Automatic speed control systems

摘要

Linkage is disclosed for adjusting the position of a diesel engine injection pump control rack in dependence on the position of the driver's accelerator pedal and also on a system for automatically maintaining the vehicle speed at a desired value. The injection pump rack is positioned by means of a pneumatic piston-cylinder assembly and connecting linkage. The pressure in the piston-cylinder assembly is adjusted by means of a driver-controlled valve in a supply line from a pressure source, and this valve is adjusted by the driver's accelerator pedal. A normally open valve is also connected in the pressure circuit and a normally closed exhaust valve is provided. When the automatic speed control system is in operation, the driver fully opens the driver-controlled valve (by fully depressing his foot pedal) and the automatic system adjusts the other valves to hold the speed at the desired value. When the driver releases his foot pedal, the driver-controlled valve shuts, preventing the automatic speed control having any further effect on engine power.