JPH0152571B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a device for measuring the amount of fuel to be supplied, which has a measuring mechanism that generates an electric signal, and this electric signal is generated by a piezoelectric effect in the measuring mechanism. Ru,
The present invention relates to a fuel injection device for an internal combustion engine.

[Conventional technology]

A flow rate measuring device using piezoelectric effect is well known (Japanese Patent Application Laid-open No. 147864/1983), in which an orifice plate with a flange is provided in the middle of the pipe, and a concave plate diametrically opposed and extending from the flange to near the orifice is installed. A piezoelectric element is inserted into each of the holes, and is integrated with the orifice plate using a sealing body such as a glass plate.

Such a device requires two piezoelectric elements, which must be housed in special orifice plate recesses and constructed integrally with the orifice plate, and is relatively complex and expensive in construction.

[Problem to be solved by the invention]

An object of the invention is to provide a device of simple and inexpensive construction.

[Means to solve the problem]

In order to solve this problem, according to the present invention, the measuring mechanism is a quartz compression orifice plate, metal electrodes are provided on both end faces of the quartz compression orifice plate which receives a differential pressure, and the electric current generated in the quartz compression orifice plate is provided. Signals are fed via these metal electrodes to an electronic control unit in which a comparison between the actual value and the setpoint value takes place and a correction signal is generated which correctly determines the fuel quantity.

〔Effect of the invention〕

Thus, according to the present invention, the measuring mechanism is one quartz compression orifice plate, that is, the piezoelectric element itself is also the orifice plate at the same time, so the structure is simpler and cheaper than the conventional one. Further, since metal electrodes are provided on both end faces of the quartz compression orifice plate, it becomes possible to measure the differential pressure and therefore the fuel flow rate with one quartz compression orifice plate. Moreover, the electronic control unit allows the necessary amount of fuel to be metered out precisely on demand, based on the measurement results.

〔Example〕

Embodiments of the invention are described below with reference to the drawings.

The pump plunger of the fuel injection device, designated 10 in FIG. 1, is guided in a leak-tight manner in the cylinder 11. This pump plunger 10 sucks fuel from an inflow line 12 and supplies it to a line 13 leading to an injection nozzle (not shown). A measuring mechanism 14 is provided in the inlet line 12 to measure the amount of fuel supplied to the injection nozzle. The fuel injection device can preferably be constructed as a pump nozzle in the cylinder head of the internal combustion engine.

The measuring mechanism 14 consists of a disk-shaped single crystal quartz plate piece 15 having a cylindrical orifice hole, ie, aperture hole 16 in the center.
made of. This crystal plate piece 15 is connected to the inflow pipe 1
It is provided in a cylindrical case 18 inserted into the cylindrical case 2. Both end faces 19, 20 are sealed against the outside by sealing rings 21, 22 provided at their outer edges to prevent fuel from flowing around the outer edges of the quartz plate. The central restrictor hole 16 acts like a standard orifice plate to detect the amount of liquid flowing within the conduit. The throttle hole 16 has the same diameter over its entire length since it is used as an orifice plate for short-term forward and reverse flow.

Metal electrodes 23 and 24 are deposited on each end surface 19 and 20 of the crystal plate piece 15. As shown in FIG. Fuel throttle hole 16
The pressure difference created as it flows through the quartz plate exerts different pressures on the opposite end faces of the quartz plate. The resulting piezoelectric effect causes charges to move through the single crystal, creating a small voltage of less than about 1 V at the metal electrodes.
This voltage is supplied to a charge amplifier 26 via an insulated and sealed lead-out and is amplified. This charge amplifier is resettable, thereby allowing a zero state setting when there is no flow. The voltage developed at the output of charge amplifier 26 is proportional to the square of the fuel flow rate. An electric square root system 27 is connected after the charge amplifier 26 in order to obtain a voltage proportional to the flow rate. If the voltage is negative, ie if fuel flows backward during the feed stroke, the flattening device 27 also supplies a corresponding negative voltage.

The amount of fuel injected as a whole during the forward and backward strokes of the plunger 10 is obtained by integrating the voltage supplied by the open flat device 27 over time. This step is performed in electronic integrator 28 according to the following equation.

The output voltage of integrator 28 is a measure of the amount of fuel flowing through the quartz plate. After comparison with the setpoint value in the electric comparator 29 and the start of any necessary readjustment process of the injection quantity, the integrator 28 must be reset to zero. This provides initial conditions for measuring the fuel quantity for the next injection process.

