Engine torque, what is it?

Engine torque

The mechanisms, components or parts of the car, all together and each individually, are certainly important, but the main design element, of course, is the engine.

Analysis of the technical characteristics of this driving force generator allows us to judge how quickly a car picks up a certain speed, how its traction and dynamic capabilities change with an increase in its weight and driving in difficult road conditions.

The basic parameters of internal combustion engines, gasoline or diesel, which are installed on the vast majority of modern passenger cars, can be divided into two groups.

Structurally specified characteristics are laid down during the design and production process of the power unit, and are unchanged during operation:

• engine type (petrol or diesel);
• working volume;
• compression ratio of the air-fuel mixture.

Indicators characterizing the operation of the motor or the so-called operating parameters are:

• power;
• torque;
• specific fuel consumption.

Of greatest interest are the parameters on which the dynamic properties of the car directly depend - engine power and torque. What are these characteristics?

What is engine power

In official descriptions of the technical characteristics of power units, in parallel with the indication of power, the value of torque is necessarily given.

The concept of engine power and understanding of this parameter, as a rule, does not cause difficulties - it is a physical quantity that characterizes the engine work performed per unit of time.

That is, power shows how quickly a car with a certain mass can cover a given distance. The more power, the higher the maximum speed with a constant curb weight.

Power is measured in watts or kilowatts (kW), as well as horsepower. It is worth noting that “horsepower” is a non-system unit of measurement (1 horsepower = 735.5 W or 1 kW = 1.36 hp).

What is engine torque

The situation with the understanding of torque is somewhat different, but knowing the basic laws of physics and the basic structure of the power unit, you can easily clarify this concept.

Engine torque is a qualitative indicator characterizing the rotational force of the crankshaft.

This parameter is calculated as the product of the force applied to the piston and the arm (the distance from the central axis of rotation of the crankshaft to the place where the piston is attached (crank pin)). Torque is measured in newtons per meter (Nm).

The torque on the crankshaft, as follows from the above formula, depends on the force of gas pressure on the piston, as well as on the engine displacement and the degree of compression of the fuel mixture in the cylinders.

By the way, the significantly higher torque of diesel engines, compared to gasoline engines of similar volume, is explained by the extremely high compression ratio of the mixture of diesel fuel and air in the combustion chambers (gasoline - about 10:1, diesel - about 20:1).

The high engine torque provides the car with excellent acceleration dynamics even at low crankshaft speeds, significantly increases the traction characteristics of the power unit - increases the car's load capacity and its cross-country ability.

An internal combustion engine reaches its maximum torque value at certain speeds. For gasoline engines this figure is higher than for diesel engines.

Power or torque - what's more important?

If we conduct a comparative assessment of two engine performance characteristics - power and torque, then the following facts become obvious:

• torque on the crankshaft is the main parameter characterizing the operation of the power unit;
• engine power is a secondary performance characteristic of the motor, which, in essence, is a derivative of torque;
• the dependence of power on torque is expressed by the relation: P = M*n, where P is power, M is torque, n is the number of crankshaft revolutions per minute;
• engine power is linearly dependent on the crankshaft speed: the higher the speed, the greater the engine power (naturally, up to certain limits);
• torque also increases with increasing engine speed, but having reached its maximum value (at a certain crankshaft speed), its performance decreases, regardless of further increase in speed (the graph of torque versus engine speed looks like an inverted parabola).

Some conclusions

• When assessing the operational parameters of a car and the direct performance characteristics of its engine, the amount of torque has a higher priority than power.
• Among power units that have similar design and operating parameters, those with more torque are preferable.
• To ensure the best dynamics of vehicle acceleration and ensure optimal traction properties of the engine, the crankshaft speed must be maintained in the range of values ​​​​at which the torque reaches its peak values.

Change in torque and vehicle dynamics

To provide the best dynamic performance, automakers strive to install powertrains in vehicles that have maximum torque over a wider engine speed range. High torque is typical for diesel power units, as well as multi-cylinder and turbocharged engines.

To correctly assess the role of power and torque in shaping the dynamic characteristics of a car, you need to understand the following facts:

• a car with a more powerful engine, but not having sufficient torque, will be inferior in acceleration dynamics to a car with high torque;
• high torque, “picked up” by the engine at low speeds, allows the car to accelerate much more efficiently;
• the maximum possible speed of a car directly depends on the engine power, and torque does not affect this indicator: cars with enormous torque can develop a very modest maximum speed; example: sports cars (low driveshaft torque and high speed) or heavy SUVs (impressive torque and low top speed).

