A specific system increasing horsepower. What is horsepower in a car. Crossovers - choosing the best power rating

Traditionally, car engine power is measured in horsepower (hp). The term was coined by Scottish engineer and inventor James Watt in 1789 to demonstrate the numerical advantage of his steam engines over horses.

This is a historical unit of measurement of power. It is not part of the International System of Units (SI) and is not unified and generally accepted, nor is it derived from the unified SI units. Different countries have developed different numerical values ​​for horsepower. Power is more accurately described by the watt, introduced in 1882. In practice, kilowatts (kW, kW) are more often used.

In many PTS, the engine is still characterized by the number of “horses”. When this value needs to be converted into kilowatts, the main thing to remember is how many kilowatts are in horsepower. There are few calculation methods; with their help, values ​​are calculated quickly and easily.

How to convert horsepower to kW

There are several options for the mutual translation of these units of measurement:

1. Online calculators. The simplest and quick way. Requires constant access to the Internet.
2. Correspondence tables. Contains the most frequently occurring values ​​and is always at hand.
3. Translation formulas. Knowing the exact correspondence of units, you can quickly convert one number to another and vice versa.

In practice, the following numerical values ​​are used:

• 1 l. With. = 0.735 kW;
• 1 kW = 1.36 l. With.

The second correspondence is most often used: numbers greater than one are easier to work with. To carry out calculations, the kW indicator is multiplied by this coefficient. The calculation looks like this:

88 kW x 1.36 = 119.68 = 120 l. With.

Meters, elastic horses and Newtons with engines. When buying a car, almost everyone pays attention to the number of “horses” in it; some, however, look more at the color and the presence of mirrors in the sun visor.
Any motorist will tell you that the average value of "horses" for budget sedan these days - around 100-120. But not many people know what torque is, why it is needed and how Newton affects horses.
Today we will try to figure it all out.
How often, when pressing the gas, have you noticed that the car “doesn’t move”, although under the hood there seemed to be a herd of 150 head of purebred Japanese (German/Korean or other) horses? I had to observe how lazily the tachometer needle starts moving from 2000 , and when reaching the mark of 3000-3200, the car appears with wings and the acceleration dynamics increase sharply?
Manufacturers usually list the maximum horsepower of their vehicles. Maximum - because it is not always available. During normal city driving, only part of the vehicle's horsepower is used. Maximum “horses” are achieved at fairly high speeds. For four-cylinder “civilian” cars, this figure is within 5-6 thousand revolutions, but power affects the maximum speed more, but the acceleration dynamics depend on the torque and the elasticity of the engine.

Torque is the product of force by the arm of the lever to which it is applied, Mkr = F x L. Force is measured in newtons, lever - in meters. 1 Nm is the torque created by a force of 1 N applied to the end of a lever 1 m long. In an engine internal combustion The role of the lever is played by the crankshaft crank. The force generated by the combustion of fuel acts on the piston, through which it creates torque. What is important for the motorist is that torque is the quantity that determines how quickly the engine can gain maximum power, which means it will achieve maximum acceleration dynamics. Just like power, maximum torque is indicated for specific engine speeds. At the same time important parameter It is not so much the magnitude of the torque as the speed at which it is achieved. For example, for sharp acceleration at quiet ride(2500-3000 rpm) the more preferable engine is the one whose torque is achieved at low speeds - press the pedal and the car fires.

The figure shows the dynamics BMW car 318i.

The graph shows that the power is constantly growing, up to 6500 rpm, but the maximum torque is in the range of 3400-4000 rpm, which seems not entirely logical, because the engine speed is still growing.
However, if you look more closely, there are no contradictions in this graph. The fact is that the torque in the cylinder does continue to increase, but the torque is measured at the exit of the engine, and a standard four-stroke civil car engine most often has four cylinders. It turns out that part of the torque of the first cylinder is spent on the exhaust stroke of the second cylinder, and the third cylinder needs to go through the compression stroke of the fuel mixture, which is quite difficult to do with an increase in the speed of the cylinders, and in the fourth - the intake stroke, which also wastes energy.
So we see that when high speed we will have enough power to achieve maximum speed, but it will take a long time. To reduce acceleration time and make it smooth and comfortable, you need to take into account the elasticity of the engine, that is, that segment of the torque graph where the indicators are closest to the maximum. In our case it is 3400-3800 rpm. Thus, having reached the mark of 4000-4200, you should switch to a higher one, then the speed will drop to 3000-3200 rpm, which, when you press the gas, will quickly bring the engine to the maximum torque zone. The same circuit works in reverse when reducing speed and switching down.

