JPH04121623A - Injection quantity measuring device - Google Patents

Abstract

PURPOSE:To achieve a high-speed and accurate measurement by injecting a fluid from a fuel injection pump into a closed pressure container when measuring the injection quantity of the fuel injection pump and then measuring pressure change within the above pressure container individually at a plurality of injection points and then performing calculation. CONSTITUTION:A fluid from a fluid injection pump 6 which is driven by a motor 5 is injected into a pressure container 1 through an injection pipe 8 and a flow injection nozzle 7. Output of a pressure sensor 2, a volume measuring means 15, and an encoder 9 is fed to a calculation means 16. The pressure container 1 is filled with the fluid, a specified pressure is maintained by a rear pressure value 4, and an electromagnetic valve 3 closes it. Pilot injection and main injection are performed within one injection process. The calculation means 16 measures pressure increase due to injection with the pressure sensor 2 and calculates the quantity of the injected fluid. When one injection process is completed, the electromagnetic valve 3 is opened and the fluid is discharged through the rear pressure valve 4. The discharged fluid volume is integrated by a volume measuring means 15.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a device for measuring the amount of fluid injected in a fluid injection device, and more specifically, it relates to a device for measuring the amount of fluid injected in a fuel injection pump. The present invention relates to a measuring device.

[Conventional technology]

Conventionally, the amount of fuel injected by a fuel injection pump has been determined by collecting fuel injected from an injection nozzle into a predetermined container and measuring the volume of the fuel using a differential transformer, a lift sensor, or the like. However, in such conventional methods of measuring the volume of fluid such as fuel, it takes time for the volume of the fluid to stabilize after injection is completed, and high-speed and automatic measurement cannot be performed.

In addition, fuel injection pumps with a pilot injection mechanism perform main injection immediately after the pilot injection, so a means that can respond quickly is required to measure the injection amount, but conventional methods do not respond at high speed. It was impossible to measure the two injections separately because there was no means of measuring volume that could respond to the two injections.

[Problems to be Solved by the Invention] An object of the present invention is to provide a fluid injection amount measuring device that can improve the above-mentioned drawbacks of the prior art and can accurately measure the injection amount of an injection fluid automatically and at high speed. At the same time, the so-called
It is possible to automatically measure the pilot injection amount and main injection amount in injection pumps for fluids containing fuel, etc., which have a pilot injection mechanism, and to measure the above two injection amounts with high accuracy without being affected by temperature. The present invention provides a fluid injection amount measuring device that can independently measure the amount of fluid ejected.

[Means to solve the problem]

In order to achieve the above object, the present invention employs the technical configuration described below.

That is, basically, in the injection process, a fluid injection pump that injects fluid, a closed pressure vessel having a predetermined volume that temporarily stores the fluid injected by the fluid injection pump,
An injection amount measuring device comprising a pressure change measuring means for measuring the pressure change of the fluid in the sealed pressure vessel, and a measuring means for measuring the amount of fluid injected within one injection process from the output of the pressure change measuring means. The fluid injection pump is configured to inject the fluid multiple times during the injection process, and at each time the fluid is injected from the fluid injection pump multiple times. The first invention is an injection amount measuring device that includes calculation means for individually measuring pressure changes in the pressure vessel and calculating the results, and further includes: a fluid injection pump that injects fluid, a sealed pressure vessel having a predetermined volume that temporarily stores the fluid injected by the fluid injection pump, a pressure change measuring means that measures a pressure change of the fluid in the sealed pressure vessel, and In an injection amount measuring device comprising a measuring means for measuring the amount of fluid injected within one injection process from the output of the pressure change measuring means, the fluid injection pump measures the injection amount of the fluid within one injection process. The fluid injection pump is configured to inject fluid multiple times, and the pressure change in the pressure vessel is individually measured at each time the fluid is injected multiple times from the fluid injection pump, and the results are calculated. and a means for discharging a fluid corresponding to the fluid injected into the closed pressure vessel by the fluid injection pump from the closed pressure vessel, and within one injection process. an injection amount measuring device that includes a fluid amount calculation means capable of measuring the injection amount of each fluid injected multiple times in one injection process by measuring the volume of the fluid injected in the injection process. This is the second invention.

