US3585975A

US3585975A - Fluid-operated rpm regulator for internal combustion engines

Info

Publication number: US3585975A
Application number: US831085A
Authority: US
Inventors: Hiroshi Tonegawa; Tadayuki Kawasaki; Kenji Nakayama
Original assignee: Diesel Kiki Co Ltd
Current assignee: Bosch Corp
Priority date: 1968-06-10
Filing date: 1969-06-06
Publication date: 1971-06-22
Anticipated expiration: 1988-06-22
Also published as: GB1264526A; DE1918370A1; FR2010538A1

Abstract

In a fluid-operated r.p.m. regulator, in which the output channels of a fluid amplifier element carry r.p.m.-proportionate pressures applied to both sides of a fuel control rod to displace the same for varying the r.p.m., the transitional period between the moment of change (e.g. increase or decrease in the engine load) and the moment of stabilization of the automatically adjusted new r.p.m. is decreased by the provision, between said amplifier element and said rod, of components which respond to a change in said r.p.m.-proportionate pressures by generating an output flow of increased pressure in one of the output channels of a component and switching said output flow to another output channel thereof after a predetermined interval.

Description

United States Patent l5ll Hiroshi Tonegswa Kmvagoeshi;

Tadaynki Kawasaki, Higeshi-Matsuyamashi; Kenji Nakayama, Bignami-Matsuyama- Inventors FLUID-OPERATED RPM REGULATOR FR INTERNAL COMBUSTION ENGINES sclaimsnnwingrigs.

usci 12s/103, 12s/97, 12a/10s, 12s/14o, lav/81.5 lnul rozen/os, Fozd 1/o2,F15c1/12 Fieldofsmcn 12S/103,

Primary Examiner-Wendell E. Bums Attorney-Edwin E. Greigg ABSTRACT: In a fluid-operated r.p.m. regulator, in which the output channels of a fluid amplier element carry r.p.m.-proportionate pressures applied to both sides of a fuel control rod to displace the same for varying the r.p.m., the transitional period between the moment of change (e.g. increase or decrease in the engine'load) and the moment of stabilization of the automatically adjusted new r.p.m. is decreased by the provision, between said amplifier element and said rod, of components which respond to a change in said r.p.m.-proportionate preures by generating an output flow of increased pressure in one of the output channels of a component and switching said output flow to another output channel thereof after a predetermined interval.

AT2 AT1 A mmWMM N 2 EEW .nw VNM T Nm A A IHInMN 5. www v m mmm F 7\ 2 FLUID-OPERATED RPM REGULATOR FOR INTERNAL COMBUSTION ENGINES BACKGROUND OF THE INVENTION The invention relates to a fluid- (liquid or gas) operated r.p.m. regulator for internal combustion engines particularly of the type operating on injected fuel, wherein pressure pulses, the frequency of which is proportionate to the engine r.p.m., are admitted through two conduits of different lengths to two control channels of a fluid logic element. The output flow of the said fluid logic element and a flow having a constant pressure arbitrarily set by a throttle valve, constitute control flows applied to a fluid amplier element.

An r.p.m. regulator of the aforenoted type is the subject of Tonegawa et al. application Ser. No. 815,549, entitled Fluid- Operated RPM Regulator for lntemal Combustion Engines, f'iled Apr. l4, i969. ln a regulator of this type, a proportionate regulation is performed as a result of a continuously proportionate relationship between the input signals and the output signals of the control. Since the permanent deviation of the engine r.p.m. (P-range) is small and the amplification factor of the r.p.m. regulator is large, the time period during which the r.p.m. is set, that is, the transitional period upon variation of the load conditions or upon arbitrary readjustment of the fixed r.p.m., is undesirably long; in extreme cases a permanent r.p.m. fluctuation (a so-called seesawing" or hunting" effect) may appear. ln a proportional r.p.m. regulator, the permanent deviation of the control magnitude (P-deviation) and the transitional control deviation or transitional period are inversely related to one another. Therefore, it is extremely difficult to improve both at the same time.

OBJECT AND SUMMARY OF THE INVENTION It is an object of the invention to provide a fluid-operated r.p.m. regulator of the aforenoted type in which the transitional behavior is improved without affecting the pennanent P-deviation.

