GB2377507A - Failure detection in coil circuits of fuel injection apparatus - Google Patents
Failure detection in coil circuits of fuel injection apparatus Download PDFInfo
- Publication number
- GB2377507A GB2377507A GB0200830A GB0200830A GB2377507A GB 2377507 A GB2377507 A GB 2377507A GB 0200830 A GB0200830 A GB 0200830A GB 0200830 A GB0200830 A GB 0200830A GB 2377507 A GB2377507 A GB 2377507A
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- Prior art keywords
- circuit
- voltage
- electromagnetic coil
- fuel injection
- microprocessor
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Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/22—Safety or indicating devices for abnormal conditions
- F02D41/221—Safety or indicating devices for abnormal conditions relating to the failure of actuators or electrically driven elements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/20—Output circuits, e.g. for controlling currents in command coils
- F02D2041/2086—Output circuits, e.g. for controlling currents in command coils with means for detecting circuit failures
- F02D2041/2093—Output circuits, e.g. for controlling currents in command coils with means for detecting circuit failures detecting short circuits
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/40—Engine management systems
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
- Fuel-Injection Apparatus (AREA)
Abstract
The circuit detects an abnormality (short or open circuit) in a single injector coil circuit, or a short circuit between the circuits of different injector coils in a multicylinder engine. Common ON/OFF elements 11 (TR13), 21 (TR42) feed drive voltage 3 to a group of cylinders 5, 8 or 6,7. Individual ON/OFF elements 13 (TR1), 14 (TR3), 23 (TR4), 24 (TR2), select the individual cylinders in the correct sequence. Off-surge detection circuits 35, 36 detect when the off-surge voltage Vs, created when the current through a valve coil is broken, exceeds a predetermined level. Failure, and the type of failure is determined from the absence or duplication of the off-surge signals. Low current hold circuits 19, 29 feed a reduced current holding signal to the coils after an initial high current actuates the coils.
Description
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FAILURE DETECTION CIRCUIT OF A FUEL INJECTION APPARATUS
BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a failure detection circuit of a fuel injection apparatus with respect to a multi-cylinder engine on a vehicle, and the like, and particularly, to a failure detection circuit of an fuel injection apparatus for detecting a disconnection or a short circuit of an electromagnetic coil for driving a fuel injecting electromagnetic valve, the disconnection or the short circuit of a driving element of the electromagnetic coil, the disconnection or the short circuit of a wiring line of the electromagnetic coil, or the like in order to alarm and display an abnormality to execute an escaping operation.
2. Description of the Related Art
Both a steep overexcitation control and an operation holding control by low-current are normally used for control of the electromagnetic coil for driving the fuel injecting electromagnetic valve, whereby responsiveness of the electromagnetic valve is improved and the temperature rise of the electromagnetic valve is suppressed. In the conventional method, the disconnection or the short circuit trouble of the electromagnetic coil, the wiring line, an ON/OFF element and the like is detected by monitoring voltage or current of each portion of the electromagnetic coil drive circuits. Further, there is a well-known concept simplifying a
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signal process by implementing OR gate combination of a failure detection signal with respect to multi-channel load.
Japanese Patent Application Laid-open No. Hei 10-257799 "Output open detection apparatus of a multi-channel output apparatus" discloses such a concept that, a load circuit is disconnected by supplying micro-current to load at the load non-driving time with respect to multi-channel load such as an exciting coil of a stepping motor, both ends voltage of load increases, and a disconnection is detected by this increase.
Though there is no reference to a detection of short-circuit of load in this official gazette, it shows such a concept that a disconnection detection signal is supplied to a common comparison judgment circuit by a diode OR circuit.
Contrary to this, according to Japanese Patent Application Laid-open No. Sho 62-290111"Failure detection circuit of a fuel injection valve drive circuit for an internal combustion engine", there is shown such a concept that a batch detection of the disconnection or the short circuit trouble of the electromagnetic coil, the wiring line, the ON/OFF element or the like is implemented by detecting an OFF-surge voltage arising at the time of breaking current-flowing of the fuel injection valve driving electromagnetic coil.
Further, according to Japanese Patent Application Laid-open No. Hei 9-112735"Electromagnetic valve drive apparatus", for
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example, relating to the driving electromagnetic coil of the fuel injection electromagnetic valve, there is shown such a concept that a steep driving booster circuit and an operation holding low-current circuit are provided and the disconnection, the short circuit or the like of a plurality of electromagnetic coils and the wiring line is detected by monitoring charged voltage and discharged voltage of a condenser in the booster circuit.
Another concept shown in this example, in particular, is described that a plurality of fuel injection valve driving electromagnetic coils are divided into some groups and the escaping operation is'smoothly executed based on a failure determination result.
Still further, according to Japanese Patent Application Laid-open No. Hei 10-318025"Control apparatus of fuel injecting injector", there is shown an ON/OFF control concept such that one ends of a plurality of injector coils having an interval of fuel injection sequence in two lines degree or more and not-including an overlap of current-flowing timing are connected with a common drive output circuit and the other ends of the injector coils are connected with a apparatus for changing ON/OFF separately at a current-flowing timing of each injector coil.
Japanese Patent Application No. Hei 12-380652"Abnormality detection apparatus of an electrical loading drive system on vehicle" describes such a method that an abnormality detection
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signal combined by an OR gate is separately detected in a microprocessor. This concept is used in the present invention.
In the conventional techniques described above, various types of the abnormality detection methods relating to the disconnection or the short circuit of t. he electrical load of the electromagnetic coil or the like, the disconnection or the short circuit of the ON/OFF control element of the electromagnetic coil, the disconnection or the short circuit of the wiring line of the electromagnetic coil, or the like are devised.
However, in either conventional techniques, there is a problem in that a failure detection circuit for systematically detecting an abnormality with respect to various kinds of supposed abnormality including an interphase short circuit of much electrical load and an earth is not constructed.
SUMMARY OF THE INVENTION
The present invention has been made to solve the abovedescribed problem and to provide a method including a countermeasure accompanying with a failure detection, and in particular, an object of the present invention is to provide a failure detection circuit of a simply-constructed fuel injection apparatus for detecting an abnormality of each phase or an abnormality of interphase short circuit in a drive circuit of a fuel injecting electromagnetic valve with respect to each cylinder of a multi-cylinder engine and
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conducting an escaping operation.
The failure detection circuit of the fuel injection apparatus according to the present invention is comprised of: a plurality of electromagnetic coils for driving a fuel injecting electromagnetic valve with respect to each cylinder of a multi-cylinder engine; a microprocessor for generating a pulse group of drive signals and a steep overexcitation control signal; a plurality of separated ON/OFF elements for driving the electromagnetic coils executing sequentially an ON/OFF operation, corresponding to the pulse group of drive signal generated by the microprocessor; a plurality of groups of common ON/OFF element for driving a batch feed into electromagnetic coils in the group composed of at least a plurality of electromagnetic coils having the interval of fuel injection sequence in two lines degree or more, corresponding to the steep overexcitation control signal generated by the microprocessor; and a plurality of OFF-surge detection circuits for detecting an OFF-surge voltage induced by opening the circuit of the separated ON/OFF element corresponding to the electromagnetic coil involved in at least a different group, and the microprocessor compares detection signals detected by the plural OFF-surge detection circuits to judge an abnormality based on whether a failure of the detection signal and a duplication of the detection signal are included.
