WO1981001591A1

WO1981001591A1 - Regulator for idle running of internal combustion engines,particularly injection engines with controlled ignition

Info

Publication number: WO1981001591A1
Application number: PCT/EP1980/000129
Authority: WO
Inventors: A Michassouridis; G Fischer
Original assignee: Bayerische Motoren Werke Ag; A Michassouridis; G Fischer
Priority date: 1979-12-01
Filing date: 1980-11-13
Publication date: 1981-06-11
Also published as: EP0029928B1; EP0029928A1; DE3067885D1; DE2948501B1; DE2948501C2; JPS56501618A

Abstract

The regulator comprises a bypass valve which is parallel to a throttle arranged in a suction pipe and which is actuated by a servomotor. In order to adapt it to the different running states of the engine, the maximum opening cross section area (14, 114, 214, 314) of the bypass valve (1, 101, 201, 301) is determined by a stop (lift rod 27, 127, stop sleeve 227) which may be moved by an actuator (24, 124, 224) and which reduces the travel of the valve body (29, 129, 229, 329) in relation to at least one running parameter of the engine, such as running temperature, time interval from cold start, number of combustion chambers operating.

Description

Control device for the idle speed of internal combustion engines, in particular spark-ignited injection internal combustion engines

The invention relates to a control device of the type described in the preamble of claim 1.

When using a control device of this type, e.g. according to German Patent No. 26 55 171 »in motor vehicles with manual transmissions can be caused by sudden

If the idle load on the warm machine falls, there is a brief, sharp increase in engine speed, for example when the motor vehicle is braked at idle and only then disengaged. This sharp increase in speed, for example to 2,000 to 3,000 rpm, is not harmful since it is quickly stopped again. However, it gives the impression of a malfunction of the control device, in particular that according to the above-mentioned patent, since it is particularly pronounced due to its progressive increase in the opening cross section. The object of the invention is to improve the control device according to the preamble of claim 1 in such a way that no excessive speed increase occurs even in such operating conditions.

The invention solves this problem by the characterizing features of claim 1.

This configuration of the control device reliably prevents a disturbingly high idle speed increase in any operating state of the internal combustion engine or such a speed increase within narrow limits, e.g. 1,500 / min, because the largest possible opening cross section of the bypass valve is adapted to the highest possible power requirement of the machine when idling, which is significantly influenced by the operating state.

Features further developing the subject matter of the invention are characterized in the subclaims. The features of claims 2 to * contain a temperature-dependent stop and further develop it. The features of claims 5 to 7 each further develop the actuator for the stop. The features of claims 8 to 11 further develop the control of the actuator and claim 12 results in a space-saving structure of the valve with the additional actuator for the stop. The features of claim 13 include the adaptation of the control to internal combustion engines with cylinder deactivation and the features of claims 14 to 6 prevent a change in the characteristic of the bypass valve when setting the idle nominal speed, so that the

O full diaphragm stroke of the servomotor can be used for the control range and the bypass valve can be kept small. In addition, the idle channel prevents the maximum speeds determined by the stop from being changed when setting the idle flow rate.

In the drawing, exemplary embodiments of the invention are shown, based on which the invention is explained below. It shows:

1 is a central longitudinal section of a control device for the idle speed of internal combustion engines with a schematic representation of their connections with respect to the intake manifold,

2 is a partial view of the control device in the direction of arrow II in FIG. 1,

3 shows a central longitudinal section of another exemplary embodiment of the control device shown in FIG. 1,

4 shows a central longitudinal section of a further exemplary embodiment of the control device according to FIG. 1,

3 shows a section along the line V-V of the control device according to FIG. 3 on an enlarged scale,

Fig. 6 is a section along the line VI-VI of the control device according to Fig. 5 and FIG. 7 shows a section similar to FIG. 5 of a further exemplary embodiment of the control device.

1 shows as a control device a bypass valve 1 with its connections to a collecting suction pipe 2 with oscillating pipes 3 and to the suction pipe 4 with the throttle valve 5. The bypass valve 1 is located in a bypass line 6, which is seen in the suction flow direction, is connected in front of the throttle valve 5 and opens into the manifold 2 behind it.

The bypass valve 1 comprises a membrane box 7, the chamber 8 of which can be acted upon by the intake manifold pressure via a line 9, and a housing 10. The housing 10 has a bore 11 and, perpendicularly thereto, a further bore 12. A circular insert 13 is fitted into the bore 11 adjacent to the bore 12. The insert 13 is designed similar to an aperture and has an opening 14 as a control cross section, the width of which increases progressively starting from the upper edge region of the insert 13 parallel to the bore 12.