Horsepower is certainly one of the most ironic units of measurement. Its presence in mechanical form has practically eliminated the need to use “biological” horsepower, but we still measure the power of any car in the good old “horses”. Imagine if we were still judging the brightness of a light bulb in candles! So where did this term come from?

It turns out that it was invented by James Watt, a famous Scottish engineer and inventor. In 1763 he was asked to repair a working model of Newcomen's steam engine. The prototype was equipped with a two-inch cylinder and had a piston stroke of six inches. After a series of experiments, Watt replaced the metal cylinder with a wooden one lubricated with linseed oil and dried in an oven, and also reduced the amount of water raised per cycle.

The prototype worked, and the inventor became convinced of the inefficiency of the steam engine and made numerous improvements to the design, which increased productivity by more than four times. As a result, Watt's work marked the beginning of the Industrial Revolution, first in England and then throughout the world. But to steam engines sold well, buyers needed to clearly and clearly explain their advantages.

For example, to demonstrate how many horses’ work these same steam engines can replace. At that time, in England, barrels with a volume of 140.9 to 190.9 liters were used to lift coal, water and people from mines. One barrel weighed 172.4 kilograms, and two horses could pull such a barrel using a rope thrown over a block. The effort of an average horse during 8 hours of work is 15% of its weight or 75 kilogram-force for a horse weighing 500 kg.

Watt concluded that a 180-kilogram barrel could be pulled out of a shaft by two horses at a speed of 2 mph. Then, multiplying ½ barrel by 2 mph, we find that one horsepower is equal to 1 barrel · mph. Rounding the calculations to pound-feet per minute, the inventor decided that the horsepower would be 33,000 pound-feet per minute. In most European countries and Russia, horsepower is defined as 75 kgf m/s, that is, as the power expended during a uniform vertical lift of a load weighing 75 kg at a speed of 1 m/s and standard acceleration of gravity.

In this case, 1 hp. is exactly 735.49875 watts - this value is also called “metric” horsepower" At the Second Congress of the British Scientific Association in 1882, a new unit of power was adopted - the “watt”, named, in fact, in honor of James Watt. But instead of virtual watts, we prefer to use good old horsepower. Agree, it’s much clearer this way.

Each car owner must register his vehicle (VV) in accordance with the procedure established by law, and regularly pay the appropriate transport tax. The subtleties of calculating this mandatory payment are regulated by regional laws on transport tax, specifying the terms, benefits and base rates within the limits outlined by the provisions of Chapter 28 of the Tax Code of the Russian Federation (TC RF). The question arises: “How to calculate car tax?”

Vehicle owners themselves are responsible for monitoring the correct calculation of transport tax, as well as promptly providing changes in information regarding car ownership and documents confirming the right to a tax benefit.

Calculation of transport tax on a car

The amount of automobile transport tax is determined using a standard formula. Specified in technical passport of a car, the number of horsepower (hp) is sequentially multiplied by the current tax rate, and then by a coefficient calculated as the ratio of the number of complete months of owning the car to the total number of months in the year, that is, by 12.

Example 1.

Let's say we are car owners Renault Logan, engine power is 75 horsepower and we live in the Moscow region. The transport tax rate in Moscow and Moscow Region today is 12 rubles. Then the cost of transport tax for 1 year will be:

12 rubles x 75 horsepower = 900 rubles.

Example 2.

Let's say we have owned a VAZ Priora car for 9 months and live in Moscow. The rate in Moscow is 12 rubles per hp. The car's power is 98 horsepower. Then the cost of transport tax for 9 months will be:

12 rub. x 98 hp x ((9 months we own the car) / (12 months a year)) = 882 rubles.

