JP2014227929A - Failure detection device of injector energization cutoff function - Google Patents

Abstract

To provide a failure detection device for an injector energization cutoff function capable of detecting a failure of an injector energization cutoff function by ensuring the number of single injections when an ignition switch is off. The failure detection device for the injector energization cutoff function detects a failure in the energization cutoff function of the injector 23 when the ignition switch is off, and performs injection control by an angle synchronous drive system when the engine 1 is operated. At the time of detecting a failure of the energization cutoff function of the injector 23, the injection control by the time synchronous drive method is performed. [Selection] Figure 6

Description

  The present invention relates to a failure detection device for an injector energization cutoff function.

  2. Description of the Related Art Conventionally, a diagnostic device for a drive control device for a fuel injection valve that includes an ECU (Engine Control Unit) and an injector drive device that drives an injector based on an injection signal transmitted from the ECU has been disclosed (for example, Patent Literature 1). 1). In this diagnostic device, after the ignition is turned off, the power supply to the injector driving device is stopped, and the injector driving device is forcibly transmitted from the ECU to the injector driving device in a state where the injector driving power source is cut off. It is possible to determine whether or not there is a failure.

  Also disclosed is a start control device for a fuel injection device of an internal combustion engine that injects and supplies fuel by a time synchronous drive method within a predetermined time after the starter switch is turned on, and injects and supplies fuel by an angle synchronous drive method after a predetermined time has elapsed. (For example, refer to Patent Document 2). In this start control device, it is possible to obtain a higher number of injections by injecting and supplying the fuel by the time-synchronized drive method than when injecting and supplying the fuel by the angle-synchronized drive method.

Japanese Patent Laid-Open No. 11-13519 Japanese Patent Laid-Open No. 5-163977

  By the way, since the injector driving (injection control) by the angle synchronous driving system is performed based on the rotational driving (input) of the crankshaft of the engine, the crankshaft is not rotationally driven at low speed or when the engine is stopped. In the case of (no input signal), there is a disadvantage that the injector drive (injection control) is not performed.

  Therefore, in the angle synchronous drive system, when the ignition switch is turned off from a rotation stop state or a state close thereto, for example, when the ignition switch is turned off from the idle stop, or after the ignition switch is turned off, injection for vibration suppression at the stop is performed to extremely low rotation. In such a case, it is difficult to secure the number of times of single injection (determination number) at the time of failure detection. As a result, there is a problem in that it is difficult to detect a failure of the power-off function of the injector when the ignition switch is off. In addition, Patent Documents 1 and 2 do not suggest or describe a point related to the failure detection of the current-carrying-off function of the injector when the ignition switch is off.

  The present invention has been made in view of the above problems, and when the ignition switch is OFF, the failure of the injector energization cutoff function that can detect the failure of the injector energization cutoff function by securing the number of single injections The object is to provide a detection device.

  As means for solving the above-described problems, a failure detection apparatus for an injector energization cutoff function according to the present invention is configured as follows.

  That is, the failure detection apparatus for the injector energization cutoff function according to the present invention is premised on a configuration for detecting a failure of the injector energization cutoff function when the ignition switch is off. In addition, the failure detection device for the injector energization cutoff function according to the present invention performs injection control by the angle-synchronized drive system during engine operation, and performs injection control by the time-synchronization drive system when the failure of the energization cutoff function is detected. It is what.

  According to the failure detection device of the injector energization cutoff function having such a configuration, there is no input signal from the crankshaft of the engine when the ignition switch is off by switching to the injection control by the time-synchronized drive method when the failure of the energization cutoff function is detected. Even in this case, it is possible to ensure the number of times of single injection by performing single injection by the time synchronous drive method, and to ensure the number of determinations. Thereby, when the ignition switch is OFF, the failure detection (determination) of the injector energization cutoff function can be performed by securing the number of single injections.

  As specific configurations of the present invention, the following plural ones are listed.

  In the failure detection apparatus for the injector energization cutoff function according to the present invention, preferably, when the ignition switch is off, the injection control by the time-synchronized drive method is performed when the engine speed is equal to or lower than the predetermined speed and the fuel injection is stopped. It is characterized by. According to this configuration, when the ignition switch is off and the engine speed is equal to or lower than the predetermined speed and the fuel injection is stopped, the failure detection of the power cut-off function can be started. Fault detection can be started.

