GB2237900A

GB2237900A - Idling speed control of a multiple throttle I.C. engine

Info

Publication number: GB2237900A
Application number: GB9022022A
Authority: GB
Inventors: Gabriele Serra
Original assignee: Weber SRL
Current assignee: Weber SRL
Priority date: 1989-10-13
Filing date: 1990-10-10
Publication date: 1991-05-15
Anticipated expiration: 2010-10-10
Also published as: GB9022022D0; DE4032295A1; BR9005310A; IT222286Z2; DE4032295C2; IT8953413V0; IT8953413U1; FR2653172B1; FR2653172A1; GB2237900B

Abstract

A system for controlling the idling speed of an IC engine having a plurality of throttled bodies (1) regulating the air supply to at least one cylinder wherein a mechanical device (7) operated by a pedal (8) synchronously controls the setting of the throttles (6) on the aforementioned bodies (1). The control system comprising an electronic control system (3) for processing input signals relative to parameters and operating conditions of the vehicle and/or engine, and an actuating device (5) controlled by the electronic control system (3) and designed, at idling speed, to arrest the position of the mechanical device (7) and therefore also the setting of the plurality of throttles (6) and so regulate the idling speed of the engine. <IMAGE>

Description

:2 l- ;13 -;7 tD C_> cl) 0 SYSTEM FOR CONTROLLING THROTTLED BODIES

REGULATING AIR SUPPLY TO AN INTERNAL COMBUSTION ENGINE The present invention relates to a system for controlling throttled bodies regulating air supply to an internal combustion engine, in particular, to an engine featuring an electronic injection system.

sports car engines are known to be multicylinder types in which the cylinders are usually supplied in groups of four on eight-cylinder engines, in groups of three on six-cylinder engines, and so on. on engines with an electronic injection system, each cylinder is supplied with fuel by a respective injector, whereas the air supply for the air- fuel mixture is regulated by a single throttled body which distributes the air supply to all the cylinders on the engine via an intake manifold. The throttled body is fitted with an additional air supply valve for supplying extra air when cold starting the engine, and which is controlled by an electronic system on the basis of various physical parameters and the operating conditions of certain parts of the engine. Using a single throttled body, however, results in Interaction between the various cylindersi due to the pressure pulsations produced inside each cylinder by the intake cycle and the members regulating the valves on each cylinder. This obviously results in interaction between the cylinders in the sense that the pressure pulsations in one cylinder affect the intake capacity of the others. one possible solution to the problem is to provide a throttled body for each cylinder. while at the same time reducing the volume defined between the throttle and respective cylinder head. A reduction in this volume in fact is known to result in improved, faster response by the engine to the power requested via the accelerator pedal. Providing each cylinder with a throttled body however requires a linkage system by which to synchronize operation of the throttles. Moreover. each throttled body must be provided with a member for regulating the idling speed setting of the throttle. as well as an additional air supply valve.

The multi-throttle solution therefore involves numerous drawbacks. not least of which is the difficulty posed by synchronizing the idling speed setting of the throttles using a regulating member for each throttled body,, which difficulty is further compounded if the throttled bodies form_ part of two parallel groups. Moreover,, the construction of an additional air supply valve for each throttled body is both complex and expensive. bearing in mind also that all the valves must be controlled by an electronic control system.

1 1 1 The aim of the present invention is to provide a system for controlling throttled bodies regulating air supply to an internal combustion engine. and designed to overcome the above drawbacks. A With this aim in view, according to the present invention, there is provided a control system for regulating air supply to an internal combustion engine, c haracterised by the fact that it comprises:

- at least two throttled bodies, each featuring a throttle the setting of which determines air supply to at least one cylinder on said engine; - a mechanical device for synchronously controlling the settings of all said throttles; - a pedal controlling the setting of said throttles via said mechanical device; - an electronic control system for processing a number of input signals relative to physical parameters and the operating conditions of parts of the vehicle on which said engine is installed; and - an actuating device having an axially-sliding rod. the axial position of which is controlled by said electronic control system on the basis of said input signals, and designed to arrest the position of said mechanical device and consequently the idling speed setting of said throttles so as to regulate said idling speed.

A preferred non-limiting embodiment of the present invention will be described by way of example with reference to the accompanying drawing,, which shows a 1 system for controlling a number of throttled bodies 1 regulating air supply to the cylinders of an internal combustion engine featuring an electronic injection system 2. The system according to the present inveption comprises:

- an electronic control system 3 for controlling electronic injection system 2 and the axial position of a rod 4 on an actuating device 5 regulating the idling speed setting of a number of throttles 6; - a mechanical device 7 for controlling. via accelerator pedal 8, the settings of all throttles 6 and consequently air supply to the cylinders of said engine; and lever 11 operated via actuating device 5 and designed to act. at idling speed, on said mechanical device 7 for varying the idling speed setting of throttles 6.