Each of the OFF-surge detection circuits detects the OFF-
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surge voltage by detecting a higher voltage value of both ends of the separated ON/OFF element than that of a voltage source at the time of opening of the circuit of the separated ON/OFF element is opened.
Each of the OFF-surge detection circuits detects the OFFsurge voltage by detecting the higher voltage of a negative side terminal of the electromagnetic coil than that of a feeder terminal connected with the common ON/OFF element at the time of opening of the circuit of the separated ON/OFF element and the circuit of the common ON/OFF element are opened.
The common ON/OFF element includes an OR circuit for implementing an OR gate combination of detection signals output by the respective OFF-surge detection circuits with respect to the electromagnetic coil included in a different group.
The microprocessor judges an abnormality based on an output of the OR circuit.
The common ON/OFF element is operated corresponding to the steep overexcitation control signal generated by the microprocessor and a low-current holding control signal for holding the operation of the electromagnetic coil.
An overexciting booster circuit for boosting a power supply voltage is equipped. The common ON/OFF element is composed of: a high-voltage-side ON/OFF element for driving to feed into the electromagnetic coil through the overexciting booster circuit; and
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a low-voltage-side ON/OFF element for driving to feed into the electromagnetic coil, corresponding to the low-current holding control signal for holding the operation of the electromagnetic coil.
The high-voltage-side ON/OFF elements share the overexciting booster circuit, and the overexciting booster circuit is shared with respect to all of the electromagnetic coils.
In the case where the microprocessor judges an abnormality based on the detection signal detected by the OFF-surge detection circuit, apparatus for breaking a group current-flowing for breaking the corresponding common ON/OFF element and the separated ON/OFF element connected with the common ON/OFF element in series is provided, and the electromagnetic coil included in a group except for the group having the broken separated ON/OFF element executes an escaping operation.
When the microprocessor judges an abnormality based on a failure of the OFF-surge voltage, in the case where there is a duplication of a current-flowing period of the electromagnetic coil in tandem, a treatment for shortening a current-flowing period of the pulse group of the drive signal is implemented.
Apparatus for notifying an abnormality after receiving an abnormality signal is provided, and when the microprocessor judges an abnormality based on the detection signal detected by the OFF-surge detection circuit, the abnormality signal is output to
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the apparatus for notifying the abnormality.
The microprocessor is provided with a connecting interface circuit with an external tool.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
Fig. 1 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 2 is a partially detailed diagram showing the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 3 is a layout showing a cylinder of the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 4 is a timing chart for explaining a normal operation of the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 5 is a schematic block diagram showing an abnormality in phases in the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 6 is a timing chart explaining an occurrence of an abnormality of an earth in the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present
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invention;
Fig. 7 is a schematic block diagram explaining an occurrence of an abnormality of interphase short circuit in the failure detection circuit of the fuel injection apparatus relating to Embodiment 1 of the present invention;
Fig. 8 is a timing chart explaining an occurrence of an abnormality of a group-in interphase short circuit in the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 9 is a timing chart explaining an occurrence of an abnormality of a group-across interphase short circuit in the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 10 is a flowchart showing an operation in the failure detection circuit of the fuel injection apparatus according to Embodiment 1 of the present invention;
Fig. 11 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 2 of the present invention; and
Fig. 12 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 3 of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
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Embodiment 1
Fig. 1 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 1 of the present invention. The configuration of this circuit will be described below.
In Fig. 1, a fuel injection control apparatus 1 is mainly composed of a microprocessor 9, a first drive circuit 10, a second drive circuit 20 and the like, as described below. A power supply switch 2 connects a voltage source 3 such as a battery on a vehicle with the fuel injection control apparatus 1.
A sensor group 4 for deciding a timing of fuel injection, a fuel amount (fuel period) and the like is composed of a crank angle sensor, a cam angle sensor, a throttle position sensor and the like.
An input signal from the sensor group 4 is supplied to the microprocessor 9.
The first drive control circuit 10 and the second drive control circuit 20 control and drive a first electromagnetic coil 5, a second electromagnetic coil 6, a third electromagnetic coil 7 and a fourth electromagnetic coil 8. The electromagnetic coils 5 to 8 execute an ON/OFF control of a fuel injection valve equipped on each cylinder of an engine shown in Fig. 3 described below.
The configuration elements of the first drive control circuit 10 will be described. A common ON/OFF element 11 is a transistor or the like which is connected between one end of the first
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electromagnetic coil 5 and one end of the fourth electromagnetic coil 8, and the voltage source 3. A commutation diode 12 is connected between a load side of the common ON/OFF element 11 and a negative side terminal of the voltage source 3. A separated ON/OFF element 13 is connected with the other end of the first electromagnetic coil 5 and is a transistor or the like for closing a circuit corresponding to a separated drive signal SW1 output by the microprocessor 9. Similar to the separated ON/OFF element 13, a separated ON/OFF element 14 is connected with the other end of the fourth electromagnetic coil 8 and is a transistor or the like for closing a circuit corresponding to a separated drive signal SW3 output by the microprocessor 9.
A current sensing resistor 15 is connected between the separated ON/OFF element 13 and the separated ON/OFF element 14, and the negative side terminal of the voltage source 3. The separated ON/OFF elements 13 and 14 do not close the circuit at the same time. An OR gate element 16 brings the common ON/OFF element 11 into conduction, corresponding to a steep overexcitation control signal SW13 output by the microprocessor 9 and executes an ON/OFF control of the common ON/OFF element 11 by an output signal of an AND gate element 18 described below.
An OR gate element 17 outputs the separated drive signals SW1 and SW3 as input signals to the AND gate element 18. A low-current holding control circuit 19 is an ON/OFF control circuit for
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supplying low-current (low-current for holding operation) for holding the operation of the first (or the fourth) electromagnetic coil 5 (or 8). Therefore, when the voltage of both ends of the current sensing resistor 15 is lower than the predetermined voltage, the low-current holding control circuit 19 outputs a low-current holding control signal DT13 to bring the common ON/OFF element 11 into conduction through the AND gate element 18 and the OR gate element 16.
In the structural elements of the second drive control circuit 20,21-29 are equal to 11-19 described above. A SW4 indicates a signal equal to the SW1. A SW2 indicates a signal equal to the SW3.
An INJ2 indicates an electromagnetic coil equal to an INJ1. An INJ3 indicates an electromagnetic coil equal to an INJ4. Therefore, the description of these elements of the second drive control circuit 20 is omitted.
A diode 31 connect. s with an anode at a connection point of the first electromagnetic coil 5 and the separated ON/OFF element 13. A diode 32 connects with an anode at a connection point of the second electromagnetic coil 6 and a separated ON/OFF element 23.
