JP2008215201A - Fuel injection pressure control device and fuel injection pressure control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection pressure control device acquiring the pressure property of each intended system even when there is an individual difference (difference between devices) in pressure properties between various devices relating to pressure control, and to provide a fuel injection pressure control system. <P>SOLUTION: The fuel injection pressure control device (an ECU 30) feedback controls rail pressure to be a target value through the variable control of a driving current amount for a suction adjusting valve (a valve for adjusting a fuel suction amount for a fuel pump 14). It comprises a program for finding a fuel leak amount (an actual leak amount) during a time when predetermined stabilizing conditions showing the stabilization of the rail pressure are established, in accordance with a relationship of "fuel consumption = fuel injection amount of fuel injection valve + fuel leak amount". In details, the actual leak amount is found in accordance with a pressure controlled variable I term (an integration term) at this time. Furthermore, a control gain of the driving current amount is corrected in accordance with the actual leak amount. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection pressure control device and a fuel injection pressure control system that control a fuel injection pressure when fuel is supplied to a cylinder of a target engine or an intake passage or an exhaust passage thereof.

  As is well known, for example, an engine (internal combustion engine) used as a power source of an automobile or the like ignites and burns fuel supplied by a fuel supply system to generate output torque. That is, the performance (characteristics) of the fuel supply system (fuel supply system) is one of important factors (factors) that determine the output characteristics of the engine when the engine is controlled. In recent years, in diesel engines and the like, as such a fuel supply system, high-pressure fuel (for example, light oil having a fuel pressure of about “1400 atm”) is accumulated and held in a common rail (accumulation piping), and the high-pressure fuel is supplied to the target engine as needed. Common rail fuel injection systems that supply fuel are being adopted. As a general configuration of this system, in addition to the above-mentioned common rail, a fuel pressure sensor that measures the pressure in the common rail (rail pressure), and a fuel that pumps a predetermined fuel (for example, light oil) from a fuel tank and pumps it to the common rail. A pump, a suction control valve (SCV) that makes the amount of fuel sucked into the pump variable, and high-pressure fuel (pressurized fuel) accumulated in the common rail is injected and supplied to the target engine (specifically, the specified cylinder) There is known an apparatus further including an injector (fuel injection valve) or the like.

In such a common rail fuel injection system, it is important to manage rail pressure. This is because the rail pressure is a main parameter that determines the fuel injection pressure of the fuel injection valve when fuel is supplied by injection. For this reason, generally, feedback control (PID control) that brings the rail pressure value (actually measured value) closer to its target value based on the above configuration, as in the fuel injection pressure control device described in Patent Document 1, for example. Like to do. Specifically, for example, by adjusting a supply current amount (corresponding to a drive amount of the suction adjustment valve) with respect to the suction adjustment valve while referring to a control map (adaptation map) created in advance by experiments or the like, The discharge amount of the fuel pump is variably controlled to a desired amount (target value). By doing so, the rail pressure is controlled to a target value, and fuel supply (injection supply) to the target engine is performed at an appropriate fuel injection pressure.
JP 2005-147005 A

  However, even with such a method (pressure control method), the rail pressure and thus the fuel injection pressure cannot always be controlled with high accuracy. For example, when mass-producing and selling each element of the fuel supply system, the fuel pump, the intake adjustment valve, the ECU (electronic control unit), the battery, etc. There are some individual differences (machine differences) in the characteristics of various control parts including In particular, in a fuel injection system that injects high-pressure fuel such as a common rail fuel injection system, the amount of fuel leakage increases, and the influence of individual differences on the amount of fuel leakage tends to be a problem.

  Specifically, in a general fuel supply system for combustion engines, including the system described in Patent Document 1, the fuel in a sealed fuel passage is pressurized through fuel pumping by a fuel pump. Thus, the fuel is supplied. However, fuel pumps and injectors (fuel injection valves) that constitute such a system are sealed as they are (the degree of sealing is high as such), but there is a considerable amount of fuel leakage. For example, a dynamic leak or a static leak occurs in an injector (fuel injection valve), and an internal leak occurs in a fuel pump. In particular, in a system that supplies high-pressure fuel, these leaks increase, and therefore, the influence of the individual difference on the amount of fuel leakage increases when fuel is supplied.

