Electronic control device and control method for electronic control device

Abstract

Provided is an electronic control device that drivably controls a fuel injection valve, wherein a boost current of a boost circuit is increased only in situations requiring an increase in boost energy from a short-term boost, and the boost current of the boost circuit is reduced in other situations. The electronic control device is characterized by comprising a boost circuit, a boost setting controller that holds boost control information for the boost circuit, a boost controller that controls a current supplied to the boost circuit on the basis of a current set value from the boost setting controller, and a fuel injection circuit that supplies a current to a fuel injection valve using voltage generated by the boost circuit, the boost setting controller reducing the boost speed of the boost circuit when information pertaining to an engine temperature becomes higher than a predetermined value.

Description

[Technical Field]

[0001] The present invention relates to a configuration of an electronic control unit that drives and controls a load and a control method thereof, and in particular to a technique that is effective when applied to an on-vehicle electronic control unit that requires high reliability. [Background technology]

[0002] From the perspective of environmental conservation, there is a demand for reducing harmful exhaust gases such as CO, HC, and NOx contained in the exhaust gases of gasoline-powered vehicles, and regulations are becoming stricter every year. Measures to suppress fuel injection penetration have been implemented, and multi-stage injection technology is one of them (various patent documents available). It is also known that multi-stage injection is more effective in suppressing exhaust gases when performed at low engine temperatures with a certain number of stages or more, and the number of injection stages in multi-stage injection is increasing every year.

[0003] Because a certain amount of energy is required to open a fuel injection valve (injector), the common method is to boost the battery voltage using a boost circuit. However, because multi-stage injection involves successive fuel injections within a certain period of time, the charging speed through boosting must also be increased to ensure that the energy supply for each stage is sufficient, and this places an increasing burden on the boost circuit every year.

[0004] Known techniques for varying the boost charge rate in a fuel injection device (boost circuit system of an electronic control device) include, for example, the technique described in Patent Document 1. In the boost device for driving an injector in Patent Document 1, when the fuel injection interval is within a certain period, the duty ratio of the boost control is varied to increase the charge rate and reduce fuel injection variations.

[0005] Furthermore, in the fuel control device for an internal combustion engine disclosed in Patent Document 2, the upper or lower limit of the boost current is adjusted according to the fuel injection interval, thereby suppressing heat generation in the boost circuit and extending the life of the components. By adjusting the value of the average boost current in response to changes in the fuel injection interval depending on the engine speed, heat generation in the boost circuit is optimized for each engine speed. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] International Publication No. 2017 / 033643 [Patent Document 2] Japanese Patent Application Publication No. 2016-217322 Summary of the Invention [Problem to be solved by the invention]

[0007] The technology of Patent Document 1 focuses on boosting the voltage in a short time, and although it is effective in suppressing fuel injection variations, it increases the burden on the boost circuit, and in automobiles that are used for long periods of time, the burden on the boost circuit will naturally also be long, so there is room for improvement in terms of the device lifespan.

[0008] In the technology of Patent Document 2, the injection interval is detected from the rotation angle of the internal combustion engine, and there is room for improvement in dealing with cases where the injection interval varies independently of the rotation speed, such as in multi-stage injection.

[0009] Furthermore, a protection circuit is required to prevent the injection interval from becoming too short due to the detection, causing the boosting energy of the boosting circuit to become excessive, and a mechanism for measuring the circuit temperature is also required, which results in a problem of an increased circuit size.

[0010] Therefore, an object of the present invention is to provide an electronic control device and a control method for the electronic control device that drives and controls a fuel injection valve, which increases the boost current of a boost circuit only when an increase in boost energy is required through short-term boosting, and reduces the boost current of the boost circuit in other situations. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention provides: In automobiles that perform multi-stage injection at a certain number of stages or more at low engine temperatures,The system comprises a boost circuit, a boost setting controller that holds boost control information for the boost circuit, a boost controller that controls the current flowing through the boost circuit based on a current setting value from the boost setting controller, and a fuel injection circuit that supplies current to a fuel injection valve using the voltage generated by the boost circuit, wherein the boost setting controller reduces the boost speed of the boost circuit when information relating to engine temperature is higher than a predetermined value.