Similarly, a diode 33 connects with an anode at a connection point of the third electromagnetic coil 7 and a separated ON/OFF element 24 and a diode 34 connects with an anode at a connection point of the fourth electromagnetic coil 8 and the separated ON/OFF element
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An OFF-surge detection circuit 35 includes a comparator circuit 35a. Partial resistances 35b and 35c divide the voltage supplied from a cathode of the diodes 31, 33. An OFF-surge detection circuit 36 includes a comparator circuit 36a (not shown). Partial resistances 36b and 36c (not shown) divide the voltage supplied from a cathode of the diodes 34,32.
When a partial voltage by the partial resistances 35b and 35c is higher than that of the voltage source 3, the comparator circuit 35a generates a detection signal IN13 of a logic level IlL" to supply the signal to the microprocessor 9. Similarly, when the partial voltage by the partial resistances 36b and 36c is higher than that of the voltage source 3, the comparator circuit 36a generates a detection signal IN42 of the logic level"L"to supply the signal to the microprocessor 9.
An external tool 40 writes a control program with respect to the microprocessor 9 and reads out and displays a content of data memory (not shown). An interface circuit 41 is equipped between the external tool 40 and the microprocessor 9. An abnormality alarm/display apparatus 42 is driven based on an abnormal signal and the like of the microprocessor 9.
Fig. 2 is a partially detailed diagram showing a feeder circuit with respect to the first electromagnetic coil 5 in Fig. 1. The construction of the feeder circuit will be described below.
In Fig. 2, a pull-down resistance 12a is connected with the
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commutation diode 12 in parallel. Constant voltage diodes 13a and 14a equally execute an OFF voltage restricted function of the separated ON/OFF elements 13,14. A low-current for holding operation Ih is the current flowing in the first electromagnetic coil 5.
When both the common ON/OFF element 11 and the separated ON/OFF element 13 open the circuit, an OFF-surge voltage Vs is generated. This OFF-surge voltage Vs is generated by a back electromotive force, which the first electromagnetic coil 5 generates for holding the low-current for holding operation Ih flowing so far. The OFF-surge voltage Vs is approximately equal to the restricted voltage of the equal constant voltage diode 13a.
However, this OFF-surge voltage Vs steeply drops accompanying with an attenuation of the low-current for holding operation Ih.
The pull-down resistance 12a determines the OFF-surge voltage Vs as Vs = 0.
When the circuit of the separated ON/OFF element 13 is closed due to the abnormality of the short circuit, or the like of the separated ON/OFF element 13 and the common ON/OFF element 11 breaks feeding, the steep break of the exciting coil is not executed owing to the construction of a commutation circuit composed by the commutation diode 12 and the separated ON/OFF element 13.
Therefore, the OFF-surge voltage Vs is not generated.
On the other hand, in course of opening the circuit of the
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separated ON/OFF element 13, when the separated ON/OFF element 14 is brought into conduction to electrically supply to the fourth electromagnetic coil 8, and the common ON/OFF element 11 is activated. A feeder voltage Vb of an output terminal portion of the common ON/OFF element 11 is generated as an output of the diode 31, and Vb appears as the apparent OFF-surge voltage Vs. However, the practical OFF-surge voltage Vs is higher than the feeder voltage Vb (Vb < Vs). Therefore, the above-described comparator circuit 35a is capable of executing a separate extraction of these voltages.
Fig. 3 is a layout showing a cylinder of the failure detection circuit of the fuel injection apparatus shown in Fig. 1. In Fig.
3, reference numeral 50 indicates a crankshaft of an engine.
Reference numerals 51 to 54 indicate first to fourth cylinders toward which fuel injection is conducted by the electromagnetic coils 5 to 8, respectively. When the separated ON/OF element 13 and the common ON/OF element 11 are operated to feed to the first electromagnetic coil 5 at a first time, the fuel injection towards the first cylinder 51 is executed. Next, when the separated ON/OF element 24 and a common ON/OF element 21 are operated to feed to the third electromagnetic coil 7 at a second time, the fuel injection towards the third cylinder 53 is executed. Further, when the separated ON/OF element 14 and the common ON/OF element 11 are operated to feed to the fourth electromagnetic coil 8 at a third time, the fuel injection towards the fourth cylinder 54 is executed.
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Still Further, when the separated ON/OF element 23 and the common ON/OF element 21 are operated to feed to the second electromagnetic coil 6 at a fourth time, the fuel injection towards the second cylinder 52 is executed.
In the above-described arrangement, when either the first cylinder 51 or the fourth cylinder 54 includes an abnormality in the fuel injection, both the cylinders 51 and 54 are stopped. Here, it is a stable countermeasure that the escaping operation is executed by only the second cylinder 52 and the third cylinder 53.
When either the second cylinder 52 or the third cylinder 53 includes an abnormality in the fuel injection, both the cylinders 52 and 53 are stopped. Here, it is a stable countermeasure that the escaping operation is executed by only the first cylinder 51 and the fourth cylinder 54. The common ON/OFF elements 11 and 21 in Fig. 1 are configured corresponding to this grouping.
The separated drive signals SW1-SW4 of the microprocessor 9 in Fig. 1 are numbered according to the sequence of the fuel injection.
Fig. 4 is a timing chart for explaining a normal operation of the failure detection circuit of the fuel injection apparatus according to Embodiment 1. In Fig. 4, (a) SW13 shows an output characteristic of the steep overexcitation control signal SW13 of the microprocessor 9, (b) DT13 shows an output characteristic of the low-current holding control signal DT13, (c) SWl shows an output
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characteristic of the separated drive signal SW1 of the microprocessor 9, (d) SW3 shows an output characteristic of the separated drive signal SW3 of the microprocessor 9, (e) SW42 shows an output characteristic of a steep overexcitation control signal SW42 of the microprocessor 9, (f) DT42 shows an output characteristic of a low-current holding control signal DT42, (g) SW4 shows an output characteristic of the separated drive signal SW4 of the microprocessor 9, and (h) SW2 shows an output characteristic of the separated drive signal SW2 of the microprocessor 9.
The separated drive signals SW1-SW4 sequentially execute the output. The steep overexcitation control signal SW13 generates a short-time output signal in accordance with an output timing of the separated drive signals SW1 and SW3. Similarly, the steep overexcitation control signal SW42 generates a short-time output signal in accordance with an output timing of the separated drive signals SW4 and SW2.
In Fig. 4, (i) INJl shows a current waveform of the first electromagnetic coil 5 and is obtained by composing (a) SW13, (b) DT13 and (c) SWl. Similarly, in Fig. 4, (j) INJ4 shows a current waveform of the fourth electromagnetic coil 8 and is obtained by composing (a) SW13, (b) DT13 and (d) SW13, in Fig. 4, (k) INJ2 shows a current waveform of the second electromagnetic coil 6 and is obtained by composing (e) SW42, (f) DT42 and (g) SW4, and in Fig4, (1) INJ3 shows a current waveform of the third electromagnetic coil 7 and is
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obtained by composing (e) SW12, (f) DT42 and (h) SW2.
In Fig. 4, (m) D31 shows an output waveform of the diode 31.
