JP6569604B2 - Injection control device - Google Patents

Description

  The present invention relates to an injection control device capable of diagnosing responsiveness of an exhaust gas sensor mounted on a vehicle.

  Exhaust gas discharged from an internal combustion engine such as a diesel engine contains nitrogen oxides (NOx) and particulate matter (PM) that adversely affect the environment. In recent years, systems for purifying NOx are being installed in vehicles. An example of this system is SCR (Selective Catalytic Reduction) using a selective reduction catalyst. The SCR system selectively reduces NOx, for example, supplies a reducing agent such as urea into the exhaust gas to purify the exhaust gas.

  In the SCR system, a NOx sensor for detecting the amount of NOx is provided in the exhaust passage, and the supply amount of the reducing agent is controlled based on the detected amount of NOx. Exhaust gas sensors such as NOx sensors and PM sensors are used for controlling the operating state of an internal combustion engine in addition to the control of the purification system described above. In other words, since the exhaust gas sensor controls the operation state of the internal combustion engine and the purification system based on the output value, high reliability is required for the output value of the exhaust gas sensor.

  Patent Document 1 discloses a failure diagnosis apparatus that determines the responsiveness of a NOx sensor when the amount of exhausted NOx has a predetermined relationship with a predetermined pattern. Specifically, in this failure diagnosis apparatus, a reference pattern as a reference for the temporal change of the exhaust NOx flow rate and a follow-up pattern as a reference for the temporal change of the detected NOx concentration detected by the NOx sensor are defined in advance. Yes. Then, when the internal combustion engine is in the normal operation mode, it is determined whether or not the detected NOx concentration changes with a predetermined relationship with the tracking pattern when the exhaust NOx flow rate changes with a predetermined relationship with respect to the reference pattern. Thus, the responsiveness of the NOx sensor is diagnosed.

JP 2008-190383 A

  However, the NOx sensor responsiveness diagnosis in the failure diagnosis apparatus and failure diagnosis method described in Patent Document 1 is limited to the case where the internal combustion engine is in the normal operation mode, and there is a possibility of limiting the diagnosis opportunity. .

  In addition, because the reference pattern and the follow-up pattern defined in advance are highly dependent on the environment in which the vehicle is placed, for example, environmental temperature, vehicle speed, acceleration, etc., a predetermined relationship between the actually measured exhaust NOx flow rate and the reference pattern, Alternatively, there is a problem that high accuracy cannot be obtained when determining the presence or absence of a predetermined relationship between the detected NOx concentration and the tracking pattern.

  Although it is conceivable to prepare a plurality of reference patterns and follow-up patterns and use them for determination, there is a risk of squeezing the storage capacity of the RAM or ROM in which the patterns are stored, and a predetermined relationship between the actually measured value and the pattern is calculated There is a problem that the load at the time also becomes large.

  In view of the above problems, an object of the present invention is to provide an injection control device that can realize diagnosis of an exhaust gas sensor with a simple configuration even when the internal combustion engine is in a state other than the normal operation mode.

  The invention disclosed herein employs the following technical means to achieve the above object. Note that the reference numerals in parentheses described in the claims and in this section indicate a corresponding relationship with specific means described in the embodiments described later as one aspect, and limit the technical scope of the invention. Not what you want.

In order to achieve the above object, the present invention is provided in a vehicle,
A high-pressure fuel pump (60) used for pressurizing fuel in an internal combustion engine;
A control unit (90) for controlling fuel injection;
An exhaust gas sensor (80) that is provided in an exhaust gas flow path and outputs a physical quantity related to the exhaust gas,
When the state where the engine speed is equal to or lower than a predetermined value is continued for a certain period, the control unit
Shift to high load mode to pressurize the fuel by controlling the high pressure fuel pump,
Before and after the transition to the high load mode, when the amount of change in the output of the exhaust gas sensor is below a predetermined threshold, it is determined that there is an abnormality in the exhaust gas sensor ,
When the internal combustion engine is driven in the normal operation mode, when the difference between the maximum value and the minimum value of the exhaust gas sensor output is not more than a predetermined threshold value,
The control unit shifts to the high load mode when the state where the engine speed is equal to or lower than the predetermined value is continued for a certain period .