Car tax is paid only for the period in which the car was registered to a specific owner. For the month of transfer of transport from one owner to another, only one owner pays.

When calculating the coefficient, a month of car ownership is considered complete if the car

• registered with the traffic police from the 1st to the 15th;
• or deregistered after the 15th.

In other cases, the month of registration of the car or its deregistration will be taken into account when calculating the transport tax for the other party to the purchase and sale transaction ().

Transport tax on luxury car

Formula for calculating transport tax for a car whose cost is more than 3 million. rub. and if you own it for more than 1 year:

Transport tax amount = (Tax rate) x (L. s) x (Increasing coefficient)

Calculation of tax on a car whose cost is more than 3 million. rub. and if you own it for less than 1 year:

Transport tax amount = (Tax rate) x (L. s) x (Number of months of ownership / 12) x (Increasing factor)

Increasing coefficient (Chapter 28, Article 362 of the Tax Code of the Russian Federation):

1.1 - for passenger cars with an average cost of 3 million to 5 million rubles inclusive, from the year of issue of which 2 to 3 years have passed;
1.3 - for passenger cars with an average cost of 3 million to 5 million rubles inclusive, from the year of manufacture of which 1 to 2 years have passed;
1.5 - for passenger cars with an average cost of 3 million to 5 million rubles inclusive, no more than 1 year has passed since the year of issue;
2 - for passenger cars with an average cost of 5 million to 10 million rubles inclusive, no more than 5 years have passed since the year of manufacture;
3 - in relation to passenger cars with an average cost of 10 million to 15 million rubles inclusive, no more than 10 years have passed since the year of manufacture;
3 - for passenger cars with an average cost of 15 million rubles, no more than 20 years have passed since the year of manufacture.

Online transport tax calculator

You can also use the transport tax calculator on the website of the Federal Tax Service (FTS) of Russia.

Horsepower Tax Rates

The tax rate on a car is determined by the target laws of the constituent entities of the Russian Federation, but does not go beyond the limits established by Article 361 of the Tax Code of the Russian Federation and depends on:

• machine engine power in hp. With.;
• region;
• can be differentiated taking into account the category, age and environmental class of the vehicle.

For very expensive cars with a price of 3 million rubles or more, additional increasing coefficients () are applied. In some cases, this coefficient increases the tax amount three times. Lists of models and brands of cars that are subject to increasing coefficients are updated annually by the Ministry of Industry and Trade of the Russian Federation.

Table. Transport tax rates in Moscow and Moscow Region.

For other regions of Russia, you can find out the transport tax rates.

Video: How transport tax is calculated on a car

Transport tax benefits

According to most regional laws, veterans and disabled people of the Great Patriotic War are exempt from paying car tax. Patriotic War, Heroes of the Soviet Union, Heroes of Russia and other groups of taxpayers. The list of Muscovite beneficiaries even includes representatives (one of two parents) of large families.

But in St. Petersburg, only one of the parents of a family with at least four minor children can take advantage of such a benefit, and a number of citizens will be able to use the established benefit only on the condition that their vehicle is domestically produced and has an engine with a capacity of up to 150 hp. With.

Deadlines for paying car taxes

Car tax is paid at the place of registration of the car, and in the absence of such, at the place of residence of the owner of the vehicle.

1. Individuals must pay car tax no later than December 1(), based on a tax notice received from the Federal Tax Service along with a completed payment document.

If you fail to pay your car tax on time, a penalty will be charged.

IMPORTANT! Tax authorities calculate transport tax taking into account data on the state registration of the car. If the car owner does not have the right to a preferential tax exemption, then, having not received a tax notice before December 1, the car owner is obliged to inform the territorial tax office about the tax he has. vehicle, and receive the document necessary to pay the car tax.

NOTE! Only with a certificate provided from the internal affairs bodies stating that the car is wanted, the tax office can suspend the calculation of car tax and continue it from the month of return if the car is found and returned to the owner.

