Control device and control method used for engine intake air-or-gas system

摘要

A control device of a control valve used for an intake air-gas system of an engine. The device includes, but is not limited to: the control valve which is an intake air throttle valve provided in the intake air-gas system provided in the intake air-gas system of the engine to control the flow rate of intake air to the engine, or an EGR valve provided in the intake air-gas system of the engine to control the flow rate of EGR gas to the engine; and a control unit which determines a target opening of the control valve in response to the operation conditions of the engine, and controls the opening of the control valve so that the opening conforms with the target opening.

主权项

1. A control device comprising:
a control valve used for an intake air-gas system of an engine, the control valve being
an intake air throttle valve provided in the intake air-gas system of the engine and configured to control a flow rate of intake air to the engine, oran EGR valve provided in the intake air-gas system of the engine and configured to control a flow rate of EGR gas to the engine; and a control unit configured to determine a target opening of the control valve in response to the operation conditions of the engine, and to control an opening of the control valve so that the opening conforms with the target opening, wherein an opening range of the control valve includes, from a fully closed position to a fully opened position of the control valve, a zone where the flow rate of the intake air or the flow rate of the EGR gas is determined in accordance with the opening of the control valve, and a dead zone where the opening of the control valve is larger than that in the zone and where the flow rate of the intake air or the flow rate of the EGR gas is not influenced by the opening of the control valve even when the opening of the control valve is changed; wherein the control unit is configured so that, in a case where the target opening is maintained at a same level over a fixed duration in a range of the dead zone, the target opening is changed, in time, from the target opening which is determined in response to the operation conditions of the engine, and the opening of the control valve is controlled in order to avoid the control valve from being out of order; and wherein the control unit is further configured so that in a case where the target opening, which is changed in response to the operation conditions of the engine, is not maintained at a same opening level over the fixed duration in the range of the dead zone, the target opening is forcefully fixed at a constant level in the range of the dead zone.