  According to this, when the engine speed is maintained at a predetermined value or lower for a certain period, the high pressure fuel pump is shifted to the high load mode to determine the change in the output of the exhaust gas sensor. For this reason, the exhaust gas sensor can be diagnosed without being limited to the premise that the internal combustion engine is in the normal operation mode, that is, the vehicle is operating normally.

  Further, since the exhaust gas sensor is not diagnosed when the vehicle is performing a normal driving operation, a decrease in drivability can be suppressed.

  Furthermore, since the determination for the abnormality of the exhaust gas sensor is to compare the change amount of the output of the exhaust gas sensor with a predetermined threshold value, it is compared with the mode of determining whether or not there is a relationship between the sensor output and the reference pattern or the tracking pattern. The hardware configuration or calculation load can be reduced.

  As described above, the exhaust gas sensor can be diagnosed with a simpler configuration without being limited to the premise that the vehicle is performing a normal driving operation.

It is a block diagram which shows schematic structure of the injection control apparatus in 1st Embodiment. It is a timing chart which shows operation | movement of an injection control apparatus. It is a flowchart which shows operation | movement of an injection control apparatus. It is a flowchart which shows operation | movement of the injection control apparatus in 2nd Embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same reference numerals are given to the same or equivalent parts.

(First embodiment)
The injection control device in the present embodiment is a common rail fuel injection control device mounted on, for example, a diesel engine vehicle.

  Initially, with reference to FIG. 1, schematic structure of the injection control apparatus 100 which concerns on this embodiment is demonstrated.

  As shown in FIG. 1, an injection control device 100 includes a cylinder 10 that serves as a fuel combustion chamber, an injector 20 that injects fuel into the cylinder 10, and an exhaust passage 30 that is connected to the cylinder 10 via an exhaust valve 31. A rail 40 that is disposed in front of the injector 20 to temporarily store fuel, a fuel tank 50, a high-pressure fuel pump 60 that pumps fuel from the fuel tank 50 and pumps it to the rail 40, and fuel in the rail 40 The pressure reducing valve 70 that adjusts the pressure in the rail 40 by returning the fuel to the fuel tank 50, the NOx sensor 80 disposed so as to be exposed to the exhaust gas flowing through the exhaust passage 30, and the control unit 90 are provided. ing.

  Furthermore, the injection control device 100 according to the present embodiment includes a selective catalytic reduction (SCR) device 32 and a storage device 91 associated with the control unit 90 downstream of the exhaust gas sensor 80 in the exhaust passage 30.

  The cylinder 10 is a portion where air sucked inside is mixed with fuel injected by an injector 20 described later. Air and fuel ignite and expand in the cylinder 10 to urge the piston 11. The piston 11 translates in the longitudinal direction of the cylinder 10, and this translational motion is converted into a rotational motion of the crankshaft 13 via the connecting rod 12.

  The injector 20 is a generally known fuel injection device, and injects fuel into the cylinder 10 at a predetermined timing in response to an instruction from the control unit 90. The fuel injection amount depends on the time required for injection and the pressure of the fuel. In general, the amount of NOx and PM contained in the exhaust gas increases as the fuel injection amount increases.

  The exhaust passage 30 is a passage that discharges from the cylinder 10 to the outside of the exhaust gas. The exhaust gas is a gas that remains after air and fuel are ignited in the cylinder 10 and the energy of the explosion is converted into the rotational motion of the crankshaft 30, and contains NOx and PM. The exhaust passage 30 is connected to the cylinder 10 via an exhaust valve 31. When the exhaust valve 31 is opened at a predetermined timing, the cylinder 10 and the exhaust passage 30 communicate with each other. As a result, the exhaust gas moves from the cylinder 10 toward the exhaust passage 30.

