Medium/Heavy Duty Truck Engines, Fuel, & Computerized Management Systems Chpt 6 (5th edition-Sean Bennett)

mechanical efficiency

A measure of how effectively indicated horsepower is converted tinto brake power; factors in pumping and friction losses.

brake specific fuel consuption (BSFC)

A measure of the fuel required to perform a unit of work; used in graphs of engine data designed to show fuel efficiency at specific engine loads and rpm.

dynamometer

A testing device that loads an engine by applying a resistance to turning effort (torque) and factors this agaist time to produce brake power values. Often used to performance-test or break in engines after reconditioning.

kilowatt (kW)

A unit of power measurement equivalent to 1000 watts. It is equal to 1.34 BHP.

Society of Automotive Engineers (SAE) power

An engine power output matrix using rigid guidelines to ensure reliability in making performance comparisons for different engines.

potential energy

Any of a number of different means or storing energy. A charged battery, compressed air, or unburned fule can all be said to possess this.

energy

Best expressed a stored potential. Its unit is kilowatt/hours (kW/h) or horsepower/hours (hp/h). In technology we more lcomomnly use the term potential energy.

torque rise profile

Diagrammatic representation of torque rise on a graph or fuel map.

indicated power (IP) or indicated horsepower (in the US)

Expression of gross engine power usually determined by calculation.

specific fuel consumption (SFC)

Fuel consumed per unit of work performed.

thermal efficiency

Measure of how efficiently an engine converts the potential heat energy of a fuel into usable mechanical energy; usually expressed as a percentage.

work

Name for what is accomplished when force produces a measurable result.

B-Life

OMEG-generated ratings that project the percentages of engines in a series that will fail at various mileage intervals. Correlated to a mileage value means that 10% of that engine famiy has failed at that mileage.

brake horsepower (BHP) or brake power

Power developed by an engine measured at the flywheet by a dynamometer or brake; factored by torque and rpm.

load

Ratio of power developed veersus rated peak power at the same rpm.

torsionals

Term for the uneven twisting forces to which a shaft or drivelines are subjected.

rejected heat

That portion of the potential heat energy of a fuel not converted into useful kinetic energy.

rated speed

The RPM at which an engine produces peak power.

force

The action of one body attempting to change the state of motionof another. Thea pplication of this does not necessarily result in any work being accomplished.

torque rise

The increase in torque potential designed to occur in a diesel engine as it is lugged own from the rated power rpm to the peak torque rpm, during which the power curve remains relatively flat. Engines said to be high in this are sometimes described as constant horsepower engines.

rated power (often expressed as rated speed)

The peak horsepower power produced by a diese engine; always correlated to a specific rpm.

power

The rate of accomplishing work; it is necessarily factored by time.

horsepower

The standard unit of power measureement used in North America, defined as a work rate of 33,000 lb-ft per minute; equal to 0.746 kW.

torque

Twisting effort or force. It doees not necessarily result in accomplishing work.