DE112010004995T5 - An apparatus for determining an abnormality in a fuel injection valve, and a method for determining an abnormality in a fuel injection valve - Google Patents

Abstract

An abnormality determination device for determining the presence of abnormalities in a plurality of fuel injection valves is provided. The abnormality determination device is provided with a pressure sensor and an electronic control unit. The electronic control unit determines the presence of abnormalities in a fuel injection valve based on changes in the state of the fuel detected by the pressure sensor. The electronic control unit determines whether the fuel injection valve that has injected fuel has remained open based on the changes in the state of the fuel pressure at the fuel injection valve that has injected fuel and the changes in the state of the fuel pressure at the fuel injection valve that has not injected fuel or not.

Description

TECHNICAL AREA

The present invention relates to an abnormality determination apparatus for a fuel injection valve, and more particularly to an abnormality determination apparatus for determining whether or not each of fuel injection valves provided by a plurality of cylinders in an internal combustion engine is stuck in an open state.

For determining the occurrence of sticking in an opened state in which a fuel injection valve is not closed, a method for monitoring a change in line pressure, which is the pressure of a fuel in a common rail or supply line, or a change an engine speed and for detecting that the fuel is still injected regardless of a valve closing command, based on such a change, to determine that the injection valve stuck, known.

In such a method, however, the occurrence of sticking in the opened state can not be determined unless it causes variations in the line pressure or the engine speed, whereby the process is somewhat more time consuming. In addition, it can not be readily ascertained which of the fuel injection valves respectively mounted on a plurality of cylinders is stuck in an opened state.

To solve the problem, according to a fuel injection valve abnormality determination apparatus described in Patent Literature 1, a pressure sensor which detects the pressure of fuel supplied to each of the injectors respectively mounted on a plurality of cylinders is mounted to each of these injectors. A change in the fuel pressure caused by an injection is monitored for a respective injector so that an abnormality of a respective injector can be determined based on the change.

With such a configuration, even a small fluctuation of the fuel pressure due to opening / closing of the injector by the pressure sensor mounted on each injector can be detected quickly. If accordingly z. For example, when it is detected that the fuel pressure at an injector does not rise, when the fuel pressure should increase after completion of fuel injection, it may be determined that the injector is stuck in the opened state. That is, as compared with the case where the occurrence of sticking in the open state is determined based on a change in the line pressure or the engine speed, the occurrence of sticking in the opened state can be quickly determined, and thus can be easily determined which is stuck to the injectors in the open state.

STATE OF THE ART

Patent

• Patent document 1: Japanese Patent Laid-Open Publication 2009-85164

SUMMARY OF THE INVENTION

Problem to be solved by the invention

In the case where the occurrence of sticking in the opened state is directly determined when it is detected that the fuel pressure at an injector does not increase despite the completion of the fuel injection as described above, the occurrence of sticking in the open state due to noise overlay can occur a detected value of the fuel pressure are erroneously determined. In addition, if z. For example, when a determination threshold value for the fuel pressure is changed to prevent an erroneous determination of the stuck state in the opened state, the actual occurrence of sticking in the opened state can not be determined.

It is an object of the present invention to provide a fuel injection valve abnormality determination apparatus which can rapidly detect the open-state tightness with high accuracy while preventing erroneous determination, and a method of determining abnormality of a fuel injection valve.

In order to achieve the above object and a first aspect of the present invention, there is provided a fuel injection valve abnormality determination apparatus that determines an abnormality in a plurality of fuel injection valves mounted on a plurality of cylinders of an internal combustion engine. The determination device includes a pressure sensor that is mounted on each of the fuel injection valves to detect a pressure of a fuel that is supplied to the corresponding one of the fuel injection valves, and a determination unit that determines an abnormality in a fuel injection valve based on a change in the fuel pressure is detected by the pressure sensor, and specifically determines whether the fuel injection valve, through which the fuel has just been injected, is stuck in the opened state, That is, based on the change in the fuel pressure at the fuel injection valve through which the fuel has just been injected and the change in the fuel pressure at a fuel injection valve through which no fuel has yet been injected.

According to a second aspect of the present invention, there is provided a method of determining abnormality in a plurality of fuel injection valves. The injection valves are arranged on a plurality of cylinders of an internal combustion engine. The method includes the steps of: detecting a pressure of a fuel supplied to a corresponding one of the fuel injection valves by using the pressure sensors mounted on the respective fuel injection valves; Verifying that a pressure increase due to closing of the fuel injection valve through which fuel has been injected is not reflected in a change in the fuel pressure detected by the pressure sensor mounted on that fuel injection valve; Verifying that a pressure increase due to the closing of the fuel injection valve through which fuel has been injected is not reflected in a change in the fuel pressure detected by the pressure sensor mounted on the fuel injection valve through which no fuel has been injected; and determining that the fuel injection valve through which fuel has been injected, stuck in the open state, based on a verification that no pressure increase due to the closing of the fuel injection valve, has been injected by the fuel, both in a change of the fuel pressure at the Fuel injection valve, has been injected through the fuel, as well as a change in the fuel pressure at the fuel injection valve through which no fuel has been injected, is determined.