Electronic control system 3 is a digital, microprocessor-based unit for controlling engine supply and ignition parameters, such as the amount of fuel supplied sequentially to each cylinder. fuel supply start commencing from intake by each cylinder, and Ignition advance. For calculating the above parameters control system 3 is supplied,, by sensors not shown, vith a number of input signals relative, for example, to the absolute pressure inside throttled bodies 1; intake air temperature; cooling liquid temperature; engine speed; the position of each cylinder in relation to top dead 1 1 1 center; vehicle battery voltage; and the setting of throttles 6. on the basis of the above input signals, and via device 5 and lever 11, system 3 controls the idling speed setting of all throttles 6, particularly during cold or low-temperature starting of the engine. At hot or high- temperature idling speed, the setting of throttles 6 may obviously be regulated either by standard regulating members or directly by control system 3 via device 5 and lever 11.

In the example shown in the accompanying drawing, the system according to the present invention controls eight throttled bodies 1, each having a throttle 6. Throttled bodies 1 form part of four groups 12, two of which are arranged in-line and parallel to the other two. Each group 12 thus presents two throttled bodies 1. The two throttles 6 in each group 12 are mounted on a common rod 13 extending towards group 12 in-line with its own. The end of rod 13, outside its own group 12, is fitted angularly integral with an L-shaped bracket 14 having a first portion 15 secured by a nut 16 to rod 13, and a second portion 17 which, by means of an adjustable joint 18, is connected angularly integral with second portion 17 of bracket 14 on group 12 in line with its own. Said joint 18 is of known type and substantially provides for securing the flat end of one portion 17 inside the U-shaped end of the other portion 17. By means of a screw 19, the flat end of portion 17 can be pressed on to one arm of the U-shaped end of the other portion 17, thus also enabling the two In-line. groups 12 to be aligned as required by adjusting the distance between the ends of portions 17 of facing brackets 14.

Device 7 comprises a lever 20 installed between the two in-line pairs of groups 12, and having a central portion pivoting on a pin 21. two arms 22 defined along the same longitudinal axis but extending in diametrically opposed directions from said central portion, and a third arm 23 extending from said central portion in a direction perpendicular to the longitudinal axis of arms 22. On the end of each arm 22. there pivots a first end of a tie rod 24, the second end of which is connected, by means of a known articulated ball joint 25. to the bracket 14 of one pair of in- line groups 12. The end of arm 23 is connected by a tie rod 26 to pedal 8. which. when operated,, rotates lever 20 anticlockwise and in the plane as shown in the accompanying drawing. As it rotates,, lever 20 displaces the two tie rods 24,, each of which rotates.a respective pair of brackets 14 (to one of which lever 20 is connected) about the axis of respective rods 13 which are thus also rotated. A single mechanical control thus provides for synchronously rotating all of throttles 6 despite their forming part of parallel groups 12. F Pin 21 Is fitted in idle manner with a first end of lever 11, the second end of which contacts the end of rod 4 of actuating device 5 controlled by electronic control system 3. The axial position of rod 4-determines the angular position of lever 11. In particular. if rod 4 is extracted from device 5. this rotates lever 11 anticlockwise on to an appendix 31 extending from arm 23 of lever 20. Anticlockwise rotation of lever 11 produces an equal rotation of lever 20 and. consequently. also throttles 6. which open the respective intake conduits for obtaining additional air supply. Lever 11 is rotated anticlockwise against the action of a spring 32 (shown by the dotted line). If, on the other hand, rod 4 is withdrawn, spring 32 rotates lever 11 clockwise so as to achieve permanent contact between the end of lever 11 and rod 4. In this case, anticlockwise rotation of lever 11 is also accompanied by lever 20, by virtue of a return spring which may be installed on one of brackets 14 or lever 20 itself. It should be pointed out that anticlockwise rotation of lever 20 by pedal 8 does not produce an equal rotation of lever 11, the free end of which is fitted with a push rod 33 constituting the part of lever 11 actually contacting rod 4. The axial position of push rod 33 in relation to lever 11 is adjustable by means of a screw 34. which thus provides for adjusting the position of lever 11 in relation to rod 4.

Actuating device 5 may consist of an electric step motor; a d.c. motor with a rotary-translatory transducer; an electropneumatic actuator; or a wax bulb type actuator. etc.. The position of rod 13 of one of the four groups 12 is detected by a transducer' 35, which f supplies a corresponding electric signal to control system 3. Said electric signal thus constitutes a further parameter controlled by system 3, which thus provides for effective feedback control. Transducer 35 may consist of an ordinary electric potentiometer having a resistive track connected to the positive pole of the vehicle battery and over which slides a cursor on rod 13. The system according to the present invention also features a stop 36 for determining maximum rotation of lever 11 by device 5.