[For production]

Since the present invention employs the above-mentioned technical configuration, the pressure of the fluid injected from the fluid injection pump can be measured accurately and at high speed at each injection point in one injection process. Since it is possible to measure the volume of the fluid injected in one injection process of the fluid injection pump accurately and at high speed, it is possible to perform predetermined arithmetic processing from each measurement value. According to one of the fluid injection pumps,
The amount of fluid injected at each injection point in the injection process can be measured quickly and precisely, and if a prescribed measurement is performed for multiple injection steps, the amount of each fluid injected as an average value can be measured. Since it is possible to obtain more accurate measurement values.

〔Example〕

A specific example of the injection amount measuring device according to the present invention will be described below with reference to the drawings.

The fluid used in the present invention is not particularly limited, and any fluid can be used, but it is particularly suitable for measuring the amount of fuel injected with respect to a fuel injection pump used in a fuel supply system of an internal combustion engine, etc. It is suitable for something.

First, the configuration of a specific example of the injection amount measuring device according to the present invention will be explained. As shown in FIG. 1, the injection amount measuring device according to the present invention basically consists of A fluid injection pump 6 capable of injecting fluid multiple times, a closed pressure vessel 1 having a fluid injection nozzle 7 connected to the fluid injection pump, a fluid pressure detection means 2 provided in the pressure vessel, and a pressure vessel H1. An electromagnetic valve 3 and a back pressure valve 4 are connected to each other to cause the fluid in the pressure vessel to flow out and to maintain the back pressure in the pressure vessel at a predetermined pressure, and an encoder 9 and the encoder to detect the driving state of the fluid injection pump. 9 and calculation means 1 for measuring pressure changes in the pressure vessel in response to information from the fluid pressure detection means 2 and storing the results.
It is composed of 6 and 6 parts.

Note that the fluid injection pump 6 and the injection nozzle 7 are connected to an injection pipe 8.
The fluid pumped from the fluid injection pump 6 passes through the injection pipe 8 to reach the injection nozzle 7, and is injected from the injection nozzle 7 into the pressure vessel l.

Since the pressure vessel measures the amount of fluid injected, it is maintained in a sealed state when measuring the pressure inside the pressure vessel, and in other cases, the fluid injected into the pressure vessel is discharged and the pressure is A solenoid valve 3 and a back pressure valve 4 are attached to the pressure vessel to maintain a predetermined back pressure inside the vessel.

The solenoid valve is a 2-bot, 2-position, high-speed response solenoid valve in order to maintain a closed state when measuring the pressure inside the pressure vessel and to discharge the fluid injected into the pressure vessel in other cases. It is preferable that

As will be described later, the solenoid valve 3 is opened and closed in response to a command signal from the calculation means 16.

Further, the back pressure valve 4 may have any structure as long as it can maintain a constant pressure inside the pressure vessel.

As the fluid pressure detection means 2 used in the present invention, any device that is generally referred to as a pressure sensor may be used, but for the purpose of the present invention, for example, a quartz sensor that can respond at high speed may be used. It is preferable to use a type pressure sensor or the like.

Further, in the present invention, the injection amount measuring device further includes the back pressure valve 4 connected to the fluid volume measuring means 15 via the fluid direction switching valve 10, and furthermore, the above-mentioned calculation means is connected to the fluid volume measuring means 15. It includes calculation means for measuring the volume of fluid discharged from the pressure vessel 1 in response to the information from the volume measuring means 15 and the information from the encoder 9, and for storing the results.

That is, the direction switching valve 10 is used to switch the direction in which fluid flows, for example, when discharging fluid from the pressure vessel to the volume measuring means 15, and when discharging the measured fluid from the volume measuring means 15 to the outside. The direction of the flow is changed depending on the situation. The other directional valve 10' operates in a direction opposite to that of the directional valve 10. For example, when the directional valve 10 is in the direction to discharge fluid from the pressure vessel to the deposition measuring means 15, the directional valve 10' is in the direction to discharge fluid from the volume measuring means 15 to the outside.

