JP5353670B2 - Fuel injection control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control device accurately determining fuel leak. <P>SOLUTION: The fuel injection control device calculates the pumping quantity QPMPJD of a fuel supply pump during a determination period from the determination start timing to the determination completion timing, calculates the leak quantity QINJ and injection quantity QSUM from a fuel injection valve during the determination period, and calculates the balance of the fuel quantity in a common rail from the deviation between common rail pressures at the determination start timing and the determination completion timing (S400-S406). Then, the fuel injection control device calculates the leak quantity QLEAK based on the value calculated in S400-S406 (S410). The fuel injection control device increases leak counter by 1 (S416) when the leak quantity QLEAKA calculated by filter process of the leak quantity QLEAK is larger than a leak determination threshold value QLJDA (S414:Yes), and determines that leak occurs in a fuel injection system (S420) when the leak counter continuously exceeds a predetermined number (S418:Yes). <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a fuel injection control device that determines fuel leakage in a fuel injection system that injects fuel accumulated in a common rail into each cylinder of an internal combustion engine from a fuel injection valve.

  2. Description of the Related Art Conventionally, in a fuel injection system that injects fuel accumulated in a common rail into each cylinder of an internal combustion engine from a fuel injection valve, in order to make the common rail pressure (hereinafter also referred to as common rail pressure) coincide with the target common rail pressure, The pumping amount of the supply pump is adjusted by a metering valve.

  In such a fuel injection system, for example, if the fuel leaks from a damaged part of the fuel pipe, the common rail pressure decreases. Therefore, in order to match the decreased common rail pressure with the target common rail pressure, the pumping amount of the fuel supply pump is unnecessary. Incremental control is performed.

  Therefore, calculate the balance between the amount of fuel supplied and the amount of consumption from the pumped amount of the fuel supply pump, the injection amount and leak amount of the fuel injection valve, and the change amount of the common rail pressure, and whether the fuel is leaking based on the calculated balance It is known to determine whether or not (see, for example, Patent Documents 1 and 2).

  In Patent Documents 1 and 2, when calculating the balance of the fuel supply amount and the consumption amount from the pumping amount of the fuel supply pump, the injection amount and leak amount of the fuel injection valve, and the change amount of the common rail pressure, The pumping amount is calculated on the assumption that the pumping process from the pumping start to the pumping end is completed for the number of pumping times to be subjected to the leakage determination.

  For example, in Patent Document 2, 360 ° CA is set as a determination period for determining fuel leakage, and the amount of fuel supplied and consumed are assumed to be one pumping for two injections during this determination period. An amount balance is calculated, and fuel leakage is determined based on the calculation result.

Japanese Patent No. 3508359 Japanese Patent No. 4026368

  However, during the set determination period, for example, the fuel injection valve has completed one or more fuel injections, whereas the fuel supply pump does not necessarily complete one or more pumping strokes. The fuel supply pump may be performing a pressure feed stroke at the determination start timing or determination end timing of the determination period.

  In this case, if the balance between the fuel supply amount and the consumption amount is calculated assuming that one or more pumping strokes have been completed from the fuel supply pump for one or more fuel injections from the fuel injection valve, the balance Cannot be calculated accurately, so fuel leakage cannot be determined with high accuracy.

  The present invention has been made to solve the above-described problem, and an object of the present invention is to provide a fuel injection control device that can determine fuel leakage with high accuracy.

According to the first to fourth aspects of the present invention, the fuel calculated by the injection amount calculating means in the determination period from the determination start timing to the determination end timing set so that the fuel injection valve completes one fuel injection. A single injection amount by the injection valve, a pumping amount of the fuel supply pump calculated by the pumping amount calculating means, a fuel injection valve leak amount calculated by the leak amount calculating means, and a determination end timing detected by the pressure detecting means A leakage amount calculation means calculates a fuel leakage amount of the fuel injection system based on the pressure difference of the common rail at the determination start time.

