JP2016159772A - Hybrid vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set a voltage which is fed to an injector from a battery serving as a power source of an electric motor, to be a proper value in a hybrid vehicle.SOLUTION: A hybrid vehicle 1 comprising as a driving source an internal combustion engine 2 and an electric motor 3 is provided that further comprises: an electric injector 5 which injects fuel into a combustion chamber of the internal combustion engine; a battery 6 which has a voltage higher than an applied voltage to be applied to the injector and feeds power to the electric motor; power conversion equipment 8 which steps down the voltage fed from the battery and outputs the resultant voltage as an output voltage; and a control device 9 which is connected to the power conversion equipment through a power line 51, and applies the output voltage output from the power conversion equipment, as an applied voltage to the injector at a predetermined timing. On the basis of a difference Vd between a measured value Vp of the applied voltage of the injector and a target value Vt of the applied voltage, the power conversion equipment controls the output voltage Vo so as to diminish the difference.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hybrid vehicle, and more particularly to an apparatus for supplying power to an electric injector in a hybrid vehicle.

  In a hybrid vehicle including an internal combustion engine and an electric motor, it has been studied to make the internal combustion engine a direct injection engine. For example, a hybrid vehicle according to Patent Document 1 has a 42V battery as a power source for an electric motor, and supplies a voltage of 42V to an electric injector. Injectors for direct injection engines need to drive the valve body at high speed against high-pressure fuel, and therefore, many have a rated voltage (operating voltage) of 30 to 70V. In the hybrid vehicle according to Patent Document 1, since the voltage of the battery of the electric motor and the rated voltage of the injector match, there is no need to provide a step-down device or a step-up device, and energy efficiency can be increased, and the circuit It can be simplified.

JP 2006-256607 A

  However, in a general hybrid vehicle, since the battery voltage is set to 100 to 300 V, it is necessary to step down the voltage of the battery and supply it to the injector. In this case, it is conceivable to form a step-down circuit (step-down chopper) in the injector control device. The control device includes a switching element for switching ON / OFF (injection, stop) of the injector. However, in this case, since the temperature of the control device rises due to the heat generation of the step-down circuit, the upper limit value of the ON / OFF frequency (frequency) of the switching element is lowered to suppress the temperature rise. As a result, multi-stage injection by the injector cannot be performed in the high rotation range of the internal combustion engine.

  On the other hand, when the step-down circuit is arranged at a position away from the control device and power is supplied from the step-down circuit to the control device via the harness (power line), the actual resistance is supplied to the control device and the injector by the electrical resistance of the harness. Is lower than the voltage output from the step-down circuit. This causes a problem that a delay occurs in the operation of the injector.

  In addition, in a battery such as a lithium ion battery, since the output voltage changes according to the SOC, the actual voltage supplied to the injector is lower than the intended voltage, causing a problem that the operation of the injector is delayed. .

  In view of the above background, it is an object of the present invention to set a voltage supplied to an injector from a battery that also serves as a power source of an electric motor to an appropriate value in a hybrid vehicle.

  In order to solve the above problems, the present invention is a hybrid vehicle (1) including an internal combustion engine (2) and an electric motor (3) as drive sources, and is an electric type that injects fuel into a combustion chamber of the internal combustion engine. An injector (5), a battery (6) having a voltage higher than an applied voltage applied to the injector, and supplying electric power to the motor, and a voltage from the battery is stepped down and output as an output voltage A power converter (8), and a control device connected to the power converter via a power line (51) and applying the output voltage output from the power converter as the applied voltage to the injector at a predetermined timing (9), and the power converter is based on a difference (Vd) between a measured value (Vp) of the applied voltage of the injector and a target value (Vt) of the applied voltage. And controlling the output voltage (Vo) so as to reduce said difference.

