JP2007056767A - Abnormality determination device for fuel feeder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an abnormality determination device for a fuel feeder capable of properly determining the abnormality of the fuel feeder affecting a combustion timing. <P>SOLUTION: This abnormality determination device 1 for the fuel feeder 10 feeding a fuel into the cylinders 3a of an internal combustion engine 3 comprises an actual combustion timing calculation means 2 calculating, as an actual combustion timing TICOMACT, a timing at which the combustion of the fuel fed from the fuel feeder 10 into the cylinders 3a actually occurs according to a rotating state parameter ω detected, an estimated combustion timing calculation means 2 calculating, as an estimated combustion timing TICOMES, a timing at which the combustion of the fuel fed from the fuel feeder 10 into the cylinders 3a is expected to occur, and an abnormality determination means 2 determining the abnormality of the fuel feeder 10 on the basis of the result of comparison between the calculated actual combustion timing TICOMACT and the estimated combustion timing TICOMES. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an abnormality determination device for a fuel supply device that determines an abnormality of a fuel supply device that supplies fuel into a cylinder of an internal combustion engine, particularly a compression ignition internal combustion engine such as a diesel engine.

  As a conventional abnormality determination device for a fuel supply device, for example, a device disclosed in Patent Document 1 is known. This fuel supply device includes a fuel injection nozzle that injects fuel into a cylinder of a diesel engine, a fuel tank, a fuel injection pump that is connected to a crankshaft and supplies fuel from the fuel tank to the fuel injection nozzle, and a fuel injection A timer device that is provided in the pump and changes the fuel injection timing is provided. In this fuel supply device, the target injection timing of the fuel to be injected from the fuel injection nozzle is set according to the detected rotational speed of the internal combustion engine, accelerator opening, and the like. Further, the operating amount of the timer device is obtained according to the rotational speed of the internal combustion engine, and the actual fuel injection timing (hereinafter referred to as “actual injection timing”) is calculated according to the operating amount. Then, the fuel injection timing is controlled by adjusting the operation amount of the timer device so that the actual injection timing becomes the target injection timing. The fuel injection pump is provided with an electromagnetic valve, and the fuel injection amount (hereinafter referred to as “fuel injection amount”) is controlled by controlling the valve closing time of the electromagnetic valve.

  Further, in this abnormality determination device, the absolute value of the deviation between the target injection timing obtained as described above and the actual injection timing is obtained, and if the absolute value of this deviation exceeds the threshold value, the fuel supply device is abnormally detected. Is determined to have occurred.

  In particular, in a diesel engine, it is important to appropriately control the combustion timing, and abnormal combustion timing greatly affects the exhaust gas characteristics. In addition, in order to obtain an appropriate combustion timing, it is necessary that not only the fuel injection timing by the fuel supply device but also the fuel injection amount and the degree of atomization of the fuel are in an appropriate state. On the other hand, in the conventional abnormality determination apparatus, the abnormality determination is only performed for the injection timing. For this reason, for example, when an abnormality occurs such that the actual fuel injection amount from the fuel supply device deviates from the target injection amount, the abnormality cannot be determined.

  The present invention has been made to solve such problems, and provides an abnormality determination device for a fuel supply device that can appropriately determine an abnormality of the fuel supply device that affects the combustion timing. Objective.

JP-A-9-317542

  In order to achieve this object, the invention according to claim 1 is an abnormality determination device 1 of the fuel supply device 10 for supplying fuel into the cylinder 3a of the internal combustion engine 3, wherein the rotation of the crankshaft 3d of the internal combustion engine 3 is performed. Rotation state parameter detecting means (crank angle sensor 21, ECU 2, step 22 in FIG. 4) for detecting a rotation state parameter (an angular velocity ω in the embodiment (hereinafter the same in this section)) representing the state, and the detected rotation state An actual combustion timing calculating means (ECU2, step 24) for calculating the actual combustion timing TICOMACT as the actual combustion timing TICOMACT, according to the parameters, and the actual combustion timing of the fuel supplied from the fuel supply device 10 into the cylinder 3a; Driving state detecting means (crank angle sensor 21, accelerator open) for detecting the driving state (engine speed NE, required torque PMCMD) Sensor 24, ECU 2) and an estimated combustion timing for calculating the estimated combustion timing TICOMES as the estimated timing at which combustion of the fuel supplied from the fuel supply device 10 into the cylinder 3a occurs according to the detected operating state Abnormality determining means (ECU2, Steps 6 to 6) for determining an abnormality of the fuel supply device 10 based on the calculation means (ECU2, step 5 in FIG. 3) and the comparison result between the calculated actual combustion timing TICOMMACT and the estimated combustion timing TICOMES. And 13).

