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How much horsepower is in the motor. What is one horsepower equal to? Features of determining engine power for different cars. How is engine power determined?

The concept of "car horsepower" was introduced back in the 18th century by James Watt. This is a parameter that shows the power of the car, compared with the power of the horse.

1 horsepower or hp is equal to the power required to lift a 75-kilogram load to a height of one meter in 1 second. In some cases, it is customary to translate hp. in kilowatts - then 1 horsepower will be equal to 735.5 W or 0.735 kW.

To determine the power in hp. a particular car, you need to convert the kW indicated in the passport data to horsepower. This is done as follows: the given values ​​\u200b\u200bin kilowatts are simply divided by 0.735. The final value will mean the horsepower of a particular car.

A few examples for comparison.

  1. Nissan Micra with a 1 liter engine has a power rating of 48 kW. To define a parameter in Horse power ah, we have to divide 48/0.735. It turns out 65.3 or rounded - 65 horses.
  2. Sports version of the famous Volkswagen Golf with TSI motor 2.0 liter has a power of 155 kW. By dividing the number by 0.735, we get the value in hp. - 210.
  3. The passport data of the domestic "Niva" indicates 58 kW, which is equal to 79 hp. Often this value is rounded up, and a value of 80 hp is indicated.

There is another way to calculate horses. Almost every major service station has a special setting that easily determines how much horsepower is in the car. The car is lifted onto the platform, fixed, the accelerator pedal is squeezed to the stop. In a few minutes, the computer will calculate the value.

It is customary to distinguish between 2 measurement systems: domestic and European. Both equate hp. to 75 kg x m/s.

Thus, horsepower in a car is equal to kW divided by 0.735. Kilowatt is the metric unit of horsepower. Scientifically, it is comparable to the work done in 1 second when lifting a load of 75 kg to a height of one meter. All this is subject to gravity.

A modern car is considered highly efficient if its engine has more power in relation to the mass of the vehicle. Or so: the lighter the body, the greater the power parameter will allow the car to accelerate.

This is clearly seen below in the example of high-performance cars.

  • Dodge Viper 450 HP has a gross weight of 3.3 tons. The power / weight ratio is 0.316, acceleration to hundreds is 4.1 s.
  • Ferrari 355 F1 with 375 hp - full mass 2.9 tons, ratio - 0.126, acceleration to hundreds - 4.6 s.
  • Shelby Series 1 320 hp - gross weight 2.6 tons, ratio - 0.121, acceleration to hundreds - 4.4 s.

Some automotive publications write that the price of a car is determined only by the "horses" under the hood. Is it so? And why is the torque or KM prescribed in the technical data of the car?

KM is a consequence of exerting an influence on the lever, familiar to everyone from physics lessons. Accordingly, the measurement term in Nm is also displayed. In an internal combustion engine, the crankshaft plays the role of a lever, and power or energy is born during the combustion of fuel. It acts on the piston that creates the CM.

It turns out that the value of KM is also important, as well as power. Only the last parameter implies another work done per unit of time. It shows how many times per unit time the internal combustion engine creates CM. Power is determined by the amplitude of rotation power plant or revolutions, which means it depends on the CM. That is why it is calculated in kilowatts.

Now directly about influence.

  1. Vehicle power is required to force certain resistances. The higher it is, the more machine able to outdo. In this case, the opposing forces are the friction and rolling forces of the wheels, the resistance of oncoming air, etc.
  2. KM directly affects the capabilities of the car, because next to the “horses” parameter, revolutions are always written, on which the optimal power depends.

Thus, the vaunted horsepower of a car is nothing without torque, because it is the latter indicator that determines the dynamics of acceleration, affects the engine reaching its peak of power.

Horsepower directly affects the transport tax, determined by the law of the country. The higher it is, the more you will have to pay for the car.

You can calculate the tax on a car or TN on your own, using the following formula: hp. car x the current rate and a component derived by the ratio of the period of ownership of the vehicle to the total number of months in a year.

