JPS63167054A - Fuel device for multicylinder engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine-driven pump means having a plurality of outlets, operative to control the amount of fuel delivered through each outlet, with a reduced connection to an injection nozzle of an associated engine. The invention relates to a fuel system for a multi-cylinder engine, preferably comprising electromagnetically operated valve means and a control circuit for controlling the valve means in response to actual engine operating parameters.

In one form of such a fuel system, the pump means comprises a fixed stroke plunger which sequentially delivers fuel from the pump chamber to the outlet by means of a distributor member, and the valve means comprises a fixed stroke plunger which sequentially delivers fuel from the pump chamber to the outlet by means of a distributor member and valve means is provided through the outlet to control the amount of fuel supplied from the pump chamber to the outlet. It consists of a control valve that can adjust the amount of fuel. In such devices, even though the valves can be operated in the same cycle, the amount of fuel delivered through the engine's injection nozzles may vary due to mismatched nozzles and associated connecting pipes. . Furthermore, even though the cylinders of an engine can receive the same amount of fuel, the combustion characteristics may differ.

Another form of fuel device of the type described above is described in British Patent Specification No. 2,041,577 A, in which the pumping means comprises a plurality of individual engine-operated pumps and the valve means each comprise a plurality of pumps operated by individual engines. Consists of individual electromagnetically actuated control valves associated with pumps. The valves are controlled by a controller so that theoretically the same amount of fuel is delivered through each outlet. Although the actual power produced on each working stroke of the engine may vary as described above, the device forms the pumps and valves in the same manner so that the same amount of fuel is precisely delivered through each outlet. The added disadvantage is that it cannot be done.

In yet another form of such a device, the pump is a rotary distributor pump, and the amount of fuel delivered through the outlet of the pump is controlled by an electromagnetically actuated valve to control the fl of fuel admitted into the pumping chamber of the pump during its filling cycle. Changed by using means. The valve means can take the form of an adjustable throttle.

In yet another configuration of the device, the pump again consists of a rotating distributor type, where during filling of the pumping chamber the range of motion of the pumping plunger or plungers is varied so that the amount of fuel delivered through the outlet is varied. be controlled so that it can be This is achieved by changing the axial setting of the distributor member, in which one or more plungers are mounted and which in turn determine the permissible movement of the plungers. It has the effect of changing the relative position of the stop surface. The axial setting of the distributor member is determined by varying the hydraulic pressure applied to the distributor member when using electromagnetically actuated valve means consisting of one or more valves.

Again, according to yet another device described, the extension is set to ensure that the same amount of fuel is admitted into the pumping chamber and also flows through the injection nozzle connected to the outlet, The amount of fuel may vary and also the combustion characteristics of the engine cylinders may vary. The effect is that more or less power is generated during the combustion stroke of one or more cylinders than during the combustion stroke of the remaining cylinders. This results in erratic operation of the engine, especially at low engine speeds, and this erratic operation is accompanied by excessive engine/engine noise and excessive emissions of toxic substances in the engine exhaust.

The object of the invention is to provide a specified type of fuel device in a simple and advantageous form.

According to the invention, a fuel system of the specified type includes a ninth converting means for providing a pulse signal at each working stroke of the engine, a ninth speed measuring means for measuring the time period of the continuous signal, one pulse and a ninth speed measuring means for measuring the time period of the continuous signal. means for comparing a period of time between a preceding pulse and a period of time between one pulse and a next pulse to generate a series of difference signals; and a valve for reducing said difference signal. means responsive to said difference signal for adjusting said means.

Embodiments of the fuel system according to the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the device consists of a reciprocating plunger pump, indicated generally at 10 and consisting of a cylinder 11 in which a reciprocatable plunger 12 is mounted. The plunger 12 is conveniently loaded in an outward direction by a spring, not shown, into contact with a cam 13 mounted on a camshaft which is driven in timed relation to the engine. Cylinder 11 has an outlet 14 that communicates with a fuel injection nozzle 15 by a spring-loaded delivery valve indicated at 16 .

Formed in the wall of the cylinder 11 is a filling port 17 which is not covered by the plunger 12 as it moves outwardly. The fill port 17 communicates with a fuel source 18. Also in communication with the cylinder 11 is a regulating valve 19 whose winding is controlled by an electromagnetic device indicated by the reference numeral 20 . The regulator valve is arranged such that the winding 20 must be energized to close the valve.