2. Legal entities They themselves calculate the transport tax and make quarterly advance payments (one-fourth of the total amount). If the tax is calculated on an expensive car included in a special list of the Ministry of Industry and Trade, then advance payments are paid immediately, taking into account the required increasing factor. At the end of the year, the remaining tax must be paid by February 1 of the year following the reporting year, that is, before the deadline established by law for submitting annual tax returns.

Online check

According to state registration number car, it will not be possible to find out the amount of transport tax. All data is available only if information about the owner of the vehicle is provided.

The car tax liability can be clarified online through the official websites of government agencies.

1. Personal account of the taxpayer, operating on the website of the Federal Tax Service. You will need to enter an individual taxpayer number (TIN) and password.

You will first have to activate the service by personally appearing at the tax office, where after registering the application they will issue an access password recorded in the registration card, the login will be the taxpayer’s TIN. When the deadline for accruing tax on a car comes, its amount can be checked using the “Accrued” link by selecting the appropriate object of taxation (car). Until the tax is calculated, the results can be viewed in the “Overpayment/debt” column.

2. State Services Portal, by last name, first name, patronymic and insurance number individual personal account (SNILS) of the payer. You will first have to register by entering personal data in the appropriate fields (full name, date and place of birth, residential address and email, etc.)
Then you need to fill out an application to provide information on tax debt. Information is provided free of charge, no later than 5 working days, as the system will forward the request to the Federal Tax Service.

3. Website Federal service bailiffs allows you to find out about overdue debts on transport tax . Without prior registration, by entering the full name and date of birth of the debtor in the appropriate search lines and selecting the desired region from the list.

Transport tax is paid annually by all car owners. For individuals The amount of car tax is calculated by the tax service, but citizens need to control the correctness of these calculations independently.

If inaccuracies are discovered, taxpayers are required to inform the Federal Tax Service of the errors made and the need to make appropriate changes. Thanks to the development of modern technologies, it is possible to clarify and correct calculations received from tax authorities not only by appearing in person at the tax office or by sending registered letters by mail, but also online, through the personal account of the tax payer.

The power of a car characterizes its speed qualities - the higher the power, the higher the speed can be achieved. It just so happened that in automotive world Power is usually measured in horsepower. However, engine power is not a constant value and directly depends on its speed. In other words, at low speeds, not the entire “herd of horses” is involved in engine operation, but only a certain part of it. So for most gasoline engines modern cars maximum power (which is indicated in the passport) is achieved at 5000-6000 rpm, and for diesel engines - 3000-4000. However, in everyday city driving, engine speeds tend to be lower, which means less power. Now imagine that we need to accelerate to overtake - we press the pedal and discover that “the car is not moving.” What is the reason? The reason is torque.
Torque is the product of force by the arm of the lever to which it is applied, Mkr = F x L. Force is measured in newtons, lever - in meters. 1 Nm is the torque created by a force of 1 N applied to the end of a lever 1 m long. In an internal combustion engine, the role of the lever is played by the crankshaft crank. The force generated by the combustion of fuel acts on the piston, through which it creates torque. In the context of this article, torque is the quantity that determines how quickly an engine can produce maximum power. It is not difficult to guess that it is this value that characterizes the dynamics of acceleration. Just like power, maximum torque is indicated for specific engine speeds. In this case, the important parameter is not so much the magnitude of the torque as the speed at which it is achieved. For example, for sharp acceleration during quiet driving (2000-2500 rpm), an engine whose torque is achieved at low speeds is more preferable - press the pedal and the car fires.
It is known that serial gasoline engines They do not develop the greatest torque, and the maximum value is achieved only at medium speeds (usually 3000-4000). But gasoline engines can spin up to 7-8 thousand rpm, which allows them to develop quite a lot of power. In contrast to such engines, “low-speed diesel engines”, developing no more than 5,000 rpm, have an impressive torque, accessible almost from the very bottom, while losing in maximum power.
And for dessert, a little math. Engine power can be calculated using the formula:
P = Mkr*n/9549 [kW],
where Mkr is the engine torque (Nm), n is the engine crankshaft speed (rpm).
To obtain horsepower, the result must be multiplied by a factor of 1.36.
In practice, it is known that engine power depends to a greater extent on rpm, because this value is “easier to increase” than torque.
Bottom line: engine power is important for maximum speed, and torque is important for acceleration. In this case, an important characteristic is the engine speed at which this torque is maximum, that is, at which maximum acceleration is possible.
Horsepower varies
Engine power indicators used in international practice in many cases cannot be directly compared with each other.
Horsepower (hp) Europe, pferdestarke - PS (German), cheval - ch (French) -1 hp (1 PS, 1 ch)=0.735 kW=0.9862 hp
US horsepower, horsepower - hp (English) - 1 hp = 1.0139 hp = 0.7457 kW

