JP2007113503A - Device for evaluating reliability of high pressure fuel system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform appropriate reliability evaluation of a high pressure part including an accumulator. <P>SOLUTION: In a common rail type fuel injection system including a fuel pump 11, a common rail 20 and an injector 23, actual rail pressure is variably controlled based on an engine operation condition from time to time. ECU 30 acquires rail pressure information and counts the number of pressure repetitions every amplitude of a plurality of predetermined pressure amplitudes, and judges reliability of the high pressure part including the common rail 20 based on the number of pressure repetitions every counted pressure amplitude. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reliability evaluation apparatus for a high-pressure fuel system.

  As a high pressure fuel system applied to a diesel engine or the like, a high pressure fuel corresponding to the fuel injection pressure is accumulated in a pressure accumulation container such as a common rail, and the high pressure fuel accumulated in the pressure accumulation container is passed through a fuel injection valve. An accumulator fuel injection system that supplies fuel to an engine has been put into practical use. In this accumulator fuel injection system, when fuel injection by the fuel injection valve is performed, the fuel pressure in the accumulator vessel decreases. At that time, the high pressure fuel is discharged and supplied from the fuel supply pump to the accumulator vessel. The inside of the container is held at a predetermined high pressure state.

  In the high-pressure fuel system as described above, the fuel pressure in the pressure accumulating vessel is variably adjusted based on the operating state of the engine. For example, the fuel pressure is determined based on the engine speed and the fuel injection amount at that time. And the fuel discharge amount of the fuel supply pump is feedback controlled so that the actual fuel pressure becomes the target fuel pressure. Specifically, in the case of a diesel engine, the target fuel pressure is variably set within a range of several tens of MPa to 200 MPa, and the actual fuel pressure is controlled so as to follow the target fuel pressure.

  In such a case, in the pressure accumulator vessel, pressure fluctuations are repeated according to changes in the engine operating state. If pressure fluctuations are repeated in this way, metal fatigue may occur in the pressure accumulator vessel or the high-pressure fuel pipe connected thereto, which may cause damage or the like. Therefore, there is a demand for a technique that can appropriately evaluate the reliability of the system in a state in which it has been used for a long time. In particular, in recent years, there has been a demand for further increasing the fuel pressure in the pressure accumulator vessel in order to improve exhaust emission and the like, and in such an ultra-high pressure system, it becomes necessary to evaluate the system reliability more appropriately.

  Incidentally, for example, Patent Document 1 is known as a failure determination technique in an accumulator fuel injection system. In Patent Document 1, fuel leakage is determined by comparing a target control amount of a fuel discharge control valve provided in a fuel supply pump with a reference value. Then, when determining that a fuel leak has occurred, once the safety valve is closed, the fuel leak is determined again by comparing the target control amount and the like with the reference value, and based on the result, the fuel is supplied from the fuel supply pump. The failure of the fuel supply system to the injection valve is determined.

However, in Patent Document 1, a failure determination is made after a fuel pipe or the like is actually damaged and a fuel leak occurs, and the leakage of fuel to the outside cannot be prevented. Therefore, there is a demand for a technique for evaluating the reliability of a high-pressure portion such as a pressure accumulating vessel before fuel leakage actually occurs.
JP-A-5-272425

  The main object of the present invention is to provide a reliability evaluation apparatus for a high-pressure fuel system capable of performing an appropriate reliability evaluation on a high-pressure portion including a pressure accumulating vessel.

  In the high-pressure fuel system of the present invention, the fuel pressure in the pressure accumulating vessel is variably controlled based on the engine operating state every time, and the pressure fluctuation is repeated accordingly. In such a case, in the invention described in claim 1, the fuel pressure in the pressure accumulating vessel or the pressure information correlated therewith is acquired, and the number of pressure repetitions in which the fuel pressure or the pressure information correlated therewith fluctuates with a predetermined pressure amplitude is obtained. Count. Then, the reliability of the high pressure portion including the pressure accumulating container is determined based on the number of pressure repetitions.

  According to this configuration, when there is a possibility that fatigue failure may occur in the accumulator vessel or the like due to repeated pressure fluctuations under high pressure, the possibility of fatigue failure can be properly determined. Therefore, appropriate reliability evaluation can be performed on the high-pressure portion including the pressure accumulator. In this case, an appropriate reliability evaluation can be performed before fuel leakage actually occurs.