[0012] The present invention also provides In automobiles that perform multi-stage injection at a certain number of stages or more at low engine temperatures, The method includes: (a) detecting information about engine temperature and a multi-stage injection command; (b) comparing the information about engine temperature detected in step (a) with a predetermined threshold value and selecting a boost control current value from a preset current table based on the comparison result; (c) detecting an engine rotation signal; (d) determining whether the fuel injection valve is not operating; and (e) if it is determined in step (d) that the fuel injection valve is not operating, setting a current setting value and starting boost control by the boost circuit based on the set current setting value. [Effects of the Invention]

[0013] According to the present invention, the life of the electronic control device can be extended.

[0014] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a functional block diagram of a fuel injection valve control device according to a first embodiment of the present invention. [Figure 2] 2 is a flowchart showing a control method of the fuel injection valve control device of FIG. 1. [Figure 3] 2 is a flowchart showing a control method of the fuel injection valve control device of FIG. 1. [Figure 4] 2 is a timing chart showing an example of the operation of the fuel injection valve control device of FIG. 1. [Figure 5] FIG. 5 is a functional block diagram of a fuel injection valve control device according to a second embodiment of the present invention. [Figure 6] 6 is a timing chart showing an example of the operation of the fuel injection valve control device of FIG. 5. [Figure 7] 2 is a diagram illustrating a configuration example of the boost circuit 1 of FIG. 1 and its current values. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. [Example]

[0017] A fuel injection valve control device and a control method thereof according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4 and 7. FIG.

[0018] Fig. 1 is a functional block diagram of a fuel injection valve control device 55 of this embodiment. Figs. 2 and 3 are flowcharts showing a control method of the fuel injection valve control device 55 of Fig. 1. Fig. 4 is a timing chart showing an example of the operation of the fuel injection valve control device 55 of Fig. 1. Fig. 7 is a diagram showing an example of the configuration of the boost circuit 1 of Fig. 1 and its current values.

[0019] First, the configuration of a fuel injection valve control device (electronic control device) according to a first embodiment of the present invention will be described with reference to FIGS.

[0020] As shown in FIG. 1, the fuel injection valve control device 55 of this embodiment includes, as its main components, a boost circuit 1, a fuel injection control IC 25, a computing device 30, and a fuel injection circuit 50.

[0021] 7, the boost circuit 1 includes a resistor 6, a reactor 7, and a boost driver 3 connected in series between a power source such as a battery and ground, and an output line 8 that outputs a boosted voltage is connected between the reactor 7 and the boost driver 3. A diode 9 for preventing backflow of current and a smoothing capacitor 70 are connected to the output line 8.

[0022] For example, a power MOSFET (Metal Oxide Semiconductor Field Effect Transistor) is used for the boost driver 3. Figure 7 shows an example of a power MOSFET consisting of an n-channel enhancement type MOSFET and a body diode (anti-parallel diode), with the drain terminal D of the power MOSFET connected to the power supply side and the source terminal S connected to the ground side.

[0023] The current flowing through resistor 6 is detected by current monitor 15 of fuel injection control IC 25, and gate voltage Vg output from boost controller 5 of fuel injection control IC 25 based on the detected current value is input to boost driver 3. Boost driver 3 is on / off controlled based on the input gate voltage Vg, and controls the timing of output of boost voltage from boost circuit 1. The drain voltage Vd of boost driver 3 becomes the boost voltage.

[0024] For the smoothing capacitor 70, an electrolytic capacitor is used from the viewpoint of withstand voltage.

[0025] In the boost circuit 1, increasing the boost current I1 results in an increase in the ripple current I2 of the electrolytic capacitor that flows through the smoothing capacitor (electrolytic capacitor) 70 in the downstream stage of the circuit. When increasing the current as described above, either the average current or the effective current may be used.

[0026] By boosting the battery voltage with this boost circuit 1 and supplying it to the fuel injection circuit 50, multi-stage injection by the fuel injection valve (injector) 56 connected to the fuel injection valve control device 55 becomes possible.

[0027] A characteristic of electrolytic capacitors is that their lifespan is generally directly linked to the remaining amount of electrolyte remaining. However, because electrolytic capacitors have larger losses than other capacitors, an increase in ripple current I2 increases self-heating, accelerating the evaporation of the electrolyte and significantly reducing their lifespan.

