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![Mark J [Aalborg] _](https://billeder.bazoom.dk/motorcykler/bruger/1/90/90/638314741340470000/1513/mark-j-aalborg-_.jpg)
DIN hk? DIN hk?
Hvad er det, er det en speciel måde at måle hk på? ligesom Whp....
0 synes godt om
jul 2004
Følger: 4 Følgere: 2 MC-er: 2 Emner: 59 Svar: 436
Du skulle vel ikke vide, hvordan det regnes om??
Jeg ved at kw til hk er noget med at gange med 1,3636 eller noget i den dur...
jul 2004
Følger: 4 Følgere: 2 MC-er: 2 Emner: 59 Svar: 436
Men nu vi har gang i denne ydelses-snak...er Whp så ikke det samme som bhp?....og hvor der de målt...på hjulet?
jul 2004
Følger: 4 Følgere: 2 MC-er: 2 Emner: 59 Svar: 436
mar 2005
Følger: 16 Følgere: 16 MC-er: 1 Emner: 66 Svar: 221
Grundlæggende er moment jo kraft x arm i dette tilfælde pund x fod, hvor Nm jo er newton x meter.
Så forskellen er jo bare enhederne, altså skal du gange med Nm med 0.73756212117 for at få det i lb-ft!
jul 2004
Følger: 4 Følgere: 2 MC-er: 2 Emner: 59 Svar: 436
Tak nu kan jeg pludselig få det hele til at passe.... jeg ville kunne nemlig ikke finde ud af hvilken af disse udregninger, der var rigtige: "moment (lb-ft) = 5252 x hk / rpm" eller "moment (Nm) = hk / rpm x 7120", men nu ved jeg at de begge er rigtige....:D
apr 2005
Følger: 14 Følgere: 12 MC-er: 5 Emner: 15 Svar: 492
Så er 1 Hk altså ikke defineret som den tid det tager for en hest at slæbe 1 liter kogende vand 1 kilometer???
c",)
Allan
Aprilia SL1000
mar 2005
Følger: 16 Følgere: 16 MC-er: 1 Emner: 66 Svar: 221
Hvis du søger på google efter noget lignende "unit converter" finder du en masse regnemaskiner hvor du kan indsætte alle mulige enheder og få dem ud i det du skal bruge!
jul 2004
Følger: 4 Følgere: 2 MC-er: 2 Emner: 59 Svar: 436
Allan P
Hk har faktisk noget med heste at gøre, betegnelsen er nemlig en enhed for hvad en hest kunne løfte (det skal stå hen i det uvisse hvilken hest)...så vidt jeg husker er en hestekræft den kræft der skal til at løfte 70 kg op i én meters højde på et sekundt...
maj 2005
Følger: 33 Følgere: 31 MC-er: 4 Emner: 34 Svar: 352
aug 2004
Følger: 18 Følgere: 45 MC-er: 4 Emner: 242 Svar: 1.414
maj 2005
Følger: 41 Følgere: 42 MC-er: 3 Emner: 94 Svar: 1.998
Læs det eller lad være...gad ikke selv, tror svaret er et sted
Blandet engelsk og dansk
TPC er lidt lissom SAE hestekræfter. Maskinen er skrællet til benet
for at kunne køre testen, og databasen/OS kan være patched for at
give et bedre resultat.
Men right, det giver da et eller andet billed af verden, jeg er bare ikke
helt sikker på hvor virkeligt det er.
(SAE måles uden generator, vandpumpe, luftfilter, udstødning, gearkasse og
så ellers bare maksimal fortænding. Tjah, så skal der nok ske noget
Effekt (fysik)
Fra Wikipedia, den frie encyklopædi
watt (W) er en fysisk måleenhed for effekt. Watt er afledt af SI-enheder og opkaldt efter James Watt.
Effekt (watt) er et udtryk for belastning. Effekt er ikke noget, der kan forbruges.
Hestekræfter, HK, er også en måleenhed for effekt og på andre sprog hedder hestekræfter:
• eng. HP, HorsePower
• tysk: PS, PferdStärke
• "EU" metric horsepower
Forskellige landes eller industriers hestekraft er defineret forskelligt og har derfor forskellige omregningsfaktorer. Mere information kan findes i disse adresser: horsepower og "EU" metric horsepower.