Regardless of the engine power, the acceleration dynamics of the car, as well as its ability to “briskly” climb hills, depend entirely on the magnitude of the maximum torque. The more torque is transmitted to the drive wheels and the wider the engine speed range in which it is achieved, the more confidently the car accelerates and overcomes difficult sections of the road.

It is worth noting that comparing the characteristics of engines that are structurally identical, but have different torques, makes sense only with the same transmission parameters; Gearboxes must have similar gear ratios. Otherwise, comparing engine torques makes no practical sense.

Source: http://avtonam.ru/useful/krutyashhij-moment-dvigatelya/

Torque and power: what is more important for a car - Kolesa.ru

I hope the point of view of those who say that “power is not important - only the moment is important” is clear enough? Once again: power as such depends directly on torque and is itself a mathematical, calculated quantity that cannot be measured separately from torque.

Torque, in essence, reflects the power that will be available at “partial” engine speeds, but simply when you press the gas when overtaking. And the more moments, the better! After all, the power at these speeds will be higher. And the more power, the more energy you can give to the car, the better the acceleration dynamics.

And maximum power primarily affects the maximum speed of the car.

Indeed, with correctly calculated gear ratios of the main gear and gearbox, it turns out that the maximum speed is achieved when the expended power is equal to the engine power.

And the power of all losses depends on the speed of movement, primarily on air resistance and rolling resistance of the wheels, and at some point it will definitely coincide with the power of the motor, and it is this speed that will be maximum.

There are, of course, miscalculations when the engine either cannot develop maximum power speed, or already “rests against” the limiter, but this does not happen very often.

Diesel moment

Now I will answer a typical but simple question: “Why do diesel engines traditionally have high torque, but at the same time they have low power compared to gasoline engines?” This is because diesel engines have limited operating speeds.

Due to the high compression ratio of diesel engines and slower-burning fuel, diesel engines perform worse at high speeds, but they do not have the risk of detonation, and the turbine can be installed more efficient and complex due to the lower temperature of the exhaust gases, so you can apply there is a lot of air and fuel, and the torque at low speeds will be very high. And sometimes in terms of power they will not even be so far from turbocharged gasoline ones, but the torque will be not just great, but huge.

For comparison, we present the characteristics of two three-liter engines from the modern BMW 5 series, where it will be seen that diesel engines are effective at lower speeds.

A diesel engine can be made more powerful than a gasoline engine, but then the already high torque will be increased by another quarter, which means that a new gearbox and new driveshafts capable of withstanding such power will be needed. And the engine itself will have to be made even stronger and heavier. Or you can “spin it up”, but then it will be more difficult for the fuel equipment to work, and you cannot allow the fuel to smoke and incompletely burn.

Source: https://www.kolesa.ru/article/chto-vazhnee-dlja-razgona-moschnost-ili-krutjaschij-moment-2015-02-02

What is more important: torque or engine power?

Despite the fact that horse-drawn transport has long “sunk into oblivion” and “l. With." is persona non grata in the international classification system, the “horse” unit of power measurement continues to be in demand. And not only among ordinary people, but also at the state level. To do this, just look at the receipt for payment of transport tax.

Meanwhile, “l.,” which appeared during the industrial revolution. With." very conditional.

That's because it measures the relative performance level of the average horse by determining the effort required to lift a 75-kilogram load one meter in one second.

The new unit of measurement, adopted by manufacturers to evaluate the superiority of stationary mechanisms over animals, eventually migrated to the world of rolling stock.

Later, Scottish engineer James Watt introduced the official unit of power measurement of his name - “Watt”, which was enlarged to “kW” for ease of use. Watt synchronized with HP. With.

in the ratio 1 kW = 1.36 l. s., never achieved universal love, leaving the palm to horse power.

However, power is power, but, as they say, it is not power that moves the car, but torque, measured in newton meters (N∙m).

What is torque?

Many motorists do not have an adequate idea of ​​what kind of “beast” this is. About it, however, as about power, there is a common opinion: the more, the better. In fact, these are closely related characteristics.

Power in watts is nothing more than torque in newton meters multiplied by the number of revolutions and by 0.1047.

In other words, power demonstrates the amount of work performed by the engine in a certain period of time, and torque reflects the ability of the power unit to perform this work.

If, say, a car is stuck in clay soil and immobilized, then the power it produces will be zero. After all, the work is not done. But the moment, although it is not enough for movement, is present. Torque without power can exist, but power without torque cannot.

The main achievement of a running motor when converting thermal energy into mechanical energy is torque, or thrust. High torque values ​​are typical for diesel engines, the design feature of which is a large piston stroke (larger than the cylinder diameter).