SUMMARY OF THE DRAWING

1 Fig. 10 is a schematic diagram showing an illustration of a configuration of a fuel injection device according to an embodiment of the present invention;

2 is a cross-sectional view of a fuel injection valve in the fuel injection device in 1 ;

3 Fig. 10 is a time chart showing a relationship between a change in the fuel pressure at the fuel injection valve through which fuel has been injected and a change in the fuel pressure at any other fuel injection valve through which no fuel has been injected; and

4 FIG. 15 is a flowchart showing a flow of an operation for determining a stuck open state according to the fuel injection device in FIG 1 shows.

PROCEDURE FOR CARRYING OUT THE INVENTION

Hereinafter, an embodiment in which a fuel injection valve abnormality determination apparatus according to the present invention is applied to a diesel engine fuel injection apparatus will be described with reference to FIG 1 to 4 described.

As in 1 4, a fuel injection device according to the present embodiment includes a total of four fuel injection valves 20 that correspond to a respective cylinder of a diesel engine. Every fuel injection valve 20 is over a branch line 31A with a common rail 34 connected.

The common rail 34 is with a fuel tank 32 via a supply line 31b connected, and somewhere along the line 31b is a fuel pump 33 Installed. Accordingly, a by the pressure through the fuel pump 33 transported fuel in the common rail 34 stored and also a respective fuel injection valve 20 over the common rail 34 and the branch line 31a fed.

Moreover, with every fuel injection valve 20 a return line 35 connected. The return line 35 is also with the fuel tank 32 connected so that part of the fuel, not through the fuel injector 20 is injected to the fuel tank 32 via this return line 35 can be returned.

In such a configuration, the fuel injection device according to the present embodiment is controlled by an electronic control unit 40 (Determination unit), which performs the overall control for the diesel engine.

With the electronic control unit 40 are a water temperature sensor 41 detecting an engine cooling water temperature sensor THW, a speed sensor 42 detecting an engine speed NE, an intake volume sensor 43 detecting a suction air volume GA of the diesel engine, a vehicle speed sensor 44 that detects a vehicle speed SPD and an accelerator pedal travel sensor (accelerator operation amount sensor) 45 connected, which detects an adjustment ACCP of the accelerator pedal.

As in 1 shown includes each fuel injector 20 a pressure sensor 46 , the fuel pressure PQ or the pressure of the fuel injector 20 supplied fuel detected. The pressure sensor 46 is also with the electronic control unit 40 connected.

The electronic control unit 40 receives a signal from each of the sensors 41 to 46 is output, and executes various kinds of operations based on the signal. According to the results of the operations, the electronic control unit undergoes 40 the injection of the fuel a control process.

The electronic control unit 40 chooses z. For example, an injection pattern based on the intake air volume GA and the engine speed NE, the fuel pressure PQ, the accelerator pedal operation amount ACCP and the like and calculates the target value of an opening / closing timing of each fuel injection valve 20 so as to arrive at an injection timing and an injection amount that confirm this injection pattern. The electronic control unit 40 then leads each fuel injector 20 a valve opening command and a valve closing command as injection commands to correspond to a corresponding target value, whereby a respective fuel injection valve 20 is individually opened and closed during the drive. As a result, the fuel passes through a respective fuel injection valve 20 injected in an amount that is adapted to the current operating condition of the engine in an injection pattern that matches the engine operating condition.

In the fuel injection device according to the present embodiment, a plurality of the injection patterns representing a combination of main injection, pilot injection and post injection are in the electronic control unit 40 preset and stored thereon, so that in a fuel injection control, any one of the injection patterns suitable for the current engine operating condition can be selected from the injection patterns stored in advance.

Next, the inner configuration of the fuel injection valve will be described below 20 and a position where the pressure sensor 46 according to the present embodiment, with reference to 2 described. 2 is a cross-sectional view of the fuel injection valve 20 according to the present embodiment.

As in 2 below is in a housing 21 of the fuel injection valve 20 a recording room 21a formed in which a needle valve 22 is included. In addition, at a distal end of the housing 21 a nozzle opening 21b formed by the housing 21 communicates with an outside.

In the recording room 21a is the needle valve 22 so absorbed that in its axial direction, ie in the vertical direction in 2 , can slide. Moreover, with the recording room 21a an introduction line 21c connected to the branch line 31a that with the common rail 34 is connected, communicates, so that by the common rail 34 fed fuel into the receiving space 21a through the introduction line 21c is introduced. As in 2 shown above is the pressure sensor 46 at the upper portion of the fuel injection valve 20 mounted to the pressure of the fuel in the introduction line 21c as detecting the fuel pressure PQ,

As in 2 is shown, the needle valve 22 in 2 by a spring 23 under duress constantly moved down or biased. When the distal end of the needle valve 22 on a part of the inner peripheral surface of the housing 21 which corresponds to the distal end, as in 2 is shown, rests, the introduction of the fuel from the receiving space 21a to the nozzle opening 21b interrupted, so that the injection of the fuel is suspended.

A back pressure chamber 21d is at the rear end portion of the needle valve 22 in the case 21 arranged. The back pressure chamber 21d communicates with the recording room 21a via a control chamber 21e , as in 2 is shown.

The control chamber 21e has an exhaust port formed therein 21f on that with an exhaust pipe 21g that with the return line 35 is connected, communicates, and in which a control valve 24 is included, which is the exhaust port 21f blocked. The control valve 24 is by a spring 25 constantly in a direction in which the exhaust port 21f is locked, biased.