The exhaust gas passes through the SCR device 32 and is discharged to the outside. A part of NOx contained in the exhaust gas is reduced by the SCR device 32 and changed to a gas having a relatively small environmental load such as H ₂ O or N ₂ . For example, urea can be used as the selective reduction catalyst.

  Note that when the injection control device 100 has an exhaust gas recirculation (EGR) mechanism, a part of the exhaust gas recirculates from the exhaust passage 30 toward the intake passage. The description is omitted.

  The rail 40 is a container in which fuel is stored in a common rail fuel injection system. An injector 20 corresponding to the number of cylinders is connected to the rail 40 in parallel. The fuel is stored in the rail 40 at a high pressure, and the higher the rail 40 internal pressure, the higher the fuel pressure introduced into the injector 20, and thus the amount of injection per hour increases.

  The fuel tank 50 is a tank in which fuel is stored. The fuel tank 50 is connected to the rail 40 via a high-pressure fuel pump 60 described later. Further, it is connected to the rail 40 via a pressure reducing valve 70 described later on a route different from the route via the high-pressure fuel pump 60.

  The high-pressure fuel pump 60 is a pump for pumping fuel from the fuel tank 50 and pumping it to the rail 40. When the output of the high-pressure fuel pump 60 is increased, the fuel pressure in the rail 40 increases. As the fuel pressure in the rail 40 increases, the amount of fuel injected into the cylinder 10 increases and the amount of NOx and PM contained in the exhaust gas also increases. Note that the output of the high-pressure fuel pump 60 is controlled by the control unit 90.

  The pressure reducing valve 70 is disposed with the rail 40 and the fuel tank 50 separated from each other. When the output of the high-pressure fuel pump 60 is constant, when the pressure reducing valve 70 is opened, the fuel in the rail 40 returns to the fuel tank 50 and the fuel pressure in the rail 40 decreases. On the other hand, when the pressure reducing valve 70 is closed, the fuel pressure in the rail 40 does not recirculate and remains in the rail 40. As the opening of the pressure reducing valve 70 increases, the output of the high pressure fuel pump 60 for keeping the fuel pressure in the rail 40 constant increases. For example, the condition for maximizing the opening of the pressure reducing valve 70 and maximizing the output of the high-pressure fuel pump 60 is the state of the highest load for the injection control device 100, and other conditions are included in the exhaust gas under certain conditions. The amount of NOx and PM to be maximized. The opening degree of the pressure reducing valve 70 is controlled by the control unit 90.

  The NOx sensor 80 corresponds to the exhaust gas sensor described in the claims, and is disposed in the exhaust passage 30 and exposed to the exhaust gas. As the NOx sensor 80, for example, an impedance type sensor using a solid electrolyte can be adopted. Although the detailed configuration of the NOx sensor 80 is omitted, the sensor output is determined based on the current generated by the reduction of NOx in the measurement cell constituting the NOx sensor 80. That is, the output varies depending on the amount of NOx contained in the exhaust gas. The responsiveness of the NOx sensor 80 may decrease due to accumulation of moisture or the like in the measurement cell. Moreover, there is a possibility that the responsiveness may be lowered when the temperature management of the NOx sensor 80 is in a poor state. For this reason, responsive failure diagnosis is required. The output of the NOx sensor 80 is input to the control unit 90. The control unit 90 controls the motion state of the internal combustion engine based on the output of the NOx sensor 80 and controls the supply amount of the reducing agent in the SCR device 32.

  The controller 90 is connected to the high-pressure fuel pump 60 and controls the fuel pressure in the rail 40 by controlling the output of the high-pressure fuel pump 60. The control unit 90 is connected to the pressure reducing valve 70 and controls the fuel pressure in the rail 40 by controlling the opening degree of the pressure reducing valve 70. Further, the control unit 90 is connected to the injector 20 and controls fuel injection by the injector 20 at a predetermined timing. As shown in FIG. 1, information related to the engine speed is input to the control unit 90, and the operating state of the internal combustion engine is controlled based on the engine speed.