Example 1

Lada Vesta is equipped with an engine developing 105 hp. If the owner lives in Moscow, then the tax rate for today is 12 rubles. From this it turns out that the cost of TN for 1 year will be equal to:

  • 12 × 105 = 1260 rubles.

Example 2

Volkswagen Golf, equipped with a 2.0 TSI GTI engine with a KM of 152 kW, has a power of 207 hp. Calculate tax:

  • 12×207=2484 rubles.

Example 3

The top car Ferrari GTB coupe has 270 horses under the hood. Accordingly, the tax will be:

  • 12 × 270 = 3240 rubles.

This calculator, by converting by multiplying the engine power expressed in kW by a factor of 1.3596 (that is, using a conversion factor of 1 hp = 1.35962 kW), converts the horsepower in the car to the power expressed in kW using generally accepted ratio.

How many kilowatts in one horsepower and vice versa

  • 1 kW = 1.3596 hp (for metric calculation);
  • 1 kW = 1.3783 hp (English standard);
  • 1 kW = 1.34048 hp (electric "horse").

As you can see, there are several units of measurement called "horsepower", but, as a rule, what is meant is the so-called "metric horsepower", which is equal to ≈0.7354 kW. But in the US and UK, horsepower related to cars is equated to 0.7456 kW, that is, as 75 kgf m / s, which is approximately 1.0138 metric. If we convert the power of 1 horsepower to kilowatts in industry or energy, then ≈0.746. Therefore, for the accuracy of the result, before using our kW to hp power converter, decide which standard of horses you need to choose.

How to use the kW to hp power converter

  1. To convert "horsepower to kilowatts" or vice versa, the first step is to select one of the three standards.
  2. Then select the unit to which kW/W or HP will be converted.
  3. Enter a value in the field you want to convert.

Why You Should Use an Online Horsepower Converter

This calculator for converting units of power in the international system of calculation to the one used in the standards of the CIS and Russia will help you not only find out how much HP. in 1 kW, but also to correctly convert kilowatts to horsepower, which are used in various documentation, including for calculating transport tax and OSAGO.

Horsepower

Horsepower(hp) - off-system unit of power.

In the world there are several units of measurement called "horsepower". In Russia, as a rule, horsepower means the so-called metric horsepower”, equal to approximately 735 watts.

Currently, in Russia, formally, horsepower has been taken out of use, but is still used to calculate the transport tax. In Russia and in many other countries, it is still very widespread in the environment where engines are used. internal combustion(cars, motorcycles, tractor equipment, lawn mowers, trimmers).

In the International System of Units (SI), the official unit for power is the watt.

In the English ("Imperial") system of measures, the pound-feet per second is considered the unit of power, but in reality it is no longer used in England, and in the USA it is used extremely rarely.

Horsepower Options

In most European countries, including Russia, horsepower is defined as 75 kgf / , that is, as the power expended to lift a load weighing 75 kg to a height of 1 meter in 1 second with standard free fall acceleration (9.80665 m/s²) . In this case, 1 l. With. is exactly 735.49875 watts, which is sometimes called metric horsepower (German designation. PS, fr. ch, netherl. pk ), although it is not included in the metric system of units.

In the US and UK, the automotive industry still equates horsepower to 745.69987158227022 watts. hp), which is equal to 1.013869665424 metric horsepower.

The US also uses electric horsepower and boiler horsepower (used in industry and energy).

Ratios

To calculate the engine power in kilowatts, use the ratio 1 kW = 1.3596 hp. (1 HP = 0.73549875 kW)

Story

Around 1789, the Scottish engineer and inventor James Watt coined the term "horsepower" to refer to how many horses his steam engines could replace. In particular, it is claimed that one of Watt's first machines was bought by a brewer to replace the horse that powered the water pump.