  In this way, the determination period for determining fuel leakage is defined by the determination start timing and the determination end timing, and the pumping amount pumped from the fuel supply pump is calculated during the determination period from the determination start timing to the determination end timing. Even when the fuel supply pump is pumping fuel at the determination start timing or determination end timing, the pumping amount calculation means calculates the pumping amount during the determination period.

  As a result, the fuel balance can be accurately determined based on the injection amount and leak amount of the fuel injection valve, the pumping amount of the fuel supply pump, and the pressure difference of the common rail between the determination end timing and the determination start timing during the determination period. Can be calculated. As a result, fuel leakage can be determined with high accuracy during the determination period.

  By the way, when it is determined that a fuel leak has occurred, the fuel leak is not determined by a single determination, but when the calculation result determined that the fuel leak has occurred occurs multiple times. It is desirable to determine that a leak has occurred. In this case, if the period during which the fuel injection valve injects a plurality of times is set as the determination period, a large amount of fuel leaks during the determination as many times as necessary to determine the determination.

Therefore, according to the first to fourth aspects of the present invention, the leakage amount calculating means sets the determination start timing and the determination end timing so that the fuel injection valve injects fuel once during the determination period.
Thereby, since the one determination period is shortened, it can be determined that the fuel leakage has occurred in a short time as much as possible even if a plurality of determinations are executed. As a result, for example, it is possible to promptly execute appropriate fail-safe processing for fuel leakage, such as generation of a warning sound for notifying fuel leakage and lighting of a warning light.

According to the second aspect of the present invention, the determination start timing is the rising timing of the injection command signal that commands the fuel injection valve to inject fuel, and the determination end timing is the closing timing of the fuel injection valve from the falling timing of the injection command signal. This is the closing timing of the fuel injection valve in consideration of the delay.

  Thus, the fuel injection valve reliably injects fuel once during the period from the determination start timing to the determination end timing. Therefore, during this determination period, based on the injection amount and leak amount of the fuel injection valve, the pumping amount of the fuel supply pump, and the fuel loss amount calculated from the pressure difference of the common rail between the determination end timing and the determination start timing The fuel balance can be calculated accurately.

According to the third aspect of the present invention, the pumping amount calculation means sums the pumping amounts by the plungers of the fuel supply pump during the determination period.
Thereby, even if fuel is pumped from a plurality of plungers during the determination period, the pumping amount of the fuel supply pump can be calculated with high accuracy.

According to the fourth aspect of the present invention, the pumping amount calculation means calculates the pumping amount by each plunger during the determination period based on the angular position of the plunger of the fuel supply pump at the determination start timing and the determination end timing.

  Since the pumping amount pumped from each plunger is determined according to the displacement amount of the plunger, the pumping amount by each plunger during the determination period can be calculated with high accuracy based on the angular position of the plunger.

  The functions of the plurality of means provided in the present invention are realized by hardware resources whose functions are specified by the configuration itself, hardware resources whose functions are specified by a program, or a combination thereof. The functions of the plurality of means are not limited to those realized by hardware resources that are physically independent of each other.

The block diagram which shows the fuel-injection system by 1st Embodiment. The time chart which shows the relationship between an injection command pulse and the lift amount of each plunger. The time chart which shows the relationship between the injection command pulse during the leak determination period, and the lift amount of the plunger. The flowchart which shows a fuel leak determination routine. The flowchart which shows the pumping amount calculation routine of a fuel supply pump. The block diagram which shows the fuel-injection system by 2nd Embodiment. The time chart which shows the relationship between an injection command pulse and the lift amount of each plunger. The time chart which shows the relationship between the injection command pulse during the leak determination period, and the lift amount of the plunger. The time chart which shows the relationship between the injection command pulse at the time of 1 injection 2 pressure feeding in the 6 cylinder engine by other embodiment and 2 injection 1 pressure feeding, and the lift amount of each plunger. The time chart which shows the relationship between the injection command pulse at the time of 1 injection 2 pressure feeding in the 4 cylinder engine by other embodiment and 2 injection 1 pressure feeding, and the lift amount of each plunger.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
(Fuel injection system 10)
FIG. 1 shows a fuel injection system 10 according to the first embodiment. The fuel injection system 10 is for supplying fuel to a 6-cylinder diesel engine (hereinafter also simply referred to as “engine”) 2 for an automobile, for example. The fuel injection system 10 includes a fuel supply pump 14, a common rail 20, a fuel injection valve 30, and an electronic control unit (ECU) 40.