In actual use, air supply along throttled bodies 1, and consequently the power requested of the vehicle engine, is regulated, via pedal 8., by mechanical device 7. Fuel supply, on the other hand, is regulated by electronic injection system 2 which, in known manner, features an injector for each cylinder on the vehicle engine. At low temperature idling speed, i.e. substantially when cold starting the engine, control system 3 processes its input signals, calculates the required air supply, and accordingly controls actuating device 5, i.e. the axial position required of rod 4. This determines the angular position of lever 11 and, via the latter, the angular position of lever 20 and all of throttles 6. As already stated,, this operating mode may conveniently be employed also with the engine warmed up and running at idling speed, in which case the standard idling speed regulating members may be dispensed with, with all the advantages this entails in terms of system design and 1 manufacturing cost.

The advantages of the system according to the present invention will be clear from the foregoing description.

Firstly, it provides for synchronously controlling. all of throttled bodies 1 at any engine speed. In particular. the mechanical device regulating the throttle settings is controlled by system 3 at both cold and hot idling speed, whereas, for other engine speeds, it is controlled by the user via pedal 8. obviously, once the settings of throttles 6 have been synchronized. which may be done prior to assembly on the vehicle, these remain synchronized even after assembly. As such, a throttle may be provided for each cylinder, thus eliminating, among other advantages, any interaction between the various cylinders at the intake stage, and reducing the volume defined between the cylinder head and throttle for improving engine response.

To those skilled in the art it will be clear that changes may be made to the system described and illustrated herein without. however, departing from the scope of the present invention.

In particular. changes may be made to the number and arrangement of throttled bodies 1 and, consequently, the engine cylinders; and to the design of lever 11 and the manner in which lever 20 is controlled by the same.

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Claims

1) - A control system for regulating air supply to an internal combustion engine. characterised by the fact that it comprises:

- at least two throttled bodies (1), each featuring a throttle (6) the setting of which determines air supply to at least one cylinder on said engine; - a mechanical device (7) for synchronously controlling the settings of all said throttles (6); - a pedal (8) controlling the setting of said throttles (6) via said mechanical device (7); - an electronic control system (3) for processing a number of input signals relative to physical parameters and the operating conditions of parts of the vehicle on which said engine is installed; and - an actuating device (5) having an axially-sliding rod (4), the axial position of which is controlled by said electronic control system (3) on the basis of said input signals, and designed to arrest the position of said mechanical device (7) and consequently the idling speed setting of said throttles (6) so as to regulate said idling speed.

2) - A system as claimed in Claim 1. characterised by the fact that said mechanical device (7) comprises a first lever (20) rotating about a pin (21); and a number of members (24. 141 13) whereby rotation of said first lever (20) varies the setting of said throttles (6).

i 3) - A system as claimed in Claim 2, characteri sed by the fact that it comprises a second lever (11) rotating about said pin (21) and the angular position of which is controlled by said actuating device (5); in actual, use,, and at idling speed. a portion (31) of said first lever (20) contacting said second lever (11), the position of which determines the idle speed setting of said throttles (6).

4) - A system as claimed in Claim 3. characterised by the fact that said second lever (11) presents a portion having a push rod (33) the position of which is adjustable and whereby said second lever (11) contacts one end of said rod (4).

5) - A system as claimed in at least one of the foregoing Claims, characterised by the fact that it comprises a transducer (35) for detecting the setting of said throttles (6) and supplying a corresponding electric signal to said control system (3).

6) - A system as claimed in at least one of the foregoing Claims from 2 to 5. characterised by the fact that it comprises two parallel groups (12),, each having at least two said bodies (1); said throttles (6) of said bodies (1) in each said group (12) being supported on a common rotary rod (13) fitted with a bracket (14) connected by a tie rod (24) to one arm (22) of said first lever (20).

7) - A system as claimed in at least one of the foregoing Claims from 2 to 5. characterised by the fact that it compris.es:

- two first in-line groups (12).. each having two said bodies (1); - two second in-line groups (12) parallel to and, the same as said first groups (12); - a rotary rod (13) for each said first and second group (12) and supporting both said throttles (6) of the same; - a bracket (14) for, and angularly integral with. each said rod (13); - adjustable means (18) for connecting said brackets (14) of said first groups (12); - adjustable means (18) for connecting said brackets (14) of said second groups (12); a tie rod (24) connecting one of said brackets (14) of said first groups (12) to a first arm (22) of said first lever (20); and - a tie rod (24) connecting one of said brackets (14) of said second groups (12) to a second arm (22) of said first lever (20).

8) - A system as claimed in Claim 7. characterised bythe fact that said first lever (20) presents a third arm (23) connected by a further tie rod (26) to said pedal (8).

9) - A control system for regulating air supply to an internal combustion engine, substantially as described and illustrated herein with reference to the accompanying drawing.

PubPAbed 1991 at Mae Platenit CHfice, State House. 66/71 H%LHo London WCIR47P. Further copies maybe obtained from I ]:!M SOJW Branch. Unit 6. Nkm Mile Pokit. CwmIchnfach. Cross Keys. F Nl 7H7. Printed by Multiplex techniques ltd. St Mary Cray. Kent.

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