  Further, in the failure detection device for an injector energization interruption function according to the present invention, preferably, in a state where energization to the injector is interrupted, whether the energization interruption function is normal based on the presence / absence of an energization signal with respect to an injection signal. It is characterized by performing injection control by the time-synchronized drive method for determining whether or not. If comprised in this way, it can be easily determined whether the electricity interruption | blocking function is normal by detecting the presence or absence of the electricity supply signal from an injector.

  In this case, when there is an energization signal with respect to the injection signal in a state where the energization to the injector is interrupted, it is determined that the energization cutoff function is abnormal and there is no energization signal with respect to the injection signal. In this case, it may be determined that the energization cutoff function is normal.

  In the failure detection device for injector energization interruption function according to the present invention, preferably, the engine is a compression self-ignition engine that performs combustion by self-ignition of fuel injected into the cylinder from the injector, and the compression When the self-ignition engine is operated, the injection control is performed by the angle synchronous drive method, and when the failure of the energization cutoff function is detected, the injection control by the time synchronous drive method is performed. With this configuration, in a compression auto-ignition engine (diesel engine), in which the injector is generally driven by an angle synchronous drive system, even when there is no input signal from the engine crankshaft when the ignition switch is off. Since single injection can be performed by the time-synchronized driving method, it is possible to detect (determine) a failure of the injector energization cutoff function when the ignition switch is off.

  As described above, according to the failure detection apparatus for the injector energization cutoff function according to the present invention, it is possible to detect a failure of the injector energization cutoff function by securing the number of single injections when the ignition switch is off.

1 is a schematic configuration diagram of an engine to which the present invention is applied and a control system thereof. It is sectional drawing which shows the combustion chamber of a diesel engine, and its peripheral part. It is a block diagram which shows the structure of control systems, such as ECU. It is a block diagram which shows structures, such as ECU and an injector drive device. It is the figure which compared the single injection implementation timing with an angle synchronous drive system and a time synchronous drive system. It is a flowchart which shows an example of injection control of an injector energization interruption | blocking function.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  In the present embodiment, a case where the present invention is applied to a common rail in-cylinder direct injection multi-cylinder (for example, in-line 4-cylinder) diesel engine (compression self-ignition internal combustion engine) mounted on a vehicle will be described.

-Engine configuration-
First, a schematic configuration of a diesel engine to which the present invention is applied will be described. FIG. 1 is a schematic configuration diagram of a diesel engine 1 to which the present invention is applied and a control system thereof. FIG. 2 is a cross-sectional view showing the combustion chamber 3 of the diesel engine 1 and its periphery.

  As shown in FIG. 1, a diesel engine 1 (hereinafter also referred to as “engine 1”) is configured as a diesel engine system having a fuel supply system 2, a combustion chamber 3, an intake system 6, an exhaust system 7 and the like as main parts. ing.

  The fuel supply system 2 includes a supply pump 21, a common rail 22, an injector (fuel injection valve) 23, an engine fuel passage 27, and the like.

  The supply pump 21 pumps fuel from the fuel tank, makes the pumped fuel high pressure, and supplies it to the common rail 22 via the engine fuel passage 27. The common rail 22 has a function as a pressure accumulating chamber that holds (accumulates) high-pressure fuel at a predetermined pressure, and distributes the accumulated fuel to the injectors 23. The injector 23 includes a piezoelectric element (piezo element) therein, and is configured by a piezo injector that is appropriately opened to supply fuel into the combustion chamber 3.

  The intake system 6 includes an intake manifold 63 connected to an intake port 15a (see FIG. 2) formed in the cylinder head 15 (see FIG. 2), and an intake pipe 64 is connected to the intake manifold 63. . The intake port 15a, the intake manifold 63, the intake pipe 64, and the like constitute an intake passage.

  In this intake passage, an air cleaner 65, an air flow meter 43, a compressor impeller 53 of a turbocharger 5 to be described later, an intake throttle valve (diesel throttle) 62, and the like are arranged in this order from the upstream side. The air flow meter 43 outputs an electrical signal corresponding to the amount of air flowing into the intake passage via the air cleaner 65.