[0028] When the voltage supplied from the power supply to the boost circuit 1 is constant, it is necessary to increase the boost current I1 in order to increase the boost speed. On the other hand, increasing the boost current I1 also increases the ripple current I2 of the electrolytic capacitor, shortening the life of the electrolytic capacitor.

[0029] Therefore, in the fuel injection valve control device 55 of this embodiment, the boost current of the boost circuit 1 is increased only in situations where an increase in boost energy through short-term boosting is required, and in other situations, the boost current of the boost circuit 1 is controlled to be reduced.

[0030] That is, when it is necessary to rapidly increase the drive voltage of the fuel injection valve 56 in order to achieve stable multi-stage injection, the current setting value of the boost circuit 1 is increased, and when it is not necessary to rapidly increase the drive voltage of the fuel injection valve 56, the current setting value of the boost circuit 1 is decreased in order to reduce the load on the electrolytic capacitor.

[0031] In a gasoline-powered automobile, the engine temperature is low, for example, immediately after starting the engine or immediately after starting to drive in cold climates. When the engine temperature is low, the fuel does not burn sufficiently, and the combustion energy is insufficient. In such cases, the current setting value of the boost circuit 1 is increased.

[0032] This allows short-time boosting scenes, which are a high load on the boost circuit 1 and require a large amount of boost energy, to be performed only when the engine is cold, and by reducing the boost energy under other conditions, it becomes possible to reduce the driving time of high-load short-time boosting scenes within the cumulative driving time of the boost circuit 1 in the vehicle, and as a result, it becomes possible to suppress deterioration of the smoothing capacitor (electrolytic capacitor) 70 of the boost circuit 1 and the fuel injection valve control device 55 equipped with it.

[0033] The configuration of the fuel injection valve control device 55 for executing the above control will be described in detail.

[0034] The fuel injection control IC 25 includes a boost controller 5, a current monitor 15, and a voltage monitor 20.

[0035] The computing device 30 includes a boost setting controller 35 , a current table selector 40 , and a current table 45 .

[0036] A gasoline fuel injection valve (injector) 56 is connected to the fuel injection circuit 50, and the timing of opening the fuel injection valve 56 is controlled. The valve opening energy of the fuel injection valve 56 uses the boosted voltage generated by the boost circuit 1 and the power supply voltage.

[0037] When the upper and lower limit current setting values ​​for boost control are set in the fuel injection control IC 25 from the arithmetic device 30, the boost controller 5 measures the boost voltage using the voltage monitor 20 that measures the boost voltage, and if the boost voltage is equal to or lower than a predetermined voltage, the boost controller 5 controls the boost driver 3 to start the boost operation.

[0038] During boosting, the circuit current I flowing through the boost circuit 1 is measured by the current monitor 15, and the boost controller 5 PWM controls the boost driver 3 so that the measured current value by the current monitor 15 is the same as the upper and lower current setting value.

[0039] The voltage monitor 20 measures the boosted voltage stored by the PWM control of the boost controller 5, and when the boosted voltage reaches a predetermined voltage, the boost controller 5 stops the boost operation.

[0040] The upper current setting value I set in the fuel injection control IC 25 from the arithmetic unit 30 is U (I in Figure 4 U1 ,I U2 ) and the lower current setting value I L (I in Figure 4 L1 ,I L2 ) is selected from the current table 45 by the current table selector 40.

[0041] Apart from boosting the power supply voltage of the boost circuit 1, the fuel injection control IC 25 receives a fuel injection command generated by the arithmetic unit 30 which in turn receives an engine rotation signal, and outputs a fuel injection control signal to the fuel injection circuit 50. The fuel injection circuit 50 performs fuel injection by driving a fuel injection valve 56 based on the fuel injection control signal.

[0042] The control method of the fuel injection valve control device 55 of this embodiment will be described with reference to FIGS.

[0043] FIG. 2 shows a typical operation flow of the fuel injection valve control device 55 of this embodiment.

[0044] When the fuel injection valve control device 55 starts operating, the arithmetic unit 30 receives engine coolant temperature information and a multi-stage injection command from the vehicle (step S1). In this embodiment, engine temperature is substituted with engine coolant temperature information, but other information can be used as long as it is information that can be used to identify the engine temperature, such as information that directly indicates the engine temperature itself, such as the temperature of the combustion chamber, or fuel temperature information.

