US 4,237,833 AGranted

Vehicle throttle stop control apparatus

AssigneeGeneral Motors Corporation

InventorEdwin D. Des Lauriers

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Abstract

A vehicle engine includes throttle stop control apparatus including means effective to store a plurality of induction passage pressure numbers corresponding to specified values of engine speed. Further apparatus measures engine speed and induction passage pressure and compares the induction passage pressure with a control reference number derived from the induction passage pressure reference number corresponding to the measured engine speed. When the throttle is in the idle position and the induction passage pressure signal exceeds the reference, a throttle stop control loop is closed on engine speed to maintain a predetermined engine idle speed. However, when the throttle is in the idle position and the induction passage pressure signal does not exceed the reference, the throttle stop control loop is closed on induction passage pressure to maintain substantially the reference pressure, whereby throttle position during vehicle coastdown is controlled according to a predetermined stored schedule. The control reference number may be shifted between the induction passage pressure number and a higher number as the control is shifted between idle speed and induction passage pressure control to provide hysteresis.

Claims2

Dependent claims

In a motor vehicle engine having an induction passage, a throttle effective to control the flow of air through the induction passage and further affect the pressure therein and a throttle stop effective to limit closure of the throttle and thus define an idle position therefor, throttle stop control apparatus comprising:

means effective to enerate a desired speed signal;
means effective to generate a signal indicative of engine speed;
means effective to generate a signal indicative of induction passage pressure;
means effective to store a plurality of induction passage pressure reference numbers corresponding to specified values of the engine speed signal through a predetermined engine coastdown speed range;
means effective, when the throttle is in the idle position and the induction passage pressure signal falls below the stored indication passage pressure reference number corresponding to the engine speed signal, to control the throttle stop position to minimize the difference between the induction passage pressure signal and a control reference number which is derived from the aforementioned induction passage pressure number and is at least equal thereto, said means being further effective, when the throttle is in the idle position and the induction passage pressure signal rises above the aforementioned control reference number, to control the throttle stop position to minimize the difference between the engine speed signal and desired speed signal, whereby engine idle speed control may be shifted to engine induction pressure control in a specified engine coastdown speed range to open the throttle according to a predetermined, stored schedule during vehicle coastdown.

2 more elements

means effective to generate a signal indicative of engine speed;
means effective to generate a signal indicative of induction passage pressure;
means effective to store at least one speed reference number;
means effective to store a plurality of induction passage pressure reference numbers corresponding to specified values of the engine speed signal;
means effective, when the throttle is in the idle position and the induction passage pressure signal falls below the stored induction passage pressure reference number corresponding to the engine speed signal, to control the throttle stop position to minimize the difference between the induction passage pressure signal and a control reference number derived from and greater than the stored induction passage pressure number corresponding to the engine speed signal;
and
means further effective, when the throttle is in the idle position and the induction passage pressure signal rises above said control reference number, to control the throttle stop position to minimize the difference between the engine speed signal and the speed reference number, loop on the induction passage pressure signal with reference to the control reference number and to increase the control reference number greater than the whereby engine idle speed control may be shifted to engine induction pressure control in at least one specified engine speed range to open the throttle according to a predetermined, stored schedule during vehicle coastdown, the difference between the stored induction passage pressure reference number and greater control reference number derived therefrom providing hysteresis in the shifting.

4 more elements

Dependencies are inferred from the claim text.