  Further, the control unit 90 in the present embodiment receives the output of the NOx sensor 80, controls the amount of reducing agent supplied based on the sensor output value, and performs failure diagnosis of the NOx sensor 80. Detailed procedures and methods of failure diagnosis will be described later.

  The control unit 90 is connected to the storage device 91. The storage device 91 is a RAM, for example, and temporarily stores information such as the engine speed and the output from the NOx sensor 80. The control unit 90 reads desired information from the storage device 91 and uses it for various calculations.

  Next, with reference to FIG. 2 and FIG. 3, the operation | movement flow of the injection control apparatus 100 which concerns on this embodiment is demonstrated.

  In describing the operation flow of the injection control apparatus 100, the situation shown in FIG. 2 is assumed.

  That is, the vehicle travels normally at a speed until time t1. In other words, until the time t1, the internal combustion engine is driven in the normal operation mode, the engine speed, the output of the exhaust gas sensor, the discharge amount (output) of the high-pressure fuel pump, and the outflow amount (open) of the pressure reducing valve. Degree) varies depending on the driving state of the vehicle.

  At time t1, the engine speed becomes substantially constant when the vehicle stops, and the internal combustion engine enters an idle state. Here, the idle state is a state in which the engine speed is maintained at a predetermined threshold value or less and no load is applied to the traveling of the vehicle. Whether the internal combustion engine is in an idle state may be determined by the control unit 90 from the engine speed, or may be determined by the external ECU and transmitted to the control unit 90.

  Hereinafter, an operation flow of the injection control device 100, particularly the control unit 90, will be described with reference to FIG.

  The control unit 90 executes step S1. Step S1 is a step in which the control unit 90 acquires the maximum value (Vmax) of the output of the NOx sensor 80 in a state where the vehicle is traveling normally, that is, in a state where the internal combustion engine is driven in the normal operation mode. It is. Vmax is constantly updated in the normal operation mode. Vmax may be reset every time the normal operation mode ends. Specifically, it may be reset under the condition that the ignition switch is turned off by the driver and the internal combustion engine is stopped. The value of Vmax is stored in the storage device 91.

  Next, the control unit 90 executes Step S2. Step S2 is a step in which the control unit 90 acquires the minimum value (Vmin) of the output of the NOx sensor 80 in a state where the internal combustion engine is driven in the normal operation mode. Vmin is constantly updated in the normal operation mode. Note that Vmin may also be reset every time the normal operation mode ends, similarly to Vmax. The value of Vmin is stored in the storage device 91.

  In addition, since acquisition and update of Vmax in step S1 and acquisition and update of Vmin in step S2 are always performed in the normal operation mode, the execution order of each other may be changed.

  Next, the control unit 90 executes Step S3. In step S3, the control unit 90 determines whether or not the difference (Vmax−Vmin) between the maximum value Vmax and the minimum value Vmin of the output of the NOx sensor 80 is equal to or less than a first threshold value Vth1 that is a predetermined threshold value. It is. Step S3 is periodically executed in the normal operation mode.

  Here, Vth1 is a predetermined constant. The output of the high-pressure fuel pump 60 and the opening of the pressure reducing valve 70 when the vehicle is traveling normally exceed the numerical range specific to the injection control device in order to drive the vehicle. Along with this, the amount of NOx or PM contained in the exhaust gas also exceeds the numerical range unique to the injection control device. In the present embodiment, the output of the NOx sensor 80 corresponding to a specific numerical range in which the amount of NOx can vary is the threshold value Vth1. That is, the threshold value Vth1 is a constant that can be determined by actual measurement or simulation by a running test.

