, with the help of flashing the electronic unit, it is quite realistic to easily and easily change many important parameters and characteristics of the car.
We live in the modern world and are increasingly seeing the birth of new technologies. So, everyone who is interested in cars knows Tesla, which produces electric cars. Photos of their latest model are presented below.Asynchronous electric is used as a motor there. And the torque of the asynchronous motor, depending on the model, is from 420 Nm to 600. These are huge numbers. With such specifications, the available motor can accelerate a car up to 100 kilometers per hour in 6.5 seconds with a minimum configuration.
So we know what the torque of an internal combustion engine is. If the power of the units helps to increase car sales, then the moment helps the car move forward.
But the power and power of the moment are connected.Power is the amount of work, and the moment is the ability of the engine to perform such work. This is the resistance that the unit needs to overcome.
That's what torque really is. This is an important feature paired with power.