Power line to drive a vehicle

A motor vehicle (2) comprising a power line, to drive at least one ground running wheel (4) of a motor vehicle (2), said power line comprising an internal combustion engine (8) giving a rotary motion output, fuel supply means (76;

• 80A, 84, 140;
• 150, 152) to supply fuel to said engine, said fuel supply means comprising controllable throttle means (80, 84;
• 80A, 84, 140;
• 150, 152) openable and closeable to vary the amount that the throttle means is open to increase and decrease supply of fuel to the engine, a change-speed gearbox (10) having a rotary output shaft (12) for supplying rotary motion to said ground running wheel and a rotary input shaft (14) for receiving output torque from the engine and a plurality of gear ratios between said shafts, each gear ratio being engageable and disengageable in response to operation of gear ratio selector means (16) in response to manual action of a driver of the vehicle, a clutch (20) interposed between said engine and said input shaft for transmitting engine output torque to the input shaft, clutch control means (46, 48) operable to vary the torque transmitting capacity of said clutch over a range from a pre-determined maximum capacity (Cl) to substantially zero capacity, the clutch control means being responsive to occurrence of a first signal (62) indicative of a wish by the driver to disengage the currently engaged said gear ratio and being responsive to occurrence of a second signal (60) indicative that another said gear ratio has been engaged, said clutch control means responding to said first signal to cause the clutch automatically to disengage substantially fully and responding to said second signal to cause the clutch automatically to engage substantially fully, and throttle control means (86, 88, 48, 92, 94) to open and close said throttle means in response to driver initiated throttle demand signals, characterised in that the throttle control means (48, 86, 88, 92, 94, 96) is automatically operable on occurrence of said first signal (62) to vary the amount which said throttle means (80, 84;
• 80A, 84, 140;
• 150, 152) is open and is automatically operable on the subsequent occurrence of the second signal (60) to restore the throttle means substantially to an open amount (Td) corresponding to that being demanded by the driver's current throttle demand signal (90), upon the occurrence (t1) of said first signal the throttle control means is automatically operated to least reduce the amount that the throttle means is open to a value (%T . . . Tc . . . 0) lower than that (Td) currently demanded by the driver, and upon occurrence (t4) of said second signal signifying to said clutch control means (46, 48) engagement of a higher gear ratio that the previously engaged ratio the clutch (20) is automatically engaged such that the torque transmitting capacity (C) of the clutch (20) is increased from substantially clutch fully disengaged up to a target torque transmitting capacity (Ct) which is less than said pre-determined maximum (Cl) and in the course of said increase up to the target torque transmitting capacity (Ct) the torque transmitting capacity (C) of the clutch (20) is increased at a first rate (118) and after attaining said target torque transmitting capacity (Ct) the torque transmitting capacity (C) of the clutch (20) is automatically increased at a lower second rate (124) towards said pre-determined maximum (C1), and wherein in the course of increasing the torque transmitting capacity at said first rate (118) the engaging clutch (20) causes the engine (8) to so slow that engine deceleration (120) is great than any (114) immediately before occurrence (t4) of the second signal.