  According to this configuration, the power conversion device controls the output voltage so as to reduce the difference based on the difference between the target value of the applied voltage of the injector and the measured value of the applied voltage of the injector. The measured value can be brought close to the target value of the applied voltage. According to this configuration, the measured value of the applied voltage is brought close to the target value of the applied voltage regardless of a change in electrical resistance due to a change in the length of the power line, a change in the temperature environment of the power line, or a change in the SOC of the battery. Can do. That is, the present invention can bring the measured value of the applied voltage close to the target value of the applied voltage regardless of the temperature environment and the type of vehicle applied.

  In the above invention, the control device is provided in an engine room (11) of the hybrid vehicle, and the power conversion device is provided in another part (12) of the hybrid vehicle excluding the engine room. It is good to be.

  According to this configuration, since the power conversion device is disposed at a position away from the control device, the temperature of the control device is prevented from being increased by the power conversion device. By reducing the temperature of the control device, it is possible to increase the number of multistage injections where heat generation is a problem. Further, since the control device is disposed in the engine room close to the injector, a voltage drop that occurs between the control device and the injector is suppressed.

  Further, in the above invention, the control device acquires the measured value of the applied voltage, and converts the measured value of the applied voltage or the difference between the measured value of the applied voltage and the target value of the applied voltage to the power conversion. Output to the device.

  According to this configuration, the power changing device can acquire the difference between the measured value of the applied voltage and the target value of the applied voltage, and can control the output voltage based on the difference.

  In the above invention, the control device may acquire the measured value of the applied voltage when the current supplied to the injector has a predetermined peak current value.

  According to this configuration, since the current flowing through the injector is maximized and the value when the applied voltage is the lowest is the measured value of the applied voltage, the value when the applied voltage is the lowest is the target value of the applied voltage. You can get closer. Thereby, the fall of the operating speed of an injector is suppressed.

  Further, in the above invention, the injector injects fuel at least once during one combustion cycle of the internal combustion engine, and the control device displays the measured value of the applied voltage at the first injection in one combustion cycle. Get it.

  According to this configuration, the control device can reliably acquire the measured value of the applied voltage for each combustion cycle, and the output voltage is controlled based on the measured value of the applied voltage. Even when the injector performs multi-stage injection, the second and subsequent multi-stage injections may be stopped depending on the traveling state of the hybrid vehicle, the temperature of the control device, and the like. The measured value of the applied voltage can be reliably acquired for each cycle.

  In the above invention, the control device may monitor the applied voltage, and the power conversion device may not change the output voltage when the monitored value of the applied voltage is zero.

  According to this configuration, even when a ground fault occurs on the positive electrode side of the injector, the output voltage is not set to an erroneously excessive value.

  In the above invention, the control device further includes a second battery (7) having a voltage lower than the applied voltage, and a booster (101) that boosts the voltage from the second battery. When the power conversion device fails, the voltage output from the booster device may be supplied to the injector at a predetermined timing.

  According to this configuration, since the voltage of the second battery can be boosted by the booster and applied to the injector, the injector can inject fuel even when the power converter fails.

  According to the above configuration, in the hybrid vehicle, the voltage supplied to the injector from the battery that also serves as the power source of the electric motor can be set to an appropriate value.

Configuration diagram of a hybrid vehicle according to the first embodiment Sectional drawing of the injector which concerns on 1st Embodiment 1 is a configuration diagram of a voltage conversion device according to a first embodiment. Configuration diagram of ECU according to the first embodiment Graph showing the applied voltage and drive current of the injector Flow chart showing the procedure of voltage observation control by ECU microcomputer Flow chart showing output voltage control procedure by microcomputer of voltage converter Configuration diagram of ECU according to the second embodiment

(First embodiment)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. As shown in FIG. 1, the hybrid vehicle 1 has an internal combustion engine 2 and an electric motor 3 as drive sources for rotating wheels. The internal combustion engine 2 is a direct injection gasoline engine including an injector 5 that injects fuel into a combustion chamber. The number of cylinders of the internal combustion engine 2 is arbitrary, and the injector 5 is provided in each cylinder. Further, the hybrid vehicle 1 includes a high voltage battery 6 (first battery), a low voltage battery 7, a power converter 8, and an ECU 9 (control device) that controls the injector 5.