An existing from a piezoelectric element actuator or piezoelectric actuator 26 which is obtained by stacking piezoelectric elements which expand and contract by the piezoelectric effect is at a position in the housing 21 arranged in which he is the control valve 24 with the intermediate exhaust port 21f can be opposite. A distal end 26a the actuator or piezoelectric actuator consisting of a piezoelectric element 26 adjoins the control valve 24 in the exhaust port 21f at. The piezo actuator 26 expands when a control circuit (not shown) is charging with electricity, and contracts when the control circuit discharges, ie, that it is connected to the electronic circuit control unit 40 expands and contracts controlled control current.

If the control circuit does not charge with electricity, the piezo actuator is located 26 in a contracted state, such that the control valve 24 is held in a position in which the exhaust port 21f by the biasing force of the spring 25 is closed as in 2 is shown. Accordingly, the recording room 21a , the control chamber 21e and the back pressure chamber 21d through the through the introduction line 21c introduced fuel, thereby reducing both the fuel pressure acting on a portion of the needle valve 22 on the side of the recording room 21a acting as well as the fuel pressure acting on a portion of the needle valve 22 on the side of the back pressure chamber 21d acts to be kept in a high pressure range.

In this case lies between the fuel pressure acting on the area of the needle valve 22 on the side of the recording area 21a acting, and the fuel pressure acting on the area of the needle valve 22 on the side of the back pressure chamber 21d acting, no difference before, so that the needle valve 22 by the biasing force of the spring 23 on the case 21 is held on top.

To pass through the fuel injector 20 Fuel injection operates the electronic control unit 40 the control current such that at a valve opening command of the control circuit in the piezoelectric actuator 26 charging. The piezoelectric actuator expands 26 out, leaving the control valve 24 on top of that through the distal end 26a of the piezo actuator 26 Pressure is applied, towards the side of the valve opening against the biasing force of the spring 25 is moved, causing the control chamber 21e and the exhaust pipe 21g over the exhaust port 21f can communicate with each other. When the control chamber 21e and the exhaust pipe 21g communicate with each other in this way, the fuel in the back pressure chamber 21d connected to the control chamber 21e communicates through the exhaust pipe 21g along with the fuel in the control chamber 21e in the return line 35 dissipated, reducing the pressure of the fuel in the back pressure chamber 21d is reduced. The drop in fuel pressure in the back pressure chamber 21d causes an imbalance with respect to the fuel pressure acting on the needle valve 22 acts so that the needle valve 22 is shifted in one direction, in which the volume of the back pressure chamber 21d against the biasing force of the spring 23 is reduced, ie in 2 upwards. When the needle valve 22 is shifted in this way, the fuel flows into the needle opening 21b from the recording room 21a by one between the distal end of the needle valve 22 and the inner peripheral surface of the housing corresponding to the distal end 21 resulting gap, and then out of the nozzle opening 21b injected into the appropriate cylinder.

To interrupt the injection of the fuel, the electronic control unit operates 40 the control current such that the valve closing command, the electricity from the control circuit in the piezoelectric actuator 26 unloaded. In doing so, the piezoelectric actuator pulls 26 together, leaving the control valve 24 on top of that through the distal end 26a of the piezo actuator 26 Pressure acts in the direction of the valve closing side by the biasing force of the spring 25 is shifted, causing the exhaust port 21f through the control valve 24 is closed. When the exhaust port 21f is closed in this way, the passage of the fuel from the control chamber 21e and the back pressure chamber 21d to the return line 35 interrupted so that the pressure of the fuel in the back pressure chamber 21d rises so that the needle valve 22 is displaced in one direction, in which the volume of the back pressure chamber 21d is increased, ie downwards in 2 , When the needle valve 22 shifts so that its distal end on the corresponding inner peripheral surface of the housing 21 rests, the introduction of the fuel from the receiving space 21a into the nozzle opening 21b interrupted, whereby the injection of the fuel is suspended.

Next, the description will be made with reference to FIG 3 with a change in the fuel pressure PQ passing through the pressure sensor 46 is detected at each fuel injector 20 is mounted. 3 FIG. 15 is a time chart showing a relationship between a change in the fuel pressure PQ at the fuel injection valve. FIG 20 , through which the fuel has been injected, and a change in the fuel pressure PQ at any other fuel injection valve 20 shows, through which no fuel has been injected.

When an injection command to one of the four fuel injectors 20 is given by the fuel injection control to the control current as in 3 Charging or discharging above becomes the needle valve 22 of the fuel injection valve 20 issued a corresponding injection command, so that it is driven to the fuel injection valve 20 to open or close.

When the fuel injector 20 is opened, fuel is through the fuel injector 20 injected to the fuel pressure PQ passing through the on this fuel injector 20 mounted pressure sensor 46 is detected to reduce the injected amount of the fuel, as in 3 Middle is shown (time t1 to time t2). If then that Fuel injection valve 20 is closed, the injection of the fuel is interrupted, thereby interrupting the reduction of the fuel pressure PW, so that when the fuel from the common rail 34 the fuel pressure PQ increases to return the fuel pressure PQ to almost its original value (time t2 to t3).

To a certain delay occurs when the control current is then operated when the needle valve 22 of the fuel injection valve 20 is shifted to inject the fuel. As in 3 As shown, with some delay, therefore, the fuel pressure PQ changes after a change of the control current. Due to such a change in the fuel pressure PQ acting on the injection of the fuel, a pulsation occurs in the fuel pressure PQ immediately after the fuel injection, as to the right of the center in 3 is shown (time t3 and following). Over time, the pulsation gradually approaches a predetermined value.