Here, the pressure amplitude may be set as follows, and the number of pressure repetitions may be counted for the pressure amplitude. That is,
In the second aspect of the present invention, the fuel pressure in the pressure accumulating vessel or the pressure information correlating with the pressure amplitude set by the fuel pressure in the pressure accumulating vessel before starting the engine and the maximum pressure allowed in the pressure accumulating vessel Count the number of pressure repetitions.
In the invention according to claim 3, with respect to the pressure amplitude set by the minimum fuel pressure and the maximum fuel pressure in the normal use range under the operating state of the engine, the pressure of the fuel pressure in the pressure accumulating vessel or the pressure information correlated therewith Count the number of repetitions.
In the invention according to claim 4, the number of pressure repetitions of the fuel pressure in the pressure accumulator or pressure information correlated therewith is counted for a predetermined pressure amplitude.

  According to the fifth aspect of the present invention, the fuel pressure in the pressure accumulating vessel or the pressure information correlated therewith is acquired, and the number of pressure repetitions of the fuel pressure or pressure information correlated therewith is counted for each of a plurality of preset pressure amplitudes. . Then, the reliability of the high-pressure portion including the pressure accumulating vessel is determined based on the number of pressure repetitions for each pressure amplitude.

  According to this configuration, when there is a possibility that fatigue failure may occur in the accumulator vessel or the like due to repeated pressure fluctuations under high pressure, the possibility of fatigue failure can be properly determined. Therefore, appropriate reliability evaluation can be performed on the high-pressure portion including the pressure accumulator. In this case, an appropriate reliability evaluation can be performed before fuel leakage actually occurs.

  In particular, the number of pressure repetitions is counted for each set pressure amplitude, and the reliability evaluation is performed based on the number of pressure repetitions. Therefore, compared to the case where the reliability evaluation is performed based on the number of pressure repetitions of a single pressure amplitude. The evaluation accuracy can be increased. That is, the pressure amplitude and the number of pressure repetitions have a predetermined relationship defined by an SN diagram or the like, and the number of pressure repetitions that is a reliability limit value is different if the pressure amplitude is different. In this case, the reliability evaluation can be performed by considering a plurality of reliability determination criteria in combination, and the evaluation accuracy is improved.

Here, the following method can be considered as a method for counting the number of pressure repetitions of the fuel pressure or pressure information correlated therewith for each of a plurality of pressure amplitudes. That is,
In the invention described in claim 6, the pressure accumulating vessel is set for the pressure amplitude set by the fuel pressure in the accumulating vessel before starting the engine and the maximum pressure allowed in the accumulating vessel, and another pressure amplitude different from the pressure amplitude. The number of pressure repetitions of the internal fuel pressure or pressure information correlated therewith is counted.
In the invention according to claim 7, the first pressure amplitude set by the fuel pressure in the pressure accumulating vessel before starting the engine and the maximum pressure allowed in the pressure accumulating vessel, and in the normal operating range under the operating state of the engine For the second pressure amplitude set by the minimum fuel pressure and the maximum fuel pressure and the predetermined third pressure amplitude, the fuel pressure in the pressure accumulator or the pressure repetition number of the pressure information correlated therewith is determined. Count each.

  In the invention according to claim 8, the reliability of the high pressure portion including the pressure accumulating vessel is determined based on the total number of pressure repetitions counted for each of the plurality of pressure amplitudes. As a result, it is possible to perform a reliability evaluation in consideration of a plurality of reliability determination criteria. In this case, a weighting amount is set for each pressure amplitude, and each pressure repetition number multiplied by the weighting amount is added to calculate the total pressure repetition number, and the accumulator vessel is based on the total pressure repetition number. You may make it determine the reliability of the high voltage | pressure part containing.

  In the invention according to claim 9, the reliability of the high pressure portion including the pressure accumulating vessel is determined for each pressure amplitude by comparing the reliability limit value set for each of the plurality of pressure amplitudes and the number of pressure repetitions counted by the counting means. Temporarily judge. Then, the reliability of the high pressure portion including the pressure accumulating container is finally determined based on the plurality of temporary determination results. According to this configuration, the reliability evaluation is performed in two stages, and the evaluation accuracy can be improved. In this case, the reliability limit value of the number of pressure repetitions is preferably decreased as the pressure amplitude is increased.

