US 4,378,766 AGranted

Closed loop idle engine speed control with a valve operating relative to neutral position

AssigneeNippondenso Co., Ltd.

InventorsHisamitsu Yamazoe, Ichita Sogabe, Kazuyoshi Tamaki, Matsuju Yoshida

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Abstract

In a closed loop idle engine speed control system the actual engine speed is compared with a reference idle speed during engine warm-up periods to control the amount of an air flow introduced to the engine through an auxiliary air delivery system so that the difference between the actual and reference engine speeds is reduced. The reference setting of the idle speed is varied as a function of the engine temperature in order to vary the actual engine speed in response to an increase in the engine temperature. The auxiliary air delivery system includes a linear solenoid type electromagnetic valve which comprises a spring-biased valve member normally maintained in a neutral position with respect to the valve seat to allow introduction of a predetermined amount of auxiliary air to the engine and a pair of coils energized respectively with a current representing the difference in engine speed to move the valve member in opposite directions to increase or decrease the auxiliary air supply.

Claims9

Dependent claims

A method for controlling the idle speed of an internal combustion engine by supplying thereto an auxiliary air flow through an auxiliary air delivery system including an electromagnetic valve, said valve comprising a valve member movable with respect to a valve seat, said valve member being normally located at a neutral position between two positions at which said air flow is at maximum and minimum respectively, said valve member being spaced a sufficient distance from said valve seat when located at said neutral position to prevent vapor-laden air from clogging the space between said valve member and said valve seat when the vapor is frozen, the method comprising:

(a) detecting the actual idle speed of said engine;
(b) establishing a reference idle speed;
(c) deriving a deviation signal representing the deviation of said actual idle speed with respect to said reference idle speed;
(d) deriving a valve control signal from said deviation signal;
(e) detecting whether said valve control signal is more or less than a predetermined value corresponding to said neutral position;
(f) moving said valve member in a first direction away from said neutral position when said valve control signal is more than said predetermined value to increase the auxiliary air flow and moving said valve member in a second, opposite direction away from said neutral position when said valve control signal is less than said predetermined value to decrease the auxiliary air flow;
and
(g) moving said valve member forcibly to said neutral position when said electromagnetic valve is de-energized.

5 more elements

A system for controlling the idle speed of an internal combustion engine having a primary air delivery system through which main air flow is introduced to the engine, comprising:

sensor means for detecting the speed of said engine and generating therefrom an engine speed signal;
an auxiliary air delivery system for introducing an auxiliary air flow to said engine;
an electromagnetic control valve provided in said auxiliary air delivery system and comprising a pair of first and second coils for producing a magnetic field when energized, a valve seat, and a valve member movable with respect to said valve seat in response to said magnetic field to control said auxiliary air flow, said valve member being normally located at a neutral position when said coils are de-energized between two positions at which said air flow is at maximum and minimum respectively, said valve member being spaced a sufficient distance from said valve seat when located at said neutral position to prevent vapor-laden air from clogging the space between said valve member and said valve seat when the vapor is frozen;
and
means for energizing said first coil to cause said valve member to move away from said neutral position when said engine speed is more than a reference idle speed and energizing said second coil to cause said valve member to move away in opposite direction from said neutral position when said engine speed is less than said reference idle speed.

2 more elements

Dependencies are inferred from the claim text.