[0045] The current table selector 40 in the arithmetic device 30 that has received the engine coolant temperature information determines whether the engine coolant temperature is equal to or higher than the threshold value N (step S2). If the engine coolant temperature is equal to or higher than the threshold value N (Yes), table B is selected from the current table 45 (step S3), and if it is lower than the threshold value N (No), table A is selected (step S4).

[0046] The relationship between the current setting values ​​of table A and table B is that the current of table B is less than the current of table A, meaning that table B has a lower current setting value. This current setting value may be an average current or an effective current.

[0047] After the current table selector 40 selects the current table, the arithmetic unit 30 receives an engine rotation signal from the vehicle (step S5). Upon receiving the engine rotation signal, the arithmetic unit 30 determines whether the fuel injection valve (injector: INJ) 56 is not being driven (step S6). If it is determined that the fuel injection valve (INJ) 56 is not driven (Yes), during the period when the calculation device 30 is not outputting a fuel injection command to the fuel injection control IC 25, the upper and lower current setting values ​​are set in the fuel injection control IC 25 based on the multi-stage injection command and engine rotation signal obtained from the vehicle (step S7), and boost control by the boost circuit 1 is started.

[0048] On the other hand, if it is determined that the fuel injection valve (INJ) 56 is being driven (No), the determination operation of step S6 is repeated until it is determined that the fuel injection valve (INJ) 56 is not being driven.

[0049] This allows the boost current value to be changed while the fuel injection valve 56 is open, which causes the boost voltage to fluctuate and affects fuel injection, and allows the upper and lower current setting values ​​to be reflected in the fuel injection control IC 25.

[0050] FIG. 3 shows another operation flow of the fuel injection valve control device 55 of this embodiment.

[0051] 2, there are two types of current tables 45, A and B, but if there are multiple temperature thresholds, it is also possible to set current tables according to the multiple thresholds. In that case, the average current and effective current will be lower in the current table paired with a high temperature threshold than in the current table paired with a low temperature threshold.

[0052] It is also possible to set a plurality of current tables according to the number of stages, in which case the greater the number of stages, the higher the relationship between the average current and the effective current of the current table.

[0053] FIG. 3 shows three examples of temperature thresholds, namely, -20°C, 0°C, and 60°C, and two examples of the number of stages of multi-stage injection, namely, 5 stages and 10 stages.

[0054] When the fuel injection valve control device 55 starts operating, the arithmetic unit 30 receives engine coolant temperature information and a multi-stage injection command from the vehicle (step S10). The current table selector 40 in the arithmetic unit 30 receives the engine coolant temperature information and determines whether the engine coolant temperature is lower than -20°C (step S11). If the engine coolant temperature is lower than -20°C (Yes), table A is selected from the current table 45 (step S12). If the engine coolant temperature is higher than -20°C (No), it is further determined whether the engine coolant temperature is lower than 0°C (step S13). In step S13, if it is determined that the engine coolant temperature is -20°C or higher and lower than 0°C (Yes), table B is selected (step S14), and if it is 0°C or higher (No), it is further determined whether the engine coolant temperature is lower than 60°C. (step S15) In step S15, if it is determined that the engine coolant temperature is 0°C or higher and lower than 60°C (Yes), it is further determined whether the number of stages in the multi-stage injection command is 10 or higher. (Step S16) In step S16, if it is determined that the number of stages in the multistage injection command is 10 or more (Yes), table C is selected (step S17). If it is less than 10 (No), it is further determined whether the number of stages in the multistage injection command is 5 or more and less than 10 (step S18). In step S18, if it is determined that the number of stages in the multi-stage injection command is 5 or more but less than 10 (Yes), table D is selected (step S19), and if it is determined that the number is less than 5 (No), table E is selected (step S20). If it is determined in step S15 that the engine coolant temperature is 60°C or higher (No), table F is selected (step S21). The relationship between the current setting values ​​of Table A, Table B, Table C, Table D, Table E, and Table F is: Table F current < Table E current < Table D current < Table C current < Table B current < Table A current. The average current may be used for this current setting value, or the effective current may be used.