The bore 12 is designed as a gradually narrowing blind hole. With its widest section 15 it crosses the bore 11. The wide section 15 is followed by a threaded section 16 which merges into a short smooth-walled section 17. The short, smooth-walled section 17 merges with the formation of a shoulder 18 into the narrowest section 19 of the blind hole, which is crossed by a transverse bore 20.

υ_ On the outside of the housing 10, connecting pieces 21 are connected to openings 21 formed by the transverse bore 20, via which the narrowest section 19 is included in the coolant circuit of the machine.

The housing 23 of an expansion element 24 projects into the narrowest section 19 of the stepped bore 12 and is supported on the shoulder 18 with the interposition of a sealing ring 25. The expansion element 24 is held by means of a retaining ring 26 which is provided with an external thread and which is screwed into the threaded section 16. A lifting pin 27 of the expansion element 24 projects through the retaining ring 26 and forms a stop for an actuating rod 28 of a cylindrical valve body 29 which is guided in the widest section 15 of the bore 12. The actuating rod 28 protrudes through a seal 30 out of the housing 10 into the membrane box 7, in which it is attached to the membrane 31 thereof.

A compression spring 32 is arranged in the membrane box 7, which counteracts the effect of the intake manifold pressure. The identifier of the compression spring 32 is matched to the idling behavior of the machine with regard to all possible load cases in such a way that a relatively flat identifier is associated in the area which is associated with lower loads in idle mode and one in the area which is associated with higher loads results in a relatively steep identifier with a continuous transition. The compression spring 32 is adjustable in the chamber 8 of the membrane box 7 with the interposition of a spring plate 33 by means of an adjusting screw 3 * ^ in its pretension. A concentrically arranged idle screw 3

O PI Adjusting screw 35 enables the setting of a minimum opening in the interaction of an idling stop bolt 36 with a "second spring plate 37, which is connected to a triple actuating rod 28 and thus to the valve body 29.

The basic mode of operation of the bypass valve 1 is described in German Patent No. 26 55 171. In practice it has been found that the function of the bypass valve 1 is based not only on the change in the intake manifold pressure due to changes in the speed of the machine, but also in the changes in the intake manifold pressure while the speed remains the same but the load is changed and thus changed Cross section of the opening 14 are of decisive influence. This means that a constant idling speed can be achieved without a control range. However, a coordinated dimensioning of the opening 14 can also be used to determine a value of the idling speed which is adapted to the respective requirements and which is variable via the values of the intake manifold pressure. For example, for motor vehicles with an automatic transmission and hydraulic clutch or torque converter for the load condition when the transmission is switched on, an idling speed which is about 100 rpm lower than idle when not under load can be provided, which considerably reduces the tendency of such motor vehicles to creep. Since the eerlauf speed with a loaded machine can be lower than with an unloaded machine because of the higher filling, both conditions of such motor vehicles are fully met. If the load on the machine changes while idling, the bypass valve 1 works as follows:

At an idle speed of about 700 rpm, for example, of the unloaded machine, it is additionally loaded by switching on or engaging an auxiliary unit. At first, the idle speed drops by a small amount. This causes a simultaneous increase in the intake manifold pressure in the manifold intake manifold 2. This increased value of the intake manifold pressure comes into effect in the chamber 8 of the bypass valve 1 and, in conjunction with the compression spring 32, results in the valve body 29 being adjusted in the opening direction. The thus enlarged cross section of the opening 14 also results in a further increase in the intake manifold pressure, with an increase in the filling and thus the performance of the machine and an increase in the speed. This increase in the intake manifold pressure and the drop in the same due to the increase in the rotational speed, which is effective at the same time, approximately compensate for one another. Overall, there remains an increase in the filling and thus the power of the machine and an increase in the intake manifold pressure after this control sequence, while the speed is set to the original value or, if the opening 14 is adjusted accordingly, to a new value.

In the bypass valve 1 shown in the exemplary embodiment, the expansion element 24 is increasingly heated by the coolant when the machine is warmed up. As a result, the lifting pin 27 serving as a stop is pushed forward more and more and thus prevents stood the machine that a too large opening cross section of the bypass valve 1 is released. Thus the increase in speed, which can occur due to a sudden drop in the idle load on the warm machine, is kept within narrow limits because only the narrower upper part of the opening 14 is available for regulation. As a result, the impression of a malfunction of the control device is reliably avoided.

Special coolant lines to and from the housing 10 can be saved either by mounting the housing 10 on the machine (not shown) in such a way that the expansion element 24 projects into a space through which the coolant flows, or by heating a component having the operating temperature by heat transfer.