  When there is such a fuel leak amount, even if the fuel is pressurized by the fuel pump, the pressure decreases by the amount of the fuel leak amount. Therefore, in order to accurately control the rail pressure to the target value, it is necessary to presume the pressure drop in advance and perform extra pressurization correspondingly. However, if the fuel leak amount varies due to the individual difference (machine difference), it is difficult to know the fuel leak amount in advance. In the case of mass production, for all of the products, control maps and control formulas that take into account individual differences when mounted on a vehicle (for example, associate the above-mentioned “current amount of the intake adjustment valve” and “discharge amount of the fuel pump”) Creating maps and mathematical formulas, when considered in the current production system, takes too much time and cannot be said to be realistic. For this reason, even when such a map or the like is used, it is difficult to remove the influence (variation) due to the individual difference. For example, as shown in FIG. 13, the pressure in the common rail (rail pressure) is fed back to the target value. When the control target value L50 (solid line) changes in the system being controlled, the followability of the rail pressure with respect to the change in the target value L50 (for example, the convergence with respect to the target value, the response speed with respect to the target value change, etc.) Depending on the product, it will be different. That is, products A, B, and C (product A: small leak, product B: during leak, product C: large leak) having different fuel leak amounts are indicated by broken lines L51a, L51b, and L51c in FIG. Depending on the product, excessive overshoot may occur (broken line L51a), and sufficient followability (response speed) may not be obtained (broken line L51c). Such abnormal pressure control characteristics sometimes deteriorate the combustion characteristics of the target engine, increase the combustion noise, and reduce the exhaust purification performance.

  As described above, even when using a map or mathematical formula in which a suitable value is written in advance, it is difficult to perform control in which all the influences (variations) due to the individual differences are taken into account. When an abnormality occurs in the pressure control characteristic, there is a concern about deterioration of the combustion characteristic in the target engine.

  The present invention has been made in view of such circumstances, and can acquire the pressure characteristics for each target system even when there are individual differences (machine differences) in the pressure characteristics of various devices related to the pressure control. The main object of the present invention is to provide a fuel injection pressure control device and a fuel injection pressure control system.

  Hereinafter, means for solving the above-described problems and the effects thereof will be described.

  According to the first aspect of the present invention, a cylinder that is a portion that performs fuel combustion of a target engine by using a predetermined fuel injection valve, which is a pressurized fuel in a predetermined mode (for example, by pumping). The fuel injection system is applied to a fuel supply system for injecting and supplying air into the intake passage or the exhaust passage thereof, and controls the fuel injection pressure of the fuel injection valve through variable control of a predetermined pressure parameter (for example, the pressure itself, or other parameters that affect the pressure). In a fuel injection pressure control apparatus that performs feedback control to a target value, while a predetermined stability condition indicating that the fuel injection pressure is stable is satisfied, “fuel consumption = the fuel injection regarding the pressurized fuel” Based on the relational expression “fuel injection amount by valve + fuel leakage amount”, the control amount of the pressure parameter and the control gain in the feedback control are reduced. For even one, characterized in that it comprises a control value deriving means for obtaining a correction value or the new value corresponding to the fuel leakage amount at that time.

  When the pressurized fuel is supplied to the target engine, if the above feedback control is performed under the stable pressure of the fuel, the control is performed so that the fuel supply amount and the fuel consumption amount from time to time are the same. Done. As a result, the fuel consumption corresponding to the pressure fluctuation amount (decrease amount) of the pressurized fuel is compensated. The inventor pays attention to such an event, finds that the relational expression of “fuel consumption = fuel injection amount + fuel leakage amount” is established for the pressurized fuel under pressure stability in the fuel injection system, and invents the above configuration. did. That is, in this configuration, a correction value or a new value corresponding to the fuel leak amount at that time can be obtained for a predetermined control parameter (control amount or control gain) based on the relational expression. As a result, even if there is an individual difference regarding the amount of fuel leak described above, it is easier to create a pressure map for each target system without creating a control map or control formula that takes into account the individual differences for each target system. (Control amount and control gain) can be acquired, and as a result, the fuel injection pressure can be controlled in a manner suitable for the pressure characteristics.