  The internal combustion engine 2 provided with the injector 5, the ECU 9, and the low-voltage battery 7 are disposed in the engine room 11 of the hybrid vehicle 1. The high-voltage battery 6 and the power conversion device 8 are disposed in other parts of the hybrid vehicle 1 excluding the engine room 11 (for example, a passenger compartment or a luggage compartment (trunk room)). In the present embodiment, the high voltage battery 6 and the power conversion device 8 are disposed in the lower rear part of the vehicle compartment 12.

  The high voltage battery 6 includes a rechargeable storage battery such as a lithium ion battery or a nickel metal hydride battery, and has a voltage of about 100 to 300V. The high voltage battery 6 is connected to the electric motor 3 via a motor driver (not shown) (not shown), supplies electric power to the electric motor 3, and is charged by electric power generated by the electric motor 3. The low voltage battery 7 includes a rechargeable storage battery such as a lead storage battery, and has a lower voltage (for example, 12 V) than the high voltage battery 6. The low voltage battery 7 supplies electric power to an in-vehicle device such as a headlight or a power window (not shown). Further, it is connected to the high voltage battery 6 via the power converter 8 and is charged by the electric power of the high voltage battery 6.

  As shown in FIG. 2, the injector 5 includes a cylindrical housing 15, a nozzle 16 provided at one end of the housing 15, an injection hole 17 formed at the tip of the nozzle 16, and the housing 15 and the nozzle 16. The valve body 18 is disposed and is displaceable along the axial direction to the distal end side and the proximal end side, a spring 19 that biases the valve body 18 toward the distal end side, and an electromagnet 20 provided in the housing 15. The valve body 18 closes the injection hole 17 when positioned on the distal end side, and opens the injection hole 17 when positioned on the proximal end side against the biasing force of the spring 19. The electromagnet 20 includes an iron core 20A and a coil 20B wound around the iron core 20A. The base end of the housing 15 is connected to a high-pressure fuel pipe (not shown) provided with a fuel pump (not shown), and the inside of the housing 15 and the nozzle 16 is filled with high-pressure fuel.

  In a state where no current is supplied to the coil 20B, the injection hole 17 is closed by the valve body 18 biased by the spring 19, and fuel is not injected. On the other hand, when a current is supplied to the coil 20B, the iron core 20A is magnetized, the valve body 18 is attracted to the iron core 20A, moves against the biasing force of the spring 19 and moves to the proximal end side, and the injection hole 17 is opened. Thereby, fuel is injected from the injection hole 17.

  As shown in FIGS. 1 and 3, the power converter 8 includes a first step-down circuit 23, a second step-down circuit 24, a first microcomputer 25 that controls the first and second step-down circuits 23, 24, 1 to 4th terminals 26, 27, 28 and 29. The positive terminal of the high voltage battery 6 is connected to the first terminal 26.

  The first step-down circuit 23 is provided between the first terminal 26 and the second terminal 27. The first step-down circuit 23 steps down the voltage of the high-voltage battery 6 supplied from the first terminal 26 to the overexcitation voltage (for example, about 60 V) of the injector 5 and supplies it to the second terminal 27. As will be described later, the overexcitation voltage is set to a value higher than the voltage of the low voltage battery 7. The first step-down circuit 23 includes a first switching element 31, a diode 32, an inductor 33, and a capacitor 34. The first switching element 31 is composed of, for example, a MOSFET or an IGBT, and one end thereof is connected to the first terminal 26. The other end of the first switching element 31 is connected to the cathode terminal of the diode 32. The anode terminal of the diode 32 is grounded. The gate of the first switching element 31 is connected to the first microcomputer 25. The first switching element 31 is turned on / off according to a command from the first microcomputer 25.

