ENGINE SUCTION.

Putaruru Press, Volume VI, Issue 248, 2 August 1928, Page 3

ENGINE SUCTION.

INTERESTING POSSIBILITIES. A feature of the high - speed internal-combustion engine which has ■existed since its inception is the creation of a partial vacuum in the induction pipe the extent of which varies roughly in inverse ratio to the throttle opening, the greatest suction being when the throttle is shut, but tarf it was left to the genius of a Belgian engineer in the person of M. DewSndre to devise a convenient means t>f harnessing this source of energy in the shape of the well-known servo motor for brake application which •carries his name. It is of course Jeally a means of utilising atmospheric pressure by ' exhausting air from an Open-ended cylinder containing a piston or diaphragm. Engine suction has also come to be relied upon to carry out many other important functions in modern cars ; 1 it lifts petrol from a rear tank to an auxiliary tank on the dash, operates many types of windscreen wipers, and has latterly been employed for wiother purposes, such as dipping the working signalling de.Vices, etc. Some months ago the Motor published a description of a Very ingenious servo-operated steering gear designed by M. Dewandre, j @nd in a subsequent issue appeared j

announcements concerning equallyinteresting methods of controlling a clutch and a gear-changing device by similar means. These developments lead to the intriguing speculation that, as the call nowadays is all for light controls, | cars in the near future may be fitted with containers kept partially exhausted of air by the suction of the engine, which could be utilised for the operation of servo motors and other devices. Such a system would | have several quite important advanI tages over a compressed-air system | and might well prove both cheap and ; practical. i Furthermore, it is believed it could be made to overcome a disadvantage found in many suction-operated servo | brakes at the present time, namely, the excessive foot pressure needed to operate the brakes should the engine j stop.