Nissan Motor Company Limited

Takuya Maekawa

Masahiro Iriyama

Yuzuru Tohta

Kenichiro Murakami

Yoshitaka Matsuki

Kinichiro Murakami

Yazuru Tohta

A vehicle control system includes a prime mover, a power transmission apparatus disposed between the prime mover and at least one wheel, an engaging element configured to selectively engage and disengage the prime mover from the at least one wheel, and a torque limiter configured to restrict an output torque of the prime mover to a selected percentage when in transition between an unloaded state and a loaded state, wherein the torque limiter is configured to restrict the output torque of the prime mover while the engaging element is disengaged between the prime mover and the power transmission apparatus.

Acceleration shock reduction apparatus for vehicle

An engine torque control device is configured to lessen shift shock while shortening the shift time during downshifting with an automatic transmission. When a downshift requirement is generated, a disengagement control of a higher gear clutch (current gear ratio) is commenced, and at the same time, a first synchronizing control is commenced. The first synchronizing control has a torque-up control with a first synchronizing speed DNeset as the target speed TNe, during a first control period. When the first control period has concluded and there is a transition to a second control period. In the second control period, an engagement control of a lower gear clutch (the post-shift gear ratio) is commenced, and at the same time, there is a switch to a second synchronizing control. In the second synchronizing control, the target speed TNe is set to a second synchronizing speed DNeat the post-shift gear ratio.

Engine torque control device

An engine torque control device is configured to reduce shift shock during a downshift with an automatic transmission. During a downshift with an automatic transmission having a stepped shift mechanism, when the engine output (torque) is increased so as to bring it closer to being synchronized to the post-downshift engine speed, and then the torque is reduced sharply enough to maintain the synchronizing speed, and when synchronizing control is concluded so that the torque is sharply reduced to the driver's required torque in a state in which the accelerator is released, the throttle opening is reduced while any extra torque resulting from a reduction lag in the intake air quantity is cancelled out by retarding the ignition timing, thereby sufficiently lessening shift shock.

An automatic transmission () of a vehicle performs a downshift operation when a downshift signal is ON. When the downshift signal is ON, a controller () increases an output torque of an engine () so that a predetermined torque increase amount is realized. The controller () sets a torque increase permission period which is shorter, the larger the predetermined torque increase amount is (S), and when the elapsed time from when the downshift signal is ON reaches the torque increase permission period, unnecessary increase of engine rotation speed and excessive torque load on the automatic transmission () are prevented by terminating increase of output torque (S, S).

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Zama, Japan

Takuya Maekawa