Briefly stated, according to the invention, between the individual output flows (having an rpm-proportionate pressure) of the fluid amplifier element there is provided, on 'the one hand, a differential pressure responsive device for displacing a fuel control rod of a fuel injection pump, and, on the other hand, a fluid pressure controlled assembly, hereinafter called a D-component, formed of a circuit A, responsive to pressure drops and hereinafter called D-component A, and of a circuit B, responsive to pressure increases and hereinafter called D-component B. Both are of identical structure and each includes a fluid amplifier element having two output channels. When the rpm-proportionate pressure decreases, there is generated in one output channel of D-component A a fluid flow of increased pressure which, after a predetermined delay, is switched to the other output channel of D-component A. Conversely, when the rpm-proportionate pressure increases, there is generated in one output channel of D-component B a fluid flow of increased pressure which, after a predetermined delay, is switched to the other output channel of D-component B.

The invention will be better understood and further objects as well as advantages will become more apparent from the ensuing detailed specit'ication of a preferred although exemplary embodiment taken in conjunction with the drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a diagrammatic, simplified view of a fluid-operated r.p.m. regulator according to the invention;

FIG. 2 is a diagram of the transition function of a fluidoperated r.p.m. regulator with and without a component according to the invention;

FIG.`3 is a diagram of the pressure/time function in the output channels of the fluid logic element; and

FIGS. 4 and 5 each illustrates a modification of the component according to the invention.

DESCRIPTION OF THE EMBODIMENT Turning f'irst to FIG. 2, there are shown the characteristics of regulation in the presence and in the absence of a D-component (described in detail as the specification progresses).

The transition function has an upwardly sloping linear course. lf the input signals (control deviation) are designated with N and the output signals (control magnitude) with y, then the broken line in the diagram (B) of FIG. 2 indicates the transition function of the regulator which operates merely proportionately (P-regulator), whereas the solid line designates the transition function of the regulator to which there is added the differentiating effect of the D-component (PD-regulator). If in case of an input signal of the r.p.m. devia tion AN, the regulating time (or period of control) for the output signal Ay is designated with ATl in a purely proportionate regulator, then the regulating time for the same output signal Ay is, by virtue of the D-effect, shortened to AT, and is therefore shorter than AT,. As a result, the transition period is decreased. Accordingly, the damping period is shortened and the stability of the regulating system is improved. As shown in FIG. 2, the D-effect is small when T is large, that is, when AT1/AT?, has a low value of approximatelyl QnPt he contrary, in case of a large value of the ratio AT1/AT5 the D-effect is very effective. Thus, without a deterioration of the static behavior (permanent deviation of the control magnitude), the dynamic behavior (transitional control deviation) is irnproved.

ln the description that follows, a structural embodiment of the invention will be discussed.

Turning now to FIG. 1, the embodiment depicted therein includes a fuel injection pump l having a displaceable fuel control rod 3 for regulating the fuel quantities to be delivered by the pump. One end of the fuel control rod 3 is secured to a membrane 4 separating two

chambers

6 and 7. ln chamber 7 there is disposed a spring 8 which opposes the fluid pressure dierence between the pressures in

chambers

6 and 7 and which maintains the fuel control rod 3 in a position determined by the regulator.

To one end of a fuel pump cam shaft 2 there is secured a disc 9 which is provided with a plurality of small openings 10 arranged in a circular array. Adjacent one side of the disc 9 there is disposed a fluid blower nozzle ll to which there is admitted a fluid medium from a source not shown. Adjacent the opposed side of the disc 9, in alignment with the blower nozzle l1, there is disposed a pickup nozzle 12 adapted to receive fluid medium from the blower nozzle 11. From the pickup nozzle 12 there extend a relatively short conduit 13 and a relatively long conduit 14. The ends of these conduits are connected, respectively, to the right control channel 15b and the left control channel 15a of a fluid logic element 1S. A main channel ISc of the fluid logic element 15 is connected to a fluid source (not shown) adapted to deliver fluid under pressure. The fluid stream entering the control chamber of the fluid logic element l5 from the main channel lSc is deflected, by virtue of the Coanda-effect, either by the pressure pulses from the left control channel 15a or by those from the right control channel 15b and is maintained in the last deflected condition even after cessation of said pressure pulses. As a result, in the output channel 15d or in the output channel 15e there either is a fluid flow (on-condition) or there is no flow (off-condition). The

output channels

15d and 15e are connected with the respective control channels 18a and 18b of a fluid amplifier element 18 through

fluid capacitors

16 and 17.

