JP2831359B2 - Injector operation circuit - Google Patents

Abstract

The circuit comprises: - an input (1) for connection to a low-tension supply (VS), - a storage coil (L1) for storing energy delivered by the supply (VB), and - electronic switching devices (SW1, SW2, SWi) for controlling the connection between the input (1), the storage coil (L1) and each of the loads (Li) in a predetermined manner to achieve a rapid transfer of current to each of the loads selectively, - a capacitor (C) situated in parallel with the branch circuits containing the loads (L1) and connected to the coil (L1) and the electronic switching devices (SW1, SW2, SWi), and - an electronic control unit (ECU) for piloting the electronic switching devices (SW1, SW2, SWi) according to a first operative mode in which, to transfer current to one of the loads (Li), the switching devices cause in succession, after the connection of the storage coil (L1) to the supply (VB): the connection of the storage coil (L1) to the capacitor (C) so as to form a resonant circuit, and then the discharge of the resonant circuit (L1, C) into the load (Li).

Description

Description: TECHNICAL FIELD The present invention relates to an injector operation circuit, and more particularly to an operation circuit applicable to operation of an electric injector of a diesel-cycle internal combustion engine.

More specifically, the present invention provides an input unit for connecting a low-voltage power supply, a storage coil for storing energy supplied from the low-voltage power supply, and a connection between the input unit, the storage coil, and each load in a predetermined manner. The present invention relates to an injector operation circuit constituted by electronic switch means for controlling connection and allowing current to flow rapidly into each load selectively.

TECHNICAL BACKGROUND A circuit of the above type is described in Italian Patent Application No. 67953-A / 85. This known circuit has a plurality of branch circuits, each branch circuit having a capacitor connected in parallel with the inductive load and forming a resonant circuit with the load. The rapid transfer of current to these loads is effected by first storing the energy supplied from the power supply in a storage coil and then connecting the storage coil to a resonant circuit containing the load to be activated.

Solenoids operating electric injectors for diesel engines are represented by non-linear inductive loads with relatively small inductance. Therefore, according to the conventional circuit described above, each load has high quality and high capacity in parallel,
Therefore, only large and expensive capacitors can be used to transfer sufficient energy to such loads.

SUMMARY OF THE INVENTION The object of the present invention is to provide an injector operating circuit of the type described above, in which a load which is sometimes selected without the need for a plurality of large and expensive capacitors. An object of the present invention is to provide an injector operation circuit capable of quickly supplying a large amount of energy.

This object is achieved by means of a circuit of the type described above. A storage coil and first reverse current blocking means connected in series to the battery via a first electronic switch; and a circuit connected in parallel to the storage coil via second reverse current blocking means. A plurality of branch circuits each comprising an inductive load of an electric injector and electronically operated switch means combined with the inductive load; a second branch circuit connected between the storage coil and the second reverse current blocking means. An electronic switch, connected in parallel with the plurality of branch circuits, and, when activated, cooperating with the storage coil to form a resonant circuit;
A capacitor for detecting an amount of current supplied from the battery; and sequentially selecting an inductive load to be operated in accordance with a predetermined operation order, and based on a current detection signal input from the sensor. The output state of the battery is determined, and in the first operation mode in which the current detection signal from the sensor means exceeds a predetermined reference value, the load operation electronic switch combined with the selected load, the first electronic switch, and the By sequentially controlling the opening and closing of the second electronic switch, the charge is stored in the capacitor from the battery via the storage coil with a voltage higher than the output voltage of the battery, and the charge stored in the capacitor is selected. And discharges the selected electric injector to the load with a predetermined current pattern. On the other hand, in the second operation mode in which the current detection signal is lower than the reference value, the first electronic switch and the second electronic switch are turned on and off before discharging the charge stored in the capacitor to the selected load. The electronic control unit is configured to accumulate electric charges with substantially the same voltage as in the first operation mode from the battery to the capacitor via the storage coil by opening and closing the battery. Features.