  The durability limit at which the number of pressure repetitions is infinite in the fatigue limit characteristic (SN characteristic) using the pressure amplitude and the number of pressure repetitions as parameters. It is preferable that the pressure amplitude is larger than that.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment of the invention will be described with reference to the drawings. The present embodiment embodies the present invention as a common rail fuel injection system for a vehicle diesel engine, and a detailed configuration thereof will be described below.

  FIG. 1 is a configuration diagram showing an outline of a common rail fuel injection system. In FIG. 1, a fuel tank 10 and a fuel pump 11 are connected through a fuel pipe 12, and the fuel pump 11 is driven in accordance with the rotation of an engine (not shown) to repeatedly execute intake and discharge of fuel. Reference numeral 13 in the figure denotes a fuel filter. The fuel suction portion of the fuel pump 11 is provided with an electromagnetically driven suction metering valve (SCV) 14, and the low-pressure fuel pumped up from the fuel tank 10 is supplied to the fuel of the pump 11 via the suction metering valve 14. Inhaled into the pressure chamber. In the fuel pump 11, the plunger reciprocates in synchronization with the engine rotation, whereby the pressure in the fuel pressurizing chamber is increased, and the high-pressure fuel is discharged.

  A common rail 20 is connected to the fuel pump 11 via a fuel discharge pipe 18. The high-pressure fuel discharged from the fuel pump 11 is sequentially fed to the common rail 20 through the fuel discharge pipe 18 so that the fuel in the common rail 20 is maintained in a high-pressure state. The common rail 20 is provided with a fuel pressure sensor 21. The fuel pressure sensor 21 detects the fuel pressure in the common rail 20 (hereinafter also referred to as an actual rail pressure).

  An engine (not shown) is provided with an electromagnetically driven injector 23 for each cylinder, and high pressure fuel is supplied from the common rail 20 to the injector 23 through a high pressure fuel pipe 24. Fuel is injected and supplied to each cylinder of the engine by driving the injector 23. The injector 23 has a configuration using a two-way solenoid valve or a three-way solenoid valve, and a part of the high-pressure fuel supplied to the injector 23 is returned to the fuel tank 10 through a return pipe 25.

  The common rail 20 is provided with a mechanical (or electromagnetically driven) pressure reducing valve 27. When the common rail pressure rises excessively, the pressure reducing valve 27 is opened. As a result, the high pressure fuel is returned to the fuel tank 10 through the return pipe 25, and the common rail pressure is reduced.

  The ECU 30 is an electronic control unit including a known microcomputer including a CPU, ROM, RAM, EEPROM, and the like. The ECU 30 includes a rotation signal for detecting the rotation speed of the engine in addition to the detection signal of the fuel pressure sensor 21. Detection signals are sequentially input from various sensors such as a speed sensor 31 and an accelerator sensor 32 that detects an accelerator operation amount by a driver. The ECU 30 determines an optimal fuel injection amount and injection timing based on engine operation information such as the engine rotation speed and the accelerator opening, and outputs an injection control signal corresponding to the fuel injection amount to the injector 23. Thereby, the fuel injection from the injector 23 to the combustion chamber is controlled in each cylinder.

  Further, the ECU 30 calculates the target value of the common rail pressure (injection pressure) based on the engine speed and the fuel injection amount at that time, and sets the fuel discharge amount of the fuel pump 11 so that the actual rail pressure becomes the target rail pressure. Feedback control. Actually, the target discharge amount of the fuel pump 11 is determined based on the deviation between the actual rail pressure and the target rail pressure, and the opening of the intake metering valve 14 is controlled accordingly. At this time, by controlling the command current value (drive current) for the electromagnetic solenoid of the intake metering valve 14, the opening of the intake metering valve 14 is increased or decreased, and the fuel discharge amount by the fuel pump 11 is adjusted accordingly. The

  By the way, in the common rail 20, the actual rail pressure fluctuates according to the engine operating state every time, and rises to about 200 MPa at the maximum. At this time, since the actual rail pressure is 0 before the engine is started, the maximum fluctuation range of the actual rail pressure is about 200 MPa when the engine is started. Further, assuming that the actual rail pressure is about 30 MPa in the idle state during engine operation, the maximum fluctuation range of the normal use range during engine operation is about 170 MPa.