  The exhaust system 7 includes an exhaust manifold 72 connected to an exhaust port 71 formed in the cylinder head 15 (see FIG. 2), and an exhaust pipe 73 is connected to the exhaust manifold 72. The exhaust port 71, the exhaust manifold 72, the exhaust pipe 73 and the like constitute an exhaust passage. In the exhaust passage, a turbine wheel 52 of the turbocharger 5 described later, an exhaust purification unit 77, and the like are disposed.

  The exhaust purification unit 77 includes an NSR catalyst (exhaust purification catalyst) 75 and a DPF (Diesel Particulate Filter) 76 as NOx storage reduction catalysts. A DPNR catalyst may be applied as the exhaust purification unit 77.

The NSR catalyst 75 stores NOx in a state where a large amount of oxygen is present in the exhaust gas, has a low oxygen concentration in the exhaust gas, and a large amount of reducing component (for example, an unburned component (HC) of fuel). In the existing state, NOx is reduced to NO ₂ or NO and released. NO NOx released as NO ₂ or NO, the N ₂ is further reduced due to quickly reacting with HC or CO in the exhaust.

Further, HC and CO are oxidized to H ₂ O and CO ₂ by reducing NO ₂ and NO. That is, by appropriately adjusting the oxygen concentration and HC component in the exhaust gas introduced into the NSR catalyst 75, HC, CO, and NOx in the exhaust gas can be purified.

  In the present embodiment, the oxygen concentration and HC component in the exhaust gas are adjusted by the fuel injection operation (post injection) from the injector 23 and the opening degree control of the intake throttle valve 62.

  The DPF 76 is made of, for example, a porous ceramic structure, and collects PM (Particulate Matter) contained in the exhaust gas when the exhaust gas passes through the porous wall. . The DPF 76 carries a catalyst (for example, an oxidation catalyst mainly composed of a noble metal such as platinum) for oxidizing and burning the collected PM during the DPF regeneration operation.

  Here, the structure of the combustion chamber 3 of the engine 1 and its peripheral part will be described with reference to FIG. As shown in FIG. 2, a cylinder block 11 constituting a part of the engine body is formed with a cylindrical cylinder bore 12 for each cylinder (four cylinders), and a piston 13 is formed inside each cylinder bore 12. Is accommodated so as to be slidable in the vertical direction.

  The combustion chamber 3 is formed above the top surface 13 a of the piston 13. That is, the combustion chamber 3 is defined by the lower surface of the cylinder head 15 attached to the upper portion of the cylinder block 11, the inner wall surface of the cylinder bore 12, and the top surface 13 a of the piston 13. A cavity (concave portion) 13 b is formed in a substantially central portion of the top surface 13 a of the piston 13, and this cavity 13 b also constitutes a part of the combustion chamber 3.

  The piston 13 is connected to a crankshaft, which is an engine output shaft, by a connecting rod 18. As a result, the reciprocating movement of the piston 13 in the cylinder bore 12 is transmitted to the crankshaft via the connecting rod 18, and the engine output is obtained by rotating the crankshaft.

  Further, a glow plug 19 is disposed toward the combustion chamber 3. The glow plug 19 functions as a start-up assisting device that is heated red when an electric current is applied immediately before the engine 1 is started and a part of the fuel spray is blown onto the glow plug 19 to promote ignition and combustion.

  The cylinder head 15 is formed with the intake port 15a and the exhaust port 71, respectively, and an intake valve 16 for opening and closing the intake port 15a and an exhaust valve 17 for opening and closing the exhaust port 71 are disposed. The cylinder head 15 is provided with the injector 23 that directly injects fuel into the combustion chamber 3. The injector 23 is disposed at a substantially upper center of the combustion chamber 3 in a standing posture along the cylinder center line P, and injects fuel introduced from the common rail 22 toward the combustion chamber 3 at a predetermined timing.

  As shown in FIG. 1, the engine 1 is provided with a supercharger (turbocharger) 5. The turbocharger 5 includes a turbine wheel 52 and a compressor impeller 53 that are connected via a turbine shaft 51. The compressor impeller 53 is arranged facing the inside of the intake pipe (intake passage) 64, and the turbine wheel 52 is arranged facing the inside of the exhaust pipe (exhaust passage) 73.

