Patent GB-388129-A (GB)
Title: Improvements in or relating to apparatus for the control of the velocity of a motor vehicle
Filed: 1931-11-10
Abstract: 388,129. Controlling motor vehicles. HAYES, F. A., Middletown, New Jersey, U.S.A. Nov. 10, 1931, No. 31149. Convention date, Nov. 10, 1930. [Class 79 (v).] To maintain a limited motor-vehicle velocity, the driver raises the accelerator pedal, which instead of partially closing the throttle, leaves the throttle wide open, but increases the speedratio of an automatic transmission so that at all times the vehicle will be operating at maximum throttle and minimum engine speed, thereby providing minimum fuel consumption, noise, and vibration. The invention is described as applied to the arrangement of Specification 344,066, [Group XXIV], in which higher velocity ratios in the transmission are automatically brought in to drive the car faster when a piston such as 11 is moved to the right against a spring 16 by oil from a pump 13 driven by the engine shaft past an adjustable controlling bye-pass valve such as 24. The pressure on the piston 11 is proportional to the engine speed for any setting of the valve 24, and the greater the waste in the bye-pass 25, the smaller the oil pressure on the piston 11, and the lower the speed-ratio in the transmission. The accelerator pedal 34 is adapted for joint control of the engine throttle 32 and the ratio-controlling valve 24. The cylinder 10 of the piston 11 has an elongated port 17 connected by a duct 18 to a cylinder 19 in which slides a piston 20 connected by a rod 22 directly to the needle-valve 24, which determines the ratio of the oil pressure to the engine speed. A spring 26 normally holds the rod 22 against a stop 28 with the valve 24 open. The stop 28 is set before the car is started to determine the maximum speed of the engine before the piston 11 begins to move, preferably the engine speed developing maximum power. A floating lever 29 medially pivoted at 30 to the rod 22 is connected at one end to the pedal 34 and at the other to the throttle 32. The control stop 28 having been set to desired engine speed in low speed ratio, the car is started from the idling position shown in Fig. 1 by depressing the pedal 34 a little. The pedal 34 is then thrust right down so as to tilt the lever 29 against a stop 36 with the throttle 32 held fully open against its closing spring 35. This act increases the engine speed and accelerates the car in the low gear ratio until the engine has reached the speed for which the stop 28 has been set, after which pressure oil begins to move the piston 11 to the right. The car now accelerates at constant engine speed due to the movement of a ratio control rod 12 until the desired maximum car speed has been reached. The engine speed is balanced constant because, if it increases, the increased oil pressure would increase the speed ratio thereby loading the engine more. Early in its movement the piston 11 opens the port 17 admitting pressure oil behind the piston 20. The piston 20 cannot move because the pedal 34 is held down with the lever 29 against the stop 36. So long as the pedal 34 is held right down the car will accelerate up to the maximum velocity at which the full power of the engine can drive it, while the transmission automatically sets itself to the correct ratio for the maximum car speed attained, as described in Specification 343,988, [Group XXIV]. If now the driver desires a more moderate maximum speed, he eases the pedal 34, as shown in Fig. 3. The lever 29 turns to the left about pivot 36, allowing the piston 20 and the rod 22 to follow, thereby partially closing the valve 24. The increased oil pressure behind the piston 11 thrusts the rod 12 to the right increasing the transmission ratio, and the increased load on the engine reduces the engine speed while maintaining constant car velocity, and all the time the throttle 32 remains wide open. The throttle only begins to close to decelerate after the valve 24 has been fully closed. On the return movements, pressure oil behind the piston 11 escapes through a hole 21 in the piston itself, and through a relief port 27. The piston 11 uncovers the port 17 to open the cylinder 19 to exhaust. Proportionality of oil pressure to engine speed may be attained by a governor control of the rod 22 instead of by using the same engine to drive the pump 13.