When the current into the first electromagnetic coil 5 in (i) INJ1 is broken, that is, when the output of the separated drive signal SW1 in (c) SWl is stopped (logic level"L"), the OFF-surge voltage Vs is generated, and when the current into the fourth electromagnetic coil 8 flows, the waveform of the feeder voltage Vb is generated based on the ON/OFF operation of the common ON/OFF element 11.
Similarly, in Fig. 4, (n) D34 shows an output waveform of the diode 34, (o) D32 shows an output waveform of the diode 32, and (p) D33 shows an output waveform of the diode 33.
In Fig. 4, (q) IN13 shows a waveform of the detection signal
IN13. In (q) IN13, when the diode 31 or the diode 33 output the OFF-surge voltage Vs, the logic level is in"L". Similarly, in Fig. 4, (r) IN42 shows a waveform of the detection signal IN42. In (q) IN13, when the diode 34 or the diode 32 output the OFF-surge voltage Vs, the logic level is in"L".
The failure detection executed by the failure detection circuit of the fuel injection control apparatus in Embodiment 1 will be specifically described. Fig. 5 is a schematic block diagram showing an abnormality in phases. An earth 60 shows a state that the negative side terminal of the first electromagnetic coil 5 connects with the negative side terminal of the voltage source 3.
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When such an earth is equipped, the current flowing in the electromagnetic coil 5 is not steeply broken. Therefore, the OFF-surge voltage Vs is not generated.
This phenomenon is similar to the case where the short circuit of the separated ON/OFF element 13 includes an abnormality. Even if the common ON/OFF element 11 breaks feeding, an exciting current circulates through the commutation diode 12 and the earth circuit 60 or the separated ON/OFF element including a short circuit.
Therefore, the OFF-surge voltage Vs is not generated.
A load short circuit 61 shows a state that a short circuit occurs between the positive and negative terminals of the fourth electromagnetic coil 8. When the load short circuit 61 occurs, the exciting current does not flow through the electromagnetic coil 8. Therefore, when the circuit of the separated ON/OFF element 14 is opened, the OFF-surge voltage Vs is not generated.
While a load short circuit occurs, the separated ON/OFF elements 13,14, 23, and 24 and the common ON/OFF elements 11,21 are being protected for a short period by an overcurrent protection function included in these elements. The above-described elements are protected so as not to be burnt out due to the cancellation of the drive instruction signal by the microprocessor 9.
Reference numerals 62 to 64 show disconnection circuits.
When a disconnection of the wiring line, a disconnection of the coil, an ON/OFF failure of the ON/OFF element or the like occurs,
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the exciting current does not flow into the electromagnetic coils 6,7. Therefore, when the circuit of the separated ON/OFF elements 23,24 is opened, the OFF-surge voltage Vs is not generated.
Fig. 6 is a timing chart for explaining an operation in the t case where the earth has an abnormality in Fig. 5. Here, the difference from the timing chart of the normal operation shown in Fig. 4 will be mainly described.
In Fig. 6, an abnormal current waveform 65 in (i) INJl shows a current waveform in which no low-current drive control for holding operation is executed because the exciting current into the first electromagnetic coil 5 does not flow into the current sensing resistor 15 (see Fig. 1) due to the earth 60. A duplication current waveform 66 is a current approximately equal to the fourth electromagnetic coil 8 of (j) INJ4 in Fig. 6, and shows the state that the normally not-flowed current is flowed into the first electromagnetic coil 5 having an earth because the common ON/OFF element 11 operates.
In Fig. 6, a failure surge voltage 67 in (m) D31 shows that the OFF-surge voltage Vs to be normally generated is not generated because the exciting current of the first electromagnetic coil 5 is not steeply broken due to the earth 60. In Fig6, a failure signal 68 in (q) IN13 shows the state that there is no detection signal to be normally generated due to the failure surge voltage 67.
As described above, when the OFF-surge voltage Vs includes
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the failure brought by various abnormality in phases and the failure is detected, the common ON/OFF element of the failure phase or all of the separated ON/OFF elements connected with the common ON/OFF element in series, are broken as described below in Fig. 10. The fuel injection as the escaping operation is conducted by the electromagnetic coil in the not-broken group.
However, when the failures of the OFF-surge voltage Vs occur in either groups, all of the ON/OFF elements are broken and the engine can not be operated.
Fig. 7 is a schematic block diagram relating to an interphase abnormality in phases. In Fig. 7, an interphase short circuit 70 shows the state that a short cut occurs between the negative side terminals of the first electromagnetic coil 5 and of the fourth electromagnetic coil 8. An interphase short circuit 71 shows the state that a short cut occurs between the negative side terminal of the second electromagnetic coil 6 and of the fourth electromagnetic coil 8. The interphase short circuit 70 is a group-in interphase short circuit occurred between the electromagnetic coils driven by the same common ON/OFF element 11. The interphase short circuit 71 is a group-across interphase short circuit occurred between the electromagnetic coils driven by the different common ON/OFF elements.
Fig. 8 is a timing chart for explaining an operation at the time of the abnormality of the interphase short circuit is included
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in the group as shown in Fig. 7. The difference from the timing chart of the normal operation shown in Fig. 4 will be mainly described. An abnormal current waveform 72 of (i) INJ1 in Fig. 8 and an abnormal current waveform 75 of (j) INJ4 in Fig. 8 show the state that the low-current for holding operation Ih is reduced in half, resulting from that the first electromagnetic coil 5 and the fourth electromagnetic coil 8 are connected in parallel by the interphase short circuit 70.
A duplication current waveform 73 of (i) INJl in Fig. 8 and a duplication current waveform 74 of (j) INJ4 in Fig. 8 show the waveforms of the additional duplication current not to be normally flowed, resulting from that the first electromagnetic coil 5 and the fourth electromagnetic coil 8 are connected in parallel by the interphase short circuit 70.
A duplication surge voltage 76 of (m) D31 in Fig. 8 and a duplication surge voltage 77 of (n) D34 in Fig. 8 show the OFFsurge voltages Vs accompanying with breaking of the duplication current waveforms 73,74. A duplication signal 78 of (q) IN13 in Fig. 8 and a duplication signal 79 of (r) IN42 in Fig. 8 show the duplication detection signals accompanying with the duplication surge voltages 76,77.
Fig. 9 is a timing chart for explaining an operation at the time of the abnormality of the interphase short circuit included in the group shown in Fig. 7. The difference from the timing chart
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of the normal operation shown in Fig. 4 will be mainly described.
In an interphase short circuit such as the interphase short circuit 71 occurring across groups, when all of the separated ON/OFF elements 13,14, 23 and 24 are not simultaneously brought into conduction to each other (that is, the period for injecting fuel is relatively short), each of the electromagnetic coils 5 to 8 is normally controlled and executes the operation equal to that shown in the timing chart of Fig. 4. However, each of the electromagnetic coils 5 to 8 is in the state that the abnormality of the interphase short circuit can not be detected instead of being normally controlled. Contrary to this, the timing chart of Fig. 9 shows the case where the period for injecting fuel is long and the adjacently arranged electromagnetic coils are simultaneously brought into conduction.