ln the fluid amplifier element 18, to the left ofthe centerline of the main flow channel 18e, there are arranged the aforenoted control channel 18a, a control channel 18e through which fluid is admitted, (the constant pressure of which may be arbitrarily set by a throttle valve 19) and

output channels

18f and 18g. On the other hand, to the right of thc centerline of main control channel 18e, there are arranged the aforenoted control channel l8b, a control channel 18d carrying fluid under constant pressure constituting an auxiliary flow (bias) and output channels 18h and l8r.

The left-hand output channels lf and lg of the fluid amplifier element 18 are connected, respectively, to the relatively longer, left-hand control channel 20a and the relatively shorter,- right-hand control channel 20h of a fluid amplifier element 20 of a D-component A. Symmetrically with Dcom ponent A, the right-hand output channels llh and 113i of the fluid amplifier element 118 are connected, respectively, to the relatively shorter, left-hand control channel 2lb and the relatively Ionger, right-.hand control channel 21a of a fluid amplifier element'2l of a D-component B.

The lef`t-hand output channel 20c and the right-hand output channel 20d of' the fluid amplifier element 20 of the D-component A are connected to a left-hand and a right-hand control channel 22a and l22b, respectively, of a fluid amplifier ele ment 22; the right-hand output channel 21e and the left-hand output channel 21d of the fluid amplifier element 2l of the D- component B are, symmetrically with the channels of the fluid amplifier element 20, connected respectively to the right-hand control channel 22e and to the left-hand control channel 22d of the fluid amplifier element 22. The output channels 22e and 22j' of the fluid amplifier element 22 are connected with the

chambers

6 and 7, respectively, of the actuator responsive to the differential pressure of the fluid medium.

OPERATION OF THE EMBODIMENT The disc 9 is driven by the cam shaft 2 and at each instant when the blower nozzle l1 communicates with the pickup nozzle l2 through a momentarily aligned opening l0 in the disc 9, in the pickup nozzle l2 a pressure pulse is generated, one part of which is admitted through the conduit 13 and the control channel 15b of the fluid logic element l5 to the control chamber thereof, where it deflects the main flow, entering through the main channel 15e, into the output channel 15d. The other part of the pressure pulse is admitted through the relatively longer conduit M with a delay of To seconds to the other control channel 15a of the fluid logic element l5 and switches the main flow from the output channel 15d to the output channel 15e. As the disc 9 continues to rotate, 60/nN seconds later the successive pressure pulse is generated in the pickup nozzle l2. lt is to be noted that n designates the number of small openings l in the disc 9 whereas N designates the r.p.m. thereof. Again, the last-named pulse is divided into two parts and first, the part passing through conduit R3 deflects th'e main flow from the output channel 15e to the output channel 15d and then, the second part of the pulse entering the fluid logic element H with a time delay of T, sec. deflects the main flow from the output channel d to the output channel 15e.

The pressure signals formed of a series of pressure pulses described above, are illustrated in FIG. 3. If` time T is measured along the abscissa and pressure P is measured along the ordinate, then (a) designates the pressure pulse signal in the control channel 15b, (b) is the pressure pulse signal in control channel 15a delayed by T, seconds withrespect to the pulse signal a; (c) and (d) are the pressure pulse signals in the

output channels

15d and 15e, respectively, related to (a) and (b). The period during which the main stream flows in the output channel 15d (on-condition) is thus determined by the pulses of signal (b) delayed T, seconds due to the length difference in the conduits 13, M. Consequently, the said period is independent of the r.p.m. of the disc 9. Since, on the other hand, the pulse interval is determined by the r.p.m. N of the disc 9 and by the number n of the small openings l0, this pulse interval is, assuming n is constant, inversely proportionate to the r.p.m. N. Thus, the mean pressure generated in the output channel 15d of the fluid logic element 115 is proportionate to the r.p.m. N. On the contrary, the mean pressure generated in the output channel 15e is inversely proportionate to the r.p.m. Consequently, the pressure difference between the pressures in the

output channels

15d and 15e is indicative ofthe r.p.m.