  The fuel supply pump 14 incorporates a feed pump that pumps fuel from the fuel tank 12. The fuel supply pump 14 is a known pump that pressurizes the fuel sucked into the pressurizing chamber from the feed pump when the plunger reciprocates as the cam of the camshaft rotates.

  The fuel supply pump 14 is provided with three plungers at 120 ° intervals in the cam shaft cam rotation direction. That is, the fuel supply pump 14 pumps the fuel three times during one rotation of the camshaft. In the present embodiment, the camshaft that drives the plunger of the fuel supply pump 14 also rotates once while the crankshaft rotates once.

  The metering valve 16 serving as a metering actuator is installed on the suction side of the fuel supply pump 14 and controls the amount of fuel sucked by each plunger of the fuel supply pump 14 in the suction stroke by current control. . By adjusting the fuel intake amount, the fuel pumping amount from each plunger of the fuel supply pump 14 is adjusted.

  The common rail 20 is a hollow member that accumulates fuel pumped from the fuel supply pump 14. The common rail 20 is provided with a pressure sensor 22 for detecting the internal fuel pressure (common rail pressure), and a pressure reducing valve 24 for reducing the common rail pressure by overflowing the internal fuel to the fuel tank 12 side. A pressure limiter may be installed in place of the pressure reducing valve 24, and when the common rail pressure exceeds a predetermined pressure, the fuel in the common rail 20 may be discharged to the fuel tank 12 side to prevent the common rail pressure from exceeding the predetermined pressure.

  The engine 2 is provided with a rotational speed sensor 32 that detects an engine rotational speed (NE) as a sensor that detects an operating state. Further, as other sensors for detecting the driving state, an accelerator sensor for detecting an accelerator opening (ACCP) that is an operation amount of an accelerator pedal by a driver, a temperature of cooling water (water temperature), a temperature of intake air (intake air temperature). The fuel injection system 10 is provided with a temperature sensor or the like for detecting each of these.

  The fuel injection valve 30 is installed in each cylinder of the engine 2 and injects fuel accumulated in the common rail 20 into the cylinder. The fuel injection valve 30 is, for example, a known electromagnetic valve that controls the lift of the nozzle needle that opens and closes the nozzle hole with the pressure in the control chamber. The injection amount of the fuel injection valve 30 is controlled by the pulse width of the injection command signal commanded from the ECU 40. As the pulse width of the injection command signal becomes longer, the injection amount increases.

  The ECU 40 is mainly configured by a microcomputer centering on a CPU, RAM, ROM, flash memory and the like. The ECU 40 executes various control of the fuel injection system 10 based on output signals taken from various sensors including the pressure sensor 22 and the rotation speed sensor 32 by the CPU executing a control program stored in the ROM or flash memory. Run.

  For example, the ECU 40 controls the energization amount to the metering valve 16 so that the common rail pressure detected by the pressure sensor 22 becomes the target pressure, and regulates the pumping amount of the fuel supply pump 14. The ECU 40 sets a current value for controlling the metering valve 16 based on a characteristic map representing a correlation between the current value for controlling the metering valve 16 and the pumping amount.

Further, the ECU 40 controls the fuel injection amount of the fuel injection valve 30, the fuel injection timing, and the multi-stage injection pattern in which pilot injection, post injection, etc. are performed before and after the main injection.
The ECU 40 stores an injection characteristic map indicating the correlation between the pulse width of the injection command signal for instructing the fuel injection valve 30 and the injection amount in the ROM or flash memory for each predetermined pressure range of the common rail pressure. Then, when the injection amount of the fuel injection valve 30 is determined based on the engine speed and the accelerator opening, the ECU 40 refers to the injection characteristic map of the corresponding pressure range according to the common rail pressure detected by the pressure sensor 22. Then, the pulse width of the injection command signal that commands the determined injection amount to the fuel injection valve 30 is acquired from the injection characteristic map.