2.2For more than a century, internal combustion engines have been used in almost all areas of transport. They are the “heart” of a car, tractor, diesel locomotive, ship, airplane, and over the past thirty years they have come to represent a kind of fusion of the latest achievements of science and technology. Terms such as POWER and TORQUE have become familiar to us and are a necessary criterion for assessing the power capabilities of an engine. But how accurately can you assess the potential of an engine, having only meager figures with the technical data of the car in front of your eyes? I hope you will not rely entirely on the assurances of the car dealership salesperson that the engine of the car you are purchasing is powerful enough and will completely satisfy you? In order not to regret later about an unprofitable purchase, I ask you to familiarize yourself with the following.
Since ancient times, humanity has used all kinds of mechanisms and devices for construction, moving goods, and transporting people. With the invention of HIS MAJESTY'S WHEEL more than 10 thousand years ago, the theory of mechanics underwent major changes. Initially, the role of the wheel was reduced only to a banal reduction of resistance (friction force) and the transfer of friction force into rolling. Of course, rolling a round one is much more pleasant than dragging a square one! But a qualitative change in the method of using the wheel occurred much later thanks to the advent of another ingenious invention - the ENGINE! The father of the steam locomotive is often called George Stevenson, who built his famous steam locomotive "Rocket" in 1829. But back in 1808, the Englishman Richard Trevithick demonstrates one of the most revolutionary inventions in history - the first steam locomotive. But to our general joy, Trevithick first built steam car for street traffic, and then I just came up with the idea of ​​a steam locomotive. Thus, the car is in some way the progenitor of the steam locomotive. Unfortunately, the fate of the discoverer Richard Trevithick, as well as many engineers, but not businessmen, was sad. He went broke, lived for a long time in a foreign land, and died in poverty. But let's not talk about sad things...
Our task is to understand what engine torque and power are, and it will be greatly simplified if we remember the structure of a steam locomotive. In addition to the passive converter of friction from one type to another, the wheel began to perform one more task - to create a driving (traction) force, that is, pushing off from the road, setting the carriage in motion. The steam pressure acts on the piston, which in turn presses on the connecting rod, which turns the wheel, creating TORQUE. The rotation of the wheel under the influence of torque causes the appearance of a couple of forces. One of them - the frictional force between the rail and the wheel - is, as it were, pushed back from the rail, and the second - the same TRACTION FORCE we are looking for is transmitted through the wheel axis to the parts of the locomotive frame. Using the example of a steam locomotive, it is noticeable that the greater the steam pressure acting on the piston, and through it on the connecting rod, the greater the traction force will push it forward. Obviously, by changing the steam pressure, the diameter of the wheel and the position of the connecting rod attachment point relative to the center of the wheel, you can change the power and speed of the locomotive. The same thing happens in a car.
The difference is that all force transformations are carried out directly in the engine itself. At the exit from it we simply have a rotating shaft, that is, instead of a force pushing the locomotive forward, here we get a circular motion of the shaft with a certain force - TORQUE. And the POWER developed by an engine is its ability to rotate as quickly as possible, while simultaneously creating torque on the shaft. Then the car’s power transmission (transmission) comes into action, which changes this torque as we need and delivers it to the drive wheels. And only in contact between the wheel and the road surface is the torque “straightened out” again and becomes a traction force.