  The invention according to claim 2 relates to the apparatus according to claim 1, wherein the fuel injection amount of the pressurized fuel by the fuel injection valve is determined based on a command signal for controlling the drive of the fuel injection valve. A fuel consumption amount derivation for obtaining a fuel consumption amount of the pressurized fuel based on a fuel injection amount derivation means to be obtained and a pressure control amount integral term that is a part related to an integral operation of the control amount of the pressure parameter in the feedback control. And the control value deriving means obtains a correction value or a new value corresponding to the fuel leak amount at that time, based on the fuel injection amount and the fuel consumption amount at that time obtained by each means. It is characterized by being.

  When controlling the fuel injection pressure to a stable state, for example, by driving the fuel pump, the fuel is supplemented by the amount consumed by fuel injection or fuel leakage (fuel consumption) for combustion or catalytic activity in the target engine. There is a need. At this time, generally, feedback control of fuel injection pressure (for example, pressure in the common rail) is performed by proportional operation (P operation), integration operation (I operation), and differentiation operation (D operation). However, the inventor has found through experiments and the like that the feedback control of the pressure parameter is performed substantially only by the integration operation (substantially only the integration operation) under the pressure stability. That is, the fuel consumption amount of the pressurized fuel can be obtained based on the pressure control amount integral term (corresponding to the fuel compensation amount by the feedback control) on the pressure feedback control. On the other hand, a method for obtaining the fuel injection amount of the pressurized fuel based on a command signal (for example, energization time of the fuel injection valve) for controlling the drive of the fuel injection valve is used in the current in-vehicle engine. Is common. The device according to claim 2 has been invented in view of such a point, and with such a device, a correction value or a new value corresponding to the fuel leak amount can be obtained more easily and accurately. It becomes possible.

  According to a third aspect of the present invention, there is provided the apparatus according to the first or second aspect, wherein the pressurized fuel is separated from the feedback control of the fuel injection pressure by the amount of fuel consumed by fuel injection by the fuel injection valve. The control value deriving means corresponds to the fuel leak amount at least as long as the fuel consumption by the fuel injection is compensated by the injected fuel supplementing means. The corrected value or the new value is obtained based on the relational expression “fuel leak amount = pressure control amount integral term”.

  The amount of fuel consumed by fuel injection (fuel injection amount) can be obtained, for example, by actual measurement based on a fuel pressure sensor, a fuel flow rate sensor, or the like, or estimation based on a command signal for the fuel injection valve. Therefore, when the fuel pressure is stabilized, if the fuel injection amount is compensated separately from the feedback control of the fuel injection pressure, the above relational expression “fuel consumption = fuel injection amount + fuel leak amount” Fuel consumption = fuel leakage amount (leakage at the fuel pump or fuel injection valve described above) ”. Further, as described above, under pressure stability, the feedback control of the pressure parameter is performed substantially only by the integral operation (substantially integral operation). The relational expression “leak amount = pressure control amount integral term” is established. According to the above configuration based on such a principle, it becomes possible to more easily and accurately obtain a correction value or a new value corresponding to the fuel leak amount.

  According to a fourth aspect of the present invention, in the apparatus according to any one of the first to third aspects, the fuel supply system includes a fuel pump that pumps predetermined fuel into the pressurized fuel. One of the pressure parameters used for the feedback control is a parameter related to the discharge amount of the fuel pump. By doing so, it is possible to realize each of the above devices more easily and accurately.

  According to a fifth aspect of the present invention, in the apparatus according to the fourth aspect, the fuel supply system includes a suction adjustment valve that varies a fuel suction amount with respect to the fuel pump according to a drive amount, and the fuel pump. The parameter related to the discharge amount is a parameter (current amount or voltage value, etc.) related to the drive amount of the suction regulating valve. With such a configuration, the controllability when controlling the fuel injection pressure is also high.

  When executing the control value derivation (derivation of control amount and control gain) by the control value derivation means, the correlation between the fuel injection pressure of the fuel injection valve and the pressure parameter is previously determined in order to perform the feedback control accurately. It is effective to make sure that it is reliable. Therefore, for example, when a parameter related to the discharge amount of the fuel pump (such as the driving amount of the intake adjustment valve) is used as the pressure parameter, as in the device according to claim 4 or 5, the pressure parameter according to claim 6 is used. As in the invention, the correction means for correcting the discharge characteristics of the fuel pump (for example, the relationship between the drive amount of the intake adjustment valve and the fuel discharge amount, etc.) prior to the execution of the control value derivation by the control value derivation means. It is effective to provide a configuration.

