Horsepower: what is the unit of measurement and where did it come from? Horsepower is how much.

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 - the amount of mechanical work that is done in 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. Technological progress and the widespread use of steam engines have 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 power indicators differ from factory parameters and it makes sense to make real measurements:

• putting the car on a dyno - the most accurate type of diagnosis;
• 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, real indicators for different measurement methods 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 than cars with identical digital values ​​​​of net measurements.

Since in Russia the amount of tax paid for it depends on the amount of horsepower in a vehicle, 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.).

Horsepower is a unit of power. Its value is approximately equal to 75 kgf / m / s, which is equivalent to the force with which a load weighing 75 kg is lifted. to a height of one meter in one second.

This term was introduced into use in the 18th century by the inventor of the steam engine, James Watt, who lived in England. When he presented this invention to the public, many had a legitimate question whether his car was profitable, or rather, how much more profitable it was than a horse, which at that time was used as the main draft animal. It occurred to Watt to conduct an unusual experiment, he agreed with a familiar brewer that his car would compete with a horse doing the same work for eight hours. Moreover, the brewer wanted to win and mercilessly exploited his poor horse. However, even with such a brutal attitude towards the horse, the car turned out to be 4 times more efficient.

During the experiment, Watt, observing how the horse works, decided to calculate its performance. It turned out that in one minute, on average, a horse lifts a load weighing 180 pounds to a height of 181 feet. After doing these calculations in a minute, he came up with an average horsepower of 33,000 foot-pounds per minute. If this value is translated into watts, then it will be equal to 745 W with a "tail".

Although in our time in different countries, horsepower varies significantly among themselves.

Types of horsepower

hydraulic horsepower equals 745.7 W;

Electric horsepower equals 746 W., sometimes it is indicated in the instructions for electric motors;

Metric horsepower equals lifting a weight of 75 kg in a second to a height of one meter;

Boiler horsepower equals 33,475 Btu.h or 9.8 kW or 1000 kgf m / s;

mechanical horsepower equals 745.7 and is very rarely used as a unit of measurement in English-speaking countries.

At the 2nd Congress of the Scientific British Association, which took place in 1882, the unit of power was named after J. Watt - Watt. The General Conference on Weights and Measures, which was held in 1960, the Watt unit was included in the international register of SI measurements, that is, in fact, from that moment on, the Watt measurement unit took on international status. However, this almost did not affect the "horsepower" in any way.

In the Russian Federation, the amount of vehicle tax directly depends on the engine power in "horsepower"

Many people have a question, how to calculate the engine power of a car in "horsepower"?
To answer this question, you should go to Wikipedia, it states that you need to multiply the engine power in kilowatts by 1.35962.

The name "horsepower" sounds quite exotic and companies that produce non-motor products could not help but take advantage of this:

• Balm "Horsepower";
• Gel "Horsepower";
• Ointment "Horsepower";
• Shampoo "Horsepower".

What is horsepower video

Everyone knows the obsolete unit of power "Horsepower", which has now been replaced by the standard SI unit, the watt.

Clinic - http://z-clinic.ru/services/xirurgiya. Vascular surgeon queens.

However, it is still widely used, for example, in the automotive industry. Scientists rarely use this unit because of its ambiguous interpretation.

So what is "horsepower"? The physics handbooks indicate that horsepower is 75 kgf * m / s, which is exactly 735.49875 watts. To imagine when a horse develops such power, you need to turn to the history of the emergence of this unit.

"Horsepower" was first proposed by James Watt, the inventor of the steam engine. He proposed using his invention to pump water out of the mine. But how to explain to tight-fisted mine owners what they are offered to buy and what are the advantages of this new device? And in order to evaluate the power of new engines, they did the following. They harnessed the horse to a conventional horse-drawn water-lifting pump, and looked at how much water it would lift in a day. Then they attached a steam engine to the same pump and saw what the result would be in a day of its operation. They divided the second quantity by the first, and on the basis of these figures they explained to the mine owners that the pump replaces the Nth number of horses. The power obtained as a result of the first experiment became a measure and was called "horsepower".

In fact, the power that the average horse is able to develop for any long time is less than the value obtained by Watt. Either the driver worked very well, or the horse was caught very “trained”. Of course, horses are different and it is impossible to expect that both a draft horse and an Arabian horse will develop the same power. And yet, when does a horse create such power? To this question in the journal American Scientist, one of the authors proposed the following option: the power of one horsepower is developed by a horse weighing 750 kilograms, jumping over an obstacle 183 centimeters wide and high.