The high torque of a diesel engine is offset by the relatively low permissible speed, which is limited to increase the resource. High-speed gasoline engines tend to “lean” towards power, because their parts are lighter.

And the compression ratio is also lower. True, modern power units - both diesel and gasoline - as they improve, they become closer both structurally and in terms of performance. But for now, the banal rule of leverage remains: what you gain in strength, you lose in speed.

And, accordingly, at a distance.

The best features of an engine are determined by a combination of optimal power and thrust values. The earlier the maximum torque occurs and the later the peak of power, the wider the range of capabilities of the power unit. Electric motors have close to optimal characteristics.

They have traction close to maximum almost from the beginning of movement. At the same time, the power value increases progressively. A significant factor in determining power and torque is engine speed. The higher they are, the more power can be removed.

In this context, it is appropriate to mention racing engines. Due to their relatively modest volumes, they do not boast mind-blowing torque. However, they are capable of spinning up to 15–20 thousand.

revolutions per minute (min-1), which allows them to produce super power. So, if an ordinary power unit at 4000 rpm generates 250 N∙m and about 140 hp. With.

, then at 18,000 rpm it could produce around 640 hp. With.

Unfortunately, increasing the rotation speed is quite difficult. Inertial forces, loads, and friction interfere. Let's say, if you spin the motor from 6000 to 12,000 min-1, then the inertial forces will increase fourfold, which potentially threatens to overclock the motor. You can increase the torque using turbocharging, but in this case thermal loads begin to play a negative role.

The principle of maximum power output is eloquently illustrated by the engines of Formula 1 cars, which have a very modest volume (1.6 liters) and a relatively low traction index.

But due to supercharging and the ability to spin up to high speeds, they produce about 600 hp. With.

Plus, the F1 design is a hybrid, and the electric motor, which complements the main engine, adds another 160 “horses” if necessary.

An important characteristic that reflects the capabilities of the motor is the speed range at which maximum thrust is available. But even more important is the elasticity of the engine, that is, the ability to gain speed under load.

In other words, it is the ratio between the RPM for maximum power and the RPM for maximum torque. It determines the possibility of reducing and increasing speed by operating the gas pedal without changing gears. Or the ability to drive in high gears at low speeds.

Elasticity, for example, is expressed by the car's ability to accelerate in fifth gear from 80 to 120 km/h in fifth. The less time this acceleration takes, the more elastic the engine. Of two engines of the same volume and power, the one with higher elasticity is preferable.

All other things being equal, such an engine will wear out less, operate with less noise and consume less fuel, and will also make the operation of the transmission easier.

But if you still ask the question of what is more important - torque or power, dividing the world into black and white, the answer will be extremely simple: since these are dependent quantities, both are important.

Source: http://5koleso.ru/articles/garazh/krutyashchiy-moment-sila-dvigatelya

What is engine torque?

Hello, dear blog readers! The performance of the engine in a car is measured by many indicators that determine its efficiency, economy, and so on.

We talked about one of them - the compression ratio - earlier. But not many car enthusiasts know what torque is, although each of us has heard this term.

I propose to look into this issue in more detail.

   Relationship between speed and torque

It is this criterion that allows us to evaluate the potential of any internal combustion power unit. For this reason, many car enthusiasts are wondering how to increase this very moment. It is directly related to the speed of rotation of the shaft, and then, using the transmission, is transmitted to the drive wheels. They develop the necessary speed, so the car can move faster.

You can find out what speed your car produces in its technical passport. Many are interested in the maximum speeds that it is capable of delivering.

However, in practice we are faced with the following fact: up to a certain speed indicator, the car accelerates confidently and quickly, and then the engine seems to “get heavier”, the power decreases, then each new kilometer gained is given with great difficulty.

That is, the power unit delivered its maximum power at a certain number of revolutions.

At this stage, torque is put into operation, which is measured in newton meters, or Nm for short. The higher this indicator, the faster the engine will be able to collect the required horsepower.

Also, the faster it will be able to gain speed, which can be felt when pressing the accelerator pedal.

Here you can find the answer to the question: why is a car that should show high speeds not distinguished by agility and dynamics, what kind of dependence can be traced?

   Main indicators of engine performance

After the motor accelerates to a certain number of revolutions, the so-called “maximum torque” is activated.

The driver just needs to add gas to make sure that his car accelerates significantly.

This is where the main connection can be traced: the higher the torque, and the lower the number of revolutions, the more “spirited” your steel horse will be.

It would seem that this indicator should be directly related to power and nothing else.