[0055] After the current table selector 40 selects the current table, the arithmetic unit 30 receives an engine rotation signal from the vehicle (step S22). Upon receiving the engine rotation signal, the arithmetic unit 30 determines whether the fuel injection valve (injector: INJ) 56 is not being driven (step S23). If it is determined that the fuel injection valve (INJ) 56 is not driven (Yes), during the period when the calculation device 30 is not outputting a fuel injection command to the fuel injection control IC 25, the upper and lower current setting values ​​are set in the fuel injection control IC 25 based on the multi-stage injection command and engine rotation signal obtained from the vehicle (step S24), and boost control by the boost circuit 1 is started.

[0056] On the other hand, if it is determined that the fuel injection valve (INJ) 56 is being driven (No), the determination operation of step S23 is repeated until it is determined that the fuel injection valve (INJ) 56 is not being driven.

[0057] An example of the operation of the fuel injection valve control device 55 of this embodiment will be described with reference to Fig. 4. Fig. 4 is a timing chart of the boost control using the two types of tables A and B described with reference to Fig. 2.

[0058] The calculation device 30 sends the upper and lower current setting value I to the fuel injection control IC 25. UL1 When this is set, the boost operation is performed according to Table A selected based on the engine coolant temperature information, and the voltage and current values ​​of the boost circuit 1 increase. The current value of the boost circuit 1 increases according to the upper current setting value I of Table A. U1 and the lower current setting value I L1 is controlled between (period a).

[0059] When the boosted voltage of the boost circuit 1 reaches the boost stop voltage range, the boost current is stopped.

[0060] The boosted voltage of the boost circuit 1 is maintained at the boost stop voltage for a certain period of time (period b), and then decreases. During this period (period b), no multi-stage injection command is input to the calculation device 30, and no fuel injection command is output from the calculation device 30 to the fuel injection control IC 25, so no fuel injection control signal is output from the fuel injection control IC 25 to the fuel injection circuit 50, and no fuel injection valve drive current is output from the fuel injection valve control device 55 to the fuel injection valve 56.

[0061] When a multi-stage injection command is input to the arithmetic unit 30 at time t1, the boost operation is again performed according to Table A selected based on the engine coolant temperature information, and the voltage value and current value of the boost circuit 1 are increased. The current value of the boost circuit 1 is increased according to the upper current setting value I U1 and the lower current setting value I L1 is controlled between (period c).

[0062] During period c, since the engine coolant temperature is below threshold value N, table A is selected, and since a multi-stage injection command is input to calculation device 30 at time t1, a fuel injection command is output from calculation device 30 to fuel injection control IC 25, a fuel injection control signal is also output from fuel injection control IC 25 to fuel injection circuit 50, and a fuel injection valve drive current is also output from fuel injection valve control device 55 to fuel injection valve 56, and multi-stage injection is performed.

[0063] When the boosted voltage of the boost circuit 1 reaches the boost stop voltage range, the boost current is stopped.

[0064] When the input of the multi-stage injection command to the calculation device 30 stops at time t2, the output of the fuel injection command from the calculation device 30 to the fuel injection control IC 25 stops, the output of the fuel injection control signal from the fuel injection control IC 25 to the fuel injection circuit 50 also stops, and the fuel injection valve drive current from the fuel injection valve control device 55 to the fuel injection valve 56 is also stopped, and multi-stage injection is stopped.

[0065] During the period d, the boost voltage of the boost circuit 1 is maintained at the boost stop voltage. During this period d, the calculation device 30 sends the upper and lower current setting value I UL2At this time, since the multi-stage injection command is not input to the arithmetic unit 30, the boost current value is changed while the fuel injection valve 56 is open, and therefore the boost voltage fluctuates, and the boost current setting value I is set to the value I to avoid any influence on the fuel injection. UL2 is reflected in the fuel injection control IC25.

[0066] In the period e, the engine coolant temperature becomes equal to or higher than the threshold value N, and the table B is selected, and the boost operation is performed according to the table B. The current value of the boost circuit 1 is set to the upper current setting value I U2 and the lower current setting value I L2 is controlled between

[0067] During period e, for example, a multi-stage injection command with a small number of stages is input to the calculation device 30, a fuel injection command is output from the calculation device 30 to the fuel injection control IC 25, a fuel injection control signal is also output from the fuel injection control IC 25 to the fuel injection circuit 50, and a fuel injection valve drive current is also output from the fuel injection valve control device 55 to the fuel injection valve 56, and multi-stage injection with a small number of stages is performed.