The pressure signals generated in

output channels

15d and 15e are admitted through the

fluid capacitors

16 and 17, respectively, to the respective control channels 18a and l8b of the fluid amplifier element 18. The function of the capacitors is to smooth the pressure pulses and, as a result, the output distortions caused by peak pressure values are eliminated. Thereafter, the constant pressure delivered by the control channel 118e and adjustable by the throttle valve i9 is compared with the aforenoted, r.p.m.-dependent pressure delivered by the control channels 18a and 18h. As a result of this comparison, in the output channels lf, 18g, 18h and 181' of the fluid amplifier element 18 a differential pressure is generated which corresponds to the pressure difference in the control channels of the fluid amplifier element 18.

lf the load on the internal combustion engine temporarily decreases and, as a result, the r.p.m. increases, then the mean pressure in the output channels 18h and l8i of the fluid amplifier element 18 increases. Because of the unequal lengths of control channels 21a and 2lb of the fluid amplifier element 21 of the D-component B, the pressure in the control channel 2lb increases earlier than in the control channel 21a. As a result, the pressure in the output channel 21C increases which causes an increase of the pressure in the output channel 22e of the successive amplifier element 22. Consequently, the pressure in the chamber 6 will also increase so that the fuel control rod 3 is displaced towards the left, causing a decrease in the quantities of the injected fuel. As a final result, the engine r.p.m. will drop to its initially set value.

Without the presence of a D-component, the aforementioned disadvantage of a proportionate regulating system, that is, an unstable condition, would be noticeable. Since, however, immediately after the pressure increase in control channel 2lb there is a delayed pressure increase in control channel 21a and, upon occurrence of the latter, the output flow of fluid amplifier element 2l is switched from the output channel Zic to the output channel 21d. Consequently, the output flow is switched from the output channel 22e to the output channel 22f of the amplifier element 22. Thus, the maximum overshot of the output may be controlled.

Since the length of the channel extending from the output of amplifier element 18 to the control channel 21a of amplifier element 2l is related to the magnitude of the D-e'ect, said length is determined for that input frequency which is most likely to cause the aforedescribed unstable condition, that is, which corresponds to an r.p.m. (such as idling) where the appearance of r.p.m. fluctuations hunting") is preponderant.

lf the load on the engine increases causing the engine r.p.m. to drop, then the mean pressure in the output channels lf and mg increases and, since the D-component A operates in the same manner as the aforedescribed D-component B, the pressure in the output channel 22f of the amplifier element 22 increases, causing a pressure increase in the chamber 7. Consequently, the fuel control rod 3 is displaced towards the right, causing an increase in the quantities of the injected fuel. As a final result, the engine r.p.m. will increase to its initially set value. ln this case again, similarly to the aforenoted case of decreasing load, there is a control of the maximum overshot.

The above-described mode of operation occurs also in the case when, entirely independent of theA load fluctuations, the desired operating r.p.m. is changed by means of throttle valve i9, changing the pressure in the control channel 18e of the fluid amplifier element 13.

ln order to obtain a pressure signal delay in the fluid amplifier element 20 of D-component A or in the fluid amplifier element 2l of D-component B, instead of making the

respective control channels

20a and 21a longer, a fluid capacitor may be inserted. Such a fluid capacitor is designated with reference numeral 23 in FIG. t which, in an exemplary manner, shows the fluid amplifier element 2i of D-component B.

The structure and operation of a modified D-component will now be jointly described with reference to FIG. 5.

If the load on the internal combustion engine decreases, the r.p.m. thereof will increase and as a consequence, there will be an increase in the pressure of the right-hand output of the fluid amplifier element 18. This increased pressure is applied to the control channel 24a of a fluid amplifier element 24, and, as a result, the pressure will increase in its output channel 24f. This increased pressure is applied directly or through another fluid amplifier element through conduit 27 to chamber 6 (not shown) causing the fuel control rod 3 to be displaced towards the left to decrease the r.p.m.