In use, during the inward movement of the plunger 12, the filling port 1
As soon as 7 is covered by the plunger, the fuel contained in the cylinder 11 is pressurized and if the valve 19 is closed, the fuel is delivered through the outlet 14 to the injection nozzle 15 by the delivery valve 16. . During the inward movement of the plunger, if valve 19 is opened, the pressure in the cylinder drops below the pressure required to maintain the delivery valve and the valve member in the nozzle in the open position and is displaced by plunger 12. The fuel then flows to the drain via the control valve 19. During the outward movement of the plunger, fuel flows into the cylinder 11 as soon as the fill port is exposed. However, the filling of the cylinder can be arranged to take place by the valve 19 as soon as the plunger begins to move outwards, in which case the valve 19 is connected to the pressurized fuel source 18.

The parts of the equipment described in connection with FIG.
What is needed to fuel one injection nozzle and for multi-cylinder engines, since there are multiple engine cylinders, although it is understood that only a single fuel source is required, There are many components as shown in FIG.

In figure 8g2, the windings 20 of the valves 19 are respectively connected to the outputs of so-called power modules 21. This module houses a solid-state power circuit, which is a so-called distribution circuit.

The winding 20 can be operated to cause current flow in the winding 20 in response to a signal provided by the winding 22 . The distributor has two main input signals, one of which is supplied by a so-called fuel circuit 23 and the other by a sequence circuit 24. Input to the sequence circuit is obtained from a sensor 26, which is positioned so as to provide a pulse signal each time a mark 27 on the wheel 28 passes the sensor.

The wheels are driven at half the engine speed and there are as many marks 27 as there are engine cylinders.

The signals supplied by the sequence circuit 24 to the distributor 22 are such that the appropriate control valve 19 turns @20 are energized at the desired times. Fuel circuit 2
The signal supplied by 3 determines the time period by the carrot rotation phase in which a particular winding is energized. The fuel circuit receives a signal from the sequence circuit indicative of the amount of fuel and such that the signal supplied to the distributor is of a pulsed nature. Fuel circuit 25 determines the duration of fuel delivery based on control signals provided by control or governor circuit 25. Circuit 25 receives an engine speed signal from a speed circuit 30 which receives a request signal from a transducer associated with a throttle pedal of a vehicle powered by the engine and which receives as its input signal the output signal of sensor 26. do. Based on the speed signal and the demand signal, circuit 25 generates the desired fuel signal, which is processed in fuel circuit 23 so that the pulses of the pulse signal supplied to the distributor are of appropriate duration. The governor circuit may also receive further signals indicative of other engine operating parameters.

As mentioned earlier in this specification, the structure of the various components shown in FIG. The amount of fuel is now variable. For example, if one nozzle supplies significantly more fuel than the other nozzles, engine speed will temporarily increase throughout the operating cycle of the cylinder associated with that nozzle as more power is generated. . Similarly, if the nozzle supplies less fuel, the engine will slow down.

The distributor 22 has a further input from a so-called correction circuit 29, which also receives signals from a sequence circuit. A further input to the correction circuit 29 is from a comparator circuit 32 which is supplied at one input with the current speed signal from the speed circuit 30 and at the other input with the preceding speed signal generated by the speed circuit. f, which is supplied by a delay circuit 31 which is reset by a signal from the sensor. Effectively, therefore, the output of the comparator circuit is the difference between the time period between one pulse and the preceding pulse generated by the sensor and the time period between one pulse and the next pulse.

The difference signal has a sign depending on whether the next period is longer or shorter than the previous period. The difference signal is stored in a correction circuit 29 and applied to the distributor so that at the correct time the correction signal delivers more fuel to its combustion chamber and shortens the respective time period so that the injection nozzle delivers less fuel. Ru. The range of correction can be limited so that the full correction is only achieved after a number of complete engine cycles.

The wheel 28 is illustrated as having the same number of markings 27 as there are engine cylinders. However, it is possible to provide a larger number of marks, for example twice that number. In this case, the evaluation of the speed difference involves a number of pulses corresponding to a period of no more than one operating cycle of the engine. As another example, wheel 28 could be the flywheel of an engine, in which case half the number of marks would be required.

