Electrohydraulic control device for a drive train of a vehicle

An electrohydraulic control device for a drive train of a vehicle including an engine, a source of fluid under pressure, a torque converter, an input clutch located between the engine and the torque converter, a transmission having a plurality of directional and speed clutches, and transmission control means connected to the fluid pressure source for hydraulically actuating selected ones of the clutches, comprising:

• an electronic control module including a microprocessor;
• first actuator means connected to the electronic control module for operating the transmission control means and changing the direction and/or speed ratio of the transmission;
• and
• second actuator means connected to the electronic control module and the fluid pressure source for hydraulically controlling the degree of engagement of the input clutch, the second actuator means including a control member progressively manually movable between first, second and third positions, and sensor means for directing an electrical control signal to the electronic control module in proportioned response to the displacement of the control member, the degree of engagement of the input clutch being proportionately hydraulically decreased by the electronic control module as the control member is moved from the first to the second position, and being independent of movement of the control member from the second to the third position, the electronic control module including logic means for maintaining at least a minimal level of engagement of the input clutch when the control member is displaced between the second and third positions.

An electrohydraulic control device for a drive train of a vehicle including an engine, a torque converter, an input clutch connected between the engine and the torque converter, and service brake means for controllably retarding movement of the vehicle, comprising:

• an electronic control module including a microprocessor;
• actuator means including a foot pedal depressible between a first maximum torque position and a second position for delivering a first electrical signal to the electronic control module indicative of the position thereof;
• valve means for delivering fluid under pressure to the input clutch and controlling the degree of engagement thereof in response to a second electrical signal from the electronic control module reflecting the input first electrical signal;
• and
• auxiliary means for actuating the service brake means and progressively retarding the vehicle in response to further depression of the foot pedal beyond the second position and whereat the input clutch is substantially minimally engaged.

An electrohydraulic control device for a drive train of a vehicle including an engine, a torque converter, an input clutch connected between the engine and the torque converter, and a service brake, comprising:

• an electronic control module including a microprocessor;
• first actuator means including a first foot pedal manually movable between a first elevated position and a second depressed position for delivering a first electrical signal to the electronic control module indicative of the position of the first foot pedal;
• valve means for directing fluid under pressure to the input clutch and controlling the degree of engagement thereof in response to a second electrical signal from the electronic control module and the first electrical signal;
• second actuator means including a second foot pedal for engaging the service brake independently of the engagement of the input clutch;
• and
• third actuator means for controllably engaging the service brake through the second actuator means in response to depression of the first foot pedal beyond a preselected position.

An electrohydraulic control device for a drive train including an engine, a torque converter having an impeller element, a reactor element and a turbine element, an input clutch drivingly connected between the engine and the impeller element, and a lockup clutch drivingly connected between the engine and the turbine element, comprising:

• an electronic control module including a microprocessor;
• actuator means including a control member progressively movable between first, second and third positions for delivering a first electrical signal to the electronic control module indicative of the position of the control member;
• first valve means for directing fluid under pressure to the input clutch and controlling the degree of engagement thereof in response to a second electrical signal from the electronic control module;
• second valve means for directing fluid under pressure to the lockup clutch and controlling the degree of engagement thereof in response to a third electrical signal from the electronic control module;
• and
• wherein the electronic control module includes logic means for automatically modifying the second and third electrical signals as a function of the position of the control member and the speed of the impeller element.

A method of controlling an input clutch of a vehicle that is connected between an engine and a hydrodynamic torque converter, comprising the steps of:

• providing a manually operated foot pedal progressibly depressible between first, second and third positions;
• directing a first electrical signal to an electronic control module containing a microprocessor as a function of the location of the foot pedal;
• directing a second electrical signal from the electronic control module to a valve for changing the pressure level of fluid supplied to the input clutch and for changing the engagement level thereof in response to variations of the first electrical signal;
• and
• maintaining at least a relatively low pressure level to the input clutch during depression of the foot pedal between the second and third positions thereof and being otherwise independent of the movement thereof therebetween.