(Leakage determination period)
FIG. 2 shows the relationship between the injection command pulse for the fuel injection valve 30 and the lift amount of each plunger of the fuel supply pump 14. The numbers # 1 to # 6 above the injection command pulse represent cylinder numbers to be injected. In the present embodiment, the fuel is pumped six times from the fuel supply pump 14 while the fuel is injected six times from the six-cylinder fuel injection valve 30. That is, on average, one fuel pumping is executed for one fuel injection.

  In the present embodiment, a determination period including one fuel injection from the fuel injection valve 30 is set. That is, one fuel injection starts and ends during the determination period, and is completed. Then, during the set determination period, the pumping amount that the fuel supply pump 14 pumps is calculated to determine fuel leakage. Here, depending on the length of the determination period or the determination start timing and the determination end timing, one fuel pumping does not always correspond to one fuel injection.

  As shown in FIG. 3, in this embodiment, the rising timing of the injection command pulse is set as the determination start timing Ts, and the closing timing considering the closing delay Tcd of the fuel injection valve 30 from the falling of the injection pulse is determined as the determination end timing. A determination period Tp is set as Te. The rising timing Ts of the injection command pulse is set to the advance side by a predetermined angle (TFIN) from the top dead center (TDC) of the plunger of the fuel supply pump 14.

  In FIG. 3, BALCA represents an angular position at which the plunger of the fuel supply pump 14 rises from the bottom dead center position, the delivery valve opens, and fuel pumping starts from the plunger. One pumping stroke from the bottom dead center to the top dead center of each plunger is 180 ° CA. Further, the phase difference of the stroke between the plungers is 120 ° CA.

(Calculation of pumping amount)
The ECU 40 detects the actual common rail pressure from the output signal of the pressure sensor 22, and sets the target common rail pressure of the common rail based on the operating state such as the engine speed and the accelerator opening. Then, the command pumping amount QPMP per plunger is calculated from the deviation between the actual common rail pressure and the target common rail pressure.

If the bottom dead center position of the plunger is 0 ° CA, and the angular position from the bottom dead center of the plunger is PLIFTCA (° CA), the plunger at the position of the PLIFTCA will reach the TDC (180 ° CA) of the pumping stroke. The pumping amount QPMPJDB (PLIFTCA) to be pumped is expressed by the following equation (1). However, BALCA ≦ PLIFTCA <180 ° CA.
QPMPJDB (PLIFTCA) =
QPMP-QPMP × (PLIFTCA-BALCA) / (180 ° CA-BALCA)
... (1)
In Formula (1), (180 ° CA-BALCA) represents the lift angle amount of the plunger from BALCA to top dead center required for pumping QPMP, and (PLIFTCA-BALCA) represents the plunger moving from BALCA to PLIFTCA. This represents the lift angle amount.