An attenuation current waveform 80 of (j) INJ4 in Fig. 9 shows the state that the circuit of the separated ON/OFF element 14 or the circuit of the common ON/OFF element 11 is opened, and the low-current for holding operation Ih flowed through the fourth electromagnetic coil 8 is attenuated through the commutation diode 12, the interphase short circuit 71 and the separated ON/OFF element 23. A failure surge voltage 81 of (n) D34 in Fig. 9 shows the state that the OFF-surge voltage Vs to be'normally generated is not generated by such that the fourth electromagnetic coil 8 is not steeply broken. Similarly, a failure signal 82 of (r) IN42 in Fig.
<Desc/Clms Page number 24>
9 shows the state that the detection signal to be normally generated is not generated under the influence of the failure surge voltage
81.
There are four kinds of abnormalities in the interphase short circuit across groups relating to the negative side wiring line of the electromagnetic coil. In either cases, the failure of the OFF-surge voltage Vs occurs at the side of leading operation of the electromagnetic valve operating temporally in tandem. When the common ON/OFF element driving the electromagnetic coil of the side of the leading operation or the separated ON/OFF element is broken, this case can use the same countermeasure as that in the case of the abnormality in phases shown in Fig. 5. Since the countermeasure can be unified, it is convenient.
However, in this interphase short circuit across groups, when the period for injecting fuel is shortened to avoid the duplication of the period for injecting fuel, it is unnecessary for the common ON/OFF element or the separated ON/OFF element to be broken.
Further, the common ON/OFF element or the separated ON/OFF element of the side of the following operation may be broken, even in the case where the common ON/OFF element or the separated ON/OFF element is broken.
The whole operation of the failure detection circuit of the fuel injection apparatus according to Embodiment 1 as described above, will be described with reference to Fig. 10 which is a
<Desc/Clms Page number 25>
flowchart showing an operation of the microprocessor 9.
In Fig. 10, at step 100, the operation starts. At step 101 following step 100, the microprocessor 9 checks whether a reset instruction is transferred from the external tool 40. If YES at checking step 101, at step 102, the microprocessor 9 resets the failure information stored in a RAM memory therein. When the operation of step 102 is completed, or if NO at step 101, when the external tool 40 is not connected with the microprocessor 9 or when the external tool 40 does not send the reset instruction in spite of the connection with the microprocessor 9, at step 103, the microprocessor 9 checks whether a read-out instruction is transferred from the external tool 40.
If YES at checking step 103, at step 104, the microprocessor 9 sends the failure information stored in the RAM memory in the microprocessor 9 towards the external tool 40. When the operation of step 104 is completed, or if NO at step 103, when the external tool 40 is not connected with the microprocessor 9 or when the external tool 40 does not send the read-out instruction in spite of the connection with the microprocessor 9, at step 105, the microprocessor 9 checks whether it is in course of generation of the separated drive signals SW1 to SW4. If NO at step 105, when the fuel injection is not executed, the microprocessor 9 moves to step 106 and returns to start step 100 again.
If YES at step 105, at step 107, the microprocessor 9 updates
<Desc/Clms Page number 26>
the latest occurrence situation of the separated drive signals SW1 to SW4 conducting the repeat operation and obtains the situation. At step 108 following step 107, the microprocessor 9 updates the latest input situation of the detection signals IN13 and IN42 and obtains the situation. At step 110 following step 108, the microprocessor 9 checks whether there is a failure of the detection signals IN13 and IN42 just after the falling-edge (change time of logic from"H"to"L") of the separated drive signals SW1 to SW4. If YES at checking step 110, at step 111, the microprocessor 9 checks whether there is a duplication of the current-flowing period of the electromagnetic coil driven temporally in tandem in the pulse group of drive signals updated and obtained at step 105.
If YES at checking step 111, at step 112, the microprocessor 9 stores this situation to shorten the current-flowing period and to output the alarm/display with respect to the abnormality alarm/display apparatus 42. The microprocessor 9 keeps storing the stored information until the information is reset at step 102.
If NO at step 111, a1 step 113, the microprocessor 9 determines which phase of the electromagnetic coil includes a failure of the OFF-surge voltage Vs according to which separated drive signal corresponds to the failure of the OFF-surge voltage Vs and stores the determination. At step 114 following step 113, the microprocessor 9 breaks the common ON/OFF element driving the electromagnetic coil of the failure phase of the OFF-surge voltage.
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At step 115, the microprocessor 9 outputs the alarm/display with respect to the abnormality alarm/display apparatus 42. When the operation of step 115 is completed, if NO at step 110, or when the operation of step 112 is completed, the microprocessor 9 moves to step 120.
At step 113, the microprocessor 9 detects the abnormality in phase such as the short circuit, the disconnection, the breaking or the like of the electromagnetic coil, the wiring line or the drive element. At step 114, the microprocessor 9 breaks the current-flowing in groups for breaking the common ON/OFF element 11 (or 21) and breaking even the separated ON/OFF elements 13 and 14 (or 23 and 24) for safety. At step 112, the microprocessor 9 avoids the duplication of the current-flowing period of the electromagnetic coil arranged in tandem. This is a means for restraining the injection period for preventing the abnormality with respect to the group-across interphase short circuit 71 in Fig. 7.
At step 120, the microprocessor 9 checks whether there is a duplication of additional detection signals IN 13 and IN 42 just
after the falling-edge (change time of logic from"H"to"L") of the separated drive signals SW1 to SW4. If YES at checking step 120, at step 121, the microprocessor 9 determines which phase of the electromagnetic coil includes the interphase short circuit according to which separated drive signal corresponds to the
<Desc/Clms Page number 28>
duplication of the OFF-surge voltage Vs and stores the determination.
At step 122 following step 121, the microprocessor 9 breaks the common ON/OFF element driving the electromagnetic coil including the interphase short circuit. At step 123, the microprocessor 9 outputs the alarm/display with respect to the abnormality alarm/display apparatus 42. When the operation of step 123 is completed, or if NO at step 120, the microprocessor 9 moves to step 106, and then moves to start step 100 again.
At step 121, for example, the microprocessor 9 regards the abnormality as that in the first electromagnetic coil 5 or that in the fourth electromagnetic coil 8 with respect to the group-in interphase short circuit 70. At step 122, the microprocessor 9 breaks the current-flowing in groups for breaking the common ON/OFF element 11 and breaking even the separated ON/OFF elements 13 and 14 for safety.
A nonvolatile memory such as a RAM memory or EE-P ROM held in power-failure by a battery stores the number of the electromagnetic coil including the phase with the determination of the abnormality at step 113 or 121, the number of the cylinder of the engine and the like. At the time of the maintenance check, the external tool 40 reads out these numbers and displays them at step 104. Further, at step 102, these numbers are initialized and reset.
Embodiment 2
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Fig. 11 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 2 of the present invention. The difference from Embodiment 1 will be mainly described.