On the other hand, the volume measuring means 15 may be, for example, a piston-type volumetric flowmeter, and the amount of fluid discharged from the pressure vessel l is measured by a change in the position of the piston 12 of the piston-type volumetric flowmeter. It is something to do.

For this purpose, a cylinder 11 and a piston 12 are provided, and a rod 13 connected to the piston 12 is connected to displacement detection means such as a photoelectric displacement meter 14, for example.

Further, in FIG. 1, 5 is a driving means such as a motor for driving the fluid injection pump, and an encoder 9 is a driving means 5 for driving the fluid injection pump.
It detects 0 rotation and generates an appropriate pulse signal.

The calculation means 16 receives the pulse signal from the encoder, the information from the fluid pressure detection means 2, and the information from the volume measurement means 15, and executes a predetermined calculation process regarding the amount of fluid to be injected. It also controls the opening and closing of the solenoid valve.

Next, the operation of the fluid injection amount measuring device according to the present invention will be explained.

Now, in FIG. 1, it is assumed that the pressure vessel 1 with the solenoid valve 3 closed is filled with fluid such as fuel, and a back pressure PK set to a predetermined value is applied by the back pressure valve 4. When the motor 5 is driven here, the fluid injection pump 6 with a pilot injection mechanism is driven, and the fluid pumped thereby is
It passes through the injection pipe 8 and is injected from the injection nozzle 7 into the sealed pressure vessel l.

In a specific example of the present invention, one of the fluid injection pumps is
It is preferable that the fluid be ejected multiple times during the ejection process, rather than once, so that the amount of fluid injected can be measured more accurately. Therefore, in this specific example, a fluid injection pump designed to perform fluid injection at least twice in one injection process is used as the fluid injection device, and more preferably, each injection process in one injection process is The amount of fluid injected at the time of injection is made different, and the amount of fluid injected is reduced in the first stage of fluid injection in one injection process, and the amount of fluid injected in the later stage is increased. The former is generally referred to as pilot injection and the latter as main injection. Of course, in the present invention, two or more fluid injections may be performed within one injection process, and the amount of injection fluid at each injection time may be designed to be the same. When such fluid is injected into the pressure vessel 1, the pressure within the pressure vessel 1 increases in proportion to the injected fluid, so the pressure sensor serving as the pressure detection means detects this change in pressure. However, the amount of fluid injected can be measured using relational expression (1), which will be described later.

The pressure vessel 1 according to the present invention has a configuration as shown in FIG. 4, and an injection nozzle 7, a pressure sensor 2, and a solenoid valve 3 are attached to the pressure vessel 1. Further, when the solenoid valve 3 is closed according to a command from the calculation means 16, the pressure vessel is brought into a sealed state, and in this state, a predetermined fluid is injected from the injection nozzle 7 into the pressure vessel 1.
Injected inside.

Here, an example will be described in which the fluid is injected from the fluid injection nozzle 7 in one injection process in a manner that is divided into the above-mentioned pilot injection P and main injection M. In the following, the fluid injection amount injected by pilot injection is referred to as pilot injection amount,
The amount of fluid injected in the main injection is defined as the main injection amount.

Now, if fluid is injected in the apparatus shown in Fig. 1 according to the waveforms shown in Fig. 2(a), the relationship between the amount Δq of the injected fluid and the pressure change ΔP in the pressure vessel is ΔP= Δq...・(1) It can be expressed as ■.

On the other hand, the pressure change ΔP in the pressure vessel 1 is measured by a pressure sensor 2, and a pressure signal having a waveform shown in FIG. 2(b) is output.

Therefore, the pressure change ΔPP due to the pilot injection and the pressure change ΔPM due to the main injection can be measured from the pressure signal.

That is, in the waveform of FIG. 2(b), the pilot injection P
The back pressure inside the pressure vessel l before performing is P. Assuming that, as a result of pilot injection, the pressure rises to P, and as a result of main injection, the pressure increases from P, to P,4.
rise to Therefore, the pressure change ΔP due to the pilot injection P is ΔPp=Pr P. ...(2)
Also, the pressure change ΔPM due to main injection M is expressed as ΔPM=PM
PP is expressed as (3).