  According to the abnormality determination device for the fuel supply device, the rotation state parameter detection means detects the rotation state parameter of the crankshaft of the internal combustion engine, and the actual combustion timing calculation means determines the fuel according to the detected rotation state parameter. An actual combustion timing at which combustion of fuel supplied from the supply device into the cylinder actually occurs is calculated. The estimated combustion timing calculation means calculates an estimated combustion timing that is estimated to cause combustion of the fuel supplied into the cylinder, according to the detected operating state of the internal combustion engine. Further, the abnormality determination means determines an abnormality of the fuel supply device based on a comparison result between the calculated actual combustion timing and estimated combustion timing.

  When the fuel burns in the cylinder, the pressure in the cylinder rapidly increases, and accordingly, the angular velocity of the crankshaft increases temporarily and then decreases. For this reason, for example, the angular velocity is used as the rotation state parameter, and the timing at which the angular velocity temporarily increases can be specified as the actual combustion timing at which actual combustion has occurred. Further, in a compression ignition type internal combustion engine such as a diesel engine, the combustion timing depends on the fuel supply timing and the supply amount by the fuel supply device and is roughly determined according to the operation state of the internal combustion engine. It can be estimated with high accuracy from the state. Therefore, if there is no abnormality in the fuel supply timing and supply amount by the fuel supply device, the actual combustion timing calculated according to the crankshaft rotation state parameter is the estimated combustion calculated according to the operating state of the internal combustion engine. It should almost coincide with the time.

  Therefore, an abnormality can be appropriately determined based on the comparison result between the actual combustion timing and the estimated combustion timing. For example, when the deviation of the actual combustion timing from the estimated combustion timing is large, the fuel supply apparatus has an abnormality. Can be determined. In this way, by comparing the actual combustion timing with the estimated combustion timing, not only the fuel supply timing, but also the fuel supply device that affects the combustion timing, such as the difference in supply amount and the degree of fuel atomization, is reduced. Abnormalities can be determined appropriately.

  Further, since the abnormality determination is performed based on the actual combustion timing and the estimated combustion timing, the actual combustion timing is estimated when the abnormality determination device is applied to, for example, a compression ignition type internal combustion engine as well as the abnormality determination of the fuel injection device. By comparing the combustion timing, it can also be determined whether or not the actual ignition timing is appropriate. Furthermore, since the actual combustion timing is calculated in accordance with the rotation state parameter of the crankshaft, it is possible to determine whether or not a misfire state exists using the rotation state parameter. In addition, in order to calculate the actual combustion timing, it is possible to use an existing crank angle sensor which is usually provided for controlling an internal combustion engine, for example, and an extremely expensive sensor such as an in-cylinder pressure sensor is used. Since it is not necessary to provide them separately, the manufacturing cost can be reduced.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows a schematic configuration of an abnormality determination device 1 according to an embodiment of the present invention and an internal combustion engine (hereinafter referred to as “engine”) 3 to which the abnormality determination device 1 is applied. The engine 3 is, for example, an in-line four-cylinder diesel engine having four cylinders 3a (only one is shown). A combustion chamber 3e is formed between the piston 3b and the cylinder head 3c of each cylinder 3a.

  The engine 3 is integrated with a pair of intake valves 4 and 4 and a pair of exhaust valves 7 and 7 (only one is shown), an intake camshaft 5 on the intake side, and the intake camshaft 5 provided for each cylinder 3a. A fuel supply device 10 having an intake cam 6 attached to the exhaust, an exhaust camshaft 8 on the exhaust side, an exhaust cam 9 integrally attached to the exhaust camshaft 8, and a fuel injection valve 11 (hereinafter referred to as "injector"). Etc.

  Each of the intake camshaft 5 and the exhaust camshaft 8 is rotatably supported by the cylinder head 3c via a holder (not shown), and extends along the arrangement direction of the cylinders 3a. The intake camshaft 5 is connected to the crankshaft 3d via a timing chain (not shown), and rotates once every two rotations of the crankshaft 3d. The intake valve 4 is driven to open and close by the rotation of the intake cam 6 accompanying the rotation of the intake camshaft 5.

  Similarly, the exhaust camshaft 8 is connected to the crankshaft 3d via a timing chain (not shown), and rotates once for every two rotations of the crankshaft 3d. As a result, the exhaust valve 7 is driven to open and close.