When no injection command is given by the fuel injection control, the fuel pressure PQ fluctuating through the pressure sensor fluctuates 46 is detected at any other fuel injector 20 is mounted, through which no fuel has been injected, as in 3 is shown below, because a fuel injection caused by the drop in fuel pressure in the common rail 34 effect. Especially when the fuel pressure in the common rail 34 due to the fuel injection decreases, which decreases by the pressure sensor 46 detected fuel pressure PQ from (time t4 to t5). If then the fuel pressure in the common rail 34 due to suspension of fuel injection, the fuel pressure PQ increases and again reaches a value almost equal to before the injection (time t5 to t6).

Between the time of injection of the fuel by any of the fuel injection valves 20 and the time when a fluctuation of the pressure resulting from the influence of the fuel injection, on any other fuel injection valve 20 affects that with the common rail 34 is connected, there is a certain amount of time. As in 3 Accordingly, there will be a certain delay until the fuel pressure PQ at the other fuel injection valve 14 is reached 20 , through which no fuel has been injected, experiences the fluctuation due to the influence of the fuel injection. Even the fuel pressure PQ passing through the pressure sensor 46 that is on the other fuel injector 20 is detected by which no fuel has been injected is detected, undergoes a pulsation due to an influence of the fluctuation of the fuel pressure PQ immediately after the fuel injection, as shown in the lower right in 3 (from time t6) is shown.

If in a moving component, such. B. a needle valve 22 , pass foreign matter during a fuel injection, so that the fuel injection valve 20 remains in an open state, the fuel is still injected despite the fact that the control current discharges by executing the valve closing command. Accordingly, when such an open-state sticking occurs, the fuel pressure PQ flowing through a respective pressure sensor increases 46 is not set to the value before injection, but continues to decline as in 3 is shown in the middle and bottom by the double-dashed and solid line shown.

Accordingly, if a change in the fuel pressure PQ by a respective pressure sensor 46 is detected, a rise in the pressure due to a valve closing despite the discharge of the control current and the execution of the valve closing command is not reflected, it is assumed that the fuel injection valve 20 remained in the open state contrary to the valve closing command. This means that in this case it is assumed that the fuel injector 20 stuck in the open state.

The fuel injection device according to the present embodiment utilizes this relationship to carry out a stuck open determination processing that detects the occurrence of sticking in the open state in the fuel injection valve 20 based on a change in the fuel pressure PQ determined by the at each fuel injection valve 20 mounted pressure sensor 46 is detected.

Hereinafter, the determination processing of the stuck state in the open state according to the present embodiment will be described with reference to FIG 4 described. 4 FIG. 10 is a flowchart showing the flow of a series of lock-open determination operations. The determination processing of sticking in the open state is performed by the electronic control unit 40 every time it repeats when fuel passes through a respective one of the fuel injectors 20 is injected.

The electronic control unit 40 takes a change in the fuel pressure PQ caused by a fuel injection after the fuel injection, and then stores the value of the fuel pressure PQ supplied from the respective pressure sensor 46 during an engine operation is output in a memory so that each target value can be corrected at the next time of fuel injection. In the open stuck state determination processing according to the present embodiment, therefore, a determination is made as to whether sticking in the open state in the fuel injection valve 20 has occurred by referring to the change in the fuel pressure PQ stored in the memory.

In particular, when the fuel is through any of the fuel injection valves 20 is injected, leads the electronic control unit 40 the determination processing of sticking in the open state, as in 4 is shown. First, in step S100, a change in the fuel pressure PQ generated by the pressure sensor 46 is detected at the fuel injection valve 20 is measured, through which the fuel has been injected, measured to verify that the measured change in the fuel pressure PQ no pressure increase due to a closing of the fuel injection valve 20 reflects.

To verify that a change in the fuel pressure PQ does not increase the pressure due to the closing of the fuel injection valve 20 A variety of approaches are available. In the open-state determination processing of the present embodiment, a determination is made as to whether the fuel pressure PQ of the fuel injection valve 10 is 20 through which the fuel has been injected has reached a first threshold X or below, or not after the valve closing command has been executed, thereby verifying that no pressure increase has occurred based on a result of the determination.

That is, in the open state stuck state determination processing according to the present embodiment, the electronic control unit 40 refers to a detected change in the fuel pressure PQ and determines whether the fuel pressure PQ has reached the first threshold value X or below, or after the valve closing command has been executed. Then, when the fuel pressure PQ has not reached the first threshold value X or below, as shown in a solid line in the middle in FIG 3 reflects, takes the electronic control device 40 a determination that the change in the fuel pressure PQ reflects a pressure increase due to valve closure. When the fuel pressure PQ has reached the first threshold value X or below, after the valve closing command has been executed, as shown in the middle in FIG 3 The double-dashed line shown in solid lines reflects the electronic control unit 40 accordingly, there is a corresponding determination that the change in fuel pressure PQ does not reflect a pressure increase due to valve closure.