  In this case, there is a concern that the fatigue of the common rail 20 and other high-pressure fuel pipes (the fuel discharge pipe 18 and the high-pressure fuel pipe 24) may cause metal fatigue due to repeated fluctuations in the actual rail pressure. The Therefore, in the present embodiment, the fluctuation of the actual rail pressure after the vehicle ignition is turned on (after the engine is started) is monitored, and the reliability of the high-pressure portion such as the common rail 20 is determined based on the fluctuation range of the actual rail pressure.

In particular, in the present embodiment, a plurality of pressure amplitudes having different sizes are set, and when a pressure fluctuation corresponding to each pressure amplitude occurs, it is detected and the number of pressure repetitions is counted. And the reliability of high voltage | pressure parts, such as the common rail 20, etc. is determined according to the pressure repetition frequency. Specifically, the following three pressure amplitudes ΔP1 to ΔP3 are set, and the number of pressure repetitions at each pressure amplitude is counted.
(1) A pressure amplitude ΔP1 is defined as the engine starting pressure to the maximum pressure (0 to 200 MPa), and the number of pressure repetitions for ΔP1 is counted.
(2) The minimum pressure to the maximum pressure (30 to 200 MPa) in the normal use range of the engine is set as a pressure amplitude ΔP2, and the number of pressure repetitions for ΔP2 is counted.
(3) Count the number of pressure repetitions for a predetermined pressure amplitude ΔP3. For example, ΔP3 = 100 MPa.

  However, regarding the above (1) and (2), the upper limit pressure of the pressure amplitude may be set to “maximum pressure−α” instead of the maximum pressure which is the pressure resistance of the common rail 20. For example, the pressure amplitude ΔP1 in (1) is set to 0 to 180 MPa, and the pressure amplitude ΔP2 in (2) is set to 30 to 180 MPa.

  Here, the pressure amplitude (S) of the high-pressure portion such as the common rail 20 and the number of pressure repetitions (N) have the relationship shown in the SN diagram of FIG. 2, and in FIG. In the case of A1, it is considered that fatigue failure occurs when the number of pressure repetitions exceeds B1. In FIG. 2, A2 is the stress amplitude (endurance limit) that is considered to cause no fatigue failure below this value, and the pressure amplitudes ΔP1 to ΔP3 in (1) to (3) above are all A2 (endurance limit). ) Or more.

As shown in FIG. 2B, the fatigue limits corresponding to the pressure amplitudes ΔP1 to ΔP3 in the above (1) to (3) are different from each other,
In the case of pressure amplitude ΔP1, fatigue failure occurs when the number of pressure repetitions is K1,
In the case of pressure amplitude ΔP2, fatigue failure occurs when the number of pressure repetitions reaches K2,
In the case of pressure amplitude ΔP3, fatigue failure occurs when the number of pressure repetitions is K3.
it is conceivable that.

  Therefore, a determination value for the number of pressure repetitions is individually set for each pressure amplitude (reliability limit values K1, K2, K3). Then, the number of pressure repetitions at each of the pressure amplitudes ΔP1 to ΔP3 is counted, and the reliability of the high-pressure portion such as the common rail 20 is determined by comparing the count value with each determination value. Regarding the pressure amplitude ΔP3, the number of repetitions is counted each time the increase and decrease of the actual rail pressure by ΔP3 are alternately repeated.

  FIG. 3 is a time chart showing an example of the behavior of the actual rail pressure after the engine is started. FIG. 3 shows the behavior of the actual rail pressure for one trip. At the timing t1, the actual rail pressure starts to increase from 0 as the engine starts, and at the timing t13, the actual rail pressure decreases to 0. I'm going back. The first counter C1 is a counter for counting the number of pressure repetitions of the pressure amplitude ΔP1, the second counter C2 is a counter for counting the number of pressure repetitions of the pressure amplitude ΔP2, and the third counter C3 is a pressure amplitude ΔP3. It is a counter for counting the number of pressure repetitions.

  In FIG. 3, at the timing t1, the actual rail pressure starts to increase as the engine starts. For example, the engine is in an idle state for a while from the timing t2, and the actual rail pressure is controlled to about 30 MPa. Thereafter, when the engine is in a high load state, the actual rail pressure rises to the maximum pressure (about 200 MPa) at timing t4. At this time, the third counter C3 is incremented by 1 at a timing t3 when the pressure amplitude after the engine starts becomes ΔP3. Further, at the timing t4 when the actual rail pressure reaches the maximum pressure, each of the first counter C1 and the second counter C2 is incremented by one.

