| 释义 |
ˈhorsepower
Also horse-power.
1. a. The power or rate of work of a horse in drawing; hence, in Mech., a conventional unit for measuring the rate of work of a prime motor, commonly taken (after Watt) as = 550 foot-pounds per second (which is about 11/3 times the actual power of a horse). Abbreviated H.P.
1806O. Gregory Mech. (1807) II. 357 The usual method of estimating the effects of engines by what are called ‘horse powers’ must inevitably be very fallacious. 1891Electrician Sept. 551 A new and shockingly unscientific unit, the electrical horse power, is insensibly coming into use. 1897Preece in Glasgow Herald 6 Feb. 3/5 The term ‘horse-power’ has probably seen its best days..As a scientific term it has been much abused, and as a commercial term it conveys no meaning.
b. With prefixed numeral, expressing the power or rate of work of an engine, etc.; as ‘an engine of 40-horse power’, or ‘a 40-horse-power engine’.
Properly the numeral + ‘horse’ form an attrib. phrase qualifying ‘power’ (as in ‘four-horse coach’; cf. two-foot rule, half-mile race); but the whole phrase (esp. when used attrib.) is often analyzed as numeral + ‘horse-power’.
1823Byron Juan X. xxxiv. note, A metaphor taken from the ‘forty-horse power’ of a steam-engine. 1835Marryat Olla Podr. iv, She..preferred the three-horse power of the schuyt to the hundred-horse power of the steam-packet. 1851Illustr. Catal. Gt. Exhib. 214 Oscillating steam-engine, of 10-horse power. 1872R. B. Smyth Mining Statist. 50 One 25 horse-power engine, 16-inch cylinder.
c. With qualifying words, esp. brake horsepower, the power available at the shaft of an engine, measurable by means of a brake; indicated horsepower, the power produced within the cylinders, as shown by an indicator.
1859W. J. M. Rankine Man. Steam Engine v. 479 Nominal Horse-power is a conventional mode of describing the dimensions of a steam engine, for the convenience of makers and purchasers of engines, and bears no fixed relation to indicated or to effective horse-power. 1881Encycl. Brit. XII. 207/1 Nominal horse-power is a purely conventional term adopted by makers of steam-engines, and has no fixed relation to indicated horse-power. 1887Encycl. Brit. XXII. 493/2 The efficiency of the mechanism is the ratio of the ‘effective’ or ‘brake’ horse power to the indicated horse power. 1904Westm. Gaz. 30 Mar. 10/2 The Good Hope and the Drake..are of 14,100 tons displacement and 30,000 indicated horse-power. 1943A. P. Fraas Aircraft Power Plants vi. 110 The power required to turn the engine over, or friction horsepower,..increases rapidly with rpm. 1968R. H. Bacon Car ii. 17 The power developed in the cylinder..is called the indicated horsepower or i.h.p. Some of this power is absorbed by the friction of various parts of the engine. The power remaining, that is the power that can be used for work, is called the brake horsepower or b.h.p. 1972Daily Tel. 15 Mar. 11/5 The latest car is almost a hundredweight heavier while the net brake horsepower is only up by six.
2. transf. Power or rate of work as estimated by this unit; number of horse-powers. Also fig.
1860Maury Phys. Geog. Sea iv. §268 What is the horse⁓power of the Niagara? 1867Emerson Lett. & Soc. Aims, Progr. Culture Wks. (Bohn) III. 235 Enthusiasm is the leaping lightning, not to be measured by the horse-power of the understanding. 1871Tyndall Fragm. Sc. I. xx, [He] calculates the equivalent of that heat in horse-power.
3. The power or agency of a horse or horses as employed in driving machinery; hence, a machine by which the pull or weight of a horse is converted into power for driving other machinery.
1853Catal. R. Agric. Soc. Show Gloucester 50 A One Horse Power Portable Horse Gear. Ibid. 51 A useful and economical thrashing machine to be either worked by hand or horse power. 1864Webster, Horse-power..3. A machine operated by one or more horses; a horse-engine. 1875Knight Dict. Mech. s.v., An ordinary horse-power, such as is used for thrashing-machines, drag-saws, clover-hullers.
4. Comb. horsepower-hour, a unit representing the work performed or energy consumed in working at the rate of one horsepower for one hour.
1899J. Perry Steam Engine xvi. 250 Units of Energy used Commercially. 1 horse-power hour = ..1,980,000 foot-pounds. 1906Westm. Gaz. 28 June 2/1 An output of 36 cubic feet of oxygen per horse-power hour. 1949G. P. Sutton Rocket Propulsion Elem. i. 18 The specific fuel consumption is based on the horsepower output, and its units are pounds of fuel per horsepower-hour. 1963F. D. Jones & Schubert Engin. Encycl. (ed. 3) 662, 1 horsepower-hour = 0·746 kilowatt-hour. |