The first threshold X only has to be set high enough to determine that the fuel pressure PQ has continued to decrease even after execution of the valve closing command, based on the fact that the fuel pressure PQ itself exceeds this first threshold value X or below Execution of the valve closing command corresponded. Accordingly, in the present embodiment, the first threshold value X is set to a value that is the minimum value of the fuel pressure PQ at the fuel injection valve 20 slightly below, the minimum value based on a valve opening period of the fuel injection valve 20 that is involved in the fuel injection, that is, calculated on the basis of a minimum fuel pressure P1, which is the minimum value of the fuel pressure PQ in a case where the fuel injection valve 20 is properly closed, as in the middle in 3 is shown. The closer the first threshold X is set to the minimum fuel pressure P1, the easier it can be determined that no pressure increase is to be detected.

If a determination is made in step S100 that a change in the fuel pressure PQ at the fuel injection valve 20 , through which the fuel has been injected, does not reflect a pressure increase due to valve closure (YES in step S180), the process proceeds to step S200.

Then the electronic control unit reads 40 from the three fuel injection valves 20 , through which no fuel has been injected, a change in the fuel pressure PQ out through the pressure sensor 46 is detected at the fuel injection valve 20 The next time the fuel is to be injected, it verifies that the measured change in the fuel pressure PQ does not increase the pressure due to the closing of the fuel injection valve 20 through which the fuel has been injected reflects.

Of the three fuel injection valves 20 , through which no fuel has been injected, is next on the change of the fuel pressure PQ of the fuel injection valve 20 , by is injected next, referenced to verify that no pressure increase is detected because the fuel pressure PQ flowing through the pressure sensor 46 at the fuel injection valve 20 is detected, by which the fuel following the fuel injection valve 20 is to be injected, has just been injected by the fuel is extremely stable. That is, of the valves mounted on the respective cylinders, most of the time since fuel was last injected, at the fuel injection valve 20 passes, through which the fuel is to be injected following that through which the fuel has just been injected. At the fuel injection valve 20 , by which the fuel is to be injected following that through which the fuel has just been injected, accordingly, an approximation to the pulsation of the fuel pressure PQ, which takes place at the last injection at this fuel injection valve 20 so that the value of the fuel pressure PQ passing through the pressure sensor 46 is detected at this fuel injector 20 is mounted, stable.

In the open-state locked-state determination processing according to the present embodiment, a determination is made as to whether the fuel pressure PQ at the fuel injection valve 20 by which the fuel is to be subsequently injected with the valve through which the fuel has just been injected corresponding to a second threshold value Y or below after the valve closing command has been executed to verify that, based on a result of the determination no pressure increase has been detected.

That is, in the open state locked state determination processing according to the present embodiment, reference is made to a measured change in the fuel pressure PQ to make a determination as to whether or not the fuel pressure PQ corresponds to the second threshold Y or below the valve closing command has been executed, and if it should nevertheless correspond to the second threshold Y or an underlying value, as shown in a solid line below in 3 is reflected, it is determined that the change of the fuel pressure PQ reflects a pressure increase due to the valve closing. When the fuel pressure PQ corresponds to the second threshold value Y or an underlying value after the valve closing command has been executed on a corrugated pipe, as in a line indicated by a double-dashed and solid line in FIG 3 Accordingly, a determination is made that the change in the fuel pressure PQ does not reflect a pressure increase due to the valve closing.

Similar to the first threshold X, the second threshold Y must be set high enough to determine that the fuel pressure PQ has continued to decrease even after execution of the valve closing command, based on the fact that the fuel pressure PQ is equal to this second threshold Y or an underlying value even after execution of the valve closing command. Accordingly, according to the present embodiment, the second threshold Y is set to a value that is the minimum value of the fuel pressure PQ at the fuel injection valve 20 slightly below, this minimum value based on a valve opening period of the fuel injection valve 20 that is involved in the fuel injection, that is, calculated on the basis of a minimum fuel pressure P2 corresponding to the minimum value of the fuel pressure PQ in a case where the fuel injection valve 20 is properly closed, as below in 3 is shown. The closer to the minimum fuel pressure P2, the second threshold Y is set, the easier it can be determined that no pressure increase is observed.

If a determination is made in step S200 that a change in the fuel pressure PQ at the fuel injection valve 20 by which the fuel is to be injected next after that by which the fuel has been injected, does not reflect a pressure increase due to valve closure (YES in step S200), the process proceeds to step S300.

Then, in step S300, the electronic control unit determines 40 in that a sticking in the open state to the fuel injection valve 20 , through which the fuel has been injected, has occurred, and stores in the memory a result of the determination as an abnormality determination value. After the occurrence of sticking in the opened state has been determined in this way, the electronic control unit resets 40 processing temporarily.

If, in step S100, a determination is made that the change in the fuel pressure PQ at the fuel injection valve 20 , through which the fuel has been injected, reflects a pressure increase due to valve closure (NO at step S100), the electronic control unit skips 40 Step S200 to S300 to temporarily suspend the processing.

If a determination is made in step S100 that no pressure increase due to valve closing is detected (YES in step S100), but a determination is made in step S100 that a pressure increase due to valve closing is detected (NO in step S200), skips the electronic control unit 40 Step S300 to temporarily suspend processing.

That is, in the open state stuck state determination processing according to the present embodiment, on the condition that no pressure increase due to valve closing is detected in both of steps S100 and S200, a determination is made that sticking in the open state in FIG the fuel injection valve 20 occurred by the fuel has been injected.