  After timing t4, after the actual rail pressure fluctuates in accordance with each driving state, it becomes 0 when the engine is stopped. Therefore, for the first counter C1, at the timing t13 when the actual rail pressure becomes 0 when the engine stops. Count up is performed again. The second counter C2 is counted up every time the actual rail pressure alternately alternates between the pressure (30 MPa) under the idle state and the maximum pressure (200 MPa) (timing t6, t10, t12).

  Further, regarding the third counter C3, after the timing t3 when the actual rail pressure increases by the pressure amplitude ΔP3, the count-up is performed every time the decrease and increase by the pressure amplitude ΔP3 are alternately repeated (timing t5, t7). , T8, t9, t11).

  In the example of FIG. 3, each time the actual rail pressure is increased or decreased by a predetermined pressure amplitude, the counters C1 to C3 are counted up. Ascending and descending may be performed as one cycle, and the counters C1 to C3 may be counted up each time a pressure fluctuation in one cycle occurs. That is, in this case, when the actual rail pressure changes as shown in FIG. 3, the first counter C1 is incremented by “1”, the second counter C2 is incremented by “2”, and the third counter C3 is incremented by “3”. Is done.

  The count values of the counters C1 to C3 are sequentially stored in a backup memory such as an EEPROM or a backup RAM, and the stored contents (count values) are held even after the ignition switch of the vehicle is turned off. Therefore, in FIG. 3, for the sake of convenience, the count-up of each counter is started from 0, but the value of the counter is actually counted after the count value at the previous trip.

  FIG. 4 is a flowchart showing a reliability evaluation process in a high-voltage portion such as the common rail 20. This process is repeatedly executed by the ECU 30 at a predetermined time period.

  In FIG. 4, first, in step S101, the actual rail pressure calculated from the detection signal of the fuel pressure sensor 21 is read. Next, in step S102, it is determined whether or not a pressure fluctuation corresponding to the pressure amplitude ΔP1 has occurred. If YES, the first counter C1 is incremented by 1 in step S103. In step S104, it is determined whether or not a pressure fluctuation corresponding to the pressure amplitude ΔP2 has occurred. If YES, the second counter C2 is incremented by 1 in step S105. In step S106, it is determined whether or not a pressure fluctuation corresponding to the pressure amplitude ΔP3 has occurred. If YES, the third counter C3 is incremented by 1 in step S107.

Thereafter, in step S108, reliability evaluation is performed on the high voltage portion such as the common rail 20 based on the counter values of the first to third counters C1 to C3. At this time, as a reliability evaluation method,
(A) a method of performing reliability evaluation using each counter value of the first to third counters C1 to C3 independently;
(B) a method of performing reliability evaluation by using each counter value of the first to third counters C1 to C3 in combination;
One of these is adopted.

  Regarding (A), determination values K1 to K3, which are reliability limit values, are set for each pressure amplitude ΔP1 to ΔP3, and “C1 value ≧ K1?”, “C2 value ≧ K2? And “Is C3 value ≧ K3?” Individually. Then, if any of the above three determinations is YES, it is determined that the reliability of the high-voltage portion such as the common rail 20 has been reduced (that is, the fatigue limit is close). When it is determined that the reliability has been lowered, a storage process such as a diag code is performed in order to store the fact, or the driver is notified by turning on an abnormality warning lamp or the like.

  In (A), it is also possible to set a weighting amount for each pressure amplitude, and to perform reliability evaluation based on the number of pressure repetitions multiplied by the weighting amount. In other words, the weighting factors f1, f2, and f3 are set for each of the pressure amplitudes ΔP1 to ΔP3 (f1> f2> f3 because of the relationship of ΔP1> ΔP1> ΔP3), and the weighting factors f1 are set to the counter values C1 to C3, respectively. Multiply ~ 3. In this case, the same reliability limit value Kref is used, “C1 value × f1 ≧ Kref?”, “C2 value × f2 ≧ Kref?”, “C3 value × f3 ≧ Kref?” Are individually determined. Then, if any of the above three determinations is YES, it is determined that the reliability of the high voltage portion such as the common rail 20 has decreased.

  As for (B), the total count value CT is calculated by adding all the counter values of the first to third counters C1 to C3 (CT = C1 + C2 + C3). Then, the total count number CT is compared with a determination value Kth that is a reliability limit value, and when CT value ≧ Kth, it is determined that the reliability in the high-voltage portion such as the common rail 20 has decreased.