The output pressure signal appearing at 24f is also applied to the control channel 25b of a fluid amplifier element 25. As a result, an output signal is generated in the output channel 25e, which, in turn, is applied to the control channel 26a of a fluid amplifier element 26. As a result, a pressure signal apt pears at the output 26e` which, in turn, is fed back with a time delay, due to the provision of a serially connected fluid capacitor 29, into the fluid amplifier element 24 through its control channel 24d. This pressure signal causes the output flow to'be switched from the output channel 24f into the output channel 24e.

The same sequence of operation takes place in the D-component of FIG. 5 in case the load on the internal combustion engine increases. Such a load increase causes a drop in the r.p.m. which, in turn, due to the inverse proportionality causes an increase of pressure in the left control channel 24h of fluid amplifier element 24. As a result, a pressure increase appears in the output channel 24e and in conduit 28 associated with the chamber 7. The pressure increase therein will cause the fuel quality control rod 3 to be shifted to the right increasing thereby the engine r.p.m.

The pressure signal appearing in the output 24e is also applied to the control channel 25 a of fluid amplifier element 25. Thus, a pressure signal appears in the output channel 25d which, in turn, is applied to the control channel 26h of the fluid amplifier element 26. As a result, a pressure signal appears in the output 26d which, with a time delay due to the fluid capacitor 30, is applied to the control channel 24e of fluid amplifier element 24. As a result, the pressure signal that has appeared in output channel 24e (and thus in conduit 28) is, after the same time delay, switched to the output channel 24f- Tuming once more to FIG. l, due to the initial load exerted by the spring 8, despite a throttling of the adjustable throttle valve 19, the r.p.m. may not be set below a determined value. By means of the auxiliary flow (bias) in the control channel 18d, however, the pressure in the output channel 22e of `the fluid amplifier element 22 is boosted and thus, the increased pressure in chamber 6 effectively counteracts the force of spring 8. As a result, the range of displacement of the fuel control rod 3 is enlarged towards the left and consequently the r.p.m. may be set below the aforenoted determined value.

The aforedescn'bed r.p.m. regulator has the basic characteristics of r.p.m. regulators operating with fluid elements: the absence of moving mechanical parts. Since the energy required for the displacement of the fuel control rod is taken from an external source, it is unaffected by the engine r.p.m. This is not the case in conventional r.p.m. regulators of the pneumatic or of the centrifugal governor type where the said energy increases as the r.p.m. increases. Thus, fluid operated r.p.m. regulators have the particularly remarkable advantage that at any r.p.m. the output function of the regulator is always the same. ln addition, the responsiveness of fluid-operated r.p.m. regulators is greater than the transitional control deviation may be rendered small without sacrificing the P-deviation (permanent deviation of the control magnitude from the nominal value).

What we claim is:

1. In a fluid-operated r.p.m. regulator for internal comfirst fluid amplifier element controlled by said output flows and by an arbitrarily adjustable fluid flow of constant pressure and (C) a ressure difference-res onsive actuator to which the output ows of said amplifier e ement are applied for displacing a fuel quantity control member, the improvement comprising a component formed of A. at least one second fluid amplifier element having l. a plurality of oppositely working input or control channels and 2. a plurality of output channels and B. delay means coupled to at least one of said input channels for admitting therethrough a delayed pressure signal to said second fluid amplifier element to switch the output flow, caused by a pressure signal admitted precedingly through an opposing input channel, from one output channel of said second fluid amplifier element into another output channel thereof;

the output channels of said first fluid amplifier element being connected to input channels of said second fluid amplifier element, the output channels of said second fluid amplifier element being operatively coupled with said actuator.

2. An improvement as defined in claim l, wherein said component is formed of a first and a second part, each including one said second fluid amplifier element; the input channels of the second fluid amplifier element of said first part are connected to one output of said first fluid amplifier element and the input channels of the second fluid amplifier element of said second part are connected to another output of said first fluid amplifier element; one input channel of said second fluid amplifier element of each part is coupled to one of said delay means.

3. An improvement as defined in claim l, including a relatively short fluid conduit connecting an output of said first fluid amplifier element with one of said input channels of said second fluid amplifier element and a relatively long fluid conduit connecting the same output of said first fluid amplifier element with another of said input channels of said second fluid amplifier element; said relatively long fluid conduit constitutes said delay means.