  The other end of the first switching element 31 and the cathode terminal of the diode 32 are connected to one end of an inductor 33 that is a choke coil. The other end of the inductor 33 is grounded via a capacitor 34 and is connected to the second terminal 27. The first step-down circuit 23 steps down the voltage supplied to the first terminal 26 and supplies it to the second terminal 27 when the first switching element 31 is turned on / off in accordance with a command from the first microcomputer 25. The voltage (overexcitation voltage) of the second terminal 27 can be changed by changing the duty ratio (ratio of the ON period) of the first switching element 31 in accordance with a command from the first microcomputer 25.

  The second step-down circuit 24 is provided between the first terminal 26 and the third terminal 28. The first step-down circuit 23 steps down the voltage of the high voltage battery 6 supplied from the first terminal 26 to the holding voltage of the injector 5 and supplies it to the third terminal 28. As will be described later, the holding voltage is set to a value lower than the overexcitation voltage. In the present embodiment, the holding voltage is set to the same value as the voltage of the low voltage battery 7 (for example, 12V). The second step-down circuit 24 has the same configuration as the first step-down circuit 23 and includes a second switching element 36, a diode 37, an inductor 38, and a capacitor 39. The other end of the inductor 38 is grounded via a capacitor 39 and is connected to the third terminal 28. The second step-down circuit 24 turns on / off the second switching element 36 in response to a command from the first microcomputer 25, and sets the voltage at the third terminal 28 to a predetermined holding voltage.

  As shown in FIGS. 1 and 4, the ECU 9 includes a drive circuit 42, a second microcomputer 43, and fifth to ninth terminals 45, 46, 47, 48, and 49. The drive circuit 42 and the fifth to eighth terminals 45 to 48 are provided for each cylinder. For example, when the internal combustion engine 2 has four cylinders, four drive circuits 42 and fifth to eighth terminals 45 to 48 are provided. Since the configurations of the drive circuit 42 and the fifth to eighth terminals 45 to 48 for each cylinder are the same, in the following description, the drive circuit 42 and the fifth to eighth terminals 45 to 48 corresponding to one cylinder will be described. .

  The fifth terminal 45 of the ECU 9 and the second terminal 27 of the power converter 8 are connected by a first power line 51, and the sixth terminal 46 of the ECU 9 and the third terminal 28 of the power converter 8 are connected by a second power line 52. The ninth terminal 49 of the ECU 9 and the fourth terminal 29 of the power converter 8 are connected by a signal line 53. A low voltage battery 7 is connected to the second power line 52. The first and second power lines 51 and 52 and the signal line 53 may be bundled together to form a single harness. With the above connection, an overexcitation voltage is supplied to the fifth terminal 45 of the ECU 9 and a holding voltage is supplied to the sixth terminal 46.

  The drive circuit 42 includes third to fifth switching elements 56, 57, 58, a Zener diode 59, and a current measuring resistor 60. The 3rd-5th switching elements 56-58 are comprised, for example from MOSFET and IGBT.

  One end of the third switching element 56 is connected to the fifth terminal 45. The other end of the third switching element 56 is connected to the cathode terminal of the diode 62 and the seventh terminal 47. The anode terminal of the diode 62 is grounded. The gate of the third switching element 56 is connected to the second microcomputer 43.

  One end of the fourth switching element 57 is connected to the sixth terminal 46. The other end of the fourth switching element 57 is connected to the anode terminal of the diode 63. The cathode terminal of the diode 63 is connected to the other end of the third switching element 56, the cathode terminal of the diode 62, and the seventh terminal 47. The gate of the fourth switching element 57 is connected to the second microcomputer 43.

  One end of the fifth switching element 58 is connected to the eighth terminal 48. The other end of the fifth switching element 58 is grounded via a current measuring resistor 60. The gate of the fifth switching element 58 is connected to the second microcomputer 43.

  The third to fifth switching elements 56 to 58 are turned on / off according to a command from the second microcomputer 43. When a command is input from the second microcomputer 43 to the gates of the third to fifth switching elements 56 to 58, the one end and the other end of each switching element 56 to 58 are energized.

  The Zener diode 59 has a cathode side connected to the fourth terminal 29 and one end of the fifth switching element 58, and an anode side grounded via a current measuring resistor 60.