However, in addition to it, there is also the concept of “elasticity” of the engine - it represents the relationship between power, total number of revolutions and their number during the maximum value of newton meters.

An engine with good elasticity allows the driver to easily gain and reduce speed with just the gas pedal, without changing gears. Even in high gears it feels good when driving at low speeds.

   Practical value of Nm of your car engine

Understanding how torque is generated on the motor shaft, you can use these characteristics during operation, that is, in practice. They allow you to change valve timing, adjust electronic injection, use or not use turbocharging, etc.

In the future, this makes it possible not to change the speed of the vehicle, but to maintain the same traction force on the driving wheels of the vehicle.

These actions can be performed without changing the gearbox - this is what we are talking about when they talk about the “elasticity” of the internal combustion power unit.

The driver can measure this indicator on his car. To do this, he needs to move in 4th gear at a speed of 60 km/h.

Now he must try to accelerate the car to 100 km by pressing only the accelerator pedal. The less time it takes him, the more elastic the engine can be considered.

In this case, the number of revolutions per minute is no longer so important, but what is important is what practical value they represent during acceleration.

These are the characteristics that power units produced by leading European car factories are famous for. They have excellent elasticity, which provides that famous acceleration dynamics that our drivers have long appreciated.

German cars performed especially well: BMW, Audi, Mercedes.

The torque they produce gives pleasure not only when driving on country roads, but also in clogged city streets and traffic jams, when quick acceleration helps you get to your destination on time.

This will conclude today's discussion. Now, I hope you know more about the torque that a gasoline or diesel engine can produce. Visit my blog often to always keep abreast of interesting and useful news from the field of auto topics. That's all for today, and see you again!

Sincerely, blog author Andrey Kulpanov

Source: http://avto-kul.ru/poleznoe-ob-avtomobile/chto-takoe-krutyashhij-moment.html

Engine torque - what is it?

How many of us understand the power of cars and what horsepower means? The thought never occurred to compare a car with 100 hp. with a cart with a hundred horses, and is it somehow strange to compare a 1.6-liter engine with a hundred horses, which will move a tank and not just a small car?

This is a false comparison and here's why.

So, let's figure out what engine power is. In scientific definition, power refers to the rate at which energy is converted and transmitted. For an engine, this is the work it does per unit of time. Engine power is measured in Watts, although we are more accustomed to measuring it in horsepower.

The unit of measurement of one horsepower was obtained experimentally and is defined as the ability of a horse to lift 75 kg one meter per second , i.e. horsepower equals 735 watts. Instead of transferred weight, torque is used, which is equal to the force that occurs at a certain radius.

Torque is the mechanical energy from the ignitable mixture in the cylinder that is transmitted to the crankshaft, transmission, transfer case, wheels, and pushes to make the vehicle move. Engine speed has the most direct effect on torque.

For example, let's take a 1.6-liter Ford Focus engine that develops a power of 100 hp. and has a torque of 150 N*m.

If you consider that there are ten newtons in a kilogram, and if you attach a 1 meter long rod to the engine shaft, then in order to prevent the engine from rotating, it is enough to hang only 15 kg . 150 N*m is the maximum torque that develops at engine speeds close to 4000 rpm.

So why does an engine that can be held with one hand have 100 hp characteristics? All this is because power depends not only on the force developed on the motor shaft, but also on the speed of rotation of this shaft. The more revolutions an engine can develop, the more powerful it is.

As the working volume increases, the force that acts on the piston and the torque increases. Also, the stronger the pressure in the combustion chamber of the cylinder, the greater the force pressing on the piston. The larger the piston area, the lower the force and specific pressure.

For example, a 2-liter SkyActive engine from Mazda, developing 150 hp, will accelerate the car much faster than a 2-liter gasoline engine of Kia or Hyundai, and not only because the former develops more torque, but because that it develops earlier and its torque plateau is wider due to greater compression in the cylinders.

High torque helps the car accelerate faster during acceleration at low crankshaft speeds, and the traction properties of the power mechanism are improved, for example, the vehicle’s carrying capacity and its cross-country ability .

The maximum torque is achieved by the motor at specific speeds. Gasoline engines have a higher value than diesel engines.

The highest torque for a four-cylinder gasoline engine is achieved at 4000 rpm (approximately 192 N*m), for a turbocharged 4-cylinder at 4500 rpm (265 N*m), and for a 4-cylinder diesel engine at 2750 rpm (400 N*m m).

Which engine is better based on torque? This is a controversial issue - it all depends on the purpose.