4. An improvement as in claim l, wherein said delay means includes a fluid capacitor connected between the output of said first fluid amplifier element and one of said input channels of said second fluid amplifier element.

5. An improvement as defined in claim 1, wherein said component comprises A. a sole second fluid amplifier element having l. two oppositely working firs't input channels connected to the outputs of said first fluid amplifier element,

2. two oppositely working second input channels,

3. two output channels operatively connected to said actuator,

B. at least one third fluid amplifier element for amplifying at least part of the signals in said output channels of said sole second fluid amplifier element, said third fluid amplifier element has l. a first output connected through one of said delay means to one of said oppositely working second input channels and 2. a second output connected through another of said delay means to other of said oppositely working second input channels.

6. An improvement as defined in claim 5, wherein said delay means is formed of two fluid capacitors, one is connected between an output of said third fluid amplifier element and one of said oppositely working second input channels, the

bustion engines, said regulator being of the type that includes (A) a fluid logic element having a plurality of output channels carrying output flows of r.p.m.-responsive pressures, (B) a other is connected between another output of said third fluid amplifier element and the other of said oppositely working second input channels.

Claims

1. In a fluid-operated r.p.m. regulator for internal combustion engines, said regulator being of the type that includes (A) a fluid logic element having a plurality of output channels carrying output flows of r.p.m.-responsive pressures, (B) a first fluid amplifier element controlled by said output flows and by an arbitrarily adjustable fluid flow of constant pressure and (C) a pressure difference-responsive actuator to which the output flows of said amplifier element are applied for displacing a fuel quantity control member, the improvement comprising a component formed of A. at least one second fluid amplifier element having 1. a plurality of oppositely working input or control channels and 2. a plurality of output channels and B. delay means coupled to at least one of said input channels for admitting therethrough a delayed pressure signal to said second fluid amplifier element to switch the output flow, caused by a pressure signal admitted precedIngly through an opposing input channel, from one output channel of said second fluid amplifier element into another output channel thereof; the output channels of said first fluid amplifier element being connected to input channels of said second fluid amplifier element, the output channels of said second fluid amplifier element being operatively coupled with said actuator.

2. a second output connected through another of said delay means to other of said oppositely working second input channels.

2. two oppositely working second input channels,

2. An improvement as defined in claim 1, wherein said component is formed of a first and a second part, each including one said second fluid amplifier element; the input channels of the second fluid amplifier element of said first part are connected to one output of said first fluid amplifier element and the input channels of the second fluid amplifier element of said second part are connected to another output of said first fluid amplifier element; one input channel of said second fluid amplifier element of each part is coupled to one of said delay means.

2. a plurality of output channels and B. delay means coupled to at least one of said input channels for admitting therethrough a delayed pressure signal to said second fluid amplifier element to switch the output flow, caused by a pressure signal admitted precedIngly through an opposing input channel, from one output channel of said second fluid amplifier element into another output channel thereof; the output channels of said first fluid amplifier element being connected to input channels of said second fluid amplifier element, the output channels of said second fluid amplifier element being operatively coupled with said actuator.

3. two output channels operatively connected to said actuator, B. at least one third fluid amplifier element for amplifying at least part of the signals in said output channels of said sole second fluid amplifier element, said third fluid amplifier element has

3. An improvement as defined in claim 1, including a relatively short fluid conduit connecting an output of said first fluid amplifier element with one of said input channels of said second fluid amplifier element and a relatively long fluid conduit connecting the same output of said first fluid amplifier element with another of said input channels of said second fluid amplifier element; said relatively long fluid conduit constitutes said delay means.

4. An improvement as in claim 1, wherein said delay means includes a fluid capacitor connected between the output of said first fluid amplifier element and one of said input channels of said second fluid amplifier element.

5. An improvement as defined in claim 1, wherein said component comprises A. a sole second fluid amplifier element having

6. An improvement as defined in claim 5, wherein said delay means is formed of two fluid capacitors, one is connected between an output of said third fluid amplifier element and one of said oppositely working second input channels, the other is connected between another output of said third fluid amplifier element and the other of said oppositely working second input channels.