Therefore, the amount of injection fluid in each injection can be calculated from the above equation (1) and equation (2) or (3). In the present invention, when the injection process is completed, the calculation means 1
6, the solenoid valve 3 is opened, and an amount of fluid corresponding to the amount of fluid injected into the pressure vessel is discharged through the back pressure valve 4, and the inside of the pressure vessel is set in advance by the back pressure valve. The back pressure is maintained at PK.

In this specific example, the above-mentioned initial pressure P0 is equal to this back pressure PK. On the other hand, the fluid discharged from the contact pressure vessel flows into the cylinder 11 shown in FIG. 1, and the piston 12 is moved by the fluid pressure.

The displacement position l is displayed on a scale of a suitable display means (for example, a photoelectric displacement meter) 14 connected to the piston 12 by a rod 13.

Next, the procedure for carrying out the above-mentioned injection fluid amount measuring method according to the present invention will be explained using the chart of FIG. 2 and the block diagram of FIG. 5 showing the configuration of the calculation means.

In the specific example of FIG. 1 according to the present invention, the encoder 9 that detects the rotation of the motor 5 outputs two types of rotation signals RTS.
1 and RTS 2. That is, RTS 1 generates a signal (I P/Rev) of one pulse per motor revolution, and RTS 2 generates a signal (IP/Rev) per motor revolution. It is set to generate 20 pulse signals (720P/Rev). That is, the RTS 1 generates one pulse when the encoder rotates once, or in other words, when the fluid injection pump rotates once, and detects the position of the rotating short body. Therefore, the period between pulses of the rotation signal RTS1 means within one injection process. On the other hand rotation signal RT
S2 is to order 720 pulses during one rotation of the fluid injection pump, and these pulses are used to detect and store the pressure inside the pressure vessel, which will be described later. Trigger pulses (TRG 1. TRG
It is used as a timing pulse to control the timing of generation of 2°TRG3). Note that the rotation signal RTS in the present invention
The number of pulses 2 is not limited to 720P/Rev, and any number of pulses can be adopted.

The rotation signals RTS 1 and RTS 2 are taken into the calculation means 16, and the timing signal generation circuit 29 starts counting the pulses of the RTS 2 signal from the time the RTs 1 signal is input, and is triggered at a preset timing. Signal TRY; 1. TRG 2. TRG
3 and outputs a discharge signal H. The timing of each trigger signal and discharge signal can be arbitrarily set externally.

Trigger TRG 1 shown by the waveform in FIG. 2(e) is set at an appropriate time immediately before the pilot injection, and trigger TRG 2 shown by the waveform in FIG. 2(f) is set at an appropriate time between the pilot injection P and the main injection M. In addition, the trigger TRG 3 shown in FIG. 2(g) is set to output a pulse signal at an appropriate time after the main injection M. Further, the discharge signal I] is set to be output after the trigger TRG 3, and its 11 sets the time during which fluid can be discharged from the pressure vessel 1.

When the injection pump 6 rotates, the trigger TRG 1 is first output at a set timing and input to the latch circuit 21. The latch circuit 21 is a circuit for latching the pressure detection signal from the pressure sensor 7 until it is input into the computer 27 provided in the calculation means 16. pressure P
. is latched. Thereafter, the pressure P after the pilot injection P is latched by the latch circuit 22 by the trigger TRG 2, and the pressure PM after the main injection M is latched by the latch circuit 23 by the trigger TRG 3. Each latched pressure value is converted into an analog-to-digital conversion circuit 24 to
26 (A/D converter) converts the analog value into a digital value and inputs it into the computer 27. The information stored in the computer 27 is displayed on the display means 28 according to appropriate commands, either as is or after being subjected to appropriate arithmetic processing. Then, the pressure change due to pilot injection is ΔPp=PpP according to the above-mentioned equations (2) and (3).

as well as Pressure change due to main injection ΔPM=PN PF is obtained through arithmetic processing in the computer.

A drive circuit 30 that opens and closes the solenoid valve when a discharge signal H is output after a predetermined period has elapsed after the trigger TRG 3 is output.
operates, and the solenoid valve 3 opens. When the solenoid valve 3 opens, fluid passes through the back pressure valve 4 and is discharged from the pressure vessel 1. The discharge is continued until the pressure inside the pressure vessel 1 reaches a pressure PK preset by the back pressure valve 4. In other words, the amount of the injected fluid (pilot injection quantum main injection amount) is discharged.