In (B), it is also possible to set a weighting amount for each pressure amplitude, and calculate the total count number by adding the number of pressure repetitions multiplied by the weighting amount. That is, the weighting factors f1, f2, and f3 are set for each of the pressure amplitudes ΔP1 to ΔP3 (f1>f2> f3 because of the relationship of ΔP1>ΔP1> ΔP3). And
CT = C1 * f1 + C2 * f2 + C3 * f3
When CT value ≧ Kth, it is determined that the reliability of the high-voltage portion such as the common rail 20 has decreased.

  According to the embodiment described above in detail, the following excellent effects can be obtained.

  For each of a plurality of pressure amplitudes ΔP1 to ΔP3, the number of times the actual rail pressure is repeated is counted, and the reliability of the high-pressure portion such as the common rail 20 is determined based on the number of times the pressure is repeated. In the case where there is a possibility that fatigue failure may occur in the common rail 20 or the like due to repetition of the above, the possibility of the fatigue failure can be properly determined. Therefore, an appropriate reliability evaluation can be performed on the high-voltage portion including the common rail 20. In this case, an appropriate reliability evaluation can be performed before fuel leakage actually occurs.

  In this case, since the reliability evaluation is performed by counting the number of pressure repetitions with a plurality of pressure amplitudes, the evaluation accuracy can be improved compared to the case where the reliability evaluation is performed with the number of pressure repetitions of a single pressure amplitude. Can do.

  In addition, this invention is not limited to the content of description of the said embodiment, For example, you may implement as follows.

  In the above-described embodiment, the reliability evaluation is performed based on the actual rail pressure as the evaluation parameter based on the number of repetitions of the actual rail pressure, but instead, the target rail pressure is used as the evaluation parameter and the number of repetitions of the target rail pressure. It is also possible to perform reliability evaluation based on In this case, the target rail pressure corresponds to “pressure information correlating with the fuel pressure in the pressure accumulating vessel”.

  In the above-described embodiment, three pressure amplitudes ΔP1 to ΔP3 are set. However, two pressure amplitudes can be set, or four or more pressure amplitudes can be set. However, in this case, it is desirable to include a case where the pressure amplitude is at least from the engine starting pressure to the maximum pressure.

  In the configuration in which the number of pressure repetitions is counted for each of a plurality of pressure amplitudes ΔP1 to ΔP3, each counter C1 to C3 is compared with the reliability limit value for each pressure amplitude ΔP1 to ΔP3, and a temporary determination for reliability evaluation is performed. You may make it perform the final determination of reliability evaluation based on several temporary determination results. For example, when a temporary determination is made that the fatigue limit is reached (ie, the pressure is close to the fatigue limit) at two or more pressure amplitudes among the pressure amplitudes ΔP1 to ΔP3, the final determination that the fatigue limit is reached is performed. To. According to this configuration, the reliability evaluation is performed in two stages, and the evaluation accuracy can be improved. This corresponds to a combination of both methods (A) and (B).

  In the above embodiment, three pressure amplitudes ΔP1 to ΔP3 are set. However, any one of the pressure amplitudes is set, and the reliability of the high-pressure portion such as the common rail 20 is determined based on the number of pressure repetitions. It is also possible.

  In the above embodiment, the present invention is applied to a common rail fuel injection system for a diesel engine, but application to other systems is also possible. For example, the present invention is applied to a fuel injection system of a direct injection gasoline engine. Even in the case of a direct-injection gasoline engine, it is considered that high-pressure fuel is stored in an accumulator (also referred to as a delivery pipe), and pressure fluctuations are repeated at that time. Therefore, suitable reliability evaluation can be realized by applying the present invention.

It is a lineblock diagram showing an outline of a common rail type fuel injection system in an embodiment of the invention. It is a SN diagram which shows a pressure amplitude and the pressure repetition frequency as a parameter. It is a time chart which shows an example of the behavior of an actual rail pressure. It is a flowchart which shows a reliability evaluation process.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Fuel pump, 18 ... Fuel discharge piping, 20 ... Common rail, 23 ... Injector, 24 ... High pressure fuel piping, 30 ... ECU.