Obviously, it is preferable to have the greatest traction force. This will provide the required acceleration intensity, the ability to climb hills and transport more people and cargo.
The technical characteristics of the car include such parameters as the number of engine revolutions at maximum power and maximum torque and the magnitude of this power and torque. As a rule, they are measured in revolutions per minute (min־¹), kilowatts (kW) and newtonometers (Nm), respectively. It is necessary to be able to correctly understand the external speed characteristic engine.
This graphic image dependence of power and torque on crankshaft speed. It's the shape of the torque curve that's most telling, not the magnitude. The sooner the maximum is reached and the more flat the curve drops as the speed increases (that is, the engine has constant thrust), the more correctly the engine is designed and operates. However, to obtain an engine with sufficient power reserves, high speeds and even stable TORQUE at wide range revolutions, not easy. This is precisely what the use of supercharging of various systems is aimed at, electronic regulation fuel injection, variable valve timing, exhaust system tuning and a number of other measures.
Let's look at an example. You have to overcome a rise, and you cannot increase the speed (accelerate the car before the rise) due to the road situation. To maintain the pace of movement, you will need to increase the traction force. A situation often arises that looks like this: adding gas does not increase traction. This causes a decrease in speed, and hence engine speed, accompanied by a further decrease in the traction force on the drive wheels.
So what to do? How to maintain high traction force at low speeds if the engine “does not pull”, that is, does not provide sufficient TORQUE? The transmission comes into action. you manually, or automatic transmission gears yourself, change gear ratio so that the traction force and the speed of movement are in an optimal ratio. But this is an additional inconvenience in driving a car. The conclusion suggests itself: it would be better if the engine itself adapted to work in such situations. For example, you are driving uphill. The force of resistance to the movement of the car increases, the speed drops, but the traction force can be added by simply pressing the gas pedal harder. Automotive designers use the term “ENGINE ELASTICITY” to evaluate this parameter.
This is the ratio between the maximum power rpm and the maximum torque rpm (rpm Pmax/rpm Mmax). It should be such that, in relation to the maximum power speed, the maximum torque speed is as low as possible. This will allow you to reduce and increase speed only by operating the gas pedal, without resorting to changing gears, as well as driving in higher gears at low speed. You can practically evaluate the elasticity of the engine by checking the car’s ability to accelerate from 60 to 100 km/h in fourth gear. The less time this acceleration takes, the more elastic the engine.
To confirm the above, let's look at the test results Audi cars, BMW and Mercedes, held in Europe and published by the Russian publishing house of the German magazine Auto Motor und Sport in the November 2005 issue. Mainly, let's consider Audi specifications and BMW. The Audi engine, with a much smaller volume and almost the same power, is practically not inferior to the Bavarian in acceleration from a standstill, but in measurements of elasticity and efficiency it beats the competitor on both blades. Why is this happening? Because the elasticity coefficient of the Audi engine is 2.39 (4300/1800) versus 1.66 (5800/3500) for BMW, and since the weight of the cars is approximately equal, the stallion from Munich allows him to give an enviable head start to his compatriot. Moreover, these impressive results are achieved using AI-95 fuel.
So, let's sum it up!
Of two engines of the same volume and power, the one with higher elasticity is preferable. All other things being equal, such a motor will wear out less, operate with less noise and consume less fuel, and will also simplify manipulation of the gear lever. Modern supercharged gasoline and diesel engines fall under all these conditions. Operating a car with such an engine, you will get a lot of pleasant impressions!

