US 4,300,501 A · Apparatus for controlling the rotational speed of an I.C. engine in an idling operation

Abstract

Apparatus for controlling the rotational speed of an I.C. engine in an idling operation comprises a constant pressure valve, a solenoid valve, and a control signal generator. A constant vacuum pressure produced by the constant pressure valve is modified by atmospheric pressure by means of the solenoid valve which is actuated by a pulsating signal produced in the control signal generator. The pulse width of the pulsating signal is variable in accordance with a detected engine speed. The modified vacuum pressure is coupled to a chamber of a main valve of a conventional boost controlled deceleration device to control the amount of air-fuel mixture supplied to the intake manifold of the engine.

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Claims17

Dependent claims

Apparatus for controlling the rotational speed of an internal combustion engine of a vehicle in an idling operation, said engine being equipped with a carburetor having a by-pass air-fuel mixture supply passageway communicating between a source of air-fuel mixture supply and the intake manifold of said engine for supplying the intake manifold with an additional air-fuel mixture, a valve assembly disposed in said passageway to control the cross sectional area of said passageway, and an expansible chamber operatively connected to said valve assembly, wherein the improvement comprises:

(a) first passage selectively in fluid flow relation between said expansible chamber and a source of vacuum pressure of a predetermined value;
(b) a second passage connected in fluid flow relation between said first passage and atmosphere;
(c) a solenoid operated valve means interposed in said second passage for selectively shutting said second passage in response to an electrical signal fed thereto;
(d) a control signal generator for producing said electrical signal in accordance with the engine speed only when the engine is in an idling operation;
wherein said source of vacuum pressure comprises a third passage communicating with said intake manifold and a fourth passage communicating with the atmospheric air, and a fifth passage connected in fluid flow relation with said first passage, said third, fourth and fifth passages being joined at a junction, each of said third, fourth and fifth passages having an orifice in the vicinity of said junction.

2 more elements

Apparatus for controlling the rotational speed of an internal combustion engine of a vehicle in an idling operation, said engine being equipped with a carburetor having a by-pass air-fuel mixture supply passageway communicating between a source of air-fuel mixture supply and the intake manifold of said engine for supplying the intake manifold with an additional air-fuel mixture, a valve assembly disposed in said passageway to control the cross sectional area of said passageway, and an expansible chamber operatively connected to said valve assembly, wherein the improvement comprises:

(a) first passage selectively in fluid flow relation between said expansible chamber and a source of vacuum pressure of a predetermined value;
(b) a second passage connected in fluid flow relation between said first passage and atmosphere;
(c) a solenoid operated valve means interposed in said second passage for selectively shutting said second passage in response to an electrical signal fed thereto;
(d) a control signal generator for producing said electrical signal in accordance with the engine speed only when the engine is in an idling operation;
wheresaid said control signal generator comprises:
(a) first means for producing a signal indicative of engine speed;
(b) second means for producing a reference signal indicative of a preset engine speed;
(c) third means for producing a pulse width modulation signal in accordance with the signals obtained by said first and second means;
(d) fourth means for producing a signal indicative of an idling operation of said engine;
(e) fifth means for transmitting said pulse width modulation signal upon presence of the signal from said fourth means, and
(f) sixth means for producing a valve actuating signal in response to the output signal of said fifth means.

8 more elements

Apparatus for controlling the rotational speed of an internal combustion engine of a vehicle in an idling operation, said engine being equipped with a carburetor having a by-pass air-fuel mixture supply passageway communicating between a source of air-fuel mixture supply and the intake manifold of said engine for supplying the intake manifold with an additional air-fuel mixture, a valve assembly disposed in said passageway to control the cross sectional area of said passageway, and an expansible chamber operatively connected to said valve assembly, wherein the improvement comprises:

means for controlling the valve assembly to increase and decrease, by variable amounts between limits, the cross sectional area of the by-pass passageway for the mixture during idling by controlling the pressure in the chamber by variable amounts between limits as a function of engine idle speed, wherein said controlling means includes a constant pressure source, means for varying the average pressure of the source by variable amounts between limits as a function of idling engine speed, whereby a modified pressure source is derived, and a passage selectively in fluid flow relation between the modified pressure source and the chamber for selectively coupling the pressure of the modified source to the chamber so that the position of the valve assembly in the by-pass passageway during idling is a function of said average pressure.

Dependencies are inferred from the claim text.

Description6,000 words

Summary476 words

#This invention relates generally to an apparatus for controlling the rotational speed of an internal combustion engine. More specifically, the present invention relates to such an apparatus in which the engine speed is maintained constant during an idling operation.

#It is advantageous to keep the rotational speed of of an internal combustion engine crank shaft at a desired value during an idling operation. The desired idling speed provides for the stable operation of the engine, eliminates unnecessary fuel consumption and reduces harmful components contained in the exhaust gases. During an idling operation, the amount of fuel, i.e. the fuel flow ratio, is determined by an idle adjust screw disposed at an idle port of a carburetor slow circuit. The idle adjust screw is so adjusted that a predetermined amount of fuel is fed into the intake manifold so that the engine rotates at a predetermined speed which is most desirable. However, the engine speed in a idling operation is apt to vary due to various reasons, such as variations of atmospheric pressure, ambient temperature, and engine temperature. For instance, the amount of fuel and/or air induced into the intake manifold of the engine are apt to vary due to deterioration of various members such as the throttle valve and the cylinders of the engine. Further, the ignition timing influences the engine speed.

#In a conventional carburetor system, the idle adjust screw has to be adjusted each time the engine speed in an idling operation differs from the preset value. It is troublesome to manually adjust the screw which is disposed in the carburetor.

Brief description of the drawings4 figures

#These and other objects and features of the present invention will become more readily apparent from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings in which:

#FIG. 1 is a schematic view of a preferred embodiment of the apparatus according to the present invention;

#FIG. 2 is a block diagram of the detailed circuit of the control signal generator shown in FIG. 1;

Detailed description5,417 words

#FIG. 1 is an illustration of a preferred embodiment of the apparatus for controlling internal combustion engine speed during an idling operation according to the present invention. The carburetor shown is denoted generally by a reference numeral 10. By way of illustration, carburetor 10 is of the dual barrel type and thus includes two (primary and secondary) induction passages 11 and 12. The induction passages 11 and 12 have respectively butterfly type throttle valves 13 and 14 which are responsive to the accelerator pedal (not shown). Whilst the embodiment using a dual barrel carburetor is illustrated, it will be readily understood that the improvement of the present invention is feasible for a carburetor of a single barrel type or of any other type. The induction passages 11 and 12 conventionally communicate with an engine intake manifold 18.

#Each of the induction passages 11 and 12 is supplied with an air-fuel mixture through a main mixture supply passage (not shown). For light load or idling operation of the engine, a slow fuel supply passage 15 opens in the vicinity of the substantially closed throttle valve 13 through a slow port 16 and an idle port 17.

#The carburetor comprises an additional mixture supply system indicated by 20 and an actuating means 40 which are included in a conventional boost controlled deceleration device and vacuum control means 43 operatively connected to the actuating means 40. The actuating means 40 is operatively connected with an electric control means 44, the arrangement and operation of which will be later described.

Apparatus for controlling the rotational speed of an I.C. engine in an idling operation

Life of this patent

Apparatus for controlling the rotational speed of an I.C. engine in an idling operation

Life of this patent

Life of this patent

Abstract

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Drawings

Claims17

Description6,000 words

Drawings

Classification2 codes

Life of this patent

Description6,000 words