When the position of PLIFTCA is 0 ° CA ≦ PLIFTCA <BALCA and 180 ° CA ≦ PLIFTCA ≦ 360 ° CA, QPMPJDB (PLIFTCA) = 0.
Next, equations for calculating the pumping amount QPMPPLn (n is a plunger number) per plunger according to the determination start position Ts and the determination end position Te that define the determination period Tp are respectively shown.
(1) -180 ° CA <Ts <Te <BALCA
QPMPPLn = 0
(2) 0 ° CA <Ts <BALCA <Te <180 ° CA
QPMPPLn = QPMPJDB (BALCA) −QPMPJDB (Te)
(3) 0 ° CA <BALCA <Ts <Te <180 ° CA
QPMPPLn = QPMPJDB (Ts) −QPMPJDB (Te)
(4) 0 ° CA <BALCA <Ts <180 ° CA <Te
QPMPPLn = QPMPJDB (Ts)
As shown in FIG. 3, when two plungers overlap each other in the determination period Tp to pump fuel, the total QPMPJD of the pumping amount that the fuel supply pump 14 pumps in the determination period Tp is as shown in the following equation (2). The total of the pumping amount QPMPPL1 of the # 1 plunger and the pumping amount QPMPPL2 of the # 2 plunger in the determination period Tp. Depending on the setting of the determination period Tp, the pumping amount of the # 3 plunger may be added.
QPMPJD = QPMPPL1 + QPMPPL2 (2)
For example, QPMPJD in the determination period Tp shown in FIG. 3 can be calculated by substituting the following equations (3) and (4) into equation (2).
QPMPPL1 = QPMPJDB (TDC-TFIN) (3)
QPMPPL2 = QPMPJDB (TDC−120 ° CA−TFIN) −
QPMPJDB (TDC-120 ° CA-TFIN + Tp)
... (4)
(Leakage determination)
Next, the leak determination of the fuel injection system 10 will be described. In the present embodiment, the leakage amount QLEAK of the fuel injection system 10 in the determination period Tp can be calculated by the following equation (5).
QLEAK = QPMPJD− (QSUM × n + QINJ + QPc) (5)
QINJ is expressed by the following equation (6).
QINJ = QILSJD × Tp / 180 ° CA + QILDJD × n (6)
In Expressions (5) and (6), each parameter other than the above-described QPMPJD represents the following meaning.
QSUM: One command injection amount QINJ for one fuel injection valve 30: Leakage amount from the fuel injection valves 30 of all cylinders in the determination period QILSJD: All fuel injection valves of 6 cylinders per one pressure feed of the fuel supply pump 14 30 static leak amount QILDJD: dynamic leak amount per injection in one fuel injection valve QPc: common rail pressure deviation ΔPc between the determination start timing Ts and determination end timing Te defining the determination period Tp as fuel Value n converted to quantity: Number of injections during determination period (in the first embodiment, n = 1)
That is, in the determination period Tp, the total injection amount {QSUM × n (n = 1)} from the fuel injection valve 30 to the fuel injection amount (QPMPJD) pumped from the fuel supply pump 14 and the fuel injection A value obtained by subtracting the sum of the leak amount (QINJ) of the valve 30 and the fuel amount (QPc) corresponding to the deviation of the common rail pressure is represented as the fuel leak amount (QLEAK) of the fuel injection system 10.

The ECU 40 determines that fuel leakage has occurred in the fuel injection system 10 when the amount of fuel leakage calculated from the equation (5) exceeds a predetermined amount and the determination result continues for a predetermined number of times.
(Fuel leak judgment routine)
FIG. 4 shows a flowchart of a fuel leak determination routine. The routine of FIG. 4 is always executed. In FIG. 4, “S” represents a step.

  The ECU 40 calculates the pumping amount QPMPJD of the fuel supply pump 14 during the determination period Tp based on the equations (2) to (4) (S400), and calculates the leak amount QINJ from the fuel injection valve 30 during the determination period Tp. Based on (6) (S402), the injection amount QSUM of the fuel injection valve 30 during the determination period Tp is calculated (S404). A routine for calculating the pumping amount QPMPJD will be described later.

  Further, the ECU 40 calculates the balance between the fuel outflow and inflow in the common rail 20 from the deviation of the common rail pressure between the determination start timing Ts and the determination end timing Te that define the determination period Tp (S406), and the fuel leakage is detected. The determination threshold value QLJDA is calculated from a map or the like based on the common rail pressure (S408).

  Next, the ECU 40 calculates the leakage amount QLEAK of the fuel injection system 10 based on the equations (5) and (6) (S410). Then, for example, the leakage amount QLEAK is subjected to a filtering process by adding a leakage value calculated this time, a leakage amount calculated one time before, and a leakage amount calculated two times before, each of which is multiplied by a fitness value as a weighting factor. The current leakage amount is calculated as QLEAKA (S412).

