PS
This unit (German:
Pferdestärke = horse strength) is no longer a lawful unit, but is still commonly used in Europe, South America and Japan, especially by the automotive and motorcycle industry. It was adopted throughout continental Europe with designations equivalent to the English "horse power", but mathematically different from the British unit. It is defined by the
Physikalisch-Technische Bundesanstalt (PTB)
[1] in
Braunschweig as exactly:
1 PS = 75
kp·m/s = 0.73549875 kW = 0.9863201652997627 hp (SAE) The PS was adopted by the
Deutsches Institut für Normung (DIN) and then by the automotive industry throughout most of Europe, and is always measured at the wheels, as opposed to most factory horsepower figures, which are rated at the crank (which is measured right off the motor, not accounting to any drivetrain loss, which is especially considerable in an All wheel Drive configuration).
In the 19th century, the French did not use this German unit, but had their own, the
Poncelet. In 1992, the PS was rendered obsolete by EEC directives, when it was replaced by the kilo
watt as the official power measuring unit, but it continued to be used for commercial and advertising purposes, as customers were not familiar with the use of kilowatts for combustion engines.