2.3What interests people who study technical specifications this or that car? First of all, power, then fuel consumption and maximum speed. Torque is rarely mentioned. But in vain.
Since the birth of self-propelled strollers, the traction capabilities of motors have been usually assessed by power, which is expressed in horsepower. Due to the absence in those distant times of a methodology for calculating and determining power, until 1906/1907 this engine characteristic did not have a very clear designation - it showed the approximate power - “from” and “to”, for example, from 15 to 20 hp.
Since 1907, this imprecise power figure has been divided into two values, for example, 6/22 hp. The first figure included the value of the tax rate, and the second - capacity. The tax horsepower introduced corresponded to a certain engine displacement value: 261.8 cc. cm for four-stroke engines and 174.5 cc. cm - for two-stroke. The emergence of this method of establishing tax rates was due to the dependence of the engine displacement on the amount of energy it produces and fuel consumption. The denotation of power in kilowatts (kW), according to the international SI measurement system, began much later.
In fact, “power” reflects the traction capabilities of the engine only indirectly. Those who have driven classmates with engines of approximately equal power and volume will agree with this. They probably noticed that some cars are quite playful starting from low revs, others love only high revs, but at small ones they behave rather sluggishly.
Many questions arise from those who, after a passenger car with 110-120 horsepower gasoline engine got behind the wheel of the same car, but with diesel engine with a power of only 70-80 hp. According to acceleration dynamics, without using sport mode(high revs), at first glance, a low-power “diesel” will easily outperform its gasoline brother. What's the matter here?
All this confusion is caused by the fact that in each case such a value as the traction force (FT, N) applied to the drive wheels will be different. The explanation for this is easy to find from the formula: FT=Mkr i h/r, where Mkr is the engine torque, i-gear ratio transmission, h – transmission efficiency (with a longitudinal engine arrangement h=0.88-0.92, with a transverse engine – h=0.91-0.95), r – wheel rolling radius. From the formula it is clear that the greater the engine torque and gear ratio, and the smaller the losses in the transmission (i.e., the higher its efficiency) and the radius of the drive wheels, the greater the traction force. The wheel radius, gear ratio and transmission efficiency of classmates are very similar, so they do not affect traction force to the same extent as engine torque.
If we substitute real numbers into the formula, then the traction force on each drive wheel, for example, of a car Volkswagen Golf IV with a 75-horsepower engine developing a torque of 128 N m will be equal to 441 N or 45 kg s. However, these values ​​are valid when the engine speed (3300 rpm) corresponds to the maximum torque.
What is torque
You can understand what torque is at simple example. Let's take a stick and clamp one end of it in a vice. If you press on the other end of the stick, a torque (μm) will begin to act on it. It is equal to the force applied to the lever multiplied by the length of the force arm. In numbers, it looks like this: if a 10-kilogram load is hung on a lever one meter long, a torque of 10 kg m will appear. In the generally accepted SI measurement system, this indicator (multiplied by the value of the acceleration of gravity - 9.81 m/s2) will be equal to 98.1 N m. From this it follows that more torque can be obtained in two ways - by increasing the length of the lever or the weight of the load.
In an internal combustion engine there are no sticks and weights, but instead there are crank mechanism with pistons. The torque here is obtained due to the combustion of the combustible mixture, which expands and pushes the piston down. The piston, in turn, presses through the connecting rod onto the “elbow” of the crankshaft. Although the arm length is not indicated in the description of engine characteristics, this can be determined by the piston stroke (twice the crank radius).
An approximate calculation of engine torque looks like this. When the piston pushes the connecting rod with a force of 200 kg on a shoulder of 5 cm, a torque of 10 kg s, or 98.1 N m occurs. To make this figure larger, the radius of the crank should be increased or the piston should be made to press on the connecting rod journal with greater force. It is impossible to increase the radius of the crank indefinitely, since the size of the engine will also have to increase in width and height. Inertial forces also increase, requiring strengthening of the structure or reducing the maximum speed. At the same time, other negative factors also appear. In such a situation, engine designers have only one option left - to increase the force with which the piston drives the crankshaft. To do this, the fuel-air mixture in the combustion chamber must be burned more efficiently and in larger quantities. This is achieved by increasing the working volume, the diameter of the cylinders and their number, as well as improving the degree of filling of the cylinders with the fuel-air mixture, optimizing the combustion process, and increasing the compression ratio. This is confirmed by the torque calculation formula: Mkr=VH pe / 0.12566 (for four stroke engine), where VH is the engine displacement (l), pe is the average effective pressure in the combustion chamber (bar).
It is not possible to obtain maximum torque on the engine crankshaft at all speeds. U different engines Peak maximum torque is reached at various modes– for some it is greater at low speeds (in the range of 1800-3000 rpm), for others – at higher speeds (in the range of 3000-4500 rpm). This is explained by the fact that, depending on the design of the intake tract and valve timing, effective filling of the cylinders with the fuel-air mixture occurs only at certain speeds.