Method of controlling the idling speed of an engine
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorsNobuyuki Kobayashi, Hiroshi Itoh
Life of this patent
Estimating the term…
Abstract
An engine comprising 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 vlave, actuated by a step motor, is arranged in the bypass passage. When the pressure of the lubricating oil of the engine is decreased below a predetermined pressure, the idling speed of the engine is increased to a predetermined speed. In addition, when the temperature of the cooling water of the engine is increased beyond a predetermined temperature, the idling speed of the engine is also increased to a predetermined speed.
Claims12
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 passage, and a step motor actuating the control valve for controlling the amount of air flowing within the bypass passage, wherein said method comprises:
- detecting the idling speed of the engine;
- detecting the pressure of a lubricating oil of the engine;
- detecting the temperature of a coolant of the engine;
- controlling the rotating motion of the step motor so that the idling speed of the engine becomes equal to a predetermined base speed when said lubricating oil pressure is higher than a predetermined pressure and when said coolant temperature is lower than a first predetermined temperature;
- rotating the step motor in a rotating direction wherein the control valve increases a flow area of the bypass passage so that the idling speed of the engine becomes equal to a predetermined pressure control speed which is higher than said predetermined base speed when said lubricating oil pressure becomes lower than said predetermined pressure, and;
- rotating the step motor so that the idling speed of the engine becomes equal to a predetermined temperature control speed when said coolant temperature becomes higher than said first predetermined temperature.
Dependencies are inferred from the claim text.