[0068] Table B sets average currents and effective currents for performing multi-stage injection with fewer stages than those in Table A, and the boost speed by the boost circuit 1 is gentler (slower) than that in Table A.

[0069] As described above, the fuel injection valve control device 55 of this embodiment includes the boost circuit 1, the boost setting controller 35 that holds boost control information for the boost circuit 1, the boost controller 5 that controls the current flowing through the boost circuit 1 based on the current set value from the boost setting controller 35, and the fuel injection circuit 50 that supplies current to the fuel injection valve using the voltage generated by the boost circuit 1. When there is no need to rapidly increase the drive voltage of the fuel injection valve 56, that is, when information related to the engine temperature (for example, engine coolant temperature information) is higher than a predetermined value or when the number of multi-stage injections is small, the boost setting controller 35 changes the current set value so that the boost speed of the boost circuit 1 decreases in order to reduce the load on the smoothing capacitor (electrolytic capacitor) 70.

[0070] This allows short-time boosting scenes, which are a high load on the boost circuit 1 and require a large amount of boost energy, to be performed only when the engine is cold or when the number of multi-stage injections is high, i.e., when a short-time boost is truly necessary, and makes it possible to reduce the driving time in high-load short-time boosting scenes within the cumulative driving time of the boost circuit 1 in the vehicle.As a result, it becomes possible to suppress deterioration of the smoothing capacitor (electrolytic capacitor) 70 of the boost circuit 1 and the fuel injection valve control device 55 in which it is installed.

[0071] The technology of Patent Document 1 aims to reduce fuel injection variations caused by a shorter injection interval and a longer boost charging time, and therefore is premised on the use of a mechanism for detecting the injection interval. This requires processing of the detected injection interval information, which places a heavy load on the CPU (Central Processing Unit) and other computing devices in the fuel injection device, such as a microcomputer.

[0072] Furthermore, depending on the engine state, such as during acceleration, deceleration, engine start-up, or idling, boosting may not necessarily be necessary in a short period of time. Therefore, varying the boost energy based only on the boost interval may result in unnecessary increased load on the boost circuit.

[0073] The technology of Patent Document 2 focuses on increasing the pressure in a short period of time in response to the shortened injection interval, and like Patent Document 1, requires a mechanism to detect the injection interval, which places a heavy burden on the calculation unit in the fuel injection device.

[0074] In this embodiment, a boost control current value is selected from a preset current table based on engine coolant temperature information and a multi-stage injection command, and the boost control current value is set in the fuel injection control IC 25, thereby reducing the load on calculation devices such as a CPU or microcomputer.

[0075] Furthermore, the boost current of the boost circuit 1 is increased only in situations where an increase in boost energy is required through short-term boosting, such as when the engine is cold or when the number of multi-stage injections is high, and the boost current of the boost circuit 1 is reduced in other situations, thereby suppressing the load on the boost circuit 1. [Example]

[0076] Second Embodiment A fuel injection valve control device and a control method thereof according to a second embodiment of the present invention will be described with reference to FIGS.

[0077] 5 is a functional block diagram of the fuel injection valve control device 55 of this embodiment. FIG. 6 is a timing chart showing an example of the operation of the fuel injection valve control device 55 of FIG.

[0078] The fuel injection valve control device 55 of this embodiment differs from the fuel injection valve control device 55 of the first embodiment (FIG. 1) in that the arithmetic device 30 is provided with a boost voltage monitor 60. The other configurations are the same as those of the first embodiment (FIG. 1).

[0079] The boost voltage monitor 60 is a circuit that monitors the boost voltage to determine whether or not a boost operation is in progress.

[0080] The boost state determined by the boost voltage monitor 60 is immediately notified to the boost setting controller 35, and the boost setting controller 35 sets upper and lower limit currents in the fuel injection control IC 25 based on the notified boost state at a timing when boosting by the boost circuit 1 is not being performed.

[0081] According to the fuel injection valve control device 55 of this embodiment, it is possible to avoid mistakes in setting the upper and lower limit currents to the fuel injection control IC 25 due to voltage boost noise by reliably avoiding current setting during voltage boost.