In the injector operation circuit of the present invention, similarly to the conventionally known one, a capacitor is connected in parallel with each load, and when the operation of the load is stopped, the current quickly disappears. In the conventional injector operation circuit, the capacitor is similar to a capacitor having a large capacity for transferring a current to a load. In the injector operation circuit of the present invention, any capacitors connected in parallel with each load have a smaller capacity than the above-mentioned capacitors which transfer current to a load which is sometimes selected.

When the injector operating circuit of the present invention is used for operating each injector in a diesel engine, a battery of an automobile is typically used. This type of battery often cannot provide a sufficiently large current to the operating circuit so that each electric injector can be operated. This may occur, for example, when the battery is not sufficiently charged or when the impedance "sensitized" by the battery is abnormally high for various reasons. In such a case, the operation of each electric injector cannot be performed in the above-described conventional operation circuit.

The injector operation circuit of the present invention can reliably and appropriately operate each electric injector even when the battery of the vehicle cannot supply a sufficiently high current.

Further, other features and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, which illustrate, by way of example, but not by way of limitation.

(Embodiment) In FIG. 1, the operating circuit for a plurality of inductive loads according to the present invention, when used, is a low-voltage DC power supply, for example, a battery.
Comprising an input terminal 1 which is connected to the V _B. The inductive load _Li is typically a solenoid for operating an electric injector, in particular of an automotive diesel internal combustion engine. In this case, low-voltage DC power supply V _B is a car battery.

The storage coil L1 is connected to the input terminal 1 via an electronic control switch (also referred to as a first electronic switch) SW1 that is opened during a stop. In the figure, the first electronic switch SW1 is shown as a circuit breaker, and a diode D is connected in parallel with the switch SW1.
1 is connected. This switch SW1 is, for example, an integrated MOSFET
It is configured using a shape transistor. In this case, the diode D1 can be constituted by a parasitic diode of a MOSFET transistor.

The anode of a diode R1 (also referred to as first reverse current blocking means) is connected between the storage coil L1 and the first electronic switch SW1, and the cathode of the diode R1 is grounded.

Another electronic control switch (also referred to as a second electronic switch) SW2 similar to the first electronic switch SW1 is connected between the storage coil L1 and the ground in the same manner as described above.

The storage coil L1 is connected to one terminal of the capacitor C via a diode R2 (also referred to as second reverse current blocking means), and the other terminal of the capacitor C is grounded. A plurality of branch circuits are connected in parallel with the capacitor C. Each branch circuit (also referred to as a load operation electronic switch) electronic control switch connected in series to the inductive load L _i and the load L _i is a solenoid of the electrical injector is formed by a SW _i. Load operation electronic switch SW in these branch circuits
_i is the first electronic switch SW1 and the second electronic switch described above.
An electronic control switch of the same type as SW2. Each inductive load L _i and capacitor C _i is connected in parallel, quenching operation is not being load L _i, i.e., so as to disappear quickly current in the load L _i which is operating.

Switches combined for each load _Li and each load
Between the W _i, respectively, are connected to the anode of a diode D _c, the cathode between ground and a connection point N that is connected to the common of these diodes D _c, comprising a resistor R _c and a capacitor C _c connected in parallel An RC parallel circuit is connected. These diodes D _c form an OR-type circuit.

Between the connection point N and the input terminal 1, the electronic control switch SW
1, SW2, SW _i and similar electronic control switch SW3 is connected.

Electronic controller ECU manufactured by a known method, for example,
It comprises a microprocessor and an input / output interface circuit. This electronic controller ECU has a plurality of input terminals.
Plus electrode of the V _B, and is connected to a sensor S for outputting a signal indicative of the current flowing through the storage coil L1 during operation. The sensor S can be configured using, for example, a Hall effect sensor. In addition, the sensor S may be configured to detect the current flowing through the storage coil L1 by connecting the non-ground terminal of the capacitor C to the electronic controller ECU, in addition to the sensor shown in this embodiment. At a given stage, the voltage established across the terminals of the capacitor C is related to the magnitude of the current flowing through the storage coil L1.