  If the relationship of Vmax−Vmin> Vth1 is satisfied, step S3 is NO. Satisfying the relationship of Vmax−Vmin> Vth1 indicates that the output of the NOx sensor 80 shows the expected variation with respect to the variation in the amount of NOx during normal operation. That is, since the NOx sensor 80 is operating normally, the operation flow of the injection control device 100 returns to step S1. There is no notification to the driver.

  On the other hand, if the relationship of Vmax−Vmin ≦ Vth1 is satisfied, step S3 is YES and the process proceeds to step S4. Satisfying the relationship of Vmax−Vmin ≦ Vth1 means that the NOx sensor 80 does not exhibit the expected responsiveness. That is, it is a state in which the malfunction of the NOx sensor 80 is suspected.

  Step S4 is a step in which the controller 90 determines whether or not the internal combustion engine has maintained an idle state for a certain period. As described above, the idle state is a state in which the engine speed is maintained at a predetermined threshold value or less and no load is applied to the traveling of the vehicle. In FIG. 2, the idle state is started from time t1.

  Control unit 90 determines YES in step S4 if the idle state continues for a predetermined period, and determines NO if it does not continue. In the case of NO determination, the determination in step S4 is repeatedly executed until a YES determination is made. If step S4 is YES, the process proceeds to step S5. In addition, the fixed period prescribed | regulated here can be set arbitrarily. T2-t1 in FIG. 2 corresponds to this fixed period.

  If the idle state is continued at time t2 after a certain period of time has elapsed since the vehicle transitioned to the idle state at time t1, control unit 90 executes step S5. Step S5 is a step in which the control unit 90 acquires the output Voff of the NOx sensor 80 in the idle state.

  Next, the control unit 90 executes Step S6. Step S6 is a step in which the controller 90 increases the output of the high-pressure fuel pump 60, that is, the discharge amount. For example, the output of the high pressure fuel pump 60 is maximized. This intentionally increases the amount of NOx and PM.

  Next, the control unit 90 executes Step S7. Step S7 is a step in which the controller 90 increases the opening of the pressure reducing valve 70, that is, the outflow amount. For example, the opening degree of the pressure reducing valve 70 is fully opened. When the amount of fuel outflow from the rail 40 increases, the pressure of the fuel pumped by the high-pressure fuel pump 60 becomes higher. This intentionally increases the amount of NOx and PM.

  In the present embodiment, the state in which the load of the high-pressure fuel pump 60 is increased by executing Step S6 and Step S7 corresponds to the high load mode described in the claims. In FIG. 2, step S6 and step S7 are executed at time t2.

  After step S7, the amount of NOx and PM increases, so the output of the NOx sensor 80 changes. However, after the time required for the response of the NOx sensor 80, the control unit 90 executes step S8. The time required for the response of the NOx sensor 80 is a time that can be defined in advance according to the specifications of the NOx sensor 80, and is the time until the rise of the output of the NOx sensor 80 is completed. Step S8 is a step in which the controller 90 acquires the output Von of the NOx sensor 80 in the high load mode.

  Next, the control unit 90 executes Step S9. Step S9 is a step in which the control unit 90 acquires the change amount (Von-Voff) of the output of the exhaust gas sensor before and after shifting to the high load mode, and compares it with a second threshold value Vth2 that is a predetermined threshold value. Specifically, it is a step of determining whether or not the relationship of Von−Voff ≦ Vth2 is satisfied.

  Here, Vth2 is a predetermined constant. When the high-pressure fuel pump 60 shifts from the low-load idle state to the high-load mode, the output of the NOx sensor 80 should change as originally assumed. This assumed change amount is the second threshold value Vth2, and the threshold value Vth2 is a constant that can be determined by actual measurement or simulation using the NOx sensor 80.

  If the relationship of Von−Voff> Vth2 is satisfied, step S9 is NO. Satisfying the relationship of Von−Voff> Vth2 means that the output of the NOx sensor 80 is as expected with respect to the change in the amount of NOx caused by the load variation of the high-pressure fuel pump 60 before and after shifting to the high load mode. It shows that it shows the fluctuation of. That is, the operation flow of the injection control device 100 proceeds to step S11, and it is diagnosed that the NOx sensor 80 is operating normally. There is no notification to the driver.

