Method of and apparatus for controlling engine revolution speed

Abstract

A method of and an apparatus for controlling the revolution speed of an engine, suitable for use in an automobile having an automatic transmission. Flow rate of auxiliary intake air by-passing a throttle valve is controlled by an auxiliary air control valve, the opening period of which is incremented in response to a signal which represents the state of the automatic transmission shifted from neutral range to a power range so as to avoid any reduction in the engine speed or the engine stall. The valve open time is controlled as a function of the engine cooling water temperature.

What is claimed is: 
     
       1. A method of controlling revolution speed of an engine for use in an automobile having an automatic transmission through which driving power is transmitted from an engine to driving wheels, said method employing an engine revolution speed controlling apparatus which includes, at least, an auxiliary air control valve for supplying auxiliary air by-passing a throttle valve, electromagnetic means for actuating said auxiliary air control valve, a sensor for detecting the revolution speed of said engine, and control means for controlling the flow rate of said auxiliary air through said auxiliary air control valve by .[.varying the duty.]. .Iadd.control .Iaddend.of said electromagnetic means in accordance with a signal from said sensor, said method comprising the steps of: (a) effecting an increment of said .[.duty.]. .Iadd.control .Iaddend.of said electromagnetic means after a time (Tdly) upon receipt of a signal representing that the state of said transmission has been changed from the neutral state to a power transmitting state;   (b) maintaining the incremented state of .[.duty.]. .Iadd.control .Iaddend.for a period (T ND );   (c) reducing the duty at a rate (K ND ); and   (d) delivering the delay time (Tdly), period (T ND ) and the rate (K ND ) as functions of the cooling water temperature on the basis of the temperature of the engine cooling water.   
     
     
       2. An apparatus for controlling revolution speed of an engine, for use in an automobile having an automatic transmission through which driving power is transmitted from an engine to driving wheels, said apparatus having, at least, an auxiliary air control valve for supplying auxiliary air by-passing a throttle valve, electromagnetic means for actuating said auxiliary air control valve, a sensor for detecting the speed of said engine, and auxiliary air flow rate control means for controlling the flow rate of said auxiliary air through said auxiliary air control valve by varying the duty of said electromagnetic means in accordance with a signal from said sensor, said apparatus comprising: shift detection means for detecting the shifting of operation range in said automatic transmission from neutral range to a power transmitting range;   temperature detecting means for detecting the engine cooling water temperature; and   controlling means for effecting an increment of the .[.Duty.]. .Iadd.duty .Iaddend.of said electromagnetic means after a delay (Tdly) upon receipt of a signal from said shift detection means indicative of the shift from the neutral range to the power transmitting range;   said controlling means including means for maintaining the incremented duty for a predetermined period (T ND ) reducing the duty at a reducing rate (K ND ), and computing means for computing the values of the delay time (Tdly), period (T ND ) and the reduction rate (K ND ) on the basis of the temperature of engine cooling water, in accordance with a predetermined program. .Iadd.   
     
     
       3.  A method of controlling revolution speed of an engine for use in an automobile having an automatic transmission through which driving power is transmitted from the engine to driving wheels of the automobile, said method comprising the steps of: (a) supplying auxiliary air by-passing a throttle valve through an auxiliary air control valve;   (b) actuating said auxiliary air control valve using electromagnetic means;   (c) detecting the revolution speed of the engine;   (d) controlling the flow rate of said auxiliary air through said auxiliary air control valve by control of said electromagnetic means in accordance with the detected revolution speed of the engine; and   (e) effecting an incrementing of a level of control of said electromagnetic means after a delay time (Tdly) upon receive of a signal representing that the state of said transmission has been changed from the neutral state to a power transmitting state. .Iaddend. .Iadd.4. A method according to claim 3, further including the step of:   (f) varying said delay time (Tdly) as a function of the cooling water temperature of the engine cooling water. .Iaddend. .Iadd.5. A method according to claim 3, further including the steps of:   (f) maintaining the incremented level of control for a period (T ND ); and thereafter   
     
     
       (g) reducing the level of control at a rate (K ND ). .Iaddend. .Iadd.6. A method according to claim 5, further including the step of: (h) varying at least one of said delay time (Tdly), said period (T ND ) and said rate (K ND ) as a function of the cooling water temperature of the engine cooling water. .Iaddend. .Iadd.7. An apparatus for controlling revolution speed of an engine for use in an automobile having an automatic transmission through which driving power is transmitted from said engine to driving wheels of the automobile, said apparatus comprising an auxiliary air control valve for supplying auxiliary air by-passing a throttle valve; electromagnetic means for actuating said auxiliary air control valve; a sensor for detecting the speed of said engine; auxiliary air flow rate control means for controlling the flow rate of said auxiliary air through said auxiliary air control valve by varying the level of control of said electromagnetic means in accordance with a signal from said sensor; shift detection means for detecting of said automatic transmission from neutral to a power transmission position; and controlling means for incrementing the level of control of said electromagnetic means after a delay time (Tdly) after receipt of a signal from said shift detection means indicative of the shift from neutral to the power transmitting range. .Iaddend. .Iadd.8. An apparatus according to claim 7, further including temperature detecting means for detecting engine cooling water temperature, said controlling means including means for varying said delay time (Tdly) as a function of the cooling water temperature. .Iaddend.