Figure 3 shows the British patent! Other configurations of the fuel device are shown, which are described in more detail in 2.037.365. The pump consists of a drive shaft 32, the drive shaft 32
is formed integrally with an enlarged annular member 33 in which an end portion of a rotary distributor member 34, which is housed within the body portion 35, is disposed. The distributor member is axially movable and adapted to be driven from the annular member 33 by a drive member that engages in a radial slot formed in the member. The above set houses a cam follower consisting of a plurality of shoes 36 whose outer ends are connected to a ninth roller for engagement with the inner circumferential surface of a surrounding annular force ring (not shown). I support 37. The shoe is axially fixed relative to the distributor member and is radially slidable within said slot formed in the annular member 33. At their inner ends they engage plungers 38, each housed within a diametrically arranged hole formed in the distributor member. The inner surface of the annular member 33 is tapered to form a stop surface and the shoe 36
is provided with complementary stop surfaces such that the axial position of the cam follower relative to the annular member determines the maximum outward movement wJ of the plunger 38.

The central portion of the bore defined between the plungers communicates by a passageway 39 with a longitudinally extending groove 40 formed in the circumference of the distributor member and which in turn communicates with a plurality of inlets 41 formed in the body portion. can be engaged. The inlet 41 communicates with the outlet of a low pressure supply pump 42, the pressure of which is conveniently controlled by a relief valve 43 so that it varies depending on the operating speed of the device. A plurality of outlets 44, only one of which is shown, are selectively arranged with the inlet 41, and these outlets are each connected to an injection nozzle of the engine associated with use.

The distributor member is biased away from the drive shaft by a compression coil spring 45 conveniently disposed within a recess formed in the drive shaft. As the distributor member is moved by the action of the spring, the plunger 38 can move further outward while fuel is being supplied to the bore through the inlet 41 and the groove 40, thereby causing the next inward movement of the bombing plunger. Increase the amount of fuel supplied to the outlet during exercise.

Movement of the distributor 34 against the action of the spring is accomplished by supplying Arita fuel to a chamber 46 from which the end of the distributor member remote from the drive shaft projects.

The end face of the distributor member is subject to the pressure of the fuel in the chamber 46 and a force is thereby generated which presses against the distributor member against the action of the spring 45.

Control of the fuel pressure in chamber 46 is effected by valve means 47 which includes a valve member 48 whose central recess has a flat portion communicating with chamber 46 . In the central position of the valve member as shown, the passage 49 leading to the drain is covered by one flat section and the passage 50 communicating with the outlet of the low pressure pump is covered by the other flat section. The valve member can be moved in either direction by the action of actuator 51 and the arrangement is such that if the valve member is forced downwardly, chamber 46 is in communication with the drain by passage 49. On the other hand, if the valve member is moved upwardly, the chamber 46 is brought into communication with the passageway 50. In the former case, fuel can escape from chamber 46 and the distributor member moves to the right to increase the amount of fuel supplied to the associated engine. In the latter case, fuel flows into chamber 46 to move the distributor member towards the left against the action of spring 45, thereby reducing the amount of fuel supplied. Valve member 48 is returned to its intermediate position prior to engagement of the stop surface such that the distributor member is hydraulically locked before contact of the valve member and stop surface is made.

In the variation shown in FIG. 4, chamber 46 is in permanent communication with the drain by a passageway 52 that houses the restrictor.

In addition, an electromagnetically actuatable valve 53 is provided which provides permanent communication between the chamber and the outlet of the low pressure pump and which controls the magnitude of the current flowing in the solenoid winding of the valve 53. determines the degree of restriction imposed by the valve. The pressure within chamber 46 can therefore be varied by changing the current flowing in the valve windings and therefore the axial position of the distributor member can be controlled. A suitable valve for this purpose is the British Patent Specification Horn 2.0.
It is described in No. 64,72Os.

FIG. 5 shows a control circuit suitable for use with the ratio pump shown in FIG. In the pump shown in FIG. 3, the valve member 48 of the valve 49 can be moved in the opposite direction from its control position and the actuator 51 therefore has a pair of windings 54, 55f. Current flow in the windings is effected by a control circuit 56 which receives a feedback signal from a sensor 57 indicative of the position of the distributor member 34.

The control circuit receives a control signal from a so-called distributor circuit 58, and the control signal is connected to the desired distributor) I
J computer member position signal is shown. The control signal can also be subject to general level changes as the amount of fuel required to be delivered to the engine changes as a result of governor action or due to changes in operator demand, but also the fuel level described above. Instantaneous level changes can be made to account for delivery mismatches.