  Thus, by calculating the current leak amount by weighting the leak amount calculated multiple times up to now including this time as a filter process, the sensor detection signal becomes a value that deviates from the appropriate value due to noise etc. Even when the amount of leakage deviates from an appropriate value, the amount of deviation can be reduced. As a result, erroneous determination of fuel leakage can be prevented.

  The ECU 40 determines whether or not the leakage amount QLEAKA is larger than the leakage determination threshold value QLJDA (S414). If QLEAKA ≦ QLJDA (S414: No), the process proceeds to S400.

  If QLEAKA> QLJDA (S414: Yes), the ECU 40 sets the determination flag to 1 and increments the leak counter by 1 (S416). When the leak counter exceeds the predetermined number (S418: Yes), it is determined that a leak has occurred in the fuel injection system 10 (S420), and this routine is terminated.

When the leak counter is equal to or smaller than the predetermined number (S418: No), the ECU 40 ends this routine.
When the leak counter exceeds the predetermined number of times, the ECU 40 executes appropriate fail-safe processing such as generation of a warning sound and lighting of a warning light in S420 or another routine.

(Pressure feed amount calculation routine)
FIG. 5 shows a pumping amount calculation routine executed in S400 of FIG. The ECU 40 calculates the valve opening timing (BALCA) of the delivery valve of the fuel supply pump 14 in the pumping stroke from the common rail pressure and the command pumping amount to the fuel supply pump 14 (S430).

Then, the ECU 40 calculates the lift amount of each plunger at the determination start timing Ts and the determination end timing Te that define the determination period Tp (S432). The ECU 40 calculates the pumping amount of the fuel supply pump 14 during the determination period Tp based on the delivery valve opening timing and the lift amount of each plunger at the determination start timing Ts and the determination end timing Te (S434). In this embodiment, when determining the leakage of the fuel injection system 10, the pumping amount of the fuel supply pump 14 is calculated for one injection of the fuel injection valve 30 that is the minimum unit, The amount of leakage of the fuel injection system 10 is calculated. Thereby, the determination time per time required when it is determined that a leak has occurred in the fuel injection system 10 is shortened. As a result, the determination result of the fuel leak continuously occurs over a predetermined number of times, and the time required to determine that the fuel injection system 10 is leaking is shortened. Appropriate fail processing can be executed.

  In the present embodiment, the ECU 40 corresponds to the fuel injection control device of the present invention, and the engine 2 corresponds to the internal combustion engine of the present invention. 4 corresponds to the function executed by the pumping amount calculation means of the present invention, and the processing of S402 of FIG. 4 corresponds to the function executed by the leak amount calculation means of the present invention. 4 corresponds to the function executed by the injection amount calculation means of the present invention, the process of S406 corresponds to the function executed by the pressure detection means of the present invention, and the processes of S410 and S412 correspond to this function. This corresponds to the function executed by the leakage amount calculating means of the invention.

Further, the processing of S414 to S420 in FIG. 4 corresponds to the function executed by the leakage determination unit that determines the fuel leakage of the fuel injection system 10 based on the fuel leakage amount.
The ECU 40 functions as a pressure detection unit, an injection amount calculation unit, a leak amount calculation unit, a pumping amount calculation unit, a leak amount calculation unit, and a leak determination unit by executing a control program.

[Second Embodiment]
A fuel injection system according to the second embodiment is shown in FIG. The fuel injection system 50 is for supplying fuel to a four-cylinder diesel engine (hereinafter also simply referred to as “engine”) 52 for automobiles.

  The fuel supply pump 54 is provided with two plungers at positions opposite to the camshaft cam by 180 °. That is, while the camshaft makes one revolution, the fuel supply pump 54 pumps the fuel twice. In the present embodiment, the camshaft that drives the plunger of the fuel supply pump 54 also rotates once while the crankshaft rotates once.

  Therefore, as shown in FIG. 7, the fuel supply pump 54 pumps the fuel four times while the crankshaft rotates twice and the fuel injection valve 30 of the four cylinders injects a total of four times. That is, on average, one fuel pumping is executed for one fuel injection. The one-pressure feed stroke from the bottom dead center to the top dead center of each plunger is 180 ° CA as in the first embodiment. Further, the phase difference of the stroke between the plungers is 180 ° CA.

