Control system for automotive vehicle equipped with automatic transmission

摘要

In order to prevent occurrence of engine stall even when a quick braking is made in a state where a torque converter of an automatic transmission is locked up, the torque converter is locked up in accordance with a throttle opening degree and a vehicle speed, and the lock-up is released at least when the braking operation is carried out. The opening degree B of an idle speed control valve (ISCV) for bypassing a throttle valve simultaneously with the lock-up is set, and the opening degree B is set as an actual control opening degree IV of ISCV when the opening degree B is larger than the opening degree IAV of ISCV which is set in accordance with the load of an engine. When the release of the lock-up is started, the actual control opening degree IV is gradually reduced to the opening degree IAV by a prescribed attenuation amount K. As a result, the engine stall due to a response delay to the release of the lock-up clutch can be prevented.