  Accordingly, the turbocharger 5 performs a so-called supercharging operation in which the compressor impeller 53 is rotated using the exhaust flow (exhaust pressure) received by the turbine wheel 52 to increase the intake pressure. The turbocharger 5 is a variable nozzle type turbocharger, and is provided with a variable nozzle vane mechanism (not shown) on the turbine wheel 52 side. The supply pressure can be adjusted.

  The turbine wheel 52 of the turbocharger 5 is accommodated in the turbine housing 52a. The compressor impeller 53 is accommodated in the compressor housing 53a. A turbine 520 is configured by the turbine wheel 52, the turbine housing 52a, the variable nozzle vane mechanism, and the like. A compressor 530 is configured by the compressor impeller 53, the compressor housing 53a, and the like.

  An intake pipe 64 of the intake system 6 (an intake passage on the downstream side of the intake air flow of the compressor 530) is provided with an intercooler 61 for forcibly cooling intake air whose temperature has been raised by supercharging in the turbocharger 5. .

  Further, the engine 1 is provided with an exhaust gas recirculation passage (EGR passage) 8 that connects the intake system 6 and the exhaust system 7. The EGR passage 8 is configured to reduce the combustion temperature by recirculating a part of the exhaust gas to the intake system 6 and supplying it again to the combustion chamber 3, thereby reducing the amount of NOx generated.

  Further, the EGR passage 8 is opened and closed steplessly by electronic control, and an exhaust gas flowing through the EGR passage 8 (refluxing) is cooled by an EGR valve 81 that can freely adjust the exhaust flow rate flowing through the passage 8. An EGR cooler 82 is provided. The EGR passage 8, the EGR valve 81, the EGR cooler 82, and the like constitute an EGR device (exhaust gas recirculation device). In addition, as an EGR apparatus, the thing of the structure which is not equipped with the said EGR cooler 82 may be sufficient.

-Sensors-
Various sensors are attached to each part of the engine 1, and signals related to the environmental conditions of each part and the operating state of the engine 1 are output.

  For example, the air flow meter 43 outputs a detection signal corresponding to the flow rate (intake air amount) of intake air upstream of the intake throttle valve 62 in the intake system 6. The rail pressure sensor 41 outputs a detection signal corresponding to the fuel pressure stored in the common rail 22. The throttle opening sensor 42 detects the opening of the intake throttle valve 62.

  The intake pressure sensor 48 is disposed in the intake manifold 63 and outputs a detection signal corresponding to the intake air pressure. The intake manifold temperature sensor (intake air temperature sensor) 49 is disposed in the intake manifold 63 and outputs a detection signal corresponding to the temperature of intake air into the combustion chamber 3.

  The A / F (air-fuel ratio) sensors 44a and 44b are arranged on the upstream side and the downstream side of the NSR catalyst 75, respectively, and output detection signals that change continuously according to the oxygen concentration in the exhaust gas. The A / F sensor may be disposed only on the upstream side of the NSR catalyst 75 or only on the downstream side of the NSR catalyst 75.

  Similarly, the exhaust temperature sensors 45a and 45b are disposed on the upstream side and the downstream side of the NSR catalyst 75, respectively, and output detection signals corresponding to the exhaust gas temperature (exhaust temperature). The exhaust temperature sensor may be disposed only on the upstream side of the NSR catalyst 75 or only on the downstream side of the NSR catalyst 75.

-ECU-
The ECU 100 includes a microcomputer including an unillustrated CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), and an input / output circuit.

  As shown in FIG. 3, the input circuit of the ECU 100 includes a crank position sensor 40 that outputs a detection signal (pulse) every time the output shaft (crankshaft) of the engine 1 rotates by a certain angle, a rail pressure sensor 41, a throttle opening. Degree sensor 42, air flow meter 43, A / F sensors 44 a and 44 b, exhaust temperature sensors 45 a and 45 b, water temperature sensor 46 that outputs a detection signal according to the cooling water temperature of the engine 1, and a detection signal according to the depression amount of the accelerator pedal Are connected to an accelerator opening sensor 47, an intake pressure sensor 48, an intake manifold temperature sensor 49, and the like.

  On the other hand, the output circuit of the ECU 100 includes a supply pump 21, an injector 23, an injector drive device 24 that drives the injector 23 based on a signal (injection command) from the ECU 100, and a variable nozzle vane mechanism (a variable nozzle vane opening degree) of the turbocharger 5. ), An intake throttle valve 62, an EGR valve 81, and the like are connected.