In the first drive control circuit 10 of Fig. 11, the current-flowing of a high-voltage-side ON/OFF element lla is controlled by the steep overexcitation control signal SW13. The current-flowing of a low-voltage-side ON/OFF element lib is controlled corresponding to the low-current holding control signal DT13 output by the low-current holding control circuit 19 as described in Embodiment 1. A booster circuit llc boosts the voltage of the voltage source 3. A diode 16a feeds to the first electromagnetic coil 5 and the fourth electromagnetic coil 8 from the booster circuit llc through the high-voltage-side ON/OFF element lla. On the other hand, a diode 16b feeds to the first electromagnetic coil 5 and the fourth electromagnetic coil 8 from the voltage source 3 through the low-voltage-side ON/OFF element llb. In Fig. 11, the common ON/OFF element 11 shown in Fig. 1 is divided into the high-voltage-side ON/OFF element lla and the low-voltage-side ON/OFF element llb. However, both the highvoltage-side ON/OFF element lla and the low-voltage-side ON/OFF element lib are common ON/OFF elements feeding to the first electromagnetic coil 5 and the fourth electromagnetic coil 8. The second drive control circuit 20 includes the same construction as
<Desc/Clms Page number 30>
the first drive control circuit 10. Therefore, the description of the second drive control circuit 20 will be omitted here.
Next, the operation in the above-described construction will be described in detail.
In the failure detection circuit of the fuel injection apparatus according to the construction shown in Fig. 11, the voltage source 3 is, for example, the battery on a vehicle of a DC12V system. While the booster circuits llc and 21c, for example, generates a high-voltage source of DC120V from DC12V and steeply drives the electromagnetic coil.
The low-voltage-side ON/OFF elements lib and 21b supply the low-current for holding operation Ih of the electromagnetic coil.
The low-voltage-side ON/OFF elements lib and 21b execute feeding directly from the voltage source 3, whereby the temperature rise of the booster circuits llc and 21c is restrained.
In the failure detection circuit according to Embodiment 2, the exciting current of the electromagnetic coils 5,6, 7 and 8 is lower than that of the failure detection circuit in Embodiment 1. Therefore, the temperature rise of the common ON/OFF element and the separated ON/OFF element can be reduced.
Embodiment 3
Fig. 12 is a detailed electrical circuit diagram showing a failure detection circuit of a fuel injection apparatus according to Embodiment 3 of the present invention. The difference from
<Desc/Clms Page number 31>
Embodiment 1 will be mainly described.
In Fig. 12, a booster circuit lld boosts the power supply voltage by the voltage source 3. The current-flowing of the high-voltage-side ON/OFF element lla is controlled by the steep
overexcitation control signal SW13. The current-flowing of the low-voltage-side ON/OFF element lib is controlled corresponding to the low-current holding control signal DT13. The diode 16a feeds to the first electromagnetic coil 5 and the fourth electromagnetic coil 8 from the booster circuit lid through the high-voltage-side ON/OFF element lla. On the other hand, the diode 16b feeds to the first electromagnetic coil 5 and the fourth electromagnetic coil 8 from the voltage source 3 through the low-voltage-side ON/OFF element llb.
Similarly, the current-flowing of a high-voltage-side ON/OFF element 21a is controlled by the steep overexcitation control signal SW42. The current-flowing of the low-voltage-side ON/OFF element 21b is controlled corresponding to the low-current holding control signal DT42. A diode 26a feeds to the second electromagnetic coil 6 and the third electromagnetic coil 7 from a booster circuit 21d through the high-voltage-side ON/OFF element 21a. On the other hand, a diode 26b feeds to the second electromagnetic coil 6 and the third electromagnetic coil 7 from the voltage source 3 through the low-voltage-side ON/OFF element 21b.
Within the above description, there is only one difference
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between Embodiment 2 and Embodiment 3 in that the booster circuit of Embodiment 3 is constructed as the common booster circuit lid combining the booster circuits 11c and 21c.
The pull-down resistance 12a is connected with the commutation diode 12 in parallel. The voltage of the voltage source 3 is distributed to a partial resistance 12b and a partial resistance 12c. A correction resistance 12d is connected between the pull-down resistance 12a and the partial resistance 12c. The voltage of the partial resistance 12c is applied to noninvert input terminals of comparator circuits 43 and 44.
Incidentally, a resistance value R12a of the pull-down resistance 12a is set to be sufficiently smaller than resistance values R12b, R12c andR] 2d of the partial resistances 12b and 12c and the correction resistance 12d, respectively.
Similarly, a pull-down resistance 22a is connected with a commutation diode 22 in parallel. The voltage of the voltage source 3 is distributed to a partial resistance 22b and a partial resistance 22c. A correction resistance 22d is connected between the pull-down resistance 22a and the partial resistance 22c. The voltage of the partial resistance 22c is applied to noninvert input terminals of comparator circuits 45 and 46.
Incidentally, a resistance value R22a of the pull-down resistance 22a is set to be sufficiently smaller than resistance values R22b, R22c and R22d of the partial resistances 22b and 22c
<Desc/Clms Page number 33>
and the correction resistance 22d.
Reference numeral 13b indicates a diode for detecting an OFF-surge, and reference numerals 13c and 13d indicate partial resistances. The diode 13b is connected with each of the partial resistances 13c and 13d in series. The diode 13b and the partial resistances 13c and 13d are connected between the negative side terminal of the first electromagnetic coil 5 and the negative side terminal of the voltage source 3. The voltage of the partial resistance 13d is applied to an invert input terminal of the comparator circuit 43.
Similarly, reference numerals 14b, 23b and 24b indicate diodes for detecting an OFF-surge, and 14c, 14d, 23c, 23d, 24c and 24d indicate partial resistances. Similarly hereinafter, the voltages of the partial resistances 14d, 23d and 24d are applied to the invert input terminals of the comparator circuits 44 to 46, respectively.
An OR circuit 37 supplies the detection signal IN13 of the logic level"L"to the microprocessor 9 even when either of the comparator circuit 43 or 46 outputs the logic level"L". Similarly, an OR circuit 38 supplies the detection signal IN42 of the logic level"L"to the microprocessor 9 even when either of the comparator circuit 44 or 45 outputs the logic level"L".
Incidentally, an OFF-surge detection circuit 39 is composed of the comparator circuits 43,44 and the comparator circuits 45,
<Desc/Clms Page number 34>
Next, the operation in the above-described construction will be described centering on the operation of the comparator circuit 43. The high-voltage-side ON/OFF element lla and the separated ON/OFF element 13 are brought in conduction to steeply operate the first electromagnetic coil 5. Next, the high-voltage-side ON/OFF element lla is broken so that the low-voltage-side ON/OFF element lib controls the low-current for holding the operation.
Then, since the separated drive signal SW1 becomes the logic level"L", the low-voltage-side ON/OFF element lib and the separated ON/OFF element 13 are broken. As shown in Fig. 2, the OFF-surge voltage Vs is generated at the negative side terminal of the first electromagnetic coil 5 and the partial voltage by the partial resistances 13c and 13d is supplied to the invert input terminal of the comparator circuit 43.