Udover watt kan effekt f.eks. opgives i følgende enheder: J/s, A*V, Nm/s, kWh/h.
Fysisk effekt generelt (Mekanisk, atomar og elektrisk...)
Effekt er bl.a. defineret som energiændring per tidsenhed.
1 W = 1 J/(1 s), hvor den ændrede energi er 1 joule (J) over et tidsinterval på 1 sekund (s). 1 watt her er den gennemsnitlige effekt over det angivne 1 sekunds tidsinterval. Vi har ingen viden om effekten i mindre tidsintervaller eller tider, medmindre vi har energien målt i flere intervaller eller har energien målt kontinuert som funktion af tiden. Faktisk er det et specialtilfælde af matematisk differentiering med hensyn til tid.
Den "rigtige" formel for effekt med energi og tid er:
hvor
• P er effekt i (watt, W)
• E er energi i (joule, J)
• t er tiden i (sekunder, s).
horsepower (hp)
a unit of power representing the power exerted by a horse in pulling. The horsepower was defined by James Watt (1736-1819), the inventor of the steam engine, who determined after careful measurements that a horse is typically capable of a power rate of 550 foot-pounds per second. This means that a horse, harnessed to an appropriate machine, can lift 550 pounds at the rate of 1 foot per second. Today the SI unit of power is named for Watt, and one horsepower is equal to approximately 745.6999 watts. (Slightly different values have been used in certain industries.) Outside the U.S., the English word "horsepower" is often used to mean the metric horsepower, a slightly smaller unit.
metric horsepower
a unit of power, defined to be the power required to raise a mass of 75 kilograms at a velocity of 1 meter per second. This is approximately 735.499 watts or 0.986 32 horsepower. The unit is known in French as cheval vapeur, in Spanish as caballo de vapor, and in German as pferdestärke.
PS
This unit (German: Pferdestärke = horse strength) is still commonly used in Germany and central Europe, although not an lawful unit any more. It is defined by the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig as:
1 PS = 735.49875 W
• PTB http://www.ptb.de/
Horsepower
From Wikipedia, the free encyclopedia.
The horsepower (hp) is the name of several non-metric units of power. In scientific discourse the horsepower is rarely used due to the various definitions and the existence of an SI unit for power, the watt (W). However, the idea of horsepower persists as a handy term in many languages, particularly in the automotive industry for listing the maximum power of internal-combustion engines.
The various types of horsepower are:
Table of contents
1 hp
2 RAC horsepower
3 PS
4 pk
5 CV
6 ch
7 bhp
8 ihp
hp
According to the most common definition of horsepower, one horsepower is defined as exactly:
1 hp = 745.69987158227022 W
The horsepower was first used by James Watt during a business venture where his steam engines substituted horses. It was defined that a horse can lift 33,000 pounds with a speed of 1 foot per minute: 33,000 ft•lb•min-1. (This is equivalent to approximately 15,000 kg at 30 cm.)
• WebCars! What is horsepower?
RAC horsepower
This measure was instituted by the Royal Automobile Club in Britain and used to denote the power of early 20th century British cars. Many cars hence had names such as "40/50hp", which indicated the RAC figure followed by the true measured power.
RAC horsepower cannot be given as a proportion to metric power. Instead, it is derived from dimensions of the engine and certain assumptions about engine efficiency. When invented, it gave a rough guide to its true power rating; as new engines were designed with ever-increasing efficiency, it was no longer a useful measure, but was kept in use by UK regulations which used the rating for tax purposes.
<math>RAC h.p. = {D^2 * n}/2.5</math>
D is the diameter (or bore) of the cylinder in inches
n is the number of cylinders
• Wolfhound: RAC horsepower http://www.designchambers.com/wolfhound/wolfhoundRACHP.htm
PS
This unit (German: Pferdestärke = horse strength) is still commonly used in Germany and central Europe, although not an lawful unit any more. It is defined by the Physikalisch-Technische Bundesanstalt (PTB) in Braunschweig as:
1 PS = 735.49875 W
• PTB http://www.ptb.de/
pk
A dutch paardekracht equals the german Pferdestärke hence
1 pk = 735.49875 W
CV
A French unit for tax horsepower.
ch
This is a French unit, short for cheval vapeur. Some sources give it as 735.5 W, but it is generally used interchangeably with the German 'PS'.
bhp
Brake horsepower was a term commonly used before the 1970s in the USA, and is still common in the UK. It indicates the brake, the device for measuring the true power of the engine. Stating power in 'bhp' gives some indication this is a true reading, rather than a calculated or predicted one. However, several manufacturers started to strip their engines of essential ancilliaries for the purposes of getting a high horsepower figure to use in marketing the car.