In the fuel injection device according to the present embodiment, in a stuck-state determination processing, it is determined whether sticking in the open state to the fuel injection valve 20 , through which the fuel has been injected, has or has not occurred, based on the fuel pressure PQ passing through the at a respective fuel injection valve 20 mounted pressure sensor 46 is detected.

• (1) Es wird dahingehend eine Bestimmung vorgenommen, ob sich ein Festsitzen im geöffneten Zustand an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff eingespritzt worden ist, ereignet hat oder nicht, indem nicht nur auf eine Veränderung des Kraftstoffdrucks PQ an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff eingespritzt worden ist, sondern auch auf eine Veränderung des Kraftstoffdrucks PQ an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff nicht eingespritzt worden ist, Bezug genommen wird. Weil somit umfassend bestimmt wird, ob sich ein Festsitzen im geöffneten Zustand ereignet hat oder nicht, und zwar basierend auf einer Veränderung des Kraftstoffdrucks PQ, der durch einen jeweiligen Drucksensor 46 gesondert erfasst wird, wird dadurch ein Auftreten einer irrtümlichen Bestimmung eines Festsitzens im geöffneten Zustand aufgrund einer Überlagerung oder ähnlichem vom Geräuschen bei einem erfassten Wert durch den Drucksensor 46 verhindert. Zudem muss im Vergleich zu einer Anomalitätsbestimmungsvorrichtung, die ein Festsitzen im geöffneten Zustand an dem Kraftstoffeinspritzventil 20 lediglich basierend auf einer Veränderung des Kraftstoffdrucks PQ an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff eingespritzt worden ist, bestimmt, ein Bestimmen eines Festsitzens im geöffneten Zustand, indem beispielsweise ein Bestimmungsschwellwert des Kraftstoffdrucks PQ verändert wird, um irrtümliche Bestimmungen des Festsitzens im geöffneten Zustand zu verhindern, nicht verhindert werden. Demzufolge kann das Festsitzen im geöffneten Zustand, falls sich ein solches ereignet haben sollte, schnell bestimmt werden. Das heißt, dass das Auftreten des Festsitzens im geöffneten Zustand rasch und mit hoher Genauigkeit bestimmt werden kann, während irrtümliche Bestimmungen verhindert werden.
• (2) Unter der Bedingung, dass verifiziert wird, dass kein Druckanstieg aufgrund einer Ventilschließung sowohl bei einer Veränderung des Kraftstoffdrucks PQ an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff eingespritzt worden ist, als auch einer Veränderung des Kraftstoffdrucks PQ an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff im Anschluss an das Kraftstoffeinspritzventil 20 eingespritzt werden soll, durch das der Kraftstoff soeben eingespritzt worden ist, festgestellt wird, erfolgt eine Bestimmung, dass sich ein Festsitzen im geöffneten Zustand an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff eingespritzt worden ist, ereignet hat. Das Auftreten des Festsitzens im geöffneten Zustand kann daher mit hoher Genauigkeit bestimmt werden.
• (3) Wird verifiziert, dass sich an den vier Kraftstoffeinspritzventilen 20, die an jeweiligen Zylindern montiert sind, kein Druckanstieg in einer Veränderung des Kraftstoffdrucks an dem Kraftstoffeinspritzventil 20, durch das der Kraftstoff nicht eingespritzt worden ist, widerspiegelt, und zwar auf Basis einer Veränderung des Kraftstoff drucks PQ des Kraftstoffeinspritzventils 20, durch das der Kraftstoff im Anschluss an das Kraftstoffeinspritzventil, durch das der Kraftstoff soeben eingespritzt worden ist, eingespritzt werden soll. Daher kann verifiziert werden, dass kein Druckanstieg aufgrund einer Ventilschließung ohne Beeinflussung durch eine Pulsation des Kraftstoffdrucks PQ, der bei der letzten Einspritzung an diesem Kraftstoffeinspritzventil 20 vorlag, festgestellt wird, wodurch eine Verbesserung der Genauigkeit der Bestimmung des Festsitzens im geöffneten Zustand erreicht wird.

The present embodiment has the following advantages.

• (1) A determination is made as to whether sticking in the open state to the fuel injection valve 20 , through which the fuel has been injected, has or has not occurred by not only responding to a change in the fuel pressure PQ at the fuel injection valve 20 , through which the fuel has been injected, but also to a change of the fuel pressure PQ at the fuel injection valve 20 , by which the fuel has not been injected, is referred to. Thus, because it is comprehensively determined whether or not sticking has occurred in the open state based on a change in the fuel pressure PQ flowing through a respective pressure sensor 46 is detected separately, thereby an occurrence of an erroneous determination of a stuck state in the open state due to an overlay or the like of the noise at a detected value by the pressure sensor 46 prevented. In addition, compared to an abnormality determination device, the stuck state at the fuel injection valve 20 based solely on a change in the fuel pressure PQ at the fuel injection valve 20 , by which the fuel has been injected, determines not to be prevented from determining sticking in the open state, for example, by changing a determination threshold value of the fuel pressure PQ to prevent erroneous open-seat sticking determinations. As a result, sticking in the open state, if such has occurred, can be quickly determined. That is, the occurrence of sticking in the opened state can be determined quickly and with high accuracy while preventing erroneous determinations.
• (2) Under the condition that it is verified that there is no pressure increase due to valve closing in both a change of the fuel pressure PQ at the fuel injection valve 20 , through which the fuel has been injected, as well as a change in the fuel pressure PQ at the fuel injection valve 20 through which the fuel is following the fuel injector 20 is to be injected, by which the fuel has just been injected, is determined, a determination is made that a stuck in the open state at the fuel injection valve 20 through which the fuel has been injected has occurred. The occurrence of sticking in the open state can therefore be determined with high accuracy.
• (3) Verifies that there are four fuel injectors 20 mounted on respective cylinders, no pressure increase in a change of the fuel pressure at the fuel injection valve 20 , by which the fuel has not been injected, reflects, based on a change in the fuel pressure PQ of the fuel injection valve 20 by which the fuel is to be injected subsequent to the fuel injection valve through which the fuel has just been injected. Therefore, it can be verified that there is no pressure increase due to a valve closing without being affected by a pulsation of the fuel pressure PQ at the last injection on this fuel injection valve 20 is found, whereby an improvement in the accuracy of the determination of the stuck open state is achieved.