If you drive a minibus or are engaged in cargo transportation, then traction from lower revs is important - then a diesel engine with its low revving engine and high torque (i.e.

he will pull just madly). When high speed is needed - you like to spin the engine up to 6000-6500 rpm, then gasoline is needed.

Automakers are coming up with different ways to increase torque, using turbocharging, controlled valve timing, increasing the compression ratio, thanks to design innovations in internal combustion engines, etc.

Source: https://unicred.ru/krutyashhij-moment-dvigatelya-chto-eto-takoe/

What is engine torque - briefly about the main thing

Many car enthusiasts have repeatedly heard such a definition as: “ engine torque ,” ​​but not everyone can explain in their own words what this means. Which is better, high torque or low torque?

In principle, no one has ever been deprived of their license or fined for not knowing what torque is ; simply put, there is nothing terrible about it, but it seems to me that every self-respecting motorist should have an understanding of what engine torque is. Despite the fact that there are more than enough sources ready to tell you about this, today I still want to talk about engine torque and some of its aspects.

Quite often I notice that when it comes to torque, people involuntarily begin to associate it with drifting, I dare to disappoint you - there is nothing in common between these concepts, well, except that without the first there would be no second. So, let's figure out what torque is by putting everything, as they say, on the shelves.

How much torque an engine will have depends on the engine itself. In each passport for a particular car there are written numbers called maximum speeds that the car can develop due to its “horses”. Probably everyone has seen such a strange thing when the speed of 100 km/h is indicated in the passport.

, then the car normally accelerates to 70 km/h, after which the needle seems to become several kilograms heavier and it becomes more and more difficult for it to rise up. You probably noticed that when squeezing the maximum out of its engine, it gave out its power only at a certain number of revolutions.

Therefore, the more revolutions it produces, the greater the reserve of power it has, therefore, if the maximum of the car is 5000-6000 rpm, the gas pedal will no longer be so easily pressed to the floor, having a good reserve.

Although in simple urban conditions, without congestion and traffic jams, it is not so easy to gain all these momentum, for example, in order to overtake a slowly moving truck driver. As a result, it turns out that the more speed you need, the longer the engine collects all the “horses” necessary for this.

This is where the torque comes into play. The higher the car’s rating in Newton meters, the faster it will gain momentum, the faster the power of all available “horses” will gather under your foot and the gas pedal.

However, let’s return “to our sheep,” although in our case it doesn’t matter to the horses. Let's continue about our 70 km/h.

Have you ever wondered why a car with good engine torque is so difficult to accelerate? The thing is that each power unit has an indicator called maximum torque output.

Translated into “human” language, it is necessary to accelerate the engine to a certain number of revolutions, and only after that the engine will turn on, so to speak, a second wind and the maximum torque .

Then by adding gas, the driver can make the entire “herd of horses under the hood” race your car faster. That is why it is important what torque your car has, the more it is, and the lower the number of maximum revolutions at its permissible maximum, the “more lively” and faster the ride on such a vehicle will be.

So, we have briefly looked at what torque is, now I propose to talk about what it depends on.

And the torque depends on the displacement or engine size, everything seems to be clear here - the more liters, the more opportunities the car will have to quickly accelerate.

For example, everyone probably knows that in small cars - 1.5 liters and below, it is quite difficult, if not completely impossible, to accelerate sharply or “start”.

In addition to engine power and torque, there is another important concept on which the first two depend, called engine elasticity. Let's say, if you take two cars with engines of the same size and power and give them a race, then the car with the more elastic engine .

What is elasticity? This is the ratio of the maximum power of the motor, the number of its revolutions and revolutions at maximum torque. The lower the latter indicator is relative to the second, the more elastic the engine will be. Thanks to this indicator, the driver can easily operate with only one gas pedal, increasing or decreasing speed without changing gears.

Or another example, an elastic motor can drive at low speed, in high gears.

The most flexible engine with a good maximum torque will allow you to get real pleasure from driving, and your “steel pet” will become a source of pride for you and an object of desire for those who understand it!

Well, that seems to be all. I hope now you understand what torque is . I suppose now you won’t have to be timid if someone starts talking about the power of the engine or its “horsepower”. Good luck to you, come visit us often!

Source: http://avtopulsar.ru/chto-takoe-krutyashhij-moment-dvigatelya-korotko-o-glavnom/

What is car engine torque

Most car owners and drivers evaluate the driving performance of their vehicles by engine power.

During the operation of vehicles, situations often arise where it is necessary to deliberately overtake accompanying vehicles while driving.

Being in a certain rhythm of movement, the driver “presses” on the accelerator pedal and does not receive the desired overtaking acceleration. In this case, a more informative characteristic of engine response is torque at certain engine speeds.

