Method of and apparatus for regulating crawling movements of motor vehicles

In a motor vehicle, a power train comprising an energy consuming, variable-speed, variable torque transmitting prime mover;

• at least one brake engageable to influence the speed of the vehicle;
• a member operable to regulate the admission of energy to said prime mover;
• a transmission shiftable into a plurality of gears;
• an automated torque transmitting system actuatable to assume engaged and disengaged conditions as well as partly engaged conditions;
• means for operating said system including a signal receiving, processing and transmitting control unit, and means for actuating said system in response to signals from said control unit;
• and means for transmitting to said control unit signals denoting the condition of said at least one brake, the condition of said member, and changes of torque being transmitted by at least one of said prime mover and said system, said control unit comprising means for comparing torques being transmitted by said system with torques being transmitted by said prime mover and for causing, in the disengaged condition of said at least one brake and in the non-operated condition of said member, said system to assume that one of said partly engaged conditions in which the vehicle is crawling in response to shifting of said transmission into one of said gears with a resulting change of torque being transmitted by said system from a first value to a second value, at least one of (a) the torque of said prime mover and (b) the rise of torque being transmitted by said prime mover at least approximating a predeterminable value when the torque being transmitted by said system at least approximates said second value.

In a motor vehicle, a power train comprising an energy consuming, variable-speed variable torque transmitting prime mover;

• at least one brake engageable to influence the speed of the vehicle;
• a member operable to regulate the admission of energy to said prime mover;
• a transmission shiftable into a plurality of gears;
• an automated torque transmitting system actuatable to assume engaged and disengaged conditions as well as partly engaged conditions;
• means for operating said system including a signal receiving, processing and transmitting control unit, and means for actuating said system in response to signals from said control unit;
• and means for transmitting to said control unit signals denoting the condition of said member, and the torque being transmitted by said prime mover in the at least substantially disengaged and in at least partially engaged conditions of said system, said control unit comprising means for causing, in the disengaged condition of said at least one brake and in the non-operated condition of said member, said system to assume that one of a plurality of partly engaged conditions in which the vehicle is crawling in response to shifting of said transmission into one of said gears with a resulting rise of torque being transmitted by said system from a first value to a higher second value which is reached when a difference between the torques being transmitted by said prime mover in said at least one substantially disengaged and said at least one partly engaged conditions of said system assumes a preselected value.

A method of varying the condition of an automated torque transmitting system which has engaged and disengaged conditions and a plurality of partly engaged conditions and is installed in a power train of a motor vehicle wherein the power train further comprises a torque transmitting prime mover, a transmission shiftable into a plurality of gears, means for operating the torque transmitting system including a signal receiving and signal transmitting control unit and actuating means arranged to effect changes in the condition of the torque transmitting system in response to signals from the control unit, and means for transmitting to the control unit first signals denoting the torque being transmitted by the prime mover and second signals denoting differences between varying torques Mk1 and Mk2 being transmitted by the torque transmitting system on the one hand and varying torques being transmitted by the prime mover on the other hand, comprising the steps of:

• ascertaining the torque Mmot1 being transmitted by the prime mover in at least substantially disengaged condition of the torque transmitting system;
• shifting the transmission into gear to effect a crawling movement of the vehicle in response to a change in the condition of the torque transmitting system to a partly engaged condition with attendant rise of the torque being transmitted by the torque transmitting system from a first to a second value while each vehicle brake is disengaged and the gas pedal is idle;
• ascertaining the torque Mmot2 of the prime mover during said shifting of the transmission into gear;
• thereafter increasing the torque being transmitted by the prime mover;
• comparing the difference Mk2-Mk1 with the difference Mmot2-Mmot1;
• and
• raising Mk2 until one of Mmot2-Mmot1 and Mmot2 matches a preselected torque.