The embodiment described above can be modified as follows.

In the above-described embodiment, when it is determined by the open-state determination processing that an open-state sticking has occurred, a result of the determination as an abnormality determination value is stored in the memory. However, a configuration for notification of the stuck state event may be used, for example, by turning on a warning light, if it is determined that a stuck in the open state has occurred.

In the open-state fixing processing in the present embodiment, the electronic control unit first performs 40 which serves as the first verification unit, as described above, the step S100, and if it is determined in step S180, the change of the fuel pressure PQ at the fuel injection valve 20 , through which the fuel has been injected, reflects no pressure increase due to valve closure, the electronic control unit performs 40 as the second verification unit, step S200. However, the order of steps S100 and S200 may be changed over in the open state stuck state determination process.

That is, the open state determination processing must merely determine that sticking in the open state in the fuel injection valve 20 by which the fuel has been injected has occurred, provided that it is verified that no pressure increase due to valve closing is detected by both the first verifying unit and the second verifying unit, so as to modify a procedure as appropriate can be.

In addition, at step S200, it must merely be verified that there is no pressure increase due to valve closure in a change in the fuel pressure PQ at the fuel injection valve 20 through which no fuel has been injected, mirrored. Accordingly, in step S200, the fuel pressure PQ of the other fuel injection valves 20 through which the fuel has not been injected, instead of the fuel injection valve 20 , by which the fuel is to be injected following that through which the fuel has just been injected, are monitored, thereby verifying that the change in the fuel pressure PQ of the fuel injection valve 20 , through which the fuel has been injected, reflects no pressure increase.

In addition, in step S200, an average value of the fuel pressures PQ from a plurality of fuel injection valves 20 , through which no fuel has been injected, are monitored, thereby verifying that there is no pressure increase due to a closing of the fuel injection valve 20 , through which the fuel has been injected, in a change of an average value of the fuel pressures PQ of the fuel injection valves 20 through which the fuel has not been injected reflects.

If any of the fuel injectors 20 in which the fuel has not been injected, has no increase in pressure, a determination can be made that no pressure increase due to valve closure in the fuel pressure PQ of the fuel injection valves 20 , through which no fuel has been injected, is detected.

In addition, when there is no increase in the pressure due to valve closing in any of the fuel pressures PQ of all the fuel injection valves 20 can be made to determine that in the fuel pressure PQ of the fuel injection valves 20 , through which the fuel has not been injected, no pressure increase due to valve closure is detected.

In the steps S100 and S200, in the embodiment described above, a configuration is made to determine whether the fuel pressure PQ corresponds to the first threshold value X or an underlying value or the second threshold value Y or below after the closing command has been executed , as a means for verifying that no pressure increase due to valve closure is detected in a change of the fuel pressure PQ. This specific means for verifying that no pressure increase due to a valve closing is detected in a change in the fuel pressure PQ may be changed as needed.

For verifying that no pressure increase due to valve closure is detected in a change in the fuel pressure PQ, a method may be employed, e.g. For calculating a differential value of the fuel pressure PQ, so as to make a determination that no pressure increase due to valve closing is detected due to the fact that the differential value is not positive. In addition, when the fuel pressure PQ does not reach a predetermined threshold or over, when a predetermined time has elapsed since the execution of the valve closing command, a determination can be made that a pressure increase due to valve closing is detected.

Although according to the embodiment described above, a configuration is exemplified in which the pressure sensor 46 at the upper part of the fuel injection valve 20 is mounted, the arrangement of the pressure sensor 46 can be changed as needed, as long as the pressure of the fuel, the one of each of the fuel injection valves 20 is fed, can be recorded individually.

According to the above embodiment, as an example, a configuration for determining the event of sticking in an opened state in the fuel injection valve 20 in the fuel injection device, in which the piezoelectric fuel injection valves 20 including the piezo actuator 26 be used. However, the present invention is not limited to the piezoelectric fuel injection valves, and therefore, it can be applied to a fuel injection apparatus using solenoid fuel injection valves which are used in place of piezoelectric fuel injection valves 20 be driven by solenoid coils.

According to the above embodiment, as an example, a configuration for carrying out the determination processing of sticking in the open state by using the electronic control unit 40 so that the fuel injection device may be provided with a function as an abnormality determination device according to the present invention. An electronic control device for executing a stuck state determination processing in the open state may be separate from the electronic control unit 40 be provided new and together with this electronic control device and the pressure sensor 46 may be used to configure the fuel injector abnormality determination apparatus according to the present embodiment.

