Ice c-21 to 41 fundamentals

Brake Horsepower • Brake horsepower (bhp) is the measure of an

engine's horsepower before the loss in power caused by the gearbox, alternator, differential, water pump, and other auxiliary components such as power steering pump, muffled exhaust system, etc.

OR ….Brake Horsepower

• The amount of horsepower required to turn the crankshaft, pistons, gears, and accessories in a reciprocating engine and to compress the air into the cylinders. The brake horsepower actually delivered at the output shaft of the engine is the total horsepower developed by the engine, less the friction horsepower.

Brake horsepower • Brake refers to a device which was used to load

an engine and hold it at a desired RPM. During testing, the output torque and rotational speed were measured to determine the brake horsepower.

• Brake horsepower:bhp = ihp x mechanical efficiency (mech. eff. typically 80% - 94%)

Mechanical Efficiency

• It measures the effectiveness of a machine in transforming the energy and power that is input to the device into an output force and movement. Efficiency is measured as a ratio of the measured performance to the performance of an ideal machine:

Mech Efficiency = Measured Performance Ideal Performance

Mechanical Efficiency

• Because the power transmission system or mechanism does not generate power, its ideal performance occurs when the output power equals the input power, that is when there are no losses.

• Real devices dissipate power through friction, part deformation and wear.

Mechanical Efficiency

• The ideal transmission or mechanism has an efficiency of 100%, because there is no power loss. Real devices will have efficiencies less than 100% because rigid and frictionless systems do not exist.

• The power losses in a transmission or mechanism are eventually dissipated as heat.

Friction Horsepower

• Friction horsepower is the power lost in an internal-combustion engine through friction between parts of the machine itself

Friction horsepower, fhp = ihp - bhp

HORSEPOWERType of Horsepower Watts ft-lbf/min

Horsepower (also called “standard” or “mechanical”)

745.7 33,000

Boiler horsepower 9,809.50 434,107Electric horsepower 746 33,013.30Water horsepower 746.04 33,015.20Metric horsepower 735.5 32 548.60

PFERDE STARKE 735.5 32 548.60

TORQUE• It is a turning force, which in auto applications is

measured in foot-pounds (ft-lbf), Kg-m or Newton-meters (N-m).

• Torque is a measure of the ability of an engine to do work. Horsepower of the engine, on the other hand is the rate at which work can be done. In engines, power and torque are related by a simple equation that considers torque, engine speed (in RPM), and a conversion factor:

HP = Torque x RPM ÷ 5252

Power/Torque vs Speed

CONCEPT OF TORQUE VS POWER

MITSUBISHI LANCER Evolution MR

Trk 5 Ton 4x4 BMC 235 (TURKISH)

Which is more “powerful”?

Type: Turbocharged In line-4Displacement: 1997 ccHorsepower: 330 bhp @ 6000 rpmTorque: 315 lb-ft @ 5000 rpm

MITSUBISHI LANCER Evolution MR

Type: Turbocharged In line-6Displacement: 5880 ccHorsepower: 235 bhp @ 2500 rpmTorque: 589.5 lb-ft @ 1500 rpm (81.5 kgM)

Trk 5 Ton 4x4 BMC 235

MITSUBISHI LANCER Evolution MR

Trk 5 ton 4x4 BMC (Turkish)

Type: Turbocharged In line-4Displacement: 1997 ccHorsepower: 330330 bhp bhp @ 6000 rpmTorque: 315 lb-ft @ 5000 rpm

Type: Turbocharged In line-6Displacement: 5880 ccHorsepower: 235 bhp @ 2500 rpmTorque: 589.5 lb-ft @ 1500 rpm

Shaft Horsepower

• Shaft horsepower is the power output from an engine after it is put through the gear train and other components that result in a loss of power. It is usually used in respect to aeroplanes and ships though it can be used as the power output from a car’s gearbox.