Method and apparatus for controlling the idling speed of an engine
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorsHiroshi Itoh, Nobuyuki Kobayashi
Life of this patent
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Abstract
An engine has a main intake passage having a throttle valve therein. A bypass passage is branched off from the main intake passage located upstream of the throttle valve and is connected to the main intake passage located downstream of the throttle valve. A flow control valve, actuated by a stepper motor, is arranged in the bypass passage. When the engine is started, the control valve is moved from the fully opened position to a predetermined position for reducing the flow area of the bypass passage. Then, the control valve is gradually closed as the temperature of the cooling water of the engine is increased.
Claims21
A method of controlling the idling speed of an engine comprising a main intake passage, a throttle valve arranged in the main intake passage, a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve, a control valve arranged in the bypass passge, and a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage, wherein said method comprises:
- determining a first stepper motor position related to the temperature of a coolant of the engine;
- determining the speed of the engine;
- rotating the stepper motor at a first speed from an initial position wherein the control valve is opened to said first position for reducing a flow area of the bypass passage when the engine is started and the speed of the engine exceeds a predetermined speed;
- and
- increasing said predetermined speed as the temperature of the coolant of the engine is reduced.
A method of controlling the idling speed of an engine comprising a main intake passage, a throttle arranged in the main intake passage, a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve, a control valve arranged in the bypass passage, and a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage, wherein said method comprises:
- determining a first stepper motor position related to the temperature of a coolant of the engine;
- rotating the stepper motor at a first speed from an initial step position wherein the control valve is opened to said first position for reducing a flow area of the bypass passage when the engine is started;
- determining a second stepper motor position which is different from said first position and is related to the temperature of the coolant of the engine;
- rotating the stepper motor from said first position to said second position at a second speed which is lower than said first speed after the stepper motor reaches said first position;
- and
- increasing said second rotating speed as the temperature of the coolant of the engine is increased after the engine has warmed-up.
An apparatus for controlling the idling speed of an engine, comprising:
- a main intake passage;
- a throttle arranged in the main intake passage;
- a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve;
- a control valve arranged in the bypass passge;
- a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage;
- means for determining the temperature of a coolant of the engine;
- means for determining the speed of the engine;
- and processing means for,
- determining a first stepper motor position related to the temperature of the coolant,
- producing signals for rotating the stepper motor at a first speed from an initial position wherein the control valve is opened to the first position for reducing a flow area of the bypass passage when the engine is started and when the speed of the engine exceeds a predetermined speed, and
- increasing the predetermined speed as the temperature of the coolant of the engine is reduced.
An apparatus for controlling the idling speed of an engine, comprising:
- a main intake passage;
- a throttle valve arranged in the main intake passage;
- a bypass passage branched off from the main intake passage upstream of the throttle valve and connected to the main intake passage downstream of the throttle valve;
- a control valve arranged in the bypass passage;
- a stepper motor actuating the control valve for controlling the amount of air flowing within the bypass passage;
- means for determining the temperature of a coolant of the engine;
- and
- processing means for,
- determining a first stepper motor position related to the temperature of the coolant,
- producing signals for rotating the stepper motor at a first speed from an initial position wherein the control valve is opened to the first position for reducing a flow area of the bypass passage when the engine is started,
- determining a second stepper motor position which is different from said first position and is related to the temperature of the coolant of the engine,
- producing signals for rotating the stepper motor from said first position to said second position at a second speed which is lower than the first speed after the stepper motor reaches the first position, and
- increasing said second rotating speed as the temperature of the coolant of the engine is increased after the engine has warmed-up.
Dependencies are inferred from the claim text.