The fuel injection valve abnormality determination apparatus according to the present embodiment can be applied not only to a four-cylinder diesel engine but also to a two-cylinder diesel engine, a three-cylinder diesel engine, and also to a diesel engine having five or more cylinders.

Although according to the above embodiment, the fuel injection valve abnormality determination apparatus according to the present invention applied to a diesel engine fuel injection apparatus is exemplified, the fuel injection valve abnormality determination apparatus according to the present invention can be applied not only to diesel engines but also to gasoline engines and natural gas engines ,

LIST OF REFERENCE NUMBERS

20

Fuel injection valve

21

casing

21a

accommodation space

21b

nozzle opening

21c

introducing pipe

21d

Back pressure chamber

21e

control chamber

21f

exhaust port

21g

exhaust pipe

22

needle valve

23

feather

24

control valve

25

feather

26

piezo actuator

31a

branch line

31b

feed

32

Fuel tank

33

Fuel pump

34

Common rail

35

Return line

40

Electronic control unit

41

Water Temperature Sensor

42

Speed sensor

43

Intake volume sensor

44

Vehicle speed sensor

45

Accelerator opening sensor

46

pressure sensor

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• JP 2009-85164 [0006]

Claims (6)

Fuel injection valve abnormality determination device for determining an abnormality in a plurality of fuel injection valves mounted on a plurality of cylinders of an internal combustion engine, the determination device comprising: a pressure sensor mounted on each of the fuel injection valves to detect a pressure of a fuel supplied to the corresponding one of the fuel injection valves; and a determination unit that determines an abnormality in a fuel injection valve based on a change in the fuel pressure detected by the pressure sensor, and specifically determines whether the fuel injection valve through which fuel has just been injected is stuck in the open state, based on the change of the fuel pressure at the fuel injection valve through which fuel has just been injected, and the change of the fuel pressure at a fuel injection valve through which no fuel has yet been injected. An abnormality determination apparatus according to claim 1, further comprising: a first verification unit that verifies that no pressure increase due to the closing of a fuel injection valve through which fuel has been injected is reflected in a change in the fuel pressure detected by the pressure sensor mounted on that fuel injection valve; and a second verification unit that verifies that no pressure increase due to the closing of the fuel injection valve, has been injected by the fuel, in a change in the fuel pressure detected by the pressure sensor, at the fuel injection valve, through which the fuel has not been injected , is mounted, reflects, wherein the determination unit determines that the fuel injection valve through which fuel has been injected seizes in an open state based on a determination by the first verification unit and the second verification unit that no pressure increase due to the closing of the fuel injection valve, through which the fuel has been injected is detected. The abnormality determination apparatus according to claim 2, wherein the first verification unit verifies that no pressure increase due to the closing of the fuel injection valve through which the fuel has been injected is reflected in a change in the fuel pressure detected by the pressure sensor mounted on this fuel injection valve That is, based on the fact that the fuel pressure detected by the pressure sensor mounted on the fuel injection valve through which fuel has been injected is equal to a first threshold or below, after a valve closing command on that fuel injection valve is executed, wherein the first threshold value falls below a minimum fuel pressure, which is estimated based on a valve opening period. An abnormality determination apparatus according to claim 2 or 3, wherein the second verification unit verifies that no pressure increase due to the closing of the fuel injection valve through which fuel has been injected is reflected in the variation of the fuel pressure detected by the pressure sensor mounted on the fuel injection valve by which no fuel has been injected, based on a determination that the fuel pressure detected by the pressure sensor mounted on the fuel injection valve, through which no fuel has been injected, is equal to a second threshold or an underlying value is after the valve closing command for the fuel injection valve, has been injected by the fuel, has been executed, the second threshold value falls below a minimum fuel pressure, based on a valve opening period, the force substance injection, is estimated. An abnormality determination device according to any one of claims 2 to 4, wherein, in the pressure sensors disposed on the respective fuel injection valves through which no fuel has been injected, the second verification unit monitors a change in the fuel pressure detected by the pressure sensor detected on the pressure sensor Fuel injector is mounted, is to be injected through the fuel in connection to the fuel injection valve, through which fuel has been injected, thereby verifying that no pressure increase due to the closing of the fuel injection valve, by the Fuel has been injected, reflected in the change in the fuel pressure that has been detected by this pressure sensor. A method of determining an abnormality in a plurality of fuel injection valves disposed on a plurality of cylinders of an internal combustion engine, the method including: Detecting a pressure of a fuel supplied to a corresponding one of the fuel injection valves by using the pressure sensors mounted on the respective fuel injection valves; Verifying that no pressure increase due to the closing of the fuel injection valve through which fuel has been injected is reflected in a change in the fuel pressure detected by the pressure sensor mounted on that fuel injection valve; Verifying that no pressure increase due to the closing of the fuel injection valve through which fuel has been injected is reflected in a change in the fuel pressure detected by the pressure sensor mounted on the fuel injection valve through which no fuel has been injected; and Determining that the fuel injection valve through which fuel has been injected is stuck in the open state, based on a verification that no pressure increase due to the closing of the fuel injection valve has been injected by the fuel, in both a change in the fuel pressure on the fuel injection valve , has been injected through the fuel, as well as in a change in the fuel pressure on the fuel injection valve through which no fuel has been injected, is determined.

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