At this time in England, barrels (BARREL) with a volume of 140.9 to 190.9 liters were used to lift coal, water and people from mines. a typical barrel with a load weighed 400 pounds (1 pound - 0.4095 kg), i.e. 1 barrel = 163.8 kg. Naturally, only two horses could pull out such a barrel by a rope thrown over a block. The effort of an average working horse for 8 hours of work is 15% of its weight, or 75 kg with a horse weighing 500 kg. In 8 hours, a horse with such an effort can travel 28.8 km at a speed of 3.6 km / h (1 m / s). Observing the traditional source of energy - the horse, Watt came to the conclusion that only two horses could pull a 160 kg barrel from the mine at a speed of 2 miles / hour (3.6 km / h). In this case, the horsepower in English measures becomes 1 hp = 1/2 barrel * 2 mill/h = 1 barrel*mill/h. The same in smaller units is 180 pounds by 181 feet. Rounding off the calculations in foot-pounds per minute, he decided that the horsepower would be 33,000 foot-pounds per minute.

Watt's calculations referred to horse power averaged over big time. For a short time, a horse can develop a power of about 1000 kgf m / s, which corresponds to 9.8 kW or 33,475 BTU / h (boiler horsepower). According to other sources - up to 15 hp. at the peak.

At the Second Congress of the British Scientific Association in 1882, a new unit of power was adopted - Watt (symbol: W, W), named after James Watt (Watt), the creator of the universal steam engine. Prior to this, most calculations used the horsepower introduced by James Watt.

Engine power

For the power of automobile engines, there are not only different units of measurement, but also different ways of measuring, giving different results. The standard way to measure power in Europe uses kilowatts. If the power is given in horsepower, then the methods of measurement in different countries may differ (even if the same horsepower is used).

The USA and Japan use their own standards for determining engine horsepower, but they have long been almost completely unified with others. In both America and Japan, there are two types of indicators:

Net measurement

Net engine power measurement netto, net) provides for a bench test of an engine equipped with all the auxiliary units necessary for the operation of the vehicle: a generator, a silencer, a fan, etc.

Gross measurement

If the power is less than 100 hp. s., then, for example, in the Moscow region 7 rubles / l are paid. With. per year, and if a little more - already 29 rubles / l. With. in year. Moreover, from 101 hp. up to 150 hp the tax rate is the same. Thus, due to different power values, the price changes from less than 700 to several thousand rubles a year. This fact leads to annoying curiosities. Yes, power South Korean car Hyundai Accent is strictly equal to 75 kW, that is, 102 hp. With. For an American car owner, 100.7 hp would be an even more offensive figure, but in the US, the tax does not depend on horsepower. In the US, some taxes (road, environmental) are included in the price of gasoline, in addition, you have to pay personal property tax every year, which is directly proportional to the price of the car.

In the past, in some countries (eg UK, Germany, Belgium, France, Spain) the vehicle tax was based on horsepower. In some countries, the use of power in taxation was abandoned (for example, in the UK in the forties, car dimensions were used instead of power), in others (for example, in France), kilowatts were used instead of horsepower. From those times, the expressions "Caballo fiscal" and "Cheval fiscal" remained.

In Russia, many car owners, mostly truckers, underestimated the real engine power in their registration certificates in order to reduce tax costs. However, at present, tax authorities usually take information about power not from technical passports, but from general databases (which, however, do not contain data on many relatively exotic car models or equipment, which is what their owners use).

see also

Notes

Horsepower is a unit of measurement that does not have a single standard in the world, although in most countries they adhere to one of its numerical values. Horsepower is not included in the generally accepted International measurement system, and its official use was canceled in Russia. Meanwhile, this measure is used not only in everyday life, but also at the state level.

What is measured in horsepower

In horsepower - that amount mechanical work produced over a certain period of time. The most common measure is kilograms per meter per second. It is mainly used in relation to vehicles and some other mechanisms.

In Russia, the transport tax is calculated based on one horsepower, and in documents for vehicles equipped with an engine, this unit of measurement is often used to indicate its power.

What is horsepower

This measure was introduced at the end of the 18th century in England. Technical progress and ubiquitous application steam engines revealed the need for a common standard for determining their performance.

Using the method of practical measurements made during work performed by a live horse under certain conditions, he calculated that in 1 second 1 horse is able to move a load of 75 kg over a distance of 1 meter - this indicator was taken as one horsepower.