Another method of detecting the current flowing through the storage coil L1 can be performed, for example, by connecting a shunt resistor in series with the storage coil L1 and by connecting the current to the electronic controller ECU.

Electronic controller ECU includes a plurality of output terminals, they output terminal connected to the control input terminal of the switch SW1, SW2, SW3 and SW _i.

Further, in order to operate each electric injector of the diesel engine, an electric input signal such as a rotation speed of the engine may be input to the electronic controller ECU.

Before describing the operation of the circuit shown in FIG. 1, an ideal current pattern to be supplied to a solenoid for operating an electric injector of a diesel engine will be described below.

The ideal diagram of the current pattern is a function of time t, as shown in FIG. The ideal curve shown is
A rising slope portion a, stage is substantially constant high-current I _max Following the inclined portion a b, the transient phase c to change toward a substantially constant level I _H Following the said step b . This current period indicated a portion d, is held in the level I _H, then with a step f of current "turn-off" step e and the current is extinguished and reliably reversed.

In order to optimally and accurately control the operation of the injector, the operating time of each injector must be accurately controlled. To achieve this, the rise time of the current flowing through the solenoid of each injector and the subsequent current fall time must be very short and at least an order of magnitude shorter than the minimum injection time.

Figure 1, with reference to FIGS. 3 and 4, illustrating how the circuit of the present invention Upon operating each load L _i, how does a steep rise of the current in the load L _i I do.

Figure 3 is a switch SW1, SW2 and state of the load L _i combined with the switch SW _i to be added electrical energy, the current I _L1 in the storage coil L1, a capacitor C between terminals voltage V _c and the load L _i of 5 shows the locus of the current I _Li at.

For circulating current to the load L _i, the electronic controller ECU
Sets all other switches as well as switches SW1 and SW2 is closed at time t _o opened. Under this condition, as shown in FIG. 3, a gradually increasing current flows through the storage coil L1.

At the next time point t _1, while being the switches SW1 and SW2 are opened, the switch SW _i which was combined with the load L _i to be added energy is closed. In this state, storage inductor, i.e., while the storage coil L1 is cut off from the DC power supply V _B, is connected to the capacitor C to form a resonant circuit with the coil L1. A current is discharged to the load L _i from the LC resonance circuit in combination with a switch SW _i which is closed. As shown, the current I _L1 attenuates and the capacitor C
Electrode terminal voltage rises, then decreases, becomes zero at time t _2. Therefore, the current I _Li in the selected load L _i, increases from the time t ₁ to time t ₂ to reach the maximum value, then, as shown in Figure 3, it starts to decay. Electronic controller ECU is time t ₂ later, by the switch SW1 intermittently opening and closed, the time b to maintain the current in the load L _i to a high level is stretched. In this manner, "chopping" of the current I _Li is performed as shown by the broken line in FIG.

DC power supply V _B is output if a sufficiently large current,
Can be accumulated in the storage coil L1 charges and through the discharge of the resonant circuits L1-C forwards quickly energy to the inductive load L _i from the DC power supply V _B.

According to the present invention, in the electronic controller ECU, the DC power supply V
_The current supplied from _B can be detected. This is because a signal input from the sensor S is detected, or when the switches SW1 and SW2 are opened, the voltage between the terminals of the capacitor C is read, or when a shunt resistance is connected in series with the storage coil L1. This is done by reading the voltage drop. When below the reference value supply current is predetermined from the DC power supply V _B, the electronic controller ECU, by reading the output voltage of the DC power supply V _B, the feeding capacity of the current supply shortage DC power supply V _B whether based on the low, or, to determine whether based on abnormalities in the circuit connected to the direct current power source V _B, further, it may generate a signal for diagnosis.