  One end (high voltage side) of the coil 20B of the injector 5 is connected to the seventh terminal 47, and the other end (low voltage side) of the coil 20B is connected to the eighth terminal 48.

  The drive circuit 42 turns on and off the third to fifth switching elements 56 to 58 in response to a command from the second microcomputer 43, and applies an overexcitation voltage or a holding voltage to the seventh terminal 47 and the coil 20B of the injector 5. Supply. When the third switching element 56 is turned on, the fourth switching element 57 is turned off, and the fifth switching element 58 is turned on, an overexcitation voltage is supplied to the coil 20B, and a drive current flows through the coil 20B. The drive current that flows through the coil 20B when an overexcitation voltage is applied to the coil 20B is referred to as an overexcitation current. When the third switching element 56 is turned off, the fourth switching element 57 is turned on, and the fifth switching element 58 is turned on, the holding voltage is supplied to the coil 20B, and a drive current flows through the coil 20B. When a holding voltage is applied to the coil 20B, the drive current that flows through the coil 20B is referred to as a holding current.

  The second microcomputer 43 is electrically connected to the seventh terminal 47 and includes an applied voltage monitoring unit 65 that monitors an applied voltage that is a voltage of the seventh terminal 47. The applied voltage is substantially equal to the voltage actually applied to the coil 20B of the injector 5. Further, the second microcomputer 43 has a drive current monitoring unit 66 that detects a drive current flowing through the coil 20 </ b> B of the injector 5 by detecting a current flowing through the current measuring resistor 60.

  The internal combustion engine 2 is provided with a crank angle sensor 67 that detects the crank angle of the crankshaft. Further, the hybrid vehicle 1 is provided with an accelerator pedal sensor 68 that detects an operation amount of an accelerator pedal (hereinafter referred to as a pedal operation amount). Signals from the crank angle sensor 67 and the accelerator pedal sensor 68 are input to the second microcomputer 43.

  The second microcomputer 43 acquires the pedal operation amount based on the signal from the accelerator pedal sensor 68 and acquires the crank angle and the engine speed based on the signal from the crank angle sensor 67. The second microcomputer 43 sets the fuel injection amount of the injector 5 and the number of fuel injections per combustion cycle based on the pedal operation amount and the engine speed. Then, the second microcomputer 43 outputs a command to the third to fifth switching elements 56 to 58 based on the crank angle, and supplies a current to the coil 20B of the injector 5 at a predetermined timing.

  When injecting the fuel, the second microcomputer 43 first turns on the third switching element 56, turns off the fourth switching element 57, turns on the fifth switching element 58, and uses the overexcitation voltage as the applied voltage. To supply. Thereby, as shown in FIG. 5, the electric current which flows into the coil 20B increases with time. When the drive current exceeds a predetermined value, the valve element 18 moves to a position where the injection hole 17 is opened against the urging force of the spring 19, and fuel is injected from the injection hole 17.

  The second microcomputer 43 monitors the drive current by the drive current monitoring unit 66. When the drive current reaches a predetermined maximum overexcitation current, the third switching element 56 is turned off and the fourth switching element 57 is turned on. Then, the fifth switching element 58 is turned ON, and a holding voltage is applied to the coil 20B instead of the overexcitation voltage. By applying an overexcitation voltage to the coil 20B at the initial stage of fuel injection, the drive current can be rapidly increased and the operating speed of the injector 5 can be increased. After the overexcitation current flows through the coil 20B and the valve body 18 moves to a position where the injection hole 17 is opened, the valve body 18 can be maintained in the open position with a holding current smaller than the overexcitation current.

  The second microcomputer 43 maintains the voltage supplied to the coil 20 </ b> B at the holding voltage until a predetermined time elapses after the third switching element 56 is turned off. During this time, the second microcomputer 43 monitors the drive current by the drive current monitoring unit 66 and controls the fourth switching element 57 to be turned on / off so that the drive current is maintained at the holding current. Specifically, when the drive current becomes higher than the holding current, the fourth switching element 57 is turned off to lower the drive current. When the drive current becomes lower than the holding current, the fourth switching element 57 is turned off. Turn on to increase drive current.