The bypass valve 101 shown in FIG. 3 as a control device has essentially the same structure as the previously described bypass valve 1. It comprises a membrane box 107 as a servomotor with a chamber 108 which can be acted upon by the suction pipe pressure and a housing 110. The housing 110 has a bore 111 and perpendicularly to it a further bore 112. A guide bushing 113 is inserted into the bore 112. In the area of intersection of the bores 111 and 112, the bore 111 is continued on one side into the guide bush 113 and on the other side is in the wall

113

Guide bush formed an opening 114 as a control cross section, so that the guide bush 113 forms a kind of aperture for the bypass. A cylindrical valve body 129 is arranged on the actuating rod 128 within the guide bushing 113. The top of the

O V.'i Actuating rod 128 is fastened to the membrane 131 of the membrane fire 107. There is no difference in operation between the bypass valve 1 described first and the bypass valve 101 described here.

An actuator 124 is screwed into the housing 110 coaxially to the bore 112. The actuator 124 consists of an expansion element similar to that in FIG. 1 and a commercially available PTC resistor for heating it. The lifting pin 127 of the expansion element protrudes at one end of the actuator 124 in the direction of the valve body 129 and forms a stop for its stroke limitation. At the other end of the actuator 124, a contact tongue for the connection of an electrical line, not shown, is arranged. The actuator 21 can be controlled via a time-dependent switching element, not shown. It is also possible to control it by logically linking several links. The resistance of the PTC resistor increases with increasing temperature and thus ensures a temperature limitation. Appropriate selection of the PTC resistance and the expansion material allows any time constants to be represented. To ensure the start at low outside temperatures, it is possible to provide for the heating of the expansion element to be switched on only when the

The machine is in operation and the starter is no longer actuated and / or the cold start enrichment is switched off.

The following functions occur when the machine is started up in a cooled down state:

- $ ÖREA

O PI As soon as the actuator is driven 124 by putting into operation of the machine ^', a heating start of the expansion element on the PTC resistor and thus a movement of the lifting bolt 127. Its most ausge¬ retracted position takes the lifting bolts 127 a, if after an appropriate timing, the warm-up phase of the The machine has ended or the friction of the machine has decreased to a certain lower value than when it was cold due to warm-up.

The actuator 124 can also consist of a lifting magnet, not shown, which, like the expansion element, is arranged coaxially with the bore 112 and the core of which fulfills the function of the lifting pin 127.

Another possibility of designing an actuator for the stroke limitation is to arrange a lifting magnet as an actuator laterally on the lower part of the housing 110. Here, a core or an extension of the core of the lifting magnet can be moved in the movement path of the valve body 129 or an extension of the actuating rod. In this embodiment, only relatively small holding forces are required which hold the core of the lifting magnet forming the stop in its position limiting the movement path of the valve body 129. The actuation of the actuator takes place essentially in the same way as the actuation of the actuator 124.

In the exemplary embodiment shown in FIG. 4, the stopper between the actual bypass valve 201 and its membrane box 127 serving as a servomotor is an actuator 224 is arranged in the form of a vacuum servomotor or a further diaphragm box, which carries a stop sleeve 227 as a movable stop for limiting the stroke of the valve body 229. The stop sleeve 227 directly limits the path of movement of the diaphragm 231 when the actuator 224 is activated in a corresponding manner. Actuator 224 is controlled via a time-dependent solenoid-pneumatic valve and / or a temperature-dependent pneumatic valve in a vacuum line leading to actuator 224. In addition, further refinements of the control are possible, as described above in connection with the previous exemplary embodiments.

In the exemplary embodiments with a lifting magnet or a vacuum servomotor (FIG. 4) as an actuator for the stop, it is also possible to either extend or retract the stop depending on the operating mode of the machine. This is particularly important for internal combustion engines with cylinder deactivation since, depending on the number of cylinders in operation, a larger or smaller control range of the bypass valve is advantageous.

In the embodiment of the control device in

5 and 6 in the housing 110 in the region of the intersection of the bores 111 and 112 into the wall of the bore 112 is an idle channel 140 parallel to its opening 114 in the form of a valve body 129 or its guide bushing 113 Groove incorporated. The free passage cross section of the idle channel 140 can be adjusted by means of an adjusting screw 141 which projects into the idle channel 140 perpendicular to the actuating rod 128 of the bypass valve 101.

In the exemplary embodiment shown in FIG. 7, the guide ^bushing 313 of the valve body 329, which acts like a diaphragm, has a large wall thickness and is correspondingly received in a large bore 312. The idle channel 340 is machined into the outer circumference of the guide bush 313. It has the shape of an approximately semicircular-shaped groove, which extends from the part of the bore 311 which extends into the bushing 313 to the opening 314. The free passage cross section of the idle channel 340 is adjustable by means of an adjusting screw 3 1 projecting into the idle channel.