In the USA the term fell into disuse after the American Society of Automotive Engineers
What is Horsepower?
How do you define horsepower? Ask a car enthusiast and most of the time you'll get a blank look, a shrug of the shoulders and maybe a guess along the lines of "What a horse can do!".
That answer begs the question: What horse? A thoroghbred race horse that can carry the small weight of a jockey with a lot of speed, or a working horse that can pull heavy loads albeit slowly? Obviously there is a more precise answer. Car manufacturers, despite their reputation for being creative regarding the horsepower ratings of their products for marketing reasons, require a more stable definition.
Horsepower is defined as work done over time. The exact definition of one horsepower is 33,000 lb.ft./minute. Put another way, if you were to lift 33,000 pounds one foot over a period of one minute, you would have expended one horsepower.
Even more interesting is how the definition came to be. It was originated by James Watt, (1736-1819) the inventor of the steam engine and the man whose name has been immortalized by the definition of Watt as a unit of power. The next time you complain about the landlord using only 20 watt light bulbs in the hall, you are honoring the same man.
To help sell his steam engines, Watt needed a way of rating their capabilities. The engines were replacing horses, the usual source of industrial power of the day. The typical horse, attached to a mill that grinded corn or cut wood, walked a 24 foot diameter (about 75.4 feet circumference) circle. Watt calculated that the horse pulled with a force of 180 pounds, although how he came up with the figure is not known. Watt observed that a horse typically made 144 trips around the circle in an hour, or about 2.4 per minute. This meant that the horse traveled at a speed of 180.96 feet per minute. Watt rounded off the speed to 181 feet per minute and multiplied that by the 180 pounds of force the horse pulled (181 x 180) and came up with 32,580 ft.-lbs./minute. That was rounded off to 33,000 ft.-lbs./minute, the figure we use today.
Put into perspective, a healthy human can sustain about 0.1 horsepower. Most observers familiar with horses and their capabilities estimate that Watt was a bit optimistic; few horses could maintain that effort for long.
Although the standard for rating horsepower has been available for over 200 years, clever car manufacturers have found ways to change the ratings of their engines to suit their needs. During the famous horsepower wars of the 1960s, manufacturers could get higher figures by testing without auxiliary items such as alternators or even water pumps. High ratings backfired when insurance companies noticed them and started to charge more for what they saw as a higher risk. Manufacturers sometimes responded by listing lower horsepower figures, forcing enthusiasts to look at the magazine test reports to determine what was going on. In the early seventies the SAE (Society of Automotive Engineers) stepped in with standardized test procedures and the fiqures were more consistent.
Between 1922 and 1947, the Royal Automobile Club used a horsepower rating that was the basis for an automobile tax. The horsepower of an engine was determined by multiplying the square of the cylinder diameter in inches by the number of cylinders and then dividing that figure by 2.5. Using this dubious method, What we know of as a 385 horsepower motor found in the Z06 Corvette would be rated at only 48.67 hp!
There is a metric horsepower rating, although it is rarely used. The two methods are close, with one SAE horsepower equal to 1.0138697 metric horsepower.
One horsepower also equals 745.699 watts. This means that if you really want to confuse people, you could complain about the .02682 horsepower light bulb your landlord has in the hallway as opposed to the mundane 20 watt measurement.
