Torque responsive clutch control

A motor vehicle comprising:

• an internal combustion engine to generate engine torque,
• fuel supply means to supply fuel to the engine, said fuel supply means having a torque demand condition having a torque demand value which is selectively variable over a range of values extending from a minimum to a maximum demand for torque, the fuel supply means being controllable whereby the amount of fuel supplied is variable with variation in said torque demand value, and wherein the engine power output is increasable in response to increasing the fuel supply to said engine,
• drive line means to transmit rotary motion from the engine to at least one ground running wheel, said drive line means comprising changeable ratio gear means and clutch means between said engine and said gear means whereby the engine power output is input to the clutch means to be transmitted by the clutch means to give a power output providing a power input to the gear means, and said clutch means having a torque transmitting capacity which is variable between a predetermined maximum and zero whereby when the torque input to the clutch means exceeds the transmitting capacity clutch slip occurs and the power output is less than the power input to said clutch means, and
• control means for automatically causing a reduction of said torque transmitting capacity upon a demand for a change of ratio in said gear means being observed by said control means and for automatically increasing said torque transmitting capacity subsequent to the ratio change being effected,
• and observing means to observe and produce a tip-in signal which is a function of said torque demand value, said control means being responsive to said torque demand value signal and arranged to control the clutch means in a manner which produces a torque transmitting capacity in the clutch means which is a function of said torque demand value whereby at least below a predetermined magnitude of said torque demand value the torque transmitting capacity of said clutch means is less than said maximum, and the control means being arranged such that whilst the vehicle continues to run in the same gear ratio and there is an occurrence of a said tip-in signal signifying an increase in said torque demand value from a magnitude less than said predetermined magnitude the control means automatically responds to increase the torque transmitting capacity of the clutch means such that during at least part of the time of said increase the torque transmitting capacity of the clutch means is less than the output torque from the engine whereby slipping of said clutch means occurs.