The maximum power indicated in the engine specifications is given at the corresponding speed. For gasoline internal combustion engines, this value usually corresponds to 5000 - 6000 rpm, for diesel engines - approximately 3500 - 4500 rpm. Therefore, it is believed that all gasoline engines are high-speed, and diesel engines are low-speed. It is not always so.

Every car owner, especially one who wants to show his driving skills to pretty girls, should know the torque characteristics of his car.

Determining engine torque

Torque M moment of force, according to definition, is equal to the product F of the force acting on a lever L of length. The formula, known to many from school physics courses, is:

M=F*L

If we convert the input quantities into a unified measurement system, force F is measured in newtons, length (in SI) in meters, M will be measured in newtons per meter.

The force generated when the air-fuel mixture ignites drives the crank mechanism. The larger the lever, that is, the difference in distances from the center of influence to the place of its implementation, the higher the torque.

Theoretically, it is possible to increase the torque in proportion to the length of the lever. But at the same time, the engine speed will decrease and the dimensions of the crankshaft mechanism will increase.

In seagoing vessels such changes are not significant, but the car requires minimizing the size of all components.

The torque of an internal combustion engine determines its power. A simplified formula for converting torque into power parameter is:

P=M*n / 9549 , where M is torque (in N*m) at speed n (in rpm). P – power in kilowatts. 9549 is a rounded number obtained by reducing constants.

To convert power into hp, which is more familiar to car enthusiasts. the result must be multiplied by 1.36.

Thus, power is directly proportional to the number of revolutions. Due to their design, gasoline engines operate efficiently at speeds of up to 8000 rpm and above. Thus, high-speed engines can develop quite high power.

For diesel engines, the maximum torque characteristic occurs at speeds of about 3500 - 4500 rpm. Usually at such speeds the car cruising in a city rhythm occurs.

Therefore, it is easier to perform overtaking and lane changing maneuvers, sharply increasing the speed at low speeds, in cars with diesel internal combustion engines.

Torque characteristics are given in the technical parameters of the vehicle only together with the speed for which they are measured. In some reference data, automakers indicate engine torque at idle speed.

The most complete picture of engine performance parameters is provided by torque dependencies.

Relationship between engine power and torque

Torque gradually increases as engine speed increases, and at about 2800 rpm it stabilizes slightly, reaching its maximum of approximately 178 Nm at 4500 rpm.

Engine power continues to increase as rpm increases, which is consistent with the formula above.

However, after reaching 5400 rpm, torque decreases at a faster rate than the speed increases, and power decreases.

This corresponds to the physical interpretation of the processes in the engine. At low speeds, little fuel and air enter the engine, and the power is low. As the rpm increases, more fuel is burned and more energy is produced. With a further increase in engine speed, power begins to decrease for the following reasons:

• increased losses due to friction processes;
• oxygen starvation;
• inertial and other mechanical losses;
• heat losses.

ICE designers strive to expand the range of the stable portion of the torque curve. Intelligent turbocharging systems are used as one of the widely used design solutions. They allow you to avoid the situation of oxygen starvation at various speeds.

Torque is relatively stable between 2500 and 5500 rpm. Drivers can safely begin the overtaking process even at low speeds.

High-speed engines have stable torque up to 6500 – 7500 rpm. This allows maximum power to be developed at around 7500 rpm, as shown in Figure 3.

If you are serious about buying a car, it is advisable to delve into reference books, forums, read dealer information, Google, and find the relationship between torque and power. Then you will judge the driving parameters of the car from a scientific point of view.

When choosing a car for use in urban conditions, it is advisable to purchase a diesel car; if you like to drive with the wind on the autobahn, a high-speed gasoline engine will do.

How to increase torque

The engine torque characteristics are formed at the stage of design development of a specific engine model. They are also taken into account when calculating the brake system, gearbox, suspension and other systems. Increasing engine torque on your own can lead to premature wear of car parts.

There are several ways to increase torque:

• boosting the engine by changing the parameters of the piston group;
• making changes to the fuel system;
• increase in air intake performance;
• chip tuning.

Many participants in various amateur car competitions use complex engine boosting. However, it should be remembered that increasing the power and torque of an engine by a quarter reduces its service life by half.

Video

Source: http://autoiwc.ru/other/krutyashiy-moment.html

Engine torque - everything you wanted to know but were afraid to ask

Almost every article on CARakoom writes about the torque of this or that engine. But what does this torque mean? Why is it needed at all? Isn't horsepower the main indicator? Let's figure it out together! Thanks to this useful guide, you can show off your intelligence in the company of friends. Torque isn't that important.