The thus discharged fluid flows into the cylinder 11 and moves the piston 12. A photoelectric displacement meter 14 connected to the piston 12 by a rod 13 outputs a pulse proportional to the displacement l of the piston 12, and the pulse is counted by a counter 20 in the calculation means 16, and the piston displacement l is digitally calculated. The value is read into the computer 27 as a value. piston 1
2 and the cross-sectional area A of the piston 12, the IQ of the fluid injected in one injection process is determined as Q,=Ax1 peak (4). That is, it can be determined by converting the amount of fluid injected in one injection process into volume.

By proportionally distributing the injection amount Q0 of this fluid according to the ratio of the respective pressure changes in the pilot injection P and the main injection M, as shown in the following equations (5) and (6), the pilot injection IQ, , the main injection amount Q can be found. The above is the procedure for determining the total injection amount of fluid within one injection process of the fluid injection pump and the respective injection amounts at each injection time.

In the present invention, in order to more accurately measure the amount of ejected fluid, it is preferable to repeat the above measurement method multiple times and obtain the average value. Therefore, a method of measuring the average injection amount when the above-mentioned measuring method is repeated n times will be explained using the flowchart of FIG. 6. First, the number of injection measurements n is set (step a), and the position of the piston 12 at the start of measurement is measured and input (step b). Next, in step C, the aforementioned pressures Pa, PP, and PM are measured at the output timing of the trigger signals TRG1 to TRG3, and the pressure ΔPr8PM is measured and stored.

This operation is repeated until the number of injection measurements reaches n times (step d).

When the number of injection measurements reaches n times, the position L of the piston 12
Measure and input E (step e).

Next, as shown in FIG. 3, the initial position 3 and the final position 1. Displacement f of the piston 12 from the difference with E
f1L=L, -LS is calculated, and the total injection amount of fluid is found from the piston cross-sectional area A and the piston total displacement scale in the same way as described above, and by dividing by the number of times the injection pump rotates, n, the pump turns 11 times. Average injection amount per unit - Q゛.

is determined by the following equation (7).

After performing the above calculation in step f, the total sums ΣΔP and ΣΔPH of the pressure change during pilot injection and the pressure change during main injection during each injection process when measured n times are stored in the computer. From the proportional distribution formula using the following equations (8) and (9), calculate the average pilot injection amount when measuring n injections -q-7
, average main injection 1 page, is determined (step h).

The present invention enables high-speed measurement by using pressure.
Moreover, since the measurement is performed by using the short-term pressure ratio from pilot injection to main injection and by combining pressure and volume, it is possible to measure the injection amount with high precision, which is less susceptible to temperature effects.

Furthermore, in the present invention, a piston-type volumetric flow needle is used as an example of a method for measuring the amount injected in one injection process, but it is also possible to measure the amount by using other means for measuring the flow rate, such as a gear pump-type flowmeter. .

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing a specific example of an injection amount measuring device according to the present invention. FIG. 2 is a diagram showing a timing chart of each signal used in the present invention. FIG. 3 is a graph showing the relationship between the number of injection measurements and the amount of displacement of the piston in the present invention. FIG. 4 is a sectional view showing a structural example of a pressure vessel used in the present invention. FIG. 5 is a block diagram showing an example of the configuration of the calculation means used in the present invention. FIG. 6 is a flowchart for carrying out the injection amount measuring method according to the present invention. DESCRIPTION OF SYMBOLS 1... Pressure vessel, 2... Pressure change measuring means, pressure sensor, 3... Solenoid valve, 4... Back pressure valve, 5... Motor,
6... Fluid injection pump, 7... Fluid injection nozzle, 8... Injection pipe, 9... Encoder, lO... Fluid direction switching valve, 11... Cylinder, 12... Piston,
l4...Photoelectric displacement meter, 16...Calculating means, 13...Rondo, 15...Volume measuring means, 20...Counter, 2L22, 23...Latch circuit, 24.25.26 ...analog-digital converter, 2
7... Computer, 2B... Display device 29.
...Timing signal generation circuit, 30...Solenoid valve drive circuit.