  On the other hand, if the relationship of Von−Voff ≦ Vth2 is satisfied, step S9 is YES. Satisfying the relationship of Von−Voff ≦ Vth2 means that the NOx sensor 80 does not exhibit the expected responsiveness. That is, it is a state in which the malfunction of the NOx sensor 80 is suspected. That is, the operation flow of the injection control device 100 proceeds to step S10, and it is diagnosed that an abnormality has occurred in the NOx sensor 80.

  In the present embodiment, the determination in step S9 is controlled to be YES when the relationship of Von−Voff ≦ Vth2 is continuously satisfied for a predetermined filter time. The time period from time t2 to time t3 shown in FIG. 2 corresponds to the filter time, and step S9 is not determined to be YES only when the relationship of Von−Voff ≦ Vth2 is temporarily satisfied by the undershoot due to noise or the like.

  In step S10, as shown in FIG. 2, the control unit 90 turns on the abnormality flag. By turning on the abnormality flag, the abnormality of the NOx sensor 80 may be notified to the driver by some visual or auditory method. Moreover, you may make it alert | report to the maintenance company etc. of a vehicle via a cloud network etc.

  The injection control device 100 performs failure diagnosis of the NOx sensor 80 in step S10 or step S11, and ends the operation flow.

  Next, the effect by employ | adopting the injection control apparatus 100 which concerns on this embodiment is demonstrated.

  In the injection control device 100, a specific diagnosis operation of the NOx sensor 80 is executed when the vehicle is in an idle state. That is, in the idle state, the high-pressure fuel pump 60 shifts to the high load mode to promote the variation in the amount of NOx generated, and diagnoses the responsiveness of the NOx sensor 80.

  For this reason, the diagnosis of the NOx sensor 80 can be executed without being limited to the state in which the internal combustion engine is operating normally. Further, since the change in the amount of NOx generated necessary for diagnosis is also due to the predetermined load increase defined in steps S6 and S7, the amount of NOx generated that changes irregularly while the vehicle is running is used for the diagnosis. Diagnosis can be executed with higher accuracy than the form. In addition, since diagnosis is not executed during normal operation, a decrease in drivability can be suppressed.

  Further, the determination of the presence or absence of abnormality of the NOx sensor 80 with respect to the change in the output of the NOx sensor 80 is a simple comparison between Von−Voff and the second threshold value Vth2 that is a constant. Compared with the mode for determining whether or not there is a relationship with the hardware, the hardware configuration or the calculation load can be reduced.

  As described above, the diagnosis of the NOx sensor 80 can be realized with a simpler configuration without being limited to the premise that the vehicle is performing a normal driving operation.

(Second Embodiment)
In the first embodiment, the example in which the diagnosis of the NOx sensor 80 is executed by shifting the high-pressure fuel pump 60 to the high load mode when the vehicle is in an idle state is shown. However, the transition of the high-pressure fuel pump 60 to the high load mode is not limited to the idle state.

  The transition of the high-pressure fuel pump 60 to the high load mode can be executed if the engine speed is maintained at a predetermined speed or less, for example, even when the vehicle is coasting. Here, the inertia driving is a state in which the vehicle is traveling without transmitting the engine power to the vehicle, such as when traveling on a downhill without an accelerator operation.

  The operation flow of the control unit 90 in the present embodiment is a flow in which step S4 in the first embodiment is replaced with step S12 as shown in FIG.

  Step S12 is a step in which the controller 90 determines whether or not the engine speed is maintained at a predetermined threshold value Nth or less for a predetermined time (corresponding to time t1 to time t2 in FIG. 2). It is. Since the flow after YES determination and NO determination is the same as that of the first embodiment, the description thereof is omitted.

