Minimizing Fatigue in Driving
Page 53
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The Bendix Automatic Clutch Control Enables Gears to be Selected Without Manual Use of the Clutch Pedal
PARTICULARLY on routes through congested areas, clutch operation calls for the .expenditure of considerable energy by drivers of buses and other large vehicles. From that point of view, as well as from others, interest attaches to the Bendix clutch control, which is operatediri suction from the engine induction manifold and disengages, the clutch whenever the accelerator is released. Re-engagement is effected smoothly when. the •accelerator is depressed, even to quite a small extent The device Censists of two main cornpon cuts, a control valve and a suction cylinder, together with its piston. The last-mentioned is coupled to the clutch. pedal by. means of a cable. From the valve a lighter Cable is connected to the accelerator and a flexible pipe connects the inlet .manifold, by way of the control valve, to the suction cylinder.
A Humber Snipe car equipped with this device was recently placed at our disposal by Bendix-Perrot Brakes, Ltd., of TyseIey, Birmingham, which is handling the clutch control in this country. Its use on the road is interesting.
When the engine is started up, the decelerator remaining undisturbed, the clutch pedal immediately recedes as if it had been operated by the driver. Au appropriate gear can then be engaged. On depressing the accelerator, the engine speed increases in the usual way and, simultaneously, the pedal rises slowly, so that the clutch engages smoothly and the vehicle moves off.
When the next gear is required, the accelerator is released and the gear lever can, after the usual pause in neutral, then be moved into the appropriate position. Upon depressing the accelerator, the clutch again engages and the operation is completed. The same series of. events occurs during other upward gear changes.
In order to change down, too, there is no appreciable difference from the normal practice. Speeding up the engine, while in neutral, is accompanied by automatic engagement and disengagement of the clutch as the accelerator is depressed and then released.
Thus it will be seen that the operation of changing gear, either up or down, can be performed without touching the clutch pedal. Only in one particular circumstance is that pedal used. When restarting on an upward gradient it may be convenient for the driver to delay the engagement of the clutch as he speeds up the engine, so that he can be sure of releasing the brake at the same instant as the drive is taken up. This can be effected by keeping the pedal down by foot pressure, just as if no special device were fitted.
Another result is provided by the Bendix clutch control. Whenever the engine is idling, the clutch is free and thus the effect of a free wheel is obtained. Consequently, the vehicle can, for example, be allowed to coast freely, down hills without action by the driver.