Anyway, the electronic controller ECU, when the current supplied from the DC power supply V _B is detected to be below a predetermined reference value, the transfer of current to the load L _i which is sequentially selected,
Execute the second operation mode. In this second mode of operation, as will be explained with reference to FIGS. 1 and 4, the electronic control unit ECU switches the electronic control switch at times t ₀ , t ₂ and t ₄ shown in FIG. SW1 and SW2 are simultaneously closed intermittently. On the other hand, the switch SW3 and the switch SW _i is held in an open state.

Each time the switches SW1 and SW2 are closed, the storage coil L1
The current at the point where both switches SW1 and SW2 are at times t ₁ , t ₃ and
to increase as open in t _5. Each time the switches SW1 and SW2 are opened, the voltage between the terminals of the capacitor C increases.
When charging the storage coil L1, the diode R2 prevents the discharge of the capacitor C. The diode D2 is connected to the capacitor C
At the time of discharge of the switch SW2.

The voltage between the terminals of the capacitor C is, as shown in FIG.
Higher than the output voltage of the DC power supply V _B, stepwise increases until it reaches a sufficient voltage V _s to be rapidly circulated large current to the selected load L _i. Release to the load of the current, as shown in FIG. 4 is started at time t _6.
At this point t _6, it is the combined with the selected load L _i load operation the electronic switch SW _i Nomiga閉, all other switches are open.

As described with reference to FIG. 3, the circuit shown in FIG. 1 is preferably operable in a first mode of operation, as it is more advantageous in terms of energy. However, the first operation mode, the output of the power supply V _B, that is, only the current supply amount is performed only if sufficiently large. On the other hand, in the circuit of the present invention is not necessarily intended current supply amount is sufficient power V _B, as described with reference to FIG. 4, the first electronic switch SW1 and the second electronic switch SW2, at the same time, by intermittently opened and closed, the capacitor C from the power source V _B through the storage coil L1, the voltage between the terminals of the predetermined voltage V _s
By accumulating the electric charge until the load C is _reached , the stored electric charge is quickly discharged from the capacitor C to the load Li to be operated, so that the selected load L as in the first operation mode described above. _The required current can flow into the solenoid of the electric injector _i . Obviously, it takes time in the charge capacitor C, the time required for charging of the capacitor C is dependent on the strength of the current discharged from the power supply V _B. The electronic controller ECU is the fourth
As shown, it is programmed to start the charging of the capacitor C flows a current to the selected load prior to the time t ₆ to be triggered.

In practice, the input in the circuit of FIG. 1, by sequentially operating the load operation electronic switch SW _i associated with the electronic controller ECU, an electric current to each load L _i to try to sequentially operate in a predetermined order Requires a single large-capacity capacitor C.

To perform the forced commutation in the load L _i, each capacitor
A relatively small capacity of C _i is sufficient.

In the circuit of FIG. 1, and quickly by flowing current to the solenoid L _i of the inductive load, as shown in FIG. 2, two procedures for implementing a and b partially in an ideal curve is described Was. Supplying current to the load L _i, by the switch SW _i which is combined with the control switch SW1 or the load L _i is opened, the desired retention level corresponding to d part of the ideal curve shown in Figure 2 Can be maintained. Next, in order to eliminate the current I _Li in the second stage, is a switch SW _i is opened in combination with the load L _i. Applied voltage on the load L _i in this state becomes the high level in a short time. A clamp circuit is provided to limit this voltage value. The clamp circuit includes a capacitor C _c, may be connected a resistor R _c in parallel with the capacitor C _c. Are connected via a respective diode D _c for all load L _i, the diodes D _c is to form an OR circuit.

