Method and apparatus for closed loop acceleration control for vehicles

In combination with a vehicle having a chassis, an engine, a throttle controlling engine speed, a variable speed transmission having a speed ratio defined as the ratio of input speed to output speed, and ground engaging drive wheels;

• an acceleration control system comprising:
• means for adjusting said transmission to change said speed ratio thereof;
• first sensing means for sensing throttle position;
• second sensing means for sensing said transmission output speed;
• third sensing means for sensing thrust developed between said drive wheels and said chassis;
• and
• control means for controlling said adjusting means substantially simultaneously in response to said first, second and third sensing means whereby movement of said throttle in a direction for increasing engine speed tends to increase said speed ratio, while increase in said sensed thrust tends to decrease said speed ratio, and increase in said sensed transmission output speed also tends to decrease said speed ratio.

In combination with a vehicle having a chassis, an engine, a throttle controlling engine speed, a variable speed transmission having a speed ratio defined as the ratio of input speed to output speed, an axle with a housing, and ground engaging drive wheels operably secured to said axle:

• a fluid power cylinder and piston unit operably coupled with said transmission for changing said speed ratio;
• a fluid pump;
• a fluid control valve shiftable in first and second opposite directions for directing pressure fluid flow from said pump to said cylinder and piston unit to respectively increase and decrease said speed ratio;
• means for sensing the position of said throttle and operably coupled with said valve to urge the latter to shift in said first direction upon movement of said throttle to increase engine speed;
• means for sensing said output speed of the transmission and operably coupled with said valve to urge the latter to shift in said second direction as said output speed increases;
• and
• drive wheel thrust sensing means comprising a member secured in cantilevered, flexible relationship to said chassis and operably secured to said axle housing whereby said member flexes in response to thrust developed between said drive wheels and said chassis, said member disposed for operably engaging said valve to urge the latter to shift in said second direction as said secured thrust increases.