Although, wait a minute, torque is very important! So what is this all about? To be honest, despite the fact that I adore cars and everything connected with them, I myself don’t really understand what torque is. Yes, there are a lot of clever definitions on the Internet, and I know exactly how it feels when driving.

But what is he really like? Is the amount of HP? – not the only important indicator? I spent a long time understanding the definition of torque, prepared several available graphs, and finally found it possible to share my findings with you.

The first thing I came to is that horsepower is the only important indicator.

Don't rush to write angry comments, let me explain. Torque is very important, but not by itself . In order for the car to accelerate, you need to apply a certain force: F=Ma (Force = Mass x Acceleration). Torque is a force, but it does not have a time indicator. For clarity, I will give an example.

Imagine that you apply 200 Nm of torque to an iron bucket. This is, of course, cool, but this is not enough to go on a trip with it.

Enlightenment came to me thanks to... light! An ordinary light bulb consumes energy, which is measured in watts - a value named after James Watt, who also gave us the value called Horsepower. Well, at least that's what reliable sources say.

In electricity, a watt is defined as Volts times Amps, that is, voltage times current. Thus, at a voltage of 110 volts, a 60-watt light bulb has a current of 0.55 amperes, and at a voltage of 220 volts, the same light bulb has a current of 0.275 amperes.

Roughly speaking, the higher the voltage, the “slower” the current for the same “power”.

Horsepower is measured using the same scheme. LS=(KM*OB/M)/5252. We know the torque, the revolutions too, and 5252 is a unit for translation that is not even worth thinking about.

To draw an analogy with electricity, let’s imagine that Horsepower is Watts (by the way, in many countries, engine power is measured in kilowatts), torque is voltage, and revolutions per minute is current. Thus, with 135 Nm of torque at 3151 rpm, the engine will produce 60 HP.

To get the same sixty horsepower, I can double the RPM and halve the torque, or double the torque and halve the RPM. Do you feel it? In electricity, Watt is the most important quantity, because thanks to it the light burns.

You can have voltage without current, or current without voltage, but in order to have energy, both voltage and current are necessary. With torque it’s the same theme: you need horses and revs. Imagine an engine that has 1350 Nm of torque available at just 500 rpm. “Cool!” - you say. Nothing like this.

Substitute these figures into our formula, and you will understand that such an engine will squeeze out only 95 HP. Torque is a force, but that force will not work until rotation (rpm) is added to it.

The work must be done for a certain time, only then will we receive energy and acceleration, and acceleration is, in fact, the most important indicator of a car. And yes, when I say “acceleration”, I mean the transition from a static state to a dynamic one. In this case, we are talking about the physical definition of this concept, and not about acceleration to hundreds, etc.

So, if only horsepower is important, then what is the point of diesel engines ? Let's start in order:

1. We know that horsepower makes a car accelerate 2. We know that torque multiplied by revolutions per minute (all of which divided by 5252) creates that horsepower. That is, the faster the engine turns, the more horsepower. Logical? Quite. Now let's try to learn how to read these dynamics graphs.

(Graph taken from Automobile magazine)

1. Horsepower is a variable dependent on engine speed, we just learned this, but engine speed has much more potential than torque (an engine can spin up to, for example, 7000 rpm, and the torque can only be 200-400 Nm).

This means that a lot of horsepower will come from a lot of revolutions per minute, and even a small amount of torque applied to a lot of revolutions will ultimately produce good power.

This is why Formula 1 cars, or racing motorcycles... basically any vehicle equipped with high-revving engines has so much power.

2. Also, where and how you produce torque matters . Diesel engines produce a lot of torque. So many. But they squeeze it out at low revs. That low-end torque is what creates the feeling you get from a big, lazy V8 or diesel engine. But this feeling is primarily associated not with torque, but with engine power.

For clarity, I chose a small modern engine from Volkswagen - CJAA 2.0 TDI. The maximum engine torque of 319 Nm is achieved at 1700 rpm, and at 2600 rpm it begins to fade.

This is due to the fact that diesel engines are able to pump up enormous air pressure and not ignite the fuel until they are ready to do so. With this torque we have 76 hp. at 1700 rpm, 90 hp. at 2000 rpm and 116 hp. at 2600 rpm.

The graph shows how the horsepower line shoots up sharply at the point where maximum torque is reached.