  On the other hand, the injector 11 is provided for each cylinder 3 a, is attached to the cylinder head 3 c so as to inject fuel directly into the cylinder 3 a, and is connected to the high-pressure pump 13 via the common rail 12. The high-pressure pump 13 is controlled by an ECU 2 (see FIG. 2) described later. The fuel in the fuel tank 14 is boosted to a high pressure by the high-pressure pump 13, supplied to the injector 11 through the common rail 12, and injected from the injector 11 into the cylinder 3 a. The valve opening time and valve opening timing of the injector 11 are controlled by a drive signal from the ECU 2, thereby controlling the fuel injection amount QINJ and the fuel injection timing QTIM.

  The crankshaft 3d of the engine 3 is provided with a cylinder discrimination sensor 20 and a crank angle sensor 21 (rotation state parameter detection means and operation state detection means). Each of these sensors 20 and 21 includes a magnet rotor and an MRE pickup, and outputs a pulse signal at each predetermined crank angle position. Specifically, the cylinder discrimination sensor 20 generates a cylinder discrimination signal CYL (hereinafter referred to as “CYL signal”) at a predetermined crank angle position of a specific cylinder 3a.

  The crank angle sensor 21 generates first and second CRK signals and a TDC signal as the crankshaft 3d rotates. One pulse of the first CRK signal is output every predetermined crank angle (for example, 1 °), and the ECU 2 calculates the angular velocity ω (rotation state parameter) of the crankshaft 3d based on the first CRK signal. The second CRK signal is output with one pulse every predetermined crank angle (for example, 6 °) larger than the first CRK signal, and the ECU 2 determines the engine speed (hereinafter referred to as “engine speed”) based on the second CRK signal. ) Calculate NE. The TDC signal is a signal indicating that the piston 3b of each cylinder 3a is at a predetermined crank angle position slightly in front of the TDC position of the intake stroke. In this example, which is a 4-cylinder type, the crank angle is 180 °. One pulse is output every time.

  The intake camshaft 5 and the exhaust camshaft 8 are provided with an intake cam angle sensor 22 and an exhaust cam angle sensor 23, respectively. The intake cam angle sensor 22 outputs an INCAM signal that is a pulse signal for each predetermined crank angle as the intake cam shaft 5 rotates, and the exhaust cam angle sensor 23 corresponds to a predetermined crank angle as the exhaust cam shaft 8 rotates. In addition, an EXCAM signal that is a pulse signal is output to the ECU 2. Further, the ECU 2 outputs a detection signal representing an operation amount (hereinafter referred to as “accelerator opening”) AP of an accelerator pedal (not shown) from the accelerator opening sensor 24 (operating state detecting means).

  In this embodiment, the ECU 2 constitutes a rotation state parameter detection means, an actual combustion timing calculation means, an operation state detection means, an estimated combustion timing calculation means, and an abnormality determination means, and includes an I / O interface, a CPU, a RAM, It is composed of a microcomputer composed of a ROM or the like. The detection signals from the various sensors 20 to 24 described above are each output to the CPU after A / D conversion and shaping by the I / O interface.

  In accordance with these input signals, the CPU determines the operating state of the engine 3 according to a control program stored in the ROM, etc., and calculates the fuel injection amount QINJ and the fuel injection timing QTIM according to the determined operating state. The drive signal based on them is output to the injector 11. The fuel injection amount QINJ and the fuel injection timing QTIM are calculated by searching a predetermined map (not shown) according to the engine speed NE and the required torque PMCMD. The required torque PMCMD is calculated by searching a predetermined map (not shown) according to the engine speed NE and the accelerator pedal opening AP.

  Further, the CPU executes an abnormality determination process for the fuel supply device 10. This abnormality determination is performed for each cylinder 3a based on the CYL signal. In the following description, the same processing is performed for each cylinder 3a, and therefore, for convenience of description, one cylinder 3a is described.

  FIG. 3 is a flowchart showing an abnormality determination process of the fuel supply device 10. This process is executed in synchronization with the generation of the TDC signal. In this process, in step 1 (illustrated as “S1”, the same applies hereinafter), it is determined whether or not the engine 3 is in operation. If the determination result is NO and the engine 3 is not in operation, the present process is terminated without performing abnormality determination.

  On the other hand, if the determination result in step 1 is YES and the engine 3 is in operation, the counter value CTDC of a TDC counter (not shown) that counts the number of occurrences of the TDC signal is incremented (step 2). Next, the time when fuel combustion actually occurs in the cylinder 3a (hereinafter referred to as "actual combustion time") TICOMMACT is calculated (step 3).

