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A method of controlling engine idle speed in a motor vehicle having an internal combustion engine and multi-ratio transmission when launched from a neutral idle rest condition. At neutral idle, the transmission is controlled such that the input and output members are decoupled. During vehicle launch

A method of controlling engine idle speed in a motor vehicle having an internal combustion engine and multi-ratio transmission when launched from a neutral idle rest condition. At neutral idle, the transmission is controlled such that the input and output members are decoupled. During vehicle launch from neutral idle operation, two different strategies may be employed to control engine idle speed. One preferred method is to determine a feedforward or predicted torque converter load as a function of time. Another preferred method is to determine the feedforward or predicted torque converter load by comparing a maximum engine brake torque and the torque capacity of the forward clutch at any given time. Irrespective of the particular method used, other engine torque loads are added to the feedforward or predicted torque converter load to determine the engine output torque required to control engine idle speed and provide a smooth between transmission operating modes throughout the launch period.

대표청구항 ▼

A method of controlling engine idle speed in a motor vehicle having an internal combustion engine and multi-ratio transmission when launched from a neutral idle rest condition. At neutral idle, the transmission is controlled such that the input and output members are decoupled. During vehicle launch

A method of controlling engine idle speed in a motor vehicle having an internal combustion engine and multi-ratio transmission when launched from a neutral idle rest condition. At neutral idle, the transmission is controlled such that the input and output members are decoupled. During vehicle launch from neutral idle operation, two different strategies may be employed to control engine idle speed. One preferred method is to determine a feedforward or predicted torque converter load as a function of time. Another preferred method is to determine the feedforward or predicted torque converter load by comparing a maximum engine brake torque and the torque capacity of the forward clutch at any given time. Irrespective of the particular method used, other engine torque loads are added to the feedforward or predicted torque converter load to determine the engine output torque required to control engine idle speed and provide a smooth between transmission operating modes throughout the launch period. locked 4WD state in which the first side gear is connected to both the differential case and the rotation member; the switching mechanism comprising: a movable first member continually connected to the rotation member, the first member being connected to the first side gear when the first member is moved in one direction along the wheel-axis relative to the rotation member, the first member being disconnected from the first side gear when the first member is moved in an opposite direction relative to the rotation member; a movable second member continually connected to the first member, the second member being connected to the differential case when the second member is moved in one direction along the wheel-axis relative to the first member, the second member being disconnected from the differential case when the second member is moved in an opposite direction along the wheel-axis relative to the first member; the second member being positionable in a first position corresponding to the 2WD state, a second position corresponding to the differential-free 4WD state, and a third position corresponding to the differential-locked 4WD state; a relative movement inhibiting mechanism which on demand inhibits movement of the first member relative to the rotation member, and which on demand inhibits movement of the second member relative to the first member; the relative movement inhibiting mechanism being constructed so that: while the second member is positioned within a range from the first position to the second position, the relative movement inhibiting mechanism inhibits the movement of the second member relative to the first member while the first member and the second member are concurrently moved relative to the rotation member; while the second member is positioned within a range from the second position to the third position, the relative movement inhibiting mechanism inhibits the movement of only the first member relative to the rotation member, while the second member is brought into movement relative to the first member under an immovable condition of the first member along the wheel-axis. 2. The differential device as set forth in claim 1, wherein the rotation member, the first member, the second member, the first side gear and the differential case are in coaxial alignment with one another, the second member is a substantially cylindrically shaped member in spline connection with an outer surface of the first member which is a substantially cylindrically shaped member, the first member is in spline connection with an outer surface of the rotation member, the first member being connectable to the first side gear by way of a spline connection, and the second member being connectable to the differential case by way of a spline connection. 3. The differential device as set forth in claim 2, wherein the relative movement inhibiting mechanism comprises: an outer groove formed in the outer surface of the rotation member at a position toward a side of the first side gear, a radius-reduced portion formed at an inner surface of the second member and extending in a direction away from the differential case, a snap ring fixed to an end portion of the second member at a position nearer to the differential case than the radius-reduced portion and adapted to engage a side of the first member facing towards the first side gear, and a pin slidably fitted in a radially extending through-hole in the first member; the relative movement inhibiting mechanism operating such that: while the second member is positioned within the range from the first position to the second position, an inner end of the pin contacts the outer surface of the rotation member, an outer end of the pin extends from the outer surface of the first member to engage a shoulder portion of the radius-reduction portion of the second member, and the snap ring engages an end of the first member which faces towards first side gear; and while the second mem