LEADING C.M. MAKER APPROVES H t T. GOVERNOR M LICH interest has been
Page 31
If you've noticed an error in this article please click here to report it so we can fix it.
aroused by the reference to a 'device for engine governing by short-circuiting the lit. current, which appeared on our Patents page in our issue dated June 5. Now we have received, from one of the most prominent commercialvehicle manufacturers in this 'country, an account of the behaviour of this governor on engine bench tests.
For the benefit of readers who cannot call to mind the principle of the device, we will re-outline its main features. Incorporated in the rotating part of the distributor is a .heavy plunger, retained in a position remote from a live contact by a spring. When a predetermined speed is exceeded, centrifugal force causes the , plunger to approach the contact.
As a result, a parallel circuit for the h.t. current is introduced which next becomes the main circuit and would ultimately cut out the sparking plugs, although in practice this point is never reached because, if it were, the power output of the engine would fall to zero.
We are informed, by the inanufactuer referred to above, that when the governor first begins to act there is a rapid fall in engine power. As a ,rule the device comes into operation at 2,400 r.p.m. and at practically no load the crankshaft speed rises 'to 2,550 r.p.m. From this final engine speed, the device is sensitive, and in consequence there is only a small percentage of hysteresis loss on the governor.
During the period that the governor takes charge of the engine, our informant continues, there is, strange to relate, an absence-of back-firingin the -exhaust system. However, a " rumbling or roaring noise " becomes audible " such as one would experience in running an engine with one or two plugs misfiring. Power is fairly steady and the engine speed does not become unstable during the governing period."
The company is not in a position to state what may happen with prolonged governing periodsA,but surmises that with a partly worn engine and governing on full throttle, petrol wash on the cylinder walls would become severe. Oil on the plug points w,ould also pqssibly be experienced.
It points out that the device operates without regard to the position of the throttle, and therefore the above possible ill-effects, if they materialized, would always he a
• menace to .perfect