  FIG. 4 shows a subroutine for calculating the actual combustion timing TICOMMACT. First, in step 21, the generation time interval CRME of the first CRK signal is measured. The generation time interval CRME represents the generation time interval between the previous time and the current time of the first CRK signal. Next, the angular velocity ω of the crankshaft 3d is calculated according to the measured generation time interval CRME (step 22), and the angular velocity ω is stored (step 23). Next, the actual combustion timing TICOMACKT is calculated from the stored transitions of the plurality of angular velocities ω (step 24). Specifically, the time when the angular velocity ω has temporarily increased significantly is calculated as the actual combustion time TICOMACKT. This is because, as described above, when the fuel burns, the pressure in the cylinder 3a rapidly increases, and accordingly, the angular velocity ω of the crankshaft 3d increases temporarily and then decreases.

  Returning to FIG. 3, in step 4 following step 3, the crankshaft 3 d of the crankshaft 3 d between the fuel injection start timing which is the fuel injection timing QTIM and the actual combustion timing TICOMMACT obtained in step 3 is based on the first CRK signal. A crank angle (hereinafter referred to as “actual crank angle”) θACT is calculated. Next, by searching a predetermined map (not shown) according to the engine speed NE and the required torque PMCMD, the crank during the period from the fuel injection start time to the estimated combustion time TICOMES estimated to generate combustion is estimated. An angle (hereinafter referred to as “estimated crank angle”) θES is calculated (step 5).

  Next, whether or not the absolute value (= | θACT−θES |) of the difference between the actual crank angle θACT calculated in Steps 4 and 5 and the estimated crank angle θES is equal to or larger than a predetermined angle θLMT (for example, 10 °) is determined. Discriminate (step 6). When the determination result is YES and | θACT−θES | ≧ θLMT, the counter value CSθ of a combustion timing deviation counter (not shown) for counting the number of times is incremented (step 7), and then the process proceeds to step 8. On the other hand, when the determination result of step 6 is NO, step 7 is skipped and the process proceeds to step 8.

  In step 8, it is determined whether or not the counter value CTDC of the TDC counter has reached a predetermined number of times TDCLMT (for example, 400). When the determination result is NO, this process is terminated. On the other hand, if the determination result in step 8 is YES and the number of occurrences of the TDC signal has reached the predetermined number TDLMMT, the counter value CTDC of the TDC counter is reset to 0 (step 9), and then the counter of the combustion timing deviation counter It is determined whether or not the value CSθ is a predetermined number of times CSLMT (for example, 40) or more (step 10).

  When the determination result is NO and CSθ <CSLMT, that is, while the TDC signal is generated a predetermined number of times TDCLMT, the absolute value of the difference between the actual crank angle θACT and the estimated crank angle θES is equal to or greater than the predetermined angle θLMT. When the number of times is less than the predetermined number of times CSLMT, the abnormality determination flag F_SYSINGG is set to “0” on the assumption that the actual combustion timing TICOMMACT is less frequently shifted from the estimated combustion timing TICOMES and the fuel supply device 10 is normal (step). 11), the counter value CSθ of the combustion deviation counter is reset to 0 (step 12), and this process is terminated.

  On the other hand, when the determination result in step 10 is YES and the counter value CSθ is equal to or larger than the predetermined number CSLMT, the actual crank angle θACT is frequently shifted from the estimated crank angle θES, and thus the fuel supply apparatus 10 is abnormal. The abnormality determination flag F_SYSINNG is set to “1” (step 13), and this process is terminated. Note that when step 13 is executed, that is, when it is determined that an abnormality has occurred in the fuel supply device 10, this abnormality determination process is not executed thereafter.

  As described above, according to the present embodiment, the actual combustion timing TICOMMACT is obtained according to the angular velocity ω of the crankshaft 3d, and the actual crank angle θACT of the crankshaft 3d between the fuel injection start timing and the actual combustion timing TICOMMACT. Ask for. Further, an estimated crank angle θES between the fuel injection start timing and the estimated combustion timing TICOMES is obtained according to the engine speed NE and the required torque PMCMD. Then, the abnormality determination of the fuel supply device 10 is executed by comparing the difference between the two and the predetermined angle θLMT.

  As described above, if there is no abnormality in the fuel injection timing QTIM and the fuel injection amount QINJ by the fuel supply device 10, the actual combustion timing TICOMMACT should almost coincide with the estimated combustion timing TICOMES. Therefore, when the absolute value of the difference between the actual crank angle θACT and the estimated crank angle θES up to each combustion timing is equal to or larger than the predetermined angle θLMT, the actual combustion timing TICOMMACT is greatly deviated from the estimated combustion timing TICOMES, and the fuel supply It can be appropriately determined that an abnormality has occurred in the device 10. Thus, by comparing the actual crank angle θACT and the estimated crank angle θES, not only the fuel injection timing QTIM but also the actual combustion timing TICOMMACT, such as the deviation of the fuel injection amount QINJ and the degree of fuel atomization, are affected. Therefore, it is possible to appropriately determine whether or not the fuel supply apparatus 10 has an abnormality.