On the other hand, the voltage of the noninvert input terminal of the comparator circuit 43 at this point of time has the low value the power supply voltage is divided by the resistance value R12b and (R12c//R12d) because the voltage of both ends of the pulldown resistance 12a is approximately 0 V. Here, (R12c//R12d) indicates a parallel composite resistance combining the resistances R12c and R12d.
Therefore, as an input voltage of the comparator circuit 43, the voltage of the side of the noninvert input terminal is lower than that of the side of the invert input terminal. The output of
<Desc/Clms Page number 35>
the comparator circuit 43 generates the normal detection signal of the logic level"L".
However, when a short circuit 140 short-circuits the connection point of the first electromagnetic coil 5 and the fourth electromagnetic coil 8 to a power supply line, the partial voltage applied to the noninvert input terminals of the comparator circuits 43 and 44 has the high value in which the power supply voltage is divided by the resistance value (R12b//R12d) and R12c. Here, (R12b//Rl2d) indicates a parallel composite resistance combining the resistances R12b and R12d.
Therefore, as the input voltage of the comparator circuit 43, the voltage of the side of the noninvert input terminal is higher than that of the side of the invert input terminal. Since the output of the comparator circuit 43 is the logic level"H", the result is that the OFF-surge detection is not executed.
As described above, the failure detection circuit of the fuel injection apparatus shown in Fig. 12 enables detection of the abnormality of the short circuit of the common ON/OFF element side, and this is the same in other electromagnetic coils.
With respect to this abnormality of the short circuit, at step 113 of Fig. 10, the microprocessor 9 determines the failure phase and stores it. And at step 114, the microprocessor 9 breaks the common ON/OFF element 11 and the separated ON/OFF elements 13 and 14 and then holds the state.
<Desc/Clms Page number 36>
When a group-across short circuit 141 implements the short-circuit connection between a connection common point of the first electromagnetic coil 5 and the fourth electromagnetic coil 8 and a connection common point of the second electromagnetic coil 6 and the third electromagnetic coil 7, in the case where the electromagnetic coil in tandem has no duplication in the current-flowing period, there is no abnormality, and even the presence of the short circuit 141 is not detected.
On the other hand, in the case where the electromagnetic coil in tandem has some duplication in the current-flowing period, the OFF-surge voltage Vs can not be detected because the voltage of the noninvert input terminals of the comparator circuits 13b, 14b, 23b and 24b of Fig. 12 is risen when the circuit of the separated ON/OFF element is opened. At step 112 of Fig. 10, the microprocessor 9 executes the shortening treatment of the current-flowing period to execute the escaping operation.
Embodiment 4
In Embodiments 1, 2 and 3, the escaping operation method for restraining the injection period is used as a countermeasure against the group-across interphase short circuit. However, without executing the restraining process of the injection period, the common ON/OFF element and the like may be broken to brake the group current-flowing.
As far, the examples of the four-cylinder engine are described.
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Even in the case of the six-cylinder engine or the eight-cylinder engine, the common ON/OFF elements divided into two groups can be employed. Further, the common ON/OFF elements including the grouping composed of three parts (six-cylinder) or four parts (eight-cylinder) can be employed.
When a gasoline engine is used as the engine, in the case where the fuel injection control apparatus includes an ignition control function of the engine, the correction of the ignition timing as well as the correction of the fuel injection control is executed to shorten the drive at the time of the occurrence of the abnormality.
Therefore, the apparatus can obtain an improvement in executing more stable escaping operation.
Further, the abnormality alarm/display apparatus can display, for example, the state that the drive is shortened, the state that the fuel injection is entirely stopped due to the abnormality relating to the whole groups, or the stop process of the fuel injection based on the disconnection, the short circuit, the misfire or the like of the ignition apparatus group. That is, the abnormality alarm/display apparatus can execute alarm/display function integrally or hierarchically.
As described above, according to the failure detection circuit of the fuel injection apparatus according to the present invention, the single OFF-surge detection circuit enables the batch detection of the short circuit, the disconnection and the breaking in the
<Desc/Clms Page number 38>
fuel injection controlling electromagnetic coil, the ON/OFF element thereof, the wiring line thereof, and the like. Further, the OFF-surge detection circuit enables the detection of the trouble of the interphase short circuit by the failure judgment apparatus and the duplication judgment apparatus. Still further, the common ON/OFF elements are divided into some groups, whereby the stable escaping operation can be conducted.
The current control with respect to the electromagnetic coil is executed at the side of the common ON/OFF element. Therefore, the voltage of both ends of the separated ON/OFF element is monitored, whereby the OFF-surge voltage can be easily detected.
Since the OFF-surge voltage is detected by the electric potential of both ends of the electromagnetic coil, even the abnormality of the short circuit between the common ON/OFF elements and the mutual short circuit across groups can be easily detected.
The OR gate connection with respect to the OFF-surge detection circuit is appropriately implemented by the OR circuit. Therefore, the duplication of the OFF-surge voltage can be checked and the input point of the microprocessor or the number of the hardware can be reduced.
Since the common ON/OFF element executes the steep overexcitation control and the low-current control for holding operation in itself, the construction of the feeder control circuit is simplified and a good effect is obtained even with the low
<Desc/Clms Page number 39>
withstand voltage of the electromagnetic coil.
The common ON/OFF element is divided to execute the steep overexcitation control by the high-voltage and the low-current control for holding operation by the low-voltage. Thus, the current-flowing amount to the common ON/OFF element is decreased and the heat release is reduced. Therefore, the apparatus can be miniaturized.
Since the single overexciting booster circuit can execute the steep overexcitation with respect to all of the electromagnetic coils, it is effective in the miniaturization of the apparatus and the reduction in the cost of the apparatus.
When the common ON/OFF element is broken accompanying with the occurrence of the abnormality, the electromagnetic coil connected with the non-broken common ON/OFF element can stably execute the escaping operation because the common ON/OFF elements are appropriately divided into some groups.
In the case where the abnormality of the short circuit occurs across the different groups, the current-flowing period of the pulse group of drive signals is shortened, whereby more stable escaping operation can be executed.
The alarm or the display based on the abnormality in the failure or the duplication of the OFF-surge voltage is given.
Therefore, the alarm for all troubles usually supposed is given, and thus, the safety can be improved.
<Desc/Clms Page number 40>
The microprocessor is provided with the interface circuit for connecting with the external tool. Thus, the identification information of the electromagnetic coil in which an abnormality is occurred is read out, and the read-out information is displayed on the external tool. Therefore, the efficiency of the maintenance check can be improved, and the stored information can be easily initialized from the external tool.
Claims (12)
1. A failure detection circuit of a fuel injection apparatus, comprising: a plurality of electromagnetic coils for driving a fuel injecting electromagnetic valve with respect to each cylinder of a multi-cylinder engine; a microprocessor for generating a pulse group of a drive signal and a steep overexcitation control signal; a plurality of separated ON/OFF elements for driving the said electromagnetic coils executing sequentially an ON/OFF operation, corresponding to the pulse group of a drive signal generated by the said microprocessor; a plurality of groups of common ON/OFF element for driving a batch feed into electromagnetic coils in the group composed of at least a plurality of electromagnetic coils having the interval of fuel injection sequence in two lines degree or more, corresponding to the steep overexcitation control signal generated by the said microprocessor; and a plurality of OFF-surge detection circuits for detecting an OFF-surge voltage induced by opening the circuit of the said separated ON/OFF element corresponding to the said electromagnetic coil involved in at least a different group, wherein the said microprocessor compares detection signals
<Desc/Clms Page number 42>
detected by the said plural OFF-surge detection circuits to judge an abnormality based on whether a failure of the detection signal and a duplication of the detection signal are included.
2. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein each of the said OFF-surge detection circuits detects the OFF--surge voltage by detecting that a voltage value of both ends of the separated ON/OFF element becomes higher than that of a voltage source when the circuit of the said separated ON/OFF element is opened.
3. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein each of the said OFF-surge detection circuits detects the OFF-. surge voltage by detecting that a voltage of a negative side terminal of the said electromagnetic coil is higher than that of a feeder terminal connected with the said common ON/OFF element when the circuit of the separated ON/OFF element and the circuit of the said common ON/OFF element are opened.
4. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein the said common ON/OFF element includes an OR circuit for implementing an OR gate combination of detection signals output by the respective OFF-surge detection circuits with respect to the said electromagnetic coil included
<Desc/Clms Page number 43>
in a different group, and the said microprocessor judges an abnormality based on an output of the OR circuit.
5. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein each of the said common ON/OFF elements is operated corresponding to the steep overexcitation control signal generated by the said microprocessor and a low-current holding control signal for holding the said operation of the electromagnetic coil.
6. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein an overexciting booster circuit for boosting a power supply voltage is equipped, and the said common ON/OFF element is comprised of: a high-voltage-side ON/OFF element for driving to feed into the said electromagnetic coil through the said overexciting booster circuit; and a low-voltage-side ON/OFF element for driving to feed into the electromagnetic coil, corresponding to the low-current holding control signal for holding the operation of the said electromagnetic coil.
7. A failure detection circuit of a fuel injection apparatus according to claim 6, wherein the said high-voltage-side ON/OFF elements share the overexciting booster circuit, and the said overexciting booster circuit is shared with respect to all of the
<Desc/Clms Page number 44>
said electromagnetic coils.
8. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein when the said microprocessor judges an abnormality based on the detection signal detected by the said OFF-surge detection circuit, means for breaking a group current-flowing for breaking the corresponding common ON/OFF element and the separated ON/OFF element connected with the common ON/OFF element in series is provided, and the said electromagnetic coil included in a group except for the group including the broken separated ON/OFF element executes an escaping operation.
9. A failure detection circuit of a fuel injection apparatus according to claim 8, wherein when the said microprocessor judges an abnormality based on a failure of the OFF-surge voltage, in the case where there is a duplication of a current-flowing period of the said electromagnetic coil in tandem, a shortening treatment is implemented with respect to a current-flowing period of the pulse group of drive signals.
10. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein means for notifying an abnormality after receiving an abnormality signal is provided, and when the said microprocessor judges an abnormality based on the detection
<Desc/Clms Page number 45>
signal detected by the OFF-surge detection circuit, the abnormality signal is output to the said means for notifying the abnormality.
11. A failure detection circuit of a fuel injection apparatus according to claim 1, wherein the said microprocessor is provided with a connecting interface circuit with an external tool.
12. A failure detection circuit for a fuel injection apparatus substantially as hereinbefore described with reference to Figures 1 to 10; or Figure 11 ; or Figure 12 of the accompanying drawings.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001213738A JP3699370B2 (en) | 2001-07-13 | 2001-07-13 | Failure detection circuit for fuel injection device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0200830D0 GB0200830D0 (en) | 2002-03-06 |
| GB2377507A true GB2377507A (en) | 2003-01-15 |
| GB2377507B GB2377507B (en) | 2003-07-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0200830A Expired - Fee Related GB2377507B (en) | 2001-07-13 | 2002-01-15 | Failure detection circuit of a fuel injection apparatus |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JP3699370B2 (en) |
| CN (1) | CN1292160C (en) |
| DE (1) | DE10200847B4 (en) |
| GB (1) | GB2377507B (en) |
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| JP3828239B2 (en) * | 1997-05-22 | 2006-10-04 | 三菱電機株式会社 | Control device for injector for fuel injection |
| JP3916867B2 (en) * | 2000-12-14 | 2007-05-23 | 三菱電機株式会社 | In-vehicle electric load drive system abnormality detection device |
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2001
- 2001-07-13 JP JP2001213738A patent/JP3699370B2/en not_active Expired - Fee Related
-
2002
- 2002-01-11 DE DE10200847A patent/DE10200847B4/en not_active Expired - Fee Related
- 2002-01-15 GB GB0200830A patent/GB2377507B/en not_active Expired - Fee Related
- 2002-07-11 CN CN 02126425 patent/CN1292160C/en not_active Expired - Fee Related
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| WO1995007409A1 (en) * | 1993-09-07 | 1995-03-16 | Robert Bosch Gmbh | Fault diagnosis method for injectors of internal combustion engine high-pressure injection systems |
| JPH09189253A (en) * | 1996-01-09 | 1997-07-22 | Nissan Motor Co Ltd | Fuel injection valve driving circuit of multi-cylinder direct injection engine |
| JPH10154617A (en) * | 1996-11-26 | 1998-06-09 | Fujitsu Ten Ltd | Failure judging device of electromagnet device, flow rate control device, and fuel injector of internal combustion engine |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2006100924A1 (en) * | 2005-03-18 | 2006-09-28 | Toyota Jidosha Kabushiki Kaisha | Control apparatus for internal combustion engine |
| US7318420B2 (en) | 2005-03-18 | 2008-01-15 | Toyota Jidosha Kabushiki Kaisha | Control apparatus for internal combustion engine |
| CN101142396B (en) * | 2005-03-18 | 2010-04-07 | 丰田自动车株式会社 | Control device for internal combustion engine |
| CN103672111A (en) * | 2012-09-05 | 2014-03-26 | 纳博特斯克有限公司 | Drive circuit of electromagnetic valve |
| CN103672111B (en) * | 2012-09-05 | 2015-12-23 | 纳博特斯克有限公司 | The drive circuit of solenoid valve |
| US20160160783A1 (en) * | 2014-12-03 | 2016-06-09 | Denso Corporation | Injector driving apparatus |
| US9644562B2 (en) * | 2014-12-03 | 2017-05-09 | Denso Corporation | Injector driving apparatus |
| CN105042159A (en) * | 2015-07-24 | 2015-11-11 | 苏州市大力电器有限公司 | Electromagnetic valve drive device with fault diagnosis function and self-protection function |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1292160C (en) | 2006-12-27 |
| GB2377507B (en) | 2003-07-23 |
| JP3699370B2 (en) | 2005-09-28 |
| DE10200847B4 (en) | 2010-09-23 |
| GB0200830D0 (en) | 2002-03-06 |
| CN1397723A (en) | 2003-02-19 |
| JP2003027993A (en) | 2003-01-29 |
| DE10200847A1 (en) | 2003-01-30 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20160115 |