What does BHP stand for.. i know its the amount of horse power a engine puts down to the crank, wats it stnd 4

Question

its liek BHP vs Wheel Horse Power.. whats the B stand for in BHP, Bypass? horse power?

Answer 1

Yes,,,the "B" in BHP stands for BRAKE.

Nobody ever quite seems to explain "BRAKE" though.

There's all sorts of "Horsepower" measurements.

The Actual Term HORSEPOWER was originated by James Watt in late 1800's.

It's a FORMULA relating Load,Time,and Distance.
It was devised to compare the Power of Machines to the amount of Work a Horse could do.

It really did not mean much at the time.
Because there was No Consistant Standard to MEASURE Horsepower.

Here's where "BRAKE" comes into the picture.

About 50 Years after Watt invented the Term & Formula of "Horsepower",,,a guy named De Prony invented a way to MEASURE the Power Output of a Rotating Shaft.

It was called a PRONY BRAKE.

The way it worked was very similar to what we call a BAND BRAKE these days.

He Wrapped a Band,a Strap, around Shaft.

One end was Dead-Ended to a Scale,,of sorts.

The Other end was free to be Tightened or Loosened.

Ok,,,as the Shaft Rotated with the Strap Loosened,,
No Pull was being applied to the Strap,
And No Load was being applied to Shaft's Power Source.

But when the Free End of the Strap began to be Tightened,,,
It Constricted upon the Shaft.
It ACTED AS A BRAKE.

Friction began to Introduce LOAD,,,
via trying to Drive the strap ,,Pulling against the Anchored End of the strap.
Recall that the Strap was Anchored to a "Weight Scale"

The Tighter the Free End of the Strap was pulled,,,
the More Friction was introduced,,,
and the Harder the Pull against the Anchored Scale.

Same Frictional Drive principle as a Capstan or Windlass.

What was being Measured was Not HORSEPOWER,,,
But TORQUE.

The observed "Torque" figures were run thru Watt's Horsepower Equation to arrive at a Horsepower Figure

Horsepower is Derived from Load/Time/Distance factors,right?

The LOAD was how much the Shaft could Pull against the Anchored Scale.
The DISTANCE was all the Leverage Dimensions in the rigging,,,calculated to yield Results in FOOT POUNDS(in modern terms it's foot pounds,,,I cannot even Begin to imagine WHAT Scale a Frenchman used in a Scot's Formula in early 1800's???)

So,,,whatever the WEIGHT:DISTANCE Scale in fact was at the time......

A Foot Pound is :1 Pound Force applied to a 1 Foot long Lever.

But what about TIME factor in Watt's Equation?

Simple,,,,
It's the Shaft's RPM.
Rotational Speed is a measure of TIME.

Watts,De Prony,,,those guys were Great Minds,,and Mathmetician's.
I cannot barely Repeat the base formulas underlying their calculation,,,let alone Explain them.

Let it suffice to say that DeProny's BRAKE was calibrated to yield valid and accurate Ft/Lb readings.

And the Shaft's RPM was 3rd factor to suit the TIME factor in Watt's Horsepower Formula.

Result was That A Shaft ROTATING at a Certain Speed,,,producing a Certain Amount of TORQUE,,,
Yields a Certain Amount of Horsepower.

De Prony's BRAKE,,,aka "Prony Brake" thus became 1st Dynamometer to Measure Horsepower.

That's what BRAKE means,,in BHP.

"How Hard an Engine Pulls against a Static Load,,a BRAKE."

.........................
BHP is measured "at the shaft",,,the engine's output shaft.

There's all sorts of methodology & scales to measure horsepower.
They each yield Different figures,,,and it's an eternal argument which is valid,or most valid,,most accurate,most Useful,,,etc,etc.

The rationale of ALL them boil down to ,,"Who's got What Axe to grind".

The various values derived,,and the methods used to obtain them each serve certain purposes better than others.

BHP is usually the largest Numbers,,,measuring strictly Bare Engine Output

RWHP/(or WHP nowdays)--Rear Wheel HP can be considered "Corrected and USEABLE HP".
It will always be Less than BHP due to various losses in delivering the Power to Drive Wheel.

Useful to know BOTH as a comparison,,,to determine efficiencies in various systems taxing Absolute Engine power along the way to Drive Wheels.

............................................

Anyway,,,the "B" in BHP means BRAKE.
And BRAKE refers to "Prony Brake",,,
which was 1st "Horsepower measuring Dyno" invented by De Prony.

Literally a Brake that Loads the engine's output shaft rotation,,,and measures how much Torque the Brake is Resisting.

Interesting subject,really,and lots more to it.

But That's what Brake in BHP really stands for,,,and thats where the history of Horsepower MEASUREMENTS began,
Even though it was about a Half Century AFTER the Term & Formula were invented.

Hope that helps.

Have a great weekend!

Source:
Been there,Done that
Made my 1st Dyno at about age 8 or 9 for my go cart,Blew it up a lot--Yes,BOTH,,,Cart And Dyno,LOL

My last "little one" I used all day was 10,000 Ft/Lb capacity.
And a Big one I used occasionally,,,,150,000Ft/Lb cap.
Not for automotive engines obviously.

Answer 2

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Once again there are lots of people answering questions when they don't know what they're talking about. Break horsepower is a measure of the power (energy over time) that your engine can apply through the wheels of the car. It determines the *torque* (twisting power) that the wheels can then apply against the road. The horsepower that an engine produces determines two things that are noticeable to the driver: - The maximum rate of acceleration of the car - The top speed of the car. The reasons for the first are obvious. The reason for the second is, that as your car goes faster, the external forces that make your car slow down increase (wind, friction etc) therefore you need greater power to make the car go faster. There are several definitions of horsepower (it's not a metric or SI unit), but when talking about cars, the definition usually meant is 0.7457 kW (33,000 ft·lbs per minute).

Answer 3

Brake horsepower.

Brake horsepower (bhp) is the measure of an engine's horsepower without the loss in power caused by the gearbox, generator, differential, water pump, and other auxiliary components. Thus the prefix "brake" refers to where the power is measured: at the engine's output shaft, as on an engine dynamometer. The actual horsepower delivered to the driving wheels is less. An engine would have to be retested to obtain a rating in another system. The term "brake" refers to the original use of a band brake to measure torque during the test (which is multiplied by the engine RPM and a scaling constant to give horsepower).


WHP is the horsepower measured at the wheels, what actually is turning on the pavement.

Answer 4

What Does Bhp Stand For

Answer 5

Brake HorsePower

Answer 6

bhp stands for brake horse power

Answer 7

Brake horse power.

Answer 8

Brake Horse Power-The amount of HP that gets to the ground.