The clamp circuit returns the reactive power supplied to the load L _i to be selectively energized in cooperation with the switch SW3 to partially supply V _B, the recovery of energy released from the power supply V _B in this way Is performed. Recovery of electrical energy, as described below, after switching on the current to the load L _i by closing the switch SW _i which corresponds to the selected load L _i, each of the switches SW _i opened Done. This is done in principle in three states. That is, from these states, the load L when the current in the _i is changed from the maximum level to the holding level as in part c of the ideal curve of Figure 2, part of the ideal curve of the current in the load Figure 2 e, and when a "chopping" operation is performed in which the current in the load is for a short period of time but chopped, for example, as described with reference to FIG.

Figure 5 shows the current I _Li in one load L _i, the inter-terminal voltage V _c of the capacitor C _c of the clamp circuit, the corresponding state of the switch SW _i and the switch SW3 in combination with the load L _i. Electronic controller ECU at time t ₀ in FIG. 5
While the switch SW _i is opened energy is combined with the load L _i which is added together with the switch SW3 is closed, thus the current I _Li decays in accordance with a command from,
Inter-terminal voltage of the capacitor C _c of the clamp circuit is increased.
Current I _Li in the load L _i reaches the level I _H at time t ₁ (in this state can be detected by the electronic control unit ECU via another Hall effect sensor in combination with the load L _i) the electronic control unit ECU to the switch SW3 and opens with the closed switch SW _i which has been opened again. In this state, the capacitor C _c of the clamp circuit
Is maintained at the previously charged charging voltage.

Then, the electronic controller ECU at time t ₂ is a switch SW _i is opened, the current in the load is quickly attenuated. At this time, the inter-terminal voltage V _c of the capacitor C _c of the clamp circuit, the switch SW3 electronic controller ECU is at time t ₃ as shown in FIG. 5 rises to the closed, then the voltage V _c is quickly descend.

In the step of the current in the load L _i which energy is applied to decay, reactive power stored in the load by closing the switch SW3 is returned to the DC power source V _B by concomitant operation of the clamp circuit. This property is very advantageous for the application of the circuit according to the invention in the field of motor vehicles, in particular of vehicles with batteries and / or relatively low-power recharging lines.

As long as the circuit of the present invention does not perform the recovery of reactive power, resistance R _c is only necessary to extinguish the energy stored in capacitor C _c. In this case, instead of the resistor R _c, each resistor in each diode D _c may be connected in parallel.

Further, the circuit of the present invention is applied to, for example, control of each relay for scanning a perforated card or tape in a jacquard type loom, control of an electric injector of an Otto cycle engine, control of a print head of a matrix printer, and the like. Can be done.

It goes without saying that the embodiments described above merely by way of non-limiting example can be modified in a wide range without departing from the scope of the present invention, while preserving the principle of the present invention.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram of the present invention, FIG. 2 is a graph showing an ideal exciting current pattern of a solenoid for operating an electric injector of a diesel engine, and FIGS. 3 is a graph showing the state of each component of the circuit and the various signals generated in the circuit under different operating conditions. 1 ...... input terminal, SW1 ...... electronic control switch (first electronic switch), SW2 ...... electronic control switch (second electronic switch), SW3 ...... (for energy recovery) electronic control switch, SW _i ...... inducible Load operation electronic switch corresponding to load (electric injector), D ₁ , D ₂ , D ₃ , D _i ... Diode, R 1... Diode (first reverse current blocking means), R 2.
Diode (second reverse current blocking means), L1 ...... storage coil (inductor), L _i ...... inductive load (electrical injector), C ...... capacitor, C _i ...... forced commutation capacitor, S ...... sensor, ECU ...... electronic controller, D _c ...... clamp circuit diode, C _c ...... clamp circuit of a capacitor, V _B ...... low voltage DC power source (battery)

Continuation of the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H02M 3/00-3/44 F02D 41/00-41/40 H03K 17/00-17/70

Claims (9)