  Then, after a predetermined time has elapsed, the second microcomputer 43 turns off all of the third to fifth switching elements 56 to 58 and stops supplying the applied voltage to the coil 20B. When the fourth and fifth switching elements 57 and 58 are turned off, the holding current remaining in the coil 20B flows to the ground via the Zener diode 59, so that the coil 20B is rapidly brought into a non-excited state. Thereby, the valve body 18 moves to a position where the injection hole 17 is closed by the biasing force of the spring 19, and the fuel injection is stopped.

  When performing multi-stage injection, the second microcomputer 43 performs the second injection in the same manner as the first injection described above based on the crank angle.

  Next, applied voltage adjustment control performed by the second microcomputer 43 and the first microcomputer 25 in cooperation will be described. The second microcomputer 43 performs voltage observation control shown in FIG. In step S1, the second microcomputer 43 determines whether a ground fault has occurred on the high voltage side of the coil 20B of the injector 5. This determination is made based on whether or not the applied voltage is 0. If the applied voltage is 0, the process proceeds to return assuming that the high voltage side is grounded. If the applied voltage is not 0, a ground fault occurs on the high voltage side. If not, the process proceeds to step S2.

  In step S2, the second microcomputer 43 determines whether or not the current time is a timing (hereinafter referred to as an observation timing) at which the applied voltage is acquired as information (hereinafter referred to as an applied voltage measurement value) as a comparison target. The observation timing is the time of the first fuel injection in one combustion cycle, and the timing at which the drive current becomes the maximum overexcitation current (see FIG. 5). At this timing, the overexcitation voltage is selected as the applied voltage, and the current is maximized, so the amount of decrease in the overexcitation voltage is maximized. The second microcomputer 43 determines whether or not the first fuel injection in one combustion cycle is based on the crank angle, and determines whether or not the drive current is the maximum overexcitation current by the drive current monitoring unit 66. Thus, it is determined whether or not the present time is the observation timing. If the current time is not the observation timing, the process proceeds to return. If the current time is the observation timing, the process proceeds to step S3, and the applied voltage measured by the applied voltage monitoring unit 65 is set as the applied voltage measured value Vp.

  In step S4, the second microcomputer 43 calculates a difference Vd (= Vt−Vp) between the applied voltage measured value Vp and the applied voltage target value Vt. The applied voltage target value Vt is a preset value. The applied voltage target value Vt is set based on the specification of the injector 5, for example. The second microcomputer 43 transmits the calculated difference Vd to the first microcomputer 25 via the signal line 53.

  The first microcomputer 25 performs output voltage control (step-down voltage control) shown in FIG. In step S11, the first microcomputer 25 determines whether or not the difference Vd is received from the second microcomputer 43. If not, the process proceeds to return. If it is received, the process proceeds to step S12.

  In step S12, the first microcomputer 25 sets the output voltage target value Vot (overexcitation voltage target value) of the first step-down circuit 23 based on the difference Vd. In the initial state, the first microcomputer 25 sets the applied voltage target value Vt to the output voltage target value Vot, turns on and off the first switching element 31 with a duty ratio based on the output voltage target value Vot, and performs the first step-down operation. The actual output voltage Vo of the circuit 23 is made equal to the output voltage target value Vot. The applied voltage measurement value Vp is lower than the output voltage Vo due to a voltage drop caused by the electric resistance of the first power line 51 and the electric resistance of the drive circuit 42. The first microcomputer 25 sets the output voltage target value Vot based on the difference Vd so that the applied voltage measured value Vp becomes equal to the applied voltage target value Vt. For example, the first microcomputer 25 sets a value obtained by adding the difference Vd to the previous output voltage target value Vot (n−1) as the current output voltage target value Vot (n) (Vot (n) = Vot (n) -1) + Vd). In this case, since the current output voltage target value Vot (n) is increased by the difference Vd from the previous output voltage target value Vot (n−1), the output voltage Vo increases and the applied voltage measured value Vp increases. The applied voltage target value Vt is approached.