[0082] In this embodiment, the boost voltage is directly input to the arithmetic unit 30, but it is also possible to divide or reduce the voltage to a voltage that can be input by the arithmetic unit 30 before inputting it to the arithmetic unit 30. Furthermore, although the method of monitoring the boost state is realized by directly monitoring the boost voltage, it is also possible to directly transmit the boost control state from the fuel injection control IC 25 to the arithmetic unit 30.

[0083] An example of the operation of the fuel injection valve control device 55 of this embodiment will be described with reference to Fig. 6. Similar to Fig. 4, Fig. 6 is a timing chart of the boost control using the two types of tables A and B described in Fig. 2.

[0084] The calculation device 30 sends the upper and lower current setting value I to the fuel injection control IC 25. UL1 When this is set, the boost operation is performed according to Table A selected based on the engine coolant temperature information, and the voltage and current values ​​of the boost circuit 1 increase. The current value of the boost circuit 1 increases according to the upper current setting value I of Table A. U1 and the lower current setting value I L1 is controlled between (period a).

[0085] When the boosted voltage of the boost circuit 1 reaches the boost stop voltage range, the boost current is stopped.

[0086] The boosted voltage of the boost circuit 1 is maintained at the boost stop voltage for a certain period of time (period b), and then decreases. During this period (period b), no multi-stage injection command is input to the calculation device 30, and no fuel injection command is output from the calculation device 30 to the fuel injection control IC 25, so no fuel injection control signal is output from the fuel injection control IC 25 to the fuel injection circuit 50, and no fuel injection valve drive current is output from the fuel injection valve control device 55 to the fuel injection valve 56. When a multi-stage injection command is input to the arithmetic unit 30 at time t1, the boost operation is again performed according to Table A selected based on the engine coolant temperature information, and the voltage value and current value of the boost circuit 1 are increased. The current value of the boost circuit 1 is increased according to the upper current setting value I U1 and the lower current setting value I L1 is controlled between (period c).

[0087] During period c, because the engine coolant temperature is below threshold value N, table A is selected, and since a multi-stage injection command is input to arithmetic unit 30 at time t1, a fuel injection command is output from arithmetic unit 30 to fuel injection control IC 25, a fuel injection control signal is output from fuel injection control IC 25 to fuel injection circuit 50, and a fuel injection valve drive current is output from fuel injection valve control device 55 to fuel injection valve 56, and multi-stage injection is performed (period c1). When the input of the multi-stage injection command to the arithmetic unit 30 stops at time t2, the output of the fuel injection command from the arithmetic unit 30 to the fuel injection control IC 25 stops, the output of the fuel injection control signal from the fuel injection control IC 25 to the fuel injection circuit 50 also stops, and the fuel injection valve drive current from the fuel injection valve control device 55 to the fuel injector 56 also stops, and multi-stage injection is stopped (period c2). During this period c2, the calculation device 30 sends the boost control upper and lower current setting value I UL2 At this time, since a multi-stage injection command is not input to the arithmetic unit 30, the boost current value is changed while the fuel injection valve 56 is open, which causes the boost voltage to fluctuate and affects the fuel injection, and the upper / lower current set value IUL2 is reflected in the fuel injection control IC 25.

[0088] In period c2, when the boosted voltage of the boost circuit 1 reaches the boost stop voltage range, the boost current is stopped.

[0089] During the period d, the boosted voltage of the boost circuit 1 is maintained at the boost stop voltage.

[0090] In the period e, the engine coolant temperature becomes equal to or higher than the threshold value N, and the table B is selected, and the boost operation is performed according to the table B. The current value of the boost circuit 1 is set to the upper current setting value I U2 and the lower current setting value I L2 is controlled between

[0091] During period e, for example, a multi-stage injection command with a small number of stages is input to the calculation device 30, a fuel injection command is output from the calculation device 30 to the fuel injection control IC 25, a fuel injection control signal is also output from the fuel injection control IC 25 to the fuel injection circuit 50, and a fuel injection valve drive current is also output from the fuel injection valve control device 55 to the fuel injection valve 56, and multi-stage injection with a small number of stages is performed.

[0092] Table B sets average currents and effective currents for performing multi-stage injection with fewer stages than Table A, and the boost speed by the boost circuit 1 is gentler (slower) than Table A.