  As shown in FIG. 8, in the determination period Tp of the second embodiment, the rising timing of the injection command pulse is set as the determination start timing Ts, and the rising timing of the next injection pulse is set as the determination end timing Te. The rising timing Ts of the injection command pulse is set to the advance side by a predetermined angle (TFIN) from the top dead center (TDC) of the plunger of the fuel supply pump 14.

In the second embodiment, the total QPMPJD of the pumping amount that the fuel supply pump 14 pumps in the determination period Tp when the two plungers overlap and pump the fuel in the determination period Tp is expressed by the following equations (7) to (9). It is represented by
QPMPJD = QPMPPL1 + QPMPPL2 (7)
QPMPPL1 = QPMPJDB (TDC-TFIN) (8)
QPMPPL2 = QPMPJDB (BALCA) −
QPMPJDB (Tp-TFIN) (9)
Hereinafter, the ECU 60 calculates the fuel leakage amount based on the equations (5) and (6) in the same procedure as in the first embodiment, and determines the leakage of the fuel injection system 50.

In the second embodiment, the engine 52 corresponds to the internal combustion engine of the present invention, and the ECU 60 corresponds to the fuel injection control device of the present invention.
In the above-described embodiment described above, the determination period for determining the fuel leakage of the fuel injection system is defined by the determination start timing and the determination end timing, and is pumped from the fuel supply pump between the determination start timing and the determination end timing. The amount of pumping is calculated.

  As a result, the fuel balance can be accurately determined based on the injection amount and leak amount of the fuel injection valve, the pumping amount of the fuel supply pump, and the pressure difference of the common rail between the determination end timing and the determination start timing during the determination period. Can be calculated. As a result, fuel leakage can be determined with high accuracy during the determination period.

[Other Embodiments]
In the above-described embodiment, on the average, the fuel injection system leakage determination in which one fuel pump of the fuel supply pump corresponds to one fuel injection of the fuel injection valve has been described.

  On the other hand, as in the first embodiment, in a fuel injection system including a six-cylinder engine and a fuel supply pump in which three plungers are installed at 120 ° intervals, as shown in FIG. In addition, even when 12 fuel pumps are executed from the fuel supply pump for 6 fuel injections, the injection amount and the pumping amount during the determination period including one fuel injection are calculated, and the equation (5) ) And (6), the amount of leakage can be calculated. Then, it is possible to determine the leakage of the fuel injection system based on the calculated leakage amount.

  In this fuel injection system, on average, two fuel pumps of the fuel supply pump correspond to one fuel injection of the fuel injection valve. The ratio between the number of injections and the number of pumping is determined by the ratio of the number of rotations between the crankshaft and the camshaft. In FIG. 9A, when the crankshaft rotates once, the camshaft rotates twice.

  Further, as shown in FIG. 9B, in the fuel injection system that executes the fuel pumping three times from the fuel supply pump for the six fuel injections, the determination period includes one fuel injection. The injection amount and the pumping amount are calculated, and the leakage amount can be calculated from the equations (5) and (6). Then, it is possible to determine the leakage of the fuel injection system based on the calculated leakage amount.

  In this fuel injection system, on average, one fuel pumping of the fuel supply pump corresponds to two fuel injections of the fuel injection valve. When the crankshaft rotates twice, the camshaft rotates once.

  As in the second embodiment, in a fuel injection system including a 4-cylinder engine and a fuel supply pump in which two plungers are installed 180 ° opposite to each other, as shown in FIG. Even in a fuel injection system that executes fuel pumping eight times from the fuel supply pump for four fuel injections, the injection amount and the pumping amount during the determination period including one fuel injection are calculated, and the equation (5) ) And (6), the amount of leakage can be calculated. Then, it is possible to determine the leakage of the fuel injection system based on the calculated leakage amount. In this fuel injection system, on average, two fuel pumps of the fuel supply pump correspond to one fuel injection of the fuel injection valve.