The integration of an additional idle channel in the control device makes it possible to adjust the pretension of the compression spring 132 in the chamber 108 and thus the identifier of the control device during assembly, while adapting to each individual machine equipped with the control device and thus the idle setting can be carried out using the adjusting screw 141 or 341. This avoids deviations in the control behavior and the control path and thus the overall size of the control device are kept small, since the cross section for the idle throughput is separated from the passage cross section of the valve device.

Claims

Control device for the idle speed of internal combustion engines, in particular spark-ignited injection internal combustion engines,

- with a bypass valve,

- Which is parallel to an arbitrarily actuatable throttle valve arranged in the intake line and

is controlled by a servomotor, characterized in that

- That the largest possible opening cross section (14; 114; 214; 314) of the bypass valve (1: 101; 201; 301) by an adjustable by means of actuator (24; 124; 224) stop (lifting pin 27; 127; stop sleeve 227 ) is determined

- Which shortens the adjustment path of the valve body (29; 129; 229; 329) depending on at least one operating parameter of the machine, such as operating temperature, operating time from cold start, proportion of fired work rooms.

2. Control device according to claim 1, characterized gekennzeich¬ net - that the actuator consists of an expansion element (24),

- The lifting pin (27) forms the adjustable stop, and

- That the housing (23) of the expansion element (24) protrudes into a housing part through which the coolant of the machine flows.

3. Control device according to claim 2, characterized gekennzeich¬ net,

- That the expansion element (24) including Hub¬ bolt (27) and the coolant flowing through the housing part are arranged in the same axis extension of the bore (12) of the bypass valve (1), in which the valve body (29) is guided.

4. Control device according to claim 3, characterized in that

- That the bore (12) of the bypass valve (1) merges into a blind hole within the housing part,

- In which the housing (23) of the expansion element (24) rests sealingly by means of a collar on a bore step (shoulder 18) and is supported by means of a retaining ring (26) surrounding the lifting bolt (27) of the expansion element (24) and

- In each of an inlet and outlet line (cross bore 20 and nozzle 22) open for the coolant.

5. Control device according to claim 1, characterized gekennzeich¬ net,

- That the actuator (124) consists of an expansion element - which can be heated electrically by means of a PTC resistor and

- The lifting pin (127) forms or carries the adjustable stop.

6. Control device according to claim 1, characterized gekennzeich¬ net,

- That the actuator consists of an electrically actuated lifting magnet, - the core of which forms or carries the adjustable stop.

7. Control device according to claim 1, characterized gekennzeich¬ net - that the actuator (224) consists of a vacuum actuator,

- The membrane carries the adjustable stop (stop sleeve 227).

8. Control device according to one of claims 1 and 5 to 7, characterized in that

- that the time is adopted as the operating parameters which is required to achieve a specific operating state after the start of the machine _nd

- The actuator (124; 224) for the stop (lifting pin 127; stop sleeve 227) can be controlled via a time-dependent switching element,

- That is triggered when this operating state is reached.

9. Control device according to claim 8, characterized gekennzeich¬ net,

that this operating state is defined by a measure of the frictional power of the machine,

- That is reduced compared to that when the machine has cooled down.

^ ÖHΞΛ

10. Control device according to one of claims 1 and 5 to 9, characterized in that

- That a certain temperature of the machine or one of its components or its operating materials is used as the operating parameter and

- That the actuator (124; 224) can be controlled via a temperature-dependent switching element,

- That is triggered when this temperature is reached.

11. Control device according to claim 8, characterized gekennzeich¬ net,

- That the actuator (124; 224) can only be activated when the machine is running and the starter is switched off and / or the cold start enrichment is switched off.

12. Control device according to claim 7, characterized gekennzeich¬ net,

- That the actuator (224) of the stop (stop sleeve 227) between the bypass valve (201) and its servomotor (diaphragm box 207) is arranged.

13. Control device according to one of claims 1 and 6 to 12, characterized in that

- That in the case of internal combustion engines with cylinder deactivation, the connection or disconnection of fired cylinders is used as the operating parameter.

14. Control device according to one of the preceding claims, ^" characterized in that

- That in the housing (110; 310) of the bypass valve (101; 301) parallel to its opening (114; 314) an idle channel (140; 340) is arranged,

- whose cross-section is arbitrarily adjustable by means of an adjusting screw (141; 341).

15. Control device according to claim 14, characterized in that

- That the idle channel (140) is formed by a partial ring groove,

- which is arranged in a wall of a bore (112) of the housing (110) and - is covered on its inner longitudinal side by a guide bush (113) for the valve body (129) fitted into the bore (112).

16. Control device ^" according to claim 14, characterized in

- That the idle channel (340) is formed by a partial ring groove,

- Which is arranged in the outer surface of a guide bush (313) for the valve body (329) and - is covered by the wall of a bore (312) receiving the guide bush (313) on its outer longitudinal side.