  Note that various methods other than the above-described method can be applied to the method of setting the output voltage target value Vot based on the difference Vd in step S12. For example, the correction amount of the output voltage target value Vot may be set in advance as a map based on the difference Vd, and the output voltage target value Vot may be set based on the correction amount acquired with reference to this map.

  In the hybrid vehicle 1 configured as described above, the power conversion device 8 includes an applied voltage target value Vt that is a voltage to be applied to the injector 5 and an applied voltage measured value Vp that is a voltage that is actually applied to the injector 5. Since the output voltage Vo is controlled to reduce the difference based on the difference Vd, the applied voltage measurement value Vp can be brought close to the applied voltage target value Vt. By controlling the output voltage Vo based on the applied voltage measurement value Vp in this way, the applied voltage measurement value Vp can be obtained regardless of the voltage drop based on the SOC of the high-voltage battery 6 or the voltage drop based on the electrical resistance of the first power line 51. Can be made closer to the applied voltage target value Vt. In particular, the electrical resistance of the first power line 51 varies depending on the length difference and temperature environment in each vehicle type, but by controlling the output voltage Vo based on the applied voltage measurement value Vp, the electrical resistance of the first power line 51 is changed. The applied voltage measured value Vp can be brought close to the applied voltage target value Vt without considering the resistance.

  Since the power converter 8 is disposed at a position away from the ECU 9, it is possible to avoid the ECU 9 from being heated by the power converter 8. Further, since the ECU 9 is disposed in the engine room 11 close to the injector 5, a voltage drop that occurs between the seventh terminal 47 that acquires the applied voltage measurement value Vp and the coil 20 </ b> B of the injector 5 is suppressed, and the applied voltage measurement is performed. The difference between the value Vp and the voltage actually applied to the coil 20B is reduced.

  The applied voltage measurement value Vp is a value when the drive current reaches the maximum overexcitation current, that is, when the overexcitation voltage decreases most (see FIG. 5). For this reason, even when the drive current flows through the coil 20B and the overexcitation voltage decreases most, the amount of decrease from the applied voltage target value Vt becomes small.

  Further, since the second microcomputer 43 acquires the applied voltage measured value Vp at the first injection in one combustion cycle, the applied voltage measured value Vp can be reliably acquired even when the second and subsequent injections are omitted. it can.

  When the applied voltage detected by the second microcomputer 43 is 0, the second microcomputer 43 does not calculate the difference Vd and does not transmit it to the first microcomputer 25. The first microcomputer 25 does not change the output voltage target value Vot when the difference Vd is not received from the second microcomputer 43. Therefore, when the high voltage side of the coil 20B of the injector 5 is grounded, it is possible to prevent an incorrect output voltage target value Vot from being set.

(Second Embodiment)
As shown in FIG. 8, the hybrid vehicle 100 according to the second embodiment is different from the hybrid vehicle 1 according to the first embodiment in that the ECU 9 includes a booster circuit 101 and a sixth switching element 102. In the following description of the hybrid vehicle 100 according to the second embodiment, the same components as those of the hybrid vehicle 1 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The booster circuit 101 is provided between the sixth terminal 46 and the seventh terminal 47. The booster circuit 101 boosts the holding voltage supplied from the sixth terminal 46 to an overexcitation voltage and supplies the boosted voltage to the seventh terminal 47. The booster circuit 101 includes an inductor 104, a diode 105, a capacitor 106, and a seventh switching element 107. One end of the inductor 104 is connected to the sixth terminal 46. The other end of the inductor 104 is connected to one end of a seventh switching element 107 made of, for example, a MOSFET or IGBT and the anode terminal of the diode 105. The other end of the seventh switching element 107 is grounded via a resistor 108. The cathode terminal of the diode 105 is grounded via a capacitor 106 and is connected to one end of a sixth switching element 102 made of, for example, a MOSFET or IGBT. The other end of the sixth switching element 102 is connected to the seventh terminal 47. The gates of the sixth and seventh switching elements 102 and 107 are connected to the second microcomputer 43. The sixth and seventh switching elements 102 and 107 are turned on / off according to a command from the second microcomputer 43.