  Then, the ECU 100 executes various controls of the engine 1 based on outputs from the various sensors described above, calculated values obtained by arithmetic expressions using the output values, or various maps stored in the ROM. .

  For example, the ECU 100 executes pilot injection (sub-injection) and main injection (main injection) as fuel injection control of the injector 23.

  The pilot injection is an operation for injecting a small amount of fuel in advance prior to the main injection from the injector 23. The pilot injection is an injection operation for suppressing the ignition delay of fuel due to the main injection and leading to stable diffusion combustion, and is also referred to as sub-injection.

  The main injection is an injection operation (torque generation fuel supply operation) for generating torque of the engine 1. The injection amount in the main injection is basically determined so that the required torque can be obtained according to the operating state such as the engine speed (engine speed), the accelerator operation amount, the coolant temperature, the intake air temperature, and the like. .

  For example, as the engine speed (engine speed calculated based on the detection value of the crank position sensor 40; engine speed) increases, the accelerator operation amount (depressing the accelerator pedal detected by the accelerator opening sensor 47) increases. The larger the (amount) (the greater the accelerator opening), the higher the required torque value of the engine 1, and the greater the fuel injection amount in the main injection.

  As an example of a specific fuel injection mode, the pilot injection (fuel injection from a plurality of injection holes formed in the injector 23) is performed before the piston 13 reaches the compression top dead center, and the fuel injection is temporarily stopped. After that, the main injection is executed when the piston 13 reaches the vicinity of the compression top dead center after a predetermined interval.

  As a result, the fuel is combusted by self-ignition, and energy generated by this combustion is kinetic energy for pushing the piston 13 toward the bottom dead center (energy serving as engine output), and heat energy for raising the temperature in the combustion chamber 3. The heat energy is radiated to the outside (for example, cooling water) through the cylinder block 11 and the cylinder head 15.

  The fuel injection pressure when executing the fuel injection is determined by the internal pressure of the common rail 22. As the common rail internal pressure, generally, the target value of the fuel pressure supplied from the common rail 22 to the injector 23, that is, the target rail pressure, increases as the engine load (engine load) increases and the engine speed (engine speed) increases. It will be expensive.

  The target rail pressure is set according to a fuel pressure setting map stored in the ROM of the ECU 100, for example. In the present embodiment, the fuel pressure is adjusted between 30 MPa and 200 MPa according to the engine load and the like.

  In addition to the pilot injection and the main injection described above, after injection and post injection are performed as necessary. The function of these injections is well known. In particular, the post injection is used for NOx reduction processing, S poison recovery control, and DPF regeneration processing.

  Further, the ECU 100 controls the opening degree of the EGR valve 81 (including the case where the opening degree = 0 (closed)) according to the operating state of the engine 1, and the exhaust gas recirculation amount (EGR amount) toward the intake manifold 63. Adjust. This EGR amount is set according to an EGR map that is created in advance by experiments, simulations, or the like and stored in the ROM of the ECU 100. This EGR map is a map for determining the EGR amount (EGR rate) using the engine speed and the engine load as parameters.

  Further, as shown in FIG. 4, the ECU 100 includes an angle synchronous driving means 101 that performs normal fuel injection by angle synchronous driving based on a detection signal (crank angle information) output from the crank position sensor 40, and an injector energization interruption. Whether the time-synchronized drive unit 102 that injects fuel at predetermined time intervals when a function failure is detected, the drive switching determination unit 103 that switches between the angle-synchronized drive unit 101 and the time-synchronized drive unit 102, and whether the injector energization cutoff function is normal An abnormality determination unit 104 that determines whether or not a failure has occurred and an energization interruption unit 105 that interrupts energization of the injector 23 when a failure is detected. Further, the ECU 100 outputs a fuel injection command based on the drive means (the angle synchronous drive means 101 or the time synchronous drive means 102) after the determination by the drive switching determination unit 103 to the injector drive device 24.

  The injector driving device 24 includes an energization monitoring unit 241 and a power cut unit 242. The energization monitoring unit 241 monitors the energization state between the injector driving device 24 and the injector 23 and outputs the energization state to the abnormality determination unit 104 of the ECU 100 as an energization signal. The power cut means 242 cuts the power to the injector 23 based on the power cut signal input from the power cut means 105 of the ECU 100.