  In the injection control apparatus 100 according to the present embodiment, the failure diagnosis of the NOx sensor 80 can be executed not only in the idle state but also in a state where the engine speed is maintained at a predetermined threshold value Nth or less for a predetermined time. Therefore, the chance of failure diagnosis of the NOx sensor 80 can be increased as compared with the first embodiment.

(Other embodiments)
The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

  In each of the above-described embodiments, the NOx sensor 80 is described as an example of the exhaust gas sensor. However, a PM sensor can be diagnosed as the exhaust gas sensor. In addition, if the sensor has an output value that changes as the load of the high-pressure fuel pump 60 increases, the diagnosis can be executed without being limited to the above.

  In each embodiment described above, the high-pressure fuel pump 60 is triggered by the difference (Vmax−Vmin) between the maximum value Vmax and the minimum value Vmin of the exhaust gas sensor output in the normal operation mode being equal to or less than the first threshold value Vth1. Is shifted to the high load mode. That is, in the normal operation mode, when an abnormality is suspected in the output of the exhaust gas sensor, a specific failure diagnosis after step S5 is executed. However, it is not always necessary to satisfy the relationship of Vmax−Vmin ≦ Vth1, and a specific failure diagnosis may be executed when the engine speed remains below a predetermined value for a certain period. good. That is, steps S1 to S3 may be omitted in each of the above-described embodiments.

  In each of the above-described embodiments, as the high load mode, an increase in the output of the high-pressure fuel pump 60 and an increase in the opening of the pressure reducing valve 70 are assumed. However, in the high load mode, it is only necessary to increase the amount of NOx generated due to an increase in the load of the high-pressure fuel pump 60. Therefore, it is not always necessary to adjust the opening of the pressure reducing valve 70. When the adjustment of the opening degree of the pressure reducing valve 70 is not executed, step S7 may not be executed among the steps shown in FIG. 3 or FIG.

DESCRIPTION OF SYMBOLS 10 ... Cylinder, 20 ... Injector, 30 ... Exhaust flow path, 32 ... SCR apparatus, 40 ... Rail, 50 ... Fuel tank, 60 ... High pressure fuel pump, 70 ... Pressure reducing valve, 80 ... Exhaust gas sensor (NOx sensor, PM sensor) , 90 ... control unit, 100 ... injection control device

Claims (6)

Provided in the vehicle,
A high-pressure fuel pump (60) used for pressurizing fuel in an internal combustion engine;
A control unit (90) for controlling the fuel injection;
An exhaust gas sensor (80) provided in a flow path of exhaust gas and outputting a physical quantity related to the exhaust gas,
When the state where the engine speed is equal to or lower than a predetermined value is continued for a certain period, the control unit
The high pressure fuel pump is controlled to shift to a high load mode for pressurizing the fuel,
Before and after transition to the high load mode, when the amount of change in the output of the exhaust gas sensor is equal to or less than a predetermined threshold, it is determined that there is an abnormality in the exhaust gas sensor ,
When the internal combustion engine is driven in the normal operation mode, when the difference between the maximum value and the minimum value of the exhaust gas sensor output is not more than a predetermined threshold value,
The said control part is an injection control apparatus which transfers to the said high load mode, when the state whose engine speed is below a predetermined value is continued for a fixed period . Furthermore, a pressure reducing valve (70) used for pressure reduction of the fuel is provided,
The injection control device according to claim 1, wherein the control unit controls the pressure reducing valve to an open side in the high load mode. The injection control device according to claim 1 or 2 , wherein the state in which the engine speed is equal to or less than a predetermined value is that the vehicle is in an idle state. The injection control device according to claim 1 or 2 , wherein the state in which the engine speed is equal to or less than a predetermined value is that the vehicle is in a coasting operation state. The injection control device according to any one of claims 1 to 4 , wherein the exhaust gas sensor is a NOx sensor. The injection control device according to any one of claims 1 to 4 , wherein the exhaust gas sensor is a PM sensor.

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