Anecdote on the subject:
- What is one horsepower?
- This is the power of one horse with a height of one meter and a weight of one kilogram.
- Excuse me, where did you see such a horse?
- She's hard to see. It is kept in the Chamber of Weights and Measures near Paris!

Tags: unit of power; strength; story

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 internal combustion engines are used (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 a long 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. So, the power of the 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

ISO standards
Lists: List of ISO standards List of ISO romanizations List of IEC standards Categories: Category:ISO standards Category:OSI protocols
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What is 1 horsepower equal to? If you take any encyclopedia and look in it what horsepower is, then we will read that this is an off-system unit of power that is not used in Russia. Although on any website of car dealerships, engine power is indicated in horsepower.

What is this unit, what is it equal to?

When talking about engine horsepower, most of us picture a simple picture: if you take a herd of 80 horses and a car with an 80 hp engine, then their forces will be equal and no one will be able to pull the rope.

If you try to recreate such a situation in real life, then the herd of horses will still win, because in order for the engine to develop such power, it needs to spin the crankshaft to a certain number of revolutions per minute. Horses, on the other hand, rush from their place and drag the car behind them, thus breaking its gearbox.

In addition, you need to understand that horsepower is a standard unit of power, while each horse is individual and some individuals can be much stronger than others.

Horsepower was introduced into circulation in 1789. Renowned inventor James Watt wanted to demonstrate how much more profitable it was to use steam engines rather than horses to get the job done. He simply took and calculated how much energy a horse spends to use the simplest lifting mechanism - a wheel with ropes attached to it - to pull barrels of coal out of the mine or pump out water using a pump.

It turned out that one horse can pull a load weighing 75 kilograms at a speed of 1 m/s. If we translate this power into watts, it turns out that 1 hp. is 735 watts. The power of modern cars is measured in kilowatts, respectively, 1 hp. = 0.74 kW.

To convince mine owners to switch from horse-powered to steam-powered, Watt proposed a simple method: measure how much work the horses could do in a day, and then turn on the steam engine and calculate how many horses it could replace. It is clear that the steam engine turned out to be more profitable, because it was able to replace a certain number of horses. The owners of the mine realized that it was cheaper for them to maintain a car than a whole stable with all the ensuing consequences: hay, oats, manure, and so on.

It is also worth saying that Watt incorrectly calculated the strength of one horse. Only very strong animals are capable of lifting a weight of 75 kg at a speed of 1 m / s, in addition, they will not be able to work for a long time in such conditions. Although there is evidence that for a short time one horse can develop power up to 9 kW (9 / 0.74 kW \u003d 12.16 hp).

Types of horsepower

• Metric horsepower is equal to lifting 75 kg per second by 1 meter. Applied in Europe
• mechanical horsepower equals 745.7. very rarely used as a unit of measurement in English-speaking countries
• Electric horsepower equal to 746 W., sometimes indicated on the plates of electric motors.
• Boiler horsepower is equal to 1000 kgf m/s. or 9.8 kW or 33,475 Btu/hour. (unit used in USA)
• hydraulic horsepower is equal to 745.7 W.

How is engine power determined?

To date, the easiest way to measure the real power of the engine is with a dyno. The car is driven onto the stand, it is securely strengthened, then the driver accelerates the engine to maximum speed and the real power in hp is displayed on the display. Permissible error - +/- 0.1 hp As practice shows, it often turns out that the nameplate power does not correspond to the real one, and this may indicate the presence of a wide variety of malfunctions - from low-quality fuel to a drop in compression in the cylinders.

It is worth saying that due to the fact that horsepower is a non-systemic unit, it is calculated differently in different countries. In the USA and England, for example, one hp. is 745 watts, not 735 as in Russia.

Be that as it may, everyone is already accustomed to this particular unit of measurement, since it is convenient and simple. In addition, HP used when calculating the cost of OSAGO and CASCO.

Agree, if you read in the characteristics of the car - engine power is 150 hp. - it is easier for you to navigate what he is capable of. And a record like 110.33 kW is not enough to say. Although converting kilowatts to hp. quite simple: we divide 110.33 kW by 0.74 kW, we get the desired 150 hp.

I would also like to remind you that the concept of “engine power” in itself is not very indicative, you also need to take into account other parameters: maximum torque, revolutions per minute, car weight. It is known that diesel engines are low-speed and maximum power is achieved at 1500-2500 rpm, while gasoline engines accelerate longer, but show better results over long distances.

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