  Further, when the absolute value of the difference between the actual crank angle θACT and the estimated crank angle θES is greater than or equal to the predetermined angle θLMT while the TDC signal is generated a predetermined number of times TDCLMT, the fuel supply device 10 determines that an abnormality has occurred. As described above, when the actual crank angle θACT greatly deviates from the estimated crank angle θES, it is not immediately determined that there is an abnormality, but the actual number of occurrences of deviation of the actual crank angle θACT is equal to or greater than the predetermined number CSLMT. It is determined that it is abnormal when For this reason, for example, when the deviation of the actual crank angle θACT temporarily increases due to a response delay or the like even though the fuel supply device 10 is normal, it is ensured that an erroneous determination is made as abnormal. It can be avoided.

  Furthermore, by comparing the actual crank angle θACT and the estimated crank angle θES, it is possible to determine whether or not the actual fuel ignition timing is appropriate as well as determining whether the fuel supply apparatus 10 is abnormal. Further, it is possible to determine whether or not each cylinder 3a is in a misfire state using the angular velocity ω of the crankshaft 3d. For example, the peak value when the angular velocity ω temporarily rises is smaller than a predetermined value. Sometimes it can be determined that a misfire has occurred. Furthermore, since the existing crank angle sensor 21 is used to calculate the actual combustion timing TICOMACKT, it is not necessary to add a dedicated sensor for detecting the actual crank angle sensor 21, and the manufacturing cost can be reduced. it can.

  In addition, this invention can be implemented in a various aspect, without being limited to embodiment described. For example, in the embodiment, the angular speed ω of the crankshaft 3d is used as the rotation state parameter. However, the present invention is not limited thereto, and for example, the generation time interval CRME may be used. Further, the angular velocity ω may be calculated in accordance with, for example, an INCAM signal or an EXCAM signal from the intake cam angle sensor 22 or the exhaust cam angle sensor 23, and the calculation method is arbitrary. Furthermore, in the embodiment, the abnormality determination of the fuel supply device 10 is performed using the absolute value of the difference between the actual crank angle θACT and the estimated crank angle θES. However, the present invention is not limited to this, and for example, using the ratio between the two. Also good.

  Furthermore, although embodiment is an example which applied this invention to the diesel engine, this invention is not limited to this, Various engines other than a diesel engine, for example, a gasoline engine and a crankshaft, are arranged in the vertical direction. The present invention can be applied to a marine vessel propulsion engine such as an outboard motor. In addition, it is possible to appropriately change the detailed configuration within the scope of the gist of the present invention.

1 is a diagram showing a schematic configuration of an abnormality determination device of the present invention and an internal combustion engine to which the abnormality determination device is applied. It is a figure which shows a part of abnormality determination apparatus. It is a flowchart which shows the main flow of the abnormality determination process of a fuel supply apparatus. It is a flowchart which shows the calculation subroutine of the actual combustion time of FIG.

Explanation of symbols

1 Abnormality judgment device
2 ECU (rotation state parameter detection means, actual combustion timing calculation means,
Operating state detection means, estimated combustion timing calculation means and abnormality determination means)
3 Internal combustion engine
3a cylinder
3d crankshaft
10 Fuel supply device
21 Crank angle sensor (rotation state parameter detecting means and operation
State detection means)
24 Accelerator opening sensor (operating state detection means)
NE engine speed (operating condition)
AP accelerator opening (operating state)
TICOMMACT actual combustion time TICOMES estimated combustion time
ω Angular velocity (rotational state parameter)

Claims (1)

An abnormality determination device for a fuel supply device that supplies fuel into a cylinder of an internal combustion engine,
A rotation state parameter detecting means for detecting a rotation state parameter representing a rotation state of the crankshaft of the internal combustion engine;
An actual combustion timing calculating means for calculating, as an actual combustion timing, a timing at which combustion of the fuel supplied from the fuel supply device into the cylinder actually occurs according to the detected rotational state parameter;
An operating state detecting means for detecting an operating state of the internal combustion engine;
Estimated combustion timing calculation means for calculating, as an estimated combustion timing, a timing at which combustion of the fuel supplied from the fuel supply device to the cylinder is generated according to the detected operating state;
An abnormality determination means for determining an abnormality of the fuel supply device based on a comparison result between the calculated actual combustion timing and the estimated combustion timing;
An abnormality determination device for a fuel supply device, comprising:

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