Let's compare it with a gasoline engine of similar volume . In this case, consider the Subaru FA20 engine .
The maximum engine power is 200 hp, so we can say that it is more “sporty” compared to the CJAA. However, at 1700 rpm the FA20 produces only 142 Nm of torque, which corresponds to only 34 hp. At 2000 rpm, the torque is 155 Nm and produces 43 hp, at 2600 - 185 Nm and 68 hp. In fact, the FA20 doesn't make more horsepower than the CJAA until it hits 3,900 rpm. At about the same speed we drive to work and shopping. Thus, it turns out that the Subaru BRZ engine suffers from a lack of power, despite the fact that it has quite enough of it. Nonsense, but true. Look at this chart. Here you see a comparison of the performance of the two engines considered. As you can see, the horsepower curve of a diesel engine shoots up at low revs. In this graph, the orange color indicates the area in which the TDI squeezes out more power than the “more powerful” FA20 engine. Note the interval from 900 to 4500 rpm, in which the TDI produces significantly more horsepower. Two hundred horses will certainly be faster than 136, but while the BRZ slowly lazily accelerates to the required revs, the TDI will already fly into space. This explains the phenomenon of “turbo lag”: when the turbine does not work, the engine does not produce normal torque, therefore it has little power and drags along like a snail. When the turbine kicks in, the engine begins to produce torque, power and speed. Another way to understand this phenomenon is to look at horsepower over a specific rpm range, say 1100-4000 rpm, which is the average rpm of daily driving. In this zone, the FA20 averages 67 hp, while the CJAA averages 107 hp. This suggests that if the BRZ engine did not accelerate to 4000 rpm, then the nimble diesel would tear it up with almost twice the power! This is why the torque feels so "quick". The car whose engine spends more time at a higher average horsepower will accelerate faster. The problem is that, as I said earlier, engine speed is a broader measurement than torque, which means that the amount of torque that can be added at low revs is severely limited. In practice, more power can be produced by increasing engine speed than by increasing torque. At the same time, increasing engine speed is much cheaper and easier than increasing torque. It is for this reason that diesel engines are generally completely unsuitable for racing cars. We've compared the revvy FA20 sports engine and the slow diesel TDI, it's time to compare something different. Now we look at three six-cylinder SUV engines. The blue curve is for the Toyota 1FZ-FE 4.5, Toyota's latest inline-six engine in the Land Cruiser. Red Curve - Toyota 1GR-FE 4.0 - Tacoma's workhorse. And finally, the green line is the GM LFX 3.6 - V6, sitting under the hoods of the Colorado and Canyon.1. The 1FZ-FE engine (blue line) is truly old school. Its large displacement, camshaft and cylinder head design are designed to produce big power at low revs. Thanks to this, with such a car, as they say, you can uproot stumps. Despite the fact that among the three engines this one has the least amount of maximum power (212 hp), it has the maximum average power figure (128 hp) in the daily driving range, reaching its maximum power at 1800 rpm and stays at this mark the longest. This does not mean that the car is fast, far from it, it is still a snail, but its performance allows it to successfully accelerate under high loads at low revs. In addition, it is good off-road. 2. The 1GR-FE engine is characterized by its moderate character and tries to strike a balance between torque and horsepower, but at high speeds it runs out of steam, and the reason for this is the design of the cam profile. The engine performs well at low speeds. Unfortunately, at high speeds there is a strong drop in power as the engine simply does not have enough air. At the same time, the engine has the same average power rating across the rpm range in daily driving as the more powerful GM V6 (115 hp) 3. The LFX engine puts the emphasis on horsepower, but thanks to good cam timing On the intake and exhaust, as well as direct injection, the torque is also quite good. Its strong point is the fact that it continues to rev until it reaches the maximum amount of horsepower. However, at low revs this engine is less powerful than the ancient Toyota V6. Average power at daily driving revs is the same as the 1GR-FE (115 hp), and it makes 85% of its power at 1,500 rpm.

Which one is better? It depends on various factors. The largest and slowest of them is good at low speeds, but dies at high speeds. The smallest engine produces the most power, but to do this it needs to be revved up harder.

Ideally, I would like to have both. Good torque at any speed that could squeeze out a lot of horsepower. This can be achieved by increasing the engine size, but then it will be ineffective at low load. Turbocharging can also solve the problem, but the engine will drink buckets of fuel.

Diesel engines are good at low revs, but at high speeds they start to choke, so we're unlikely to ever see a diesel-powered sports car.

Unless there is some kind of technological breakthrough... I hope this educational article will help you better understand the concept of torque and learn how to weigh the pros and cons when choosing an engine.

To learn more about automotive engineering and physics, check out our Tech community.

Source: http://carakoom.com/blog/17572