Since the crystal plate 15 is mounted together with the pump nozzle on the cylinder head of the internal combustion engine, it is subjected to acceleration. If an acceleration component occurs in the flow direction of the quartz plate 5, the now occurring acceleration force supplies a disturbance voltage to the measuring electrodes 23, 24. In order to avoid the influence of this disturbance and improve the accuracy of the crystal compression orifice plate, a similarly formed crystal piece 30 (compensation crystal) is provided in the immediate vicinity of the measurement mechanism 14 so that it receives the same acceleration. This crystal piece 30 is provided in a cylindrical case 31 together with the measuring mechanism 14, and is tightened by rubber rings 32 and 33, but has a relatively large center hole 34 instead of an orifice. A metal electrode 3 is provided on the lower end surface 35 of this crystal piece 30.
6 is vapor-deposited and connected to the metal electrode 23 of the crystal plate piece 15. A metal electrode 38 is also provided on the upper end surface 37 of the compensation crystal 30 and, like the metal electrode 24 of the crystal plate piece 15, leads to the charge amplifier 26.

If both crystal blanks 15 and 30 have the same mass, the disturbance acceleration voltage is compensated for by the series connection described above. The use of parallel connections also allows compensation by charge balance, with matching polarity connections.

As shown in FIG. 3, the quartz compression orifice plate 1
5, 16 in the injection line 13 immediately before the injection nozzle 40 of conventional construction.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of an injection device according to the present invention;
FIG. 2 is a block diagram of a modification of the measuring mechanism, and FIG. 3 is a block diagram of a modification of the embodiment shown in FIG. 10...Pump plunger, 11...Cylinder, 1
2...Inflow pipe line, 13...Injection pipe line, 14...Measuring mechanism, 15...Crystal plate piece, 16...Orifice (diaphragm)
Hole, 23, 24... Electrode, 26... Charge amplifier, 27
...square root device, 28...integrator, 29...comparator, 40
...Injection nozzle.

Claims (1)

[Claims] 1. In the case where the device for measuring the amount of fuel to be supplied has a measuring mechanism that generates an electric signal, and this electric signal is generated by a piezoelectric effect in the measuring mechanism, the measuring mechanism 14 is a crystal compression orifice. Plate 15,
16, and metal electrodes 2 are provided on both end surfaces 19 and 20 of the crystal compression orifice plates 15 and 16 that receive differential pressure.
3 and 24 are provided, and the quartz compression orifice plate 1
The electrical signals generated at 5 and 16 are fed through these metal electrodes to an electronic control unit, where a comparison is made between the actual value and the rotational value, and a correction signal is generated to correctly determine the fuel quantity. A fuel injection device for an internal combustion engine, characterized in that: 2. Device according to claim 1, characterized in that the quartz compression orifice plate consists of a single crystal plate piece 15 with orifice holes 16 of the same diameter over its entire length. 3. The voltage signal is fed to a charge amplifier 26, from this to a subsequently connected square root device 27, then to an integrator 28 and finally to a comparator 29, which compares the setpoint value with the actual value. 27. Device according to claim 1, characterized in that the integrator 28 and the comparator 29 form an electronic control unit. 4. The device according to claim 3, characterized in that the charge amplifier 26 and the integrator 28 are configured to be resettable. 5. Claim 2, characterized in that both end surfaces 19, 20 of the crystal plate piece 15 are prevented from fuel flowing around the outer edges by sealing rings 21, 22 at the outer edges. The equipment described in section. 6 Compensation crystal 30 with approximately the same mass as the measurement mechanism 14
is attached, and this compensation crystal 30 is attached, and metal electrodes 36 and 38 are similarly provided on the two end faces 35 and 37 of this compensation crystal 30, and the electrodes 36 adjacent to each other on the compensation crystal 30 and the crystal plate piece 15 are provided. , 23 are connected to each other, and the electrodes 24, which are far from each other,
3. Device according to claim 2, characterized in that 38 is connected to the charge amplifier 26. 7. Device according to claim 1, characterized in that a quartz compression orifice plate 15, 16 is provided in the injection line 13 before the injection nozzle 40 of an injection pump, in particular a distributor injection pump. . 8. Device according to claim 1, characterized in that quartz compression orifice plates 15, 16 are provided in the inlet line 12 to the high-pressure supply plunger 10 of the injection pump.