  Here, in the present embodiment, when the failure detection of the injector energization cutoff function is detected, the ECU 100 determines that the engine speed is in a predetermined condition (in the present embodiment, when the ignition switch is turned off (after being turned off)). When a predetermined number of revolutions or less and a state in which fuel injection is stopped (injection cut) are established, the drive system of the injector 23 is switched to the time synchronous drive system, and the energization to the injector 23 is intentionally cut off. Then, a single injection command (injector injection command) is output to a predetermined cylinder (predetermined injector 23) during energization interruption, and whether or not the injector energization interruption function is normal based on the presence / absence of an energization signal (whether it has failed) Or not).

  In other words, when performing failure detection, a single injection is performed even when the engine rotation is stopped by adopting a time-synchronized driving method instead of driving by an angle-synchronized driving method which is a general basic driving method of diesel. It becomes possible. Thereby, in this embodiment, it is possible to earn the number of determinations for performing failure detection. Note that the cylinder that performs single injection may be determined in advance as a specific cylinder, or may be appropriately selected when single injection is performed.

  Next, with reference to FIG. 5, the effect of performing failure detection by the time synchronous drive method will be described by comparing the single injection execution timings of the angle synchronous drive method and the time synchronous drive method. In FIG. 5, while the elapsed time is shown on the horizontal axis and the engine speed is shown on the vertical axis, the engine speed decreases with time. Moreover, the triangular mark shown in FIG. 5 has shown an example of the implementation timing (number of times) of single injection.

  For example, during the period from the time t1 to the time t2, the rotational speed of the engine 1 gradually decreases while being normally driven by the angle synchronous driving method. At time t2, the engine speed is reduced to a predetermined speed, the engine speed is relatively low, and fuel injection is stopped. Thereafter, the engine speed is further reduced from time t2 to t3. At time t3, the ignition switch is turned off, and thereafter the engine rotation is stopped.

  Here, as shown in the comparative example, in the angle synchronous driving method, in the extremely low rotation state from the time t2 to the time t3, the interval of the single injection execution timing is gradually increased as time elapses. I understand that. On the other hand, as shown in the present embodiment, in the time synchronous drive method, single injection is performed at a constant timing regardless of the passage of time in the extremely low rotation state from time t2 to t3. I understand that.

  Further, in the extremely low rotation state from time t2 to t3, in the angle synchronous drive method according to the comparative example, for example, single injection is performed four times, whereas in the time synchronous drive method according to the present embodiment, single injection is performed. Has been implemented 10 times. Thereby, in the extremely low rotation state between time t2 and t3, the time synchronous drive system by this embodiment can earn the number of times of determination for performing failure detection.

  Further, in the rotation stop state after time t3, in the angle synchronous driving method according to the comparative example, since the detection signal is not output from the crank position sensor 40, it is impossible to perform the single injection, but the time synchronization according to the present embodiment. In the driving method, single injection is performed eight times. Thereby, in the rotation stop state after time t3, in the time synchronous drive system by this embodiment, it is possible to earn the frequency | count of determination for performing a failure detection.

-Failure detection control of injector deenergization function-
Next, failure detection control of the injector energization cutoff function according to the present embodiment will be described with reference to FIGS.

  In step ST1, it is determined whether or not an execution condition for detecting a failure of the injector energization cutoff function is satisfied. Here, the drive switching determination unit 103 (see FIG. 4) of the ECU 100 determines whether or not all three execution conditions are satisfied based on the signals from the respective sensors. Specifically, when the ignition switch is off (after being turned off), when the engine speed is equal to or lower than a predetermined speed and the fuel injection is stopped (injection cut) (Yes: Yes) In step ST2, the drive switching determination unit 103 (see FIG. 4) switches to time-synchronized driving, and the failure detection control of the injector energization cutoff function is started. Note that the time when the execution condition is established in step ST1 corresponds to, for example, the start of the rotation stop state at time t3 shown in FIG.

  If it is determined in step ST1 that the condition for detecting the failure of the injector energization cutoff function is not satisfied (No determination: No), the process proceeds to step ST3, and the drive switching determination unit 103 (see FIG. 4). Is switched to angle synchronous drive. Thereafter, in step ST4, injector driving by the angle synchronous driving method is performed.