  The booster circuit 101 boosts the voltage (holding voltage) of the sixth terminal 46 to the overexcitation voltage by turning on / off the seventh switching element 107 in accordance with a command from the second microcomputer 43, and supplies it to the seventh terminal 47. Supply. The overexcitation voltage can be changed by changing the duty ratio of the sixth switching element 102.

  When the voltage (overexcitation voltage) boosted by the booster circuit 101 is supplied to the coil 20B of the injector 5, the third and fourth switching elements 56 and 57 are turned off, and the fifth and seventh switching elements 58 and 107 are turned on. Good.

  The hybrid vehicle 1 according to the second embodiment includes, as a source of overexcitation voltage, a first power system that steps down the voltage of the high voltage battery 6 by the first step-down circuit 23 of the power conversion device 8, and the power conversion device 8. A second power system that boosts the holding voltage supplied from the second step-down circuit 24 or the holding voltage supplied from the low-voltage battery 7. Therefore, even if the high voltage battery 6, the first step-down circuit 23, the second step-down circuit 24, etc. fail, the overexcitation voltage can be supplied to the coil 20B of the injector 5 using the second power system.

  Although the description of the specific embodiment is finished as described above, the present invention is not limited to the above embodiment and can be widely modified.

1: Hybrid vehicle 2: Internal combustion engine 3: Electric motor 5: Injector 6: High voltage battery 7: Low voltage battery 8: Power converter 9: ECU (control device)
11: engine room 12: vehicle compartment 20B: coil 23: first step-down circuit 24: second step-down circuit 25: first microcomputer 43: second microcomputer 51: first power line 52: second power line 53: signal line 65: application Voltage monitoring unit 66: Driving current monitoring unit 100: Hybrid vehicle 101: Booster circuit

Claims (7)

A hybrid vehicle having an internal combustion engine and an electric motor as a drive source,
An electric injector for injecting fuel into the combustion chamber of the internal combustion engine;
A battery having a voltage higher than an applied voltage applied to the injector and supplying electric power to the motor;
A power converter that steps down the voltage from the battery and outputs it as an output voltage;
A control device that is connected to the power conversion device via a power line and that applies the output voltage output from the power conversion device to the injector as the applied voltage at a predetermined timing;
The power conversion device controls the output voltage to reduce the difference based on a difference between a measured value of the applied voltage of the injector and a target value of the applied voltage. The control device is provided in the engine room of the hybrid vehicle,
The hybrid vehicle according to claim 1, wherein the power conversion device is provided in another part of the hybrid vehicle except the engine room.   The control device acquires the measured value of the applied voltage, and outputs the measured value of the applied voltage or the difference between the measured value of the applied voltage and the target value of the applied voltage to the power converter. The hybrid vehicle according to claim 1 or 2.   The hybrid vehicle according to claim 3, wherein the control device acquires a measured value of the applied voltage when a current supplied to the injector has a predetermined peak current value. The injector injects fuel at least once during one combustion cycle of the internal combustion engine;
The hybrid vehicle according to claim 4, wherein the control device acquires the measured value of the applied voltage at the first injection in one combustion cycle. The controller monitors the applied voltage;
The hybrid vehicle according to any one of claims 1 to 5, wherein the power converter does not change the output voltage when the monitored value of the applied voltage is zero. A second battery having a voltage lower than the applied voltage;
A booster that boosts the voltage from the second battery;
The said control apparatus supplies the voltage output from the said pressure | voltage rise apparatus to the said injector at a predetermined | prescribed timing at the time of the failure of the said power converter device, The one of Claims 1-6 characterized by the above-mentioned. The hybrid vehicle described in 1.

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