Standard Power Units

In the International System of Measurement, the official unit for determining power is the Watt (1 kilowatt = 1000 watts). This measure will be the same all over the world.

In watts, power is measured as the rate of energy transmitted or as the amount of work produced in a certain time.

In connection with a single world standard, many manufacturers of automobiles, as well as other vehicles and mechanisms, indicate engine power in watts in the documents for equipment. However, in our country, each horsepower in a car affects the amount of transport tax, so it is more convenient to know the engine power level of your car in these units.

Metric horsepower

The world's most common calculation of horsepower (hp) occurs in the metric system. For the calculation, kilogram indicators of the weight of the load are used, and the measurement of the distance over which it is moved is made in meters.

In this case, one horsepower is equal to 735.49875 watts, which is equivalent to 0.74 kW.

One kilowatt will be equal to 1.36 liters. With.

Horsepower table

Knowing the calculation formula, you can easily convert digital indicators from one unit of measurement to another, but if you don’t want to do calculations, you can use a comparative table. The numbers below are relevant for the metric system of measurement.

The difference between the calculation of horsepower in America and the UK

In connection with the use in a number of countries, for example in the USA and Great Britain, of feet and pounds as measures of length and weight, their calculation of horsepower will differ from that adopted in most of the world's states, including Russia.

In the traditional system of measurement of these countries, one horsepower would be equal to 745.6999 W (0.746 kW) and equal to 1.014 of the metric horsepower. With equal values ​​in a given unit of measure, the engine of cars rated in feet and pounds will be more powerful during actual operation.

However, in most cases, the engine power in the accompanying documents is indicated in kW, so it can be recalculated using the standard formula.

Often real indicators powers differ from the factory parameters and it makes sense to make real measurements:

  • putting the car on a dyno - the most exact view diagnostics;
  • by installing additional electronic equipment in it (which is only advisable for vehicles that need constant monitoring of this indicator, since maintenance and purchase of special equipment will be expensive);
  • or by checking with an application downloaded to a laptop that connects to the car via a cable and takes measurements during test runs.

Features of determining gross and net engine power

Due to the peculiar system of measuring engine power used in factories that produce vehicles in Japan and some that belonged to the United States, the amount of horsepower in cars made by them differed from the actual operation.

The point is the so-called net power and gross power. When measuring the first indicator, the energy consumption for the operation of related units is taken into account - the cooling system, generator, drive belts. Their influence is not taken into account in gross power calculations. Therefore, the real figures for different ways measurements can differ significantly - by 10-25 percent.

Cars, in the documents of which the engine power is registered on the basis of the gross indicator, will be weaker cars with identical net measurement values.

Since in Russia the amount of horsepower in vehicle the amount of tax paid for it depends, it is better to find out the real performance of the engine in order to avoid overpayment, which in certain cases can be very significant. Especially if you have to not only add non-existent horsepower to pay at an identical rate, but also multiply their total number by an increased rate (this can happen if the theoretical and actual indicators are in different price groups for calculating the transport payment, for example, by documents 155 hp, but in fact less than 150, etc.).

Consider 5 popular ways how to calculate car engine power using data like:

  • engine speed,
  • engine size,
  • torque,
  • effective pressure in the combustion chamber
  • fuel consumption,
  • injector performance,
  • machine weight
  • acceleration time to 100 km.

Each of the formulas that will be used engine power calculation of the car is quite relative and cannot determine with 100% accuracy the real horsepower of the driving car. But after making calculations for each of the above garage options, relying not on one or another indicator, you can calculate, at least, the average value, whether it be a stock or a tuned engine, literally with 10 percent error.

Power- the energy generated by the engine, it is converted into torque on the output shaft of the internal combustion engine. This is not a constant value. Next to the maximum power values, the revolutions at which it can be reached are always indicated. The maximum point is reached at the highest average effective pressure in the cylinder (depends on the quality of filling with fresh fuel mixture, completeness of combustion and heat losses). the highest power modern motors give out on average at 5500-6500 rpm. In the automotive industry, engine power is measured in horsepower. Therefore, since most results are displayed in kilowatts, you will need

How to calculate power through torque

The simplest calculation of car engine power can be determine the relationship between torque and speed.