  If the injector is driven by the angle synchronous drive method before the process of step ST1 is started, the angle synchronous drive method is switched to the injector drive by the time synchronous drive method in step ST2, while In step ST3, the injector drive by the angle synchronous drive system is maintained.

  Next, in step ST5, the energization interruption of the injector 23 is performed. At this time, the power cut-off signal is output to the power cut means 242 of the injector drive device 24 by the power cut-off means 105 (see FIG. 4) of the ECU 100. Then, the power supply to the injector 23 is cut (energization cut off) by the power cut means 242 of the injector drive device 24, and the injection of each cylinder is stopped.

  Next, in step ST6, it is determined whether or not the single injection execution counter has reached a predetermined value (for example, “8 times”) set in advance. In this case, in the first order of the control flow, since the single injection has not been performed yet, the single injection execution counter becomes “0”. Thereby, it is determined that the execution counter (“0 times”) of the single injection has not reached the predetermined value (“8 times”) (No determination: No), and the process proceeds to step ST7.

  Next, in step ST7, the ECU 100 outputs an injector injection command (single injection command) to the injector drive device 24 while the power supply is cut off. Thereafter, the process proceeds to step ST8, and the execution counter is counted up. Thereafter, the process proceeds to step ST9.

  Next, in step ST9, it is determined whether or not an energization signal is returned to the injector injection command (single injection command) by the energization monitoring unit 241 (see FIG. 4) of the injector drive device 24 (presence of energization signal). Monitored. If it is determined in step ST9 that the energization monitor means 241 does not return an energization signal for the injector injection command (single injection command) (no energization signal) (No determination: No), the process returns to step ST6. .

  In step ST9, when it is determined by the energization monitoring means 241 that the energization signal for the injector injection command (single injection command) is returned (there is an energization signal) (affirmative determination: Yes), the energization signal is The current is output from the energization monitoring unit 241 to the abnormality determination unit 104 (see FIG. 4), and the process proceeds to step ST10. In step ST10, the execution counter is counted up as an abnormality counter. Thereafter, the process returns to step ST6.

  In step ST6, the ECU 100 determines whether or not the single injection execution counter has reached a predetermined value ("8 times"). For example, in the second order of the control flow, since the single injection has already been performed once in step ST7 of the first order, the execution counter becomes “one time”. As a result, it is determined that the execution counter (“1 time”) has not reached the predetermined value (“8 times”) (negative determination: No). Thereafter, the processes in steps ST6 to ST10 are repeated until the execution counter reaches a predetermined value (“8 times”).

  Thereafter, if the execution counter reaches a predetermined value (“8 times”) in step ST6, the process proceeds to step ST11. In step ST11, it is determined whether or not the execution counter and the abnormality counter are equal. Here, when the execution counter is not equal to the abnormality counter (negative determination: No), the process proceeds to step ST12. That is, in step ST9, when it is determined that there is no energization signal (normal), the execution counter is counted up, whereas the abnormality counter is not counted up and remains “0”. It is determined that the execution counter is not equal to the abnormality counter. Thereafter, the process proceeds to step ST12, where the ECU 100 (see FIG. 4) determines that the injector energization cutoff function is normal (no failure).

  Further, when it is determined in step ST11 that the execution counter and the abnormality counter are equal (positive determination: Yes), the process proceeds to step ST13. That is, in step ST9, when it is determined that there is an energization signal (abnormal), the execution counter is counted up while the abnormality counter is also counted up, so it is determined that the execution counter is equal to the abnormality counter. Is done. Thereafter, the process proceeds to step ST13, where the abnormality determining unit 104 (see FIG. 4) determines that the injector energization cutoff function is abnormal (failed).

  As described above, according to the failure detection device for the injector energization cutoff function according to the present embodiment, the effects listed below can be obtained.