  According to a seventh aspect of the present invention, in the apparatus according to any one of the first to sixth aspects, the control parameter required by the control value deriving means is a strength of an integral operation related to feedback control of the fuel injection pressure. And a control value integral term that is a correction value or a new value relating to a control amount related to the integral operation.

  As described above, under the stable fuel injection pressure, the pressure feedback control is performed substantially only by the integration operation. Therefore, the apparatus according to any one of claims 1 to 6 is particularly effective as a configuration for obtaining a control parameter (a correction value or a new value of each integral term) related to a control gain integral term or a controlled variable integral term. .

  According to an eighth aspect of the present invention, in the apparatus according to any one of the first to seventh aspects, the control value obtained by the control value deriving means is derived from the derivation time and the fuel supply condition at that time. Control value storage means for storing in a predetermined storage device in a predetermined manner according to at least one of the above.

  With such a configuration, it becomes possible to obtain the control value (correction value or new value) obtained by the control value deriving means in a state according to the deriving time and the fuel supply condition at that time. By reading the data from the storage device, it becomes possible to grasp the pressure characteristics from time to time (particularly the characteristics obtained from the control amount and control gain). Thus, for example, data analysis by data accumulation, correction of the pressure characteristics (for example, control amount and control gain), failure diagnosis of the fuel supply system, and the like can be performed more easily and accurately. .

  In addition, as a predetermined mode according to the derivation time of the control value, for example, a mode in which old data is sequentially updated to a new one and only the newest data is left or stored in association with the derivation time is adopted. Is possible. On the other hand, as the predetermined mode according to the fuel supply condition, it is possible to adopt a mode in which the pump is stored in association with values such as the pump operating condition, fuel pressure, and fuel temperature at that time.

  As the storage device, it is effective to employ a device that can hold data in a nonvolatile manner (for example, a backup memory or a nonvolatile memory). In this way, for example, even after the engine is stopped and the power supply to the device (fuel injection pressure control device) is cut off, the data is held in the storage device in a non-volatile manner. The pressure characteristics can be corrected based on the data when the engine is stopped.

  On the other hand, in the invention according to claim 9, in contrast to the inventions according to claims 1 to 8, the pressurized fuel, which is fuel pressurized in a predetermined mode, is supplied to the target engine by a predetermined fuel injection valve. The present invention is applied to a fuel supply system that injects and supplies fuel into a cylinder, which is a part that performs fuel combustion, or to an intake passage or an exhaust passage thereof. In a fuel injection pressure control apparatus that feedback-controls the fuel injection pressure of a fuel injection valve to a target value, while a predetermined stability condition indicating that the fuel injection pressure is stable is satisfied, A leak amount deriving means for obtaining the fuel leak amount at that time is provided based on the relational expression "fuel consumption = fuel injection amount by the fuel injection valve + fuel leak amount". And features.

  In such a configuration, based on the above relational expression, for example, the difference between the fuel consumption (for example, detected as a change in fuel pressure) and the fuel injection amount (for example, detected as a command value for the fuel injection valve), or the difference Thus, the fuel leak amount can be obtained based on a value obtained by subtracting the fuel compensation amount by the open control. As a result, even if there is an individual difference related to the fuel leak amount described above, the pressure characteristics (fuel leak amount) for each target system can be acquired.

  According to a tenth aspect of the present invention, in the apparatus according to the ninth aspect, at least a control amount and a control gain of the pressure parameter in the feedback control are based on the fuel leak amount obtained by the leak amount deriving unit. Control value setting means for setting one value is provided.

  With such a configuration, the optimal control value (control amount or control gain) is set for the amount of fuel leak at that time according to the configuration and characteristics of the system to be controlled, based on calculations using maps and mathematical formulas, for example. As a result, the controllability of the fuel injection pressure can be improved.

  According to an eleventh aspect of the present invention, in the apparatus according to the tenth aspect, the control value setting means sets the value of at least one of a control amount and a control gain of a pressure parameter in the feedback control as the leak amount. The larger the fuel leak amount obtained by the deriving means, the larger the value is set.