  In addition, as shown in FIG. 10B, in the fuel injection system that executes fuel pumping twice from the fuel supply pump for four fuel injections, the determination period includes one fuel injection. The injection amount and the pumping amount are calculated, and the leakage amount can be calculated from the equations (5) and (6). Then, it is possible to determine the leakage of the fuel injection system based on the calculated leakage amount. In this fuel injection system, on average, one fuel pumping of the fuel supply pump corresponds to two fuel injections of the fuel injection valve.

  The fuel leakage determination period is not limited to one fuel injection, and may be set in a range including a plurality of fuel injections. Further, the determination start timing and the determination end timing that define the determination period may be set to any timing as long as the fuel is not being injected.

  In the above embodiment, the metering valve 16 is installed on the suction side of the fuel supply pump 14, and the metering valve 16 measures the amount of fuel sucked by the fuel supply pump 14 in the suction stroke. The pumping amount of the fuel supply pump 14 was adjusted. On the other hand, a metering valve may be installed on the discharge side of the fuel supply pump 14 to meter the fuel pumping amount of the fuel supply pump 14.

  In the above embodiment, the functions of the pressure detection means, the injection amount calculation means, the leak amount calculation means, the pumping amount calculation means, the leak amount calculation means, and the leak determination means are realized by the ECUs 40 and 60 whose functions are specified by the control program. Yes. On the other hand, at least a part of the functions of the above means may be realized by hardware whose function is specified by the circuit configuration itself.

  As described above, the present invention is not limited to the above-described embodiment, and can be applied to various embodiments without departing from the gist thereof.

2, 52: diesel engine (internal combustion engine), 10, 50: fuel injection system, 14, 54: fuel supply pump, 20: common rail, 30: fuel injection valve, 40, 60: ECU (fuel injection control device, pressure detection) Means, injection amount calculation means, leak amount calculation means, pumping amount calculation means, leak amount calculation means, leak determination means)

Claims (4)

In a fuel injection control device that determines leakage of a fuel injection system that injects fuel supplied from a fuel supply pump and accumulated in a common rail from a fuel injection valve installed in each cylinder of an internal combustion engine.
Pressure detecting means for detecting the pressure of the common rail;
An injection amount calculating means for calculating an injection amount of the fuel injection valve in a determination period from a determination start timing to a determination end timing set so that the fuel injection valve completes one fuel injection ;
A leak amount calculating means for calculating a leak amount of the fuel injection valve within the determination period ;
A pumping amount calculating means for calculating a pumping amount of the fuel supply pump within the determination period ;
The Oite within the determination period, and one injection amount by the fuel injection valve, wherein the injection amount calculating means for calculating a pumping quantity of the fuel supply pump in which the pumping quantity calculating means calculates the leakage amount calculating means The leak amount calculation for calculating the fuel leak amount of the fuel injection system based on the leak amount calculated by the pressure detection means and the pressure difference of the common rail between the determination end timing and the determination start timing detected by the pressure detection means Means,
A fuel injection control device comprising: The determination start timing is a rising timing of an injection command signal for instructing the fuel injection valve to inject fuel, and the determination end timing is the time when the closing delay of the fuel injection valve is considered from the falling timing of the injection command signal. 2. The fuel injection control device according to claim 1 , wherein the fuel injection valve is closed. The fuel supply pump pressurizes and feeds fuel in a pressurizing chamber corresponding to each plunger by reciprocating a plurality of plungers,
The pumping amount calculation means sums the pumping amount by each plunger during the determination period.
The fuel injection control device according to claim 1 , wherein the fuel injection control device is a fuel injection control device. The fuel supply pump pressurizes and feeds fuel in a pressurizing chamber corresponding to each plunger by reciprocating a plurality of plungers,
The pumping amount calculation means calculates a pumping amount by each plunger during the determination period based on the angular position of the plunger at the determination start timing and the determination end timing.
The fuel injection control device according to any one of claims 1 to 3, wherein

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