(57) [Claims] 1. An injector operating circuit for operating an inductive load of a plurality of electric injectors in a diesel internal combustion engine, comprising: a battery (V _B ); a battery (V _B ) connected via a first electronic switch (SW1). A storage coil (L1) and first reverse current blocking means (R1) connected in series with each other; connected in parallel to the storage coil (L1) via second reverse current blocking means (R2); consisting inductive load of the injector and (L _i) said inductive load (L _i) in combination with an electronic operating switch means (SW _i), a plurality of branch circuits (L _i, SW _i); the storage coil (L1 ) And said second reverse current blocking means (R2)
A second electronic switch (SW2) connected in parallel with the plurality of branch circuits (L _i , SW _i ), and in operation, cooperates with the storage coil (L _i ) to operate a resonance circuit. A sensor (S) for detecting the amount of current supplied from the battery (V _B ); and an inductive load (S) to be operated according to a predetermined operation sequence. L _i ) are sequentially selected, and the output state of the battery (V _B ) is determined based on the current detection signal input from the sensor means (S), and the current detection signal from the sensor means (S) is determined in advance. and the first operation mode exceeds the reference value, the selected load (L _i) and the combined load operation the electronic switch (SW _i), the first electronic switch (SW1) and the second electronic switch (SW2) By controlling the opening and closing sequentially , After charges are accumulated with a output voltage higher (V _s) of the battery (V _B) the above capacitor (C) through the storage coil (L1) from the battery (V _B), the capacitor (C ) Is discharged to the selected load (L _i ) with a predetermined current pattern to operate the selected electric injector, while in the second operation mode in which the current detection signal is lower than the reference value. By intermittently opening and closing the first electronic switch (SW1) and the second electronic switch (SW2) before discharging the electric charge stored in the capacitor (C) to the selected load (L _i ). , The capacitor (C) from the battery (V _B ) via the storage coil (L1).
In addition, the injector operation circuit is constituted by an electronic controller (ECU) configured to accumulate electric charges with substantially the same voltage (V _s ) as in the first operation mode. 2. A further, parallel to each load (L _i), a capacitor (C) connects the forced commutation capacitor having a smaller capacitance (C _i), during operation, the corresponding load (L _i) 2. The circuit according to claim 1, wherein the current in the circuit is quickly extinguished. 3. The circuit according to claim 1, wherein the sensor means (S) comprises a shunt resistor connected in series with the storage coil (L1). 4. The circuit according to claim 1, wherein the sensor means (S) is a current-measuring sensor, in particular a Hall-effect sensor. 5. The sensor according to claim 1, wherein the sensor means (S) detects a voltage between terminals of the capacitor (C).
Circuit. 6. A clamp circuit means is connected to the branch circuit (L _i , SW _i ), and the clamp circuit means passes through a load operation electronic switch (SW _i ) associated with each load (L _i ). 6. The method according to claim 1, wherein when a current flowing into the selected load (L _i ) is cut off, a voltage generated in the load (L _i ) is limited to quickly disappear. Circuit. 7. A clamp circuit means for connecting an RC parallel circuit comprising a resistor (R _c ) connected in parallel to a capacitor (C _c ) to a load (L _i ) in each branch circuit (L _i , SW _i ). 7. The circuit according to claim 6, wherein the circuit is configured to be commonly connected to a connection point (N) between the load operation electronic switch (SW _i ) and the load operation electronic switch (D _c ). 8. An energy regenerating circuit means controlled by an electronic controller (ECU), wherein the power supply from the capacitor (C) to the selected load (L _i ) is stopped by the energy regenerating circuit means. A part of the reactive power stored in the load (L _i ) is returned to the battery (V _B ) every time.
The circuit according to claim 1. 9. The method according to claim 8, wherein the energy regenerating circuit means is a battery (V _B )
And clamping circuit means (C _c, D _c) is controlled by an electronic control unit (ECU) is connected between, including electronic control switch (SW3), the circuit according to claim 7 or claim 8.