Claims (1)

[Scope of Claims] 1. A fluid injection pump that injects fluid in the injection process, a sealed pressure vessel having a predetermined volume for temporarily storing the fluid injected by the fluid injection pump, and the hermetically sealed pressure vessel. An injection amount measuring device comprising a pressure change measuring means for measuring a pressure change of a fluid in a pressure vessel, and a measuring means for measuring an injection amount of fluid within one injection process from the output of the pressure change measuring means. The fluid injection pump is configured to inject the fluid multiple times in one injection process, and the pressure is increased at each point in time when the fluid is injected multiple times from the fluid injection pump. An injection amount measuring device characterized by including calculation means for individually measuring pressure changes in a container and calculating the results. 2. The calculation means individually measures the pressure change in the pressure vessel at each point in time when fluid is injected multiple times from the fluid injection pump, and calculates the amount of fluid injected at that point. 2. The injection amount measuring device according to claim 1, wherein the injection amount measuring device is characterized in that: 3. The injection amount measuring device according to claim 1, wherein the inside of the pressure vessel is always set at a predetermined back pressure. 4. In the injection process, a fluid injection pump that injects fluid, a sealed pressure vessel having a predetermined volume that temporarily stores the fluid injected by the fluid injection pump, and a fluid in the sealed pressure vessel. In an injection amount measuring device comprising a pressure change measuring means for measuring a pressure change of the fluid injection pump and a measuring means for measuring an injection amount of fluid within one injection process from the output of the pressure change measuring means, the fluid injection pump is configured to inject the fluid multiple times in one injection process, and the pressure in the pressure vessel at each time the fluid is injected multiple times from the fluid injection pump. A pressure change measuring means for individually measuring changes and calculating the results, and means for discharging a fluid corresponding to the fluid injected into the closed pressure vessel by the fluid injection pump from the closed pressure vessel. is provided, and by measuring the volume of the fluid injected in one injection process, a fluid amount calculation that can measure the injection amount of each fluid injected multiple times in one injection process. An injection amount measuring device characterized by comprising means. 5. Claims 1 to 4, wherein the fluid is fuel.
The injection amount measuring device according to any one of the above. 6. Means for calculating the injection amount at each point in time of the fluid injected multiple times within one injection process from the calculation result by the fluid amount calculation means and the measurement result by the pressure change measurement means. 5. The injection amount measuring device according to claim 4, further comprising: an injection amount measuring device. 7. By proportionally distributing the amount of fluid injected within one injection process obtained by the fluid amount calculation means based on the pressure change at each injection time in one injection process, 5. The injection amount measuring device according to claim 4, further comprising means for measuring the injection amount of each fluid. 8. Arithmetic processing for calculating an average value from the pressure change of the fluid at each injection point and the amount of the injection fluid obtained in each injection process by repeating the injection process a plurality of times. The injection amount measuring device according to claim 4, further comprising arithmetic processing means for performing the following. 9. The injection amount measuring device according to any one of claims 1 to 8, wherein the fluid injections executed multiple times within one injection process are a pilot injection and a main injection. 10. A fluid injection pump capable of injecting fluid multiple times in one injection process, a closed pressure vessel having a fluid injection nozzle connected to the fluid injection pump, a fluid pressure detection means provided in the pressure vessel, An electromagnetic valve and a back pressure valve that are connected to the pressure vessel to drain the fluid in the pressure vessel and maintain the back pressure in the pressure vessel at a predetermined pressure; an encoder that detects the driving state of the fluid injection pump; An injection amount measuring device comprising an encoder and a calculating means for measuring pressure changes in the pressure vessel in response to information from the fluid pressure detecting means and storing the results. 11. The injection amount measuring device according to claim 10, wherein the back pressure valve is connected to the fluid volume measuring means via a fluid direction switching valve. 12. The computing means further includes computing means for measuring the volume of fluid discharged from the pressure vessel in response to information from the volume measuring means and information from the encoder and storing the result. The injection amount measuring device according to claim 11, characterized in that: 13. The injection amount measuring device according to any one of claims 10 to 12, wherein the solenoid valve is controlled by the calculation means.