  In the present embodiment, as described above, there is no input signal from the crank position sensor 40 of the engine 1 when the ignition switch is off by switching to the injection control by the time synchronous drive method when detecting the failure of the energization cutoff function of the injector 23. Even in this case, it is possible to ensure the number of times of single injection by performing single injection by the time synchronous drive method, and to ensure the number of determinations. Thereby, when the ignition switch is OFF, it is possible to detect a failure (determination) of the energization cutoff function of the injector 23 by securing the number of single injections. In other words, in a diesel engine in which the injector 23 is generally driven by the angle-synchronized drive system, even when there is no input signal from the crank position sensor 40 of the engine 1 when the ignition switch is off, the single-shot injection is performed by the time-synchronized drive system. Therefore, when the ignition switch is off, it is possible to detect (determine) the failure of the injector energization cutoff function by securing the number of single injections.

  Further, in the present embodiment, as described above, when the engine speed is equal to or lower than the predetermined speed and the fuel injection is stopped when the ignition switch is turned off, the injection control by the time synchronous drive method is performed. As a result, when all the above conditions are satisfied, the failure detection of the power supply interruption function of the injector 23 can be started, so that the failure detection of the power supply interruption function can be effectively started.

  In the present embodiment, as described above, when there is an energization signal from the injector 23 with respect to the injection signal input to the injector driving device 24 (injector 23) in a state where the energization to the injector 23 is cut off. When it is determined that the energization cutoff function is abnormal and there is no energization signal from the injector 23 with respect to the injection signal input to the injector driving device 24 (injector 23), it is determined that the energization cutoff function is normal. . Thereby, it is possible to easily determine whether or not the energization cutoff function is normal by detecting the presence or absence of the energization signal from the injector 23.

-Other embodiments-
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  For example, in the above-described embodiment, the example in which the failure detection is performed when the engine speed is equal to or lower than the predetermined speed and the fuel injection is stopped when the ignition switch is off has been described, but the present invention is not limited to this. In the present invention, failure detection may be performed by adding other conditions to the above conditions.

  In the present embodiment, an example in which the ECU and the injector driving device are provided separately has been described, but the present invention is not limited to this. For example, the ECU may be equipped with functions similar to those of an injector driving device (energization monitoring means and power cut means).

  In the above-described embodiment, an example in which it is determined whether or not the single injection execution counter has reached a predetermined value (“8 times”) set in advance has been described, but the present invention is not limited thereto. For example, the predetermined value may be set to a number other than (“8 times”).

  INDUSTRIAL APPLICABILITY The present invention can be used for a failure detection device having an injector energization cutoff function.

1 Engine 23 Injector 24 Injector Drive Device 40 Crank Position Sensor 100 ECU
DESCRIPTION OF SYMBOLS 101 Angle synchronous drive means 102 Time synchronous drive means 103 Drive switching determination part 104 Abnormality determination part 105 Power supply interruption means 241 Power supply monitoring means 242 Power supply cut means

Claims (5)

In the failure detection device that detects the failure of the deenergization function of the injector when the ignition switch is off,
During engine operation, injection control is performed using the angle synchronous drive system.
A failure detection device for an injector energization cutoff function, wherein injection control is performed by a time-synchronized drive method when a failure of the energization cutoff function of the injector is detected. In the failure detection device of the injector energization cutoff function according to claim 1,
An injector energization cutoff function failure detection device, characterized in that when the ignition switch is off and the engine speed is equal to or lower than a predetermined speed and fuel injection is stopped, injection control by the time-synchronized drive system is performed. In the failure detection device of the injector energization cutoff function according to claim 1 or 2,
Performing injection control by the time-synchronized driving method for determining whether or not the energization cutoff function is normal based on the presence / absence of an energization signal with respect to an injection signal in a state in which energization to the injector is interrupted The failure detection device for the injector energization cutoff function. In the failure detection device of the injector energization interruption function according to claim 3,
When there is an energization signal for the injection signal in a state where the energization to the injector is interrupted, it is determined that the energization cutoff function is abnormal,
A failure detection device for an injector energization cutoff function, wherein when there is no energization signal for the injection signal, it is determined that the energization cutoff function is normal. In the failure detection apparatus of the injector energization interruption function according to any one of claims 1 to 4,
The engine is a compression self-ignition engine that performs combustion by self-ignition of fuel injected into the cylinder from the injector,
During the compression self-ignition engine operation, injection control by the angle synchronous drive system is performed,
A failure detection device for an injector energization interruption function, wherein when the failure of the injector energization interruption function is detected, injection control is performed by the time synchronous drive method.

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