Torque

The force multiplied by the shoulder of its application, which the engine can give out to overcome certain resistances to movement. Determines how quickly the motor reaches maximum power. Estimated formula for torque from engine size:

Mcr \u003d VHxPE / 0.12566, where

  • VH - engine displacement (l),
  • PE is the mean effective pressure in the combustion chamber (bar).
Engine speed

Rotational speed crankshaft.

The formula for calculating the power of an internal combustion engine of a car is as follows:

P = Mcr * n/9549 [kW], where:

  • Mcr - engine torque (Nm),
  • n - crankshaft speed (rpm),
  • 9549 - a coefficient in order to substitute the revolutions in rpm, and not in alpha cosines.

Since according to the formula, we get the result in kW, then, if necessary, you can also convert to horsepower or simply multiply by a factor of 1.36.

Using these formulas is the easiest way to convert torque to horsepower.

And in order not to go into all these details, a quick calculation of the internal combustion engine power online can be done using our calculator.

If you do not know the torque of the engine of your car, then to determine its power in kilowatts, you can also use the following formula:

Ne = Vh * pe * n/120(kW), where:

  • Vh - engine capacity, cm³
  • n - speed, rpm
  • pe - average effective pressure, MPa (on conventional gasoline engines leaves about 0.82 - 0.85 MPa, forced - 0.9 MPa, and for a diesel engine from 0.9 to 2.5 MPa, respectively).

To get the power of the engine in "horses", and not kilowatts, the result should be divided by 0.735.

Calculation of engine power from air consumption

The same approximate calculation of engine power can be determined by air consumption. The function of such a calculation is available to those who have installed on-board computer, since it is necessary to fix the consumption value when the car engine, in third gear, is spun up to 5.5 thousand revolutions. Divide the value obtained with the DMRV by 3 and get the result.

Gv [kg]/3=P[hp]

This calculation, like the previous one, shows the gross power (bench test of the engine without taking into account losses), which is 10-20% higher than the actual one. And it is also worth considering that the readings of the DMRV sensor are highly dependent on its contamination and calibrations.

Calculation of power by weight and acceleration time to hundreds

Another interesting way to calculate engine power on any type of fuel, be it gasoline, diesel or gas, is by acceleration dynamics. To do this, using the weight of the car (including the pilot) and the acceleration time to 100 km. And in order for the power calculation formula to be as close to the truth as possible, it is also necessary to take into account slip losses depending on the type of drive and the response speed of different gearboxes. Approximate loss at start for front-wheel drive will be 0.5 seconds. and 0.3-0.4 for rear-wheel drive cars.

Using this internal combustion engine power calculator, which will help determine engine power based on acceleration dynamics and mass, you can quickly and fairly accurately find out the power of your iron horse without delving into technical specifications.

Calculation of the power of the internal combustion engine according to the performance of the injectors

No less effective indicator of power car engine is an . Earlier, we considered its calculation and relationship, therefore, it will not be difficult to calculate the amount of horsepower using the formula. The calculation of the estimated power occurs according to the following scheme:

Where, the load factor is not more than 75-80% (0.75 ... 0.8) the composition of the mixture at maximum performance is somewhere around 12.5 (enriched), and the BSFC coefficient will depend on which engine you have, atmospheric or turbocharged (atmo - 0.4-0.52, for turbo - 0.6-0.75).

Having learned all the necessary data, enter the indicators into the corresponding cells of the calculator and by pressing the "Calculate" button you will immediately get a result that will show the real engine power of your car with a slight error. Note that you do not need to know all the parameters presented; you can clear the power of the internal combustion engine using a single method.

The value of the functionality of this calculator is not in calculating the power of a stock car, but if your car has been tuned and its weight and power have undergone some changes.

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