(SAE) recommended manufacturers use "hp (SAE)" to indicate the power of the engine, given that particular car's complete engine installation. The British market seemed not to need the correction.
ihp
Indicated horsepower is the theoretical power of a reciprocating engine assuming that it is completely efficient in converting the energy contained in the expanding gases in the cylinders. It is calculated from the pressures developed in the cylinders, measured by a device called an engine indicator - hence indicated horsepower. It was the figure normally used for steam engines in the 19th Century but is misleading because the mechanical efficiency an engine means that the actual power output may be only 70-90% of the indicated horsepower.
home > tech tips > horsepower
Horsepower
From: "Angela & Darren Fritzsch"
Quick questions for anybody with opinions (Guess thats everybody)
A&D,
I'm a mechanical engineer who grew up long enough ago that I was raised with Imperial units ("wotsa Futt Mista?" ), went through my training with SI (Metric) units, then worked 10 years for a Yank company who supplied us with equipment from the US, UK, Italy and Japan.
I have endured much sucking of teeth and scratching of foreheads over exactly these sorts of questions. The basic concept of power is that it is "the rate of performing work". The confusion arises out of how and where the power is measured, and who is specifying the procedures used.
A traditional "horsepower" is specified as a work-rate of (I think) 33000 foot-pounds per minute, and is actually a good deal more than the average nag can deliver for any length of time.
Similarly a Watt is specified as 1 Newton-Metre per Second. (Approximately one gerbil-power) The forces and distances can be measured linearly or rotationally, with identical power results, (i.e. Force multiplied by linear distance divided by time gives exactly the same results as Torque multiplied by angular movement divided by time). In automotive practice we are usually interested in rotational power, i.e. the combination of torque and rpm.
When you crunch the conversion numbers a traditional horsepower works out to be 746 Watts (0.746kW) Those people working in metric countries, i.e. Europe and Japan, do all their work in metric, but are trying to flog their gear to us, the UK, and more importantly the Yanks, who refuse to understand metric. They have to quote a horsepower figure because your potential customer no-comprendez this kilowatt thing. To "simplify" the conversion a metric horsepower was defined by (I think) the French as 0.75kW. I think the Japs use the same and call it a ps, but don't know about the Germans.
SAE is an American industry body (The Society of Automotive Engineers) that sets standards for all kinds of technical issues in the US auto industry, although their specs. are regularly "borrowed" by other industries.
DIN is a German technical body (The Deutsche Institut fur Normung; - equivalent to the Australian Standards) that sets standards for all kinds of industries over there. JIS is the Japanese eqivalent of DIN, AS, BSI etc. etc. and does the same job over there, and I believe sets the spec for ps.
The term "bhp" stands for "brake horse power" and derives from the days of steam and even current marine practise, when engines were running very slowly. (e.g. the main engine on the ship I currently work on has a max speed of 111rpm; mind you it has a 60cm bore and 2.3m stroke and delivers around 12000bhp) This was slow enough to measure the gas pressures inside the cylinder and plot them against the piston position over one revolution.
You could then measure the work done by the cylinder gases on the piston;- the "indicated horsepower" (ihp). By comparing this with the actual output of the engine you could see how much you were losing in making all those bits and pieces thrash up and down (i.e. work out the mechanical efficiency of the engine)
Brake horse power means you load the engine you are testing up with a brake (dynomometer), which you also use to measure the torque delivered, and by simultaneously measuring the rpm of the engine you can calculate the power delivery. Read this carefully;- brake horsepower specifies how you measured the power, not where you measured it. A manufacturer will commonly test an engine with the dynomometer attatched to the flywheel, with the whole thing mounted on a test stand, i.e. with no power steering, no air conditioning, no alternator, and often no water pump. They do this for the simple reason that it gives them the biggest figure to print in the spec. sheet. You will never find any direct admission of this in any of their literature, they will just specify a particular testing protocol as laid out by one of the standards societies, i.e a DIN, SAE, JIS spec. They are not actually lying, just trying to get you to buy their machine instead of somebody elses.
For us mug drivers the only really useful measurement of power is what you get at the back wheels, hence the usefulness of rolling dynomometers such as Bob Whyms'. The numbers measured here are always lower than the factory figures because they show what is left after taking account of the losses for all the accesories and also the drive train.
When tring to compare figures from different sources I would suggest that you convert everything to kW and compare those numbers. It is usually safe to assume that any figures you get will be engine output as described above because all the manufacturers are playing the same game.
Sorry if the above sounds like a mechanics lecture, but many skilled individuals have spent a great deal of effort over many years making a simple concept as complicated as possible.
DIN hk?