Claims (10)

A pressure accumulating container that stores high-pressure fuel corresponding to the injection pressure, a fuel supply pump that pumps high-pressure fuel to the pressure accumulating container, and a fuel injection valve that injects the fuel in the pressure accumulating container into the engine. Applied to a high pressure fuel system in which the fuel pressure in the pressure accumulating vessel is variably controlled based on the engine operating state of
Pressure acquisition means for acquiring fuel pressure in the pressure accumulator vessel or pressure information correlated therewith;
Counting means for counting the number of pressure repetitions in which the fuel pressure in the pressure accumulating vessel or pressure information correlated therewith fluctuates with a predetermined pressure amplitude;
Determination means for determining the reliability of the high-pressure portion including the pressure accumulating vessel based on the number of pressure repetitions counted by the counting means;
An apparatus for evaluating the reliability of a high-pressure fuel system, comprising:   For the pressure amplitude set by the fuel pressure in the pressure accumulating container before starting the engine and the maximum pressure allowed in the pressure accumulating container, the counting means is the number of pressure repetitions of the fuel pressure in the pressure accumulating container or pressure information correlated therewith. The high pressure fuel system reliability evaluation apparatus according to claim 1, wherein:   The counting means counts the number of pressure repetitions of the fuel pressure in the pressure accumulating vessel or pressure information correlated therewith for the pressure amplitude set by the minimum fuel pressure and the maximum fuel pressure in the normal operating range under the operating state of the engine. The reliability evaluation apparatus for a high-pressure fuel system according to claim 1.   2. The high-pressure fuel system reliability according to claim 1, wherein the counting unit counts the number of pressure repetitions of the fuel pressure in the pressure accumulating vessel or pressure information correlated therewith for a predetermined pressure amplitude. Sex evaluation device. An accumulator that stores high-pressure fuel corresponding to the injection pressure, a fuel supply pump that pumps high-pressure fuel to the accumulator, and a fuel injection valve that injects fuel in the accumulator into the engine, Applied to a high pressure fuel system in which the fuel pressure in the pressure accumulating vessel is variably controlled based on the engine operating state of
Pressure acquisition means for acquiring fuel pressure in the pressure accumulator vessel or pressure information correlated therewith;
For each of a plurality of preset pressure amplitudes, a counting means for counting the number of pressure repetitions of the fuel pressure in the accumulator vessel or pressure information correlated therewith,
Determining means for determining the reliability of the high-pressure portion including the pressure accumulating vessel based on the number of pressure repetitions for each pressure amplitude counted by the counting means;
An apparatus for evaluating the reliability of a high-pressure fuel system, comprising:   The counting means includes a fuel pressure in the pressure accumulator for a pressure amplitude set by a fuel pressure in the pressure accumulator before starting the engine and a maximum pressure allowed in the pressure accumulator and another pressure amplitude different from the pressure amplitude. 6. The reliability evaluation apparatus for a high-pressure fuel system according to claim 5, wherein the number of pressure repetitions of pressure information correlated therewith is counted.   The counting means includes a first pressure amplitude set by a fuel pressure in the pressure accumulating container before starting the engine and a maximum pressure allowed in the pressure accumulating container, and a minimum fuel pressure in a normal use range under an engine operating state. For each of the second pressure amplitude set by the maximum fuel pressure and a predetermined third pressure amplitude, the fuel pressure in the pressure accumulator or the number of pressure repetitions of pressure information correlated therewith is counted. The reliability evaluation apparatus for a high-pressure fuel system according to claim 5.   The said determination means determines the reliability of the high pressure part containing the said pressure accumulation container based on the sum total of the pressure repetition frequency counted for each of these several pressure amplitudes. Reliability evaluation system for high pressure fuel systems.   The determination means tentatively determines the reliability of the high pressure portion including the pressure accumulating vessel for each pressure amplitude by comparing the reliability limit value set for each of the plurality of pressure amplitudes and the number of pressure repetitions counted by the counting means. The reliability of the high pressure fuel system according to any one of claims 5 to 7, further comprising: means; and means for finally determining the reliability of the high pressure portion including the pressure accumulating vessel based on a plurality of temporary determination results. Sex evaluation device.   6. The plurality of pressure amplitudes are pressure amplitudes that are larger than an endurance limit at which the number of pressure repetitions is infinite in a fatigue limit characteristic using the pressure amplitude and the number of pressure repetitions as parameters. The reliability evaluation apparatus of the high pressure fuel system in any one of thru | or 9.

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