The distributor circuit 58 has two main input signals, one of which is supplied by a so-called fuel circuit 59 and the other by a sequence circuit 60. Input to the sequence circuit is obtained from a sensor 61, which is positioned to provide a pulse signal upon the passage of a mark 62 on a wheel 63 past the sensor. The wheels are driven at half the engine speed and have the same number of marks 62 as engine cylinders. As per the previous example, the wheels can be driven at engine speed by half the number of marks. The signal provided by sequence circuit 61 is such that winding 54 or 55 is energized only for a short period of time to allow adjustment of the position of the distributor member before shoe 36 engages the stop surface. A signal provided by fuel circuit 59 is indicative of the desired position of the distributor member and is determined by the fuel circuit based on an input signal provided by control or governor circuit 64. This includes an engine speed circuit 65 which receives a demand signal from a transducer (not shown) associated with the throttle pedal of a vehicle powered by the engine and also receives at its input signal the output signal of sensor 61. Receive speed. Based on the speed signal and the demand signal, circuit 64 generates a desired fuel signal, which is processed in fuel circuit 59 to provide a desired distributor member position signal.

In order to correct for mismatches in fuel delivery and engine combustion chamber characteristics, the distributor circuit 58 has a further input from a so-called correction circuit 66, which
also receives signals from sequence circuit 60. A further input to the correction circuit 66 is from a comparator 67;
The comparator 67 is fed at one input with the existing speed signal from the circuit 65 and at the other input by the preceding signal generated by the speed circuit, which is fed by a delay circuit 68 which is reset by the signal from the sensor. be done. In effect, therefore, the output of comparator 67 is the difference between the time period between one pulse and the previous pulse generated by the sensor and the time period between one pulse and the next pulse.

The difference signal has a sign depending on whether the next period is longer or shorter than the previous period. The difference signal is stored in a correction circuit 66 and at the correct time the correction signal is applied to the distributor circuit 58 so that an instantaneous change occurs in the control signal applied to the control circuit 56. The distributor member 34 is therefore moved to a new setting and then returned to its original setting to change the amount of fuel delivered on the next fuel delivery. The range of correction can be limited so that full correction is achieved only after a number of complete engine cycles.

As noted, the circuit of FIG. 5 is used with the nine pumps shown in FIG. With respect to the pump shown in FIG. 4, valve 53 must be opened at all times in order to maintain the pressure within chamber 46. The windings of the valve 56 can also be supplied from the power circuit, in which case the windings are changed at appropriate times to change the position of the distributor member to provide a change in fuel delivery by the pump to compensate for the discrepancy. There must be continuous current flow through the valve windings.

Valve t acts as an adjustable throttle to control the amount of fuel supplied to the pump during its fill stroke.
- The shape of the pump to be incorporated can be controlled by the circuit of FIG. 5 as a modification of the pump shown in FIG.

In this case the sensor 57 is responsive to the setting of the valve member of the valve.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of a fuel system, Fig. 2 is a block diagram showing electrical components that control the operation of the valve shown in Fig. 1, and Figs. FIG. 5 is a block diagram similar to FIG. 2 for controlling the operation of the valve means of the apparatus of FIG. 3; In the figure, 10 is a pump, 11 is a cylinder, 14 is an outlet, 15 is a fuel injection nozzle, 16 is a delivery valve, 19 is a control valve, 20, '54, 55 are windings, 21 is a power module, and 22 is a distributor. , 23.59 is the fuel circuit, 24.60 is the sequence circuit, 25.64 is the governor circuit, 26°57.61 is the senna, 27.62 is the mark, 28°63 is the wheel, 29.66 is the correction circuit,
30 is a speed circuit, 31 is a delay circuit, 32 is a drive shaft, 46
4 is a chamber, 47 is a valve means, 48 is a valve member, 51 is an actuator, 5
3 is an electromagnetic valve, and 67 is a comparator.

Claims (2)

[Claims] (1) pump means driven by an engine having a plurality of outlets for connection to the injection nozzle of the associated engine;
an electromagnetically actuated valve means operable to control the amount of fuel delivered through each outlet, a control circuit for controlling the valve means in response to desired and actual engine operating parameters, at each working stroke of said engine; converting means for supplying pulse signals; rate measuring means for measuring the time period between successive signals; a multi-cylinder engine, comprising: means for comparing a period of time with a time period to generate a series of difference signals; and means responsive to said difference signal to adjust said valve means to reduce said difference signal. fuel equipment. (2) The means for comparing the time periods consist of a comparator having a pair of inputs, one input being connected directly to the output of the speed measuring means and the other input being connected to the speed measuring means by means of a delay circuit. 2. A fuel system as claimed in claim 1, characterized in that the delay circuit has a reset input connected to the output of the measuring means and connected to the sensor.