[0093] As shown in period c2 in FIG. 6, even if the boost voltage monitor 60 determines that the boost operation is in progress, if the input of the multi-stage injection command to the arithmetic device 30 is stopped, the boost setting controller 35 determines that it is time to set the upper and lower current limits, and can set the upper and lower limit currents in the fuel injection control IC 25.

[0094] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0095] 1...Boost circuit, 3...Boost driver, 5...Boost controller, 6...Resistor, 7...Reactor, 8...Output line, 9...Diode, 15...Current monitor, 20...Voltage monitor, 25...Fuel injection control IC, 30...Calculation device, 35...Boost setting controller, 40...Current table selector, 45...Current table, 50...Fuel injection circuit, 55...Fuel injection valve control device (electronic control device), 56...Fuel injection valve (injector: INJ), 60...Boost voltage monitor, 70...Smoothing capacitor (electrolytic capacitor), I UL1 ,I UL2 …Up / down current setting value

Claims

1. In an automobile that performs multi-stage injection at a certain number of stages or more at low engine temperatures, A boost circuit; a boost setting controller that holds boost control information for the boost circuit; a boost controller that controls the current flowing through the boost circuit based on a current setting value from the boost setting controller; a fuel injection circuit that supplies current to a fuel injection valve by utilizing the voltage generated by the boost circuit, The boost setting controller is an electronic control device that reduces the boost speed of the boost circuit when the information relating to the engine temperature is higher than a predetermined value.

2. 2. The electronic control device according to claim 1, An electronic control device that uses the voltage generated by the boost circuit to control multi-stage injection, which causes a specific fuel injection valve to inject continuously within a certain period of time.

3. 3. The electronic control device according to claim 2, an electronic control device that reduces the boosting speed of the boost circuit when the number of multi-stage injections is small;

4. 2. The electronic control device according to claim 1, The information regarding the engine temperature is engine coolant temperature information.

5. 3. The electronic control device according to claim 2, When the information about the engine temperature is equal to or greater than a predetermined threshold, the electronic control unit selects a specific boost control current value from a preset current table.

6. 6. The electronic control device according to claim 5, The electronic control device wherein the boost control current value is lower than the boost control current value selected based on a condition other than the information regarding the engine temperature.

7. 6. The electronic control device according to claim 5, The current table includes a plurality of boost control current values ​​corresponding to information related to the engine temperature and a plurality of boost control current values ​​corresponding to the number of injection stages of the fuel injection valve.

8. 6. The electronic control device according to claim 5, The boost control current value is set at a time other than when a fuel injection command is issued, and the set boost control current value is reflected in the current set value at a time other than when fuel is injected.

9. 9. The electronic control device according to claim 8, The boost control current value is reflected in the current setting value during a period other than the boost operation.

10. 2. The electronic control device according to claim 1, The boost circuit is an electronic control device having an electrolytic capacitor as a component.

11. In an automobile in which multi-stage injection is performed at a certain number of stages or more at low engine temperatures, A method for controlling an electronic control unit, comprising the steps of: (a) detecting information about engine temperature and a multi-stage injection command; (b) comparing the information about the engine temperature detected in step (a) with a predetermined threshold value, and selecting a boost control current value from a preset current table based on the comparison result; (c) detecting an engine rotation signal; (d) determining whether the fuel injector is not actuated; (e) a step of setting a current setting value and starting boost control by a boost circuit based on the set current setting value when it is determined in the step (d) that the fuel injection valve is not driven.

12. A control method for an electronic control device according to claim 11, comprising: A control method for an electronic control device, which reduces the boosting speed of the boost circuit when the information about the engine temperature becomes higher than a predetermined value.

13. A control method for an electronic control device according to claim 11, comprising: A control method for an electronic control device that uses the voltage generated by the boost circuit to control multi-stage injection, which causes a specific fuel injection valve to inject continuously within a certain period of time.

14. A control method for an electronic control device according to claim 13, comprising: A control method for an electronic control device that reduces the boosting speed of the boost circuit when the number of multi-stage injections is small.

15. A control method for an electronic control device according to claim 11, comprising: The control method for an electronic control device, wherein the information regarding the engine temperature is engine coolant temperature information.

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