  As the amount of fuel leak increases, the amount of fuel to be compensated for in order to maintain the stability of the fuel injection pressure increases. Therefore, as described above, the configuration in which the control amount of the pressure parameter in the feedback control is increased as the fuel leak amount increases. At this time, as the control amount increases, there is a concern about a decrease in response speed with respect to a target value change. Therefore, in this case, it is effective to increase the control gain of the pressure parameter in the feedback control as the fuel leak amount increases in order to increase the response speed in the pressure control.

  Alternatively, in the apparatus according to claim 10, the control value setting means is the same as the control value setting means, and at least the fuel leak amount obtained by the leak amount deriving means is a predetermined reference value as in the invention according to claim 12. If the value is larger than the above, it is also effective to set the control gain of the pressure parameter in the feedback control to a larger value as the fuel leak amount is larger.

  The above-described decrease in response speed with respect to the target value change is considered to be particularly noticeable when the amount of fuel leak increases to some extent. Therefore, in order to simplify the control and increase the efficiency of the feedback control, a reference value is provided as in the above configuration, and only when the amount of fuel leakage is larger than the reference value, as described above, A configuration in which the control gain of the pressure parameter in the feedback control is increased as the amount of fuel leak increases.

  According to a thirteenth aspect of the present invention, in the apparatus according to any one of the ninth to twelfth aspects, the fuel leak amount obtained by the leak amount deriving means is calculated based on the derivation time and the fuel supply at that time. A fuel leak amount storing means for storing in a predetermined storage device in a predetermined mode corresponding to at least one of the conditions is provided.

  With such a configuration, it becomes possible to obtain the fuel leak amount obtained by the leak amount deriving means in a state associated with the derivation time and the fuel supply condition at that time, and as a result, those data are stored in the storage device. By reading from, it becomes possible to grasp the fuel pressure characteristics (particularly leak characteristics) from time to time. Thereby, for example, data analysis by data accumulation, correction of the pressure characteristics (for example, control amount and control gain), failure diagnosis of the fuel supply system, and the like can be performed more easily and accurately.

  As a predetermined mode according to the fuel leak amount derivation time, for example, a mode in which old data is sequentially updated to a new one and only the newest data is left or stored in association with the derivation time is adopted. It is possible. On the other hand, as the predetermined mode according to the fuel supply condition, it is possible to adopt a mode in which the pump is stored in association with values such as the pump operating condition, fuel pressure, and fuel temperature at that time.

  As the storage device, it is effective to employ a device that can hold data in a nonvolatile manner (for example, a backup memory or a nonvolatile memory). In this way, for example, even after the engine is stopped and the power supply to the device (fuel injection pressure control device) is cut off, the data is held in the storage device in a non-volatile manner. The pressure characteristics can be corrected based on the data when the engine is stopped.

  In addition, in the configuration according to the ninth to thirteenth aspects, the fuel based on the fuel injection amount based on the command signal of the fuel injection valve and the fuel based on the pressure control amount integral term is also applied in the aspect according to the second aspect. A configuration for obtaining the fuel leak amount from the consumption amount, a configuration for obtaining the fuel leak amount based on the relational expression “fuel leak amount = pressure control amount integral term” while supplementing the fuel injection consumption amount, and the leak amount deriving means It is more effective to apply a configuration in which correction relating to the discharge amount of the fuel pump is performed prior to the execution of the leak amount derivation.

  On the other hand, in the invention according to claim 14, in contrast to the inventions according to claims 1 to 13, the pressurized fuel, which is fuel pressurized in a predetermined manner (for example, by pumping by a pump), The fuel injection valve is applied to a fuel supply system that injects and supplies fuel into the cylinder, which is a part that performs fuel combustion of the target engine, or to its intake passage or exhaust passage. In the fuel injection pressure control apparatus that feedback-controls the fuel injection pressure of the fuel injection valve to a target value through variable control of the parameter of the fuel), the amount of fuel leakage when the fuel injection pressure is stable is controlled by the feedback control at that time. And a leak amount deriving unit that is obtained based on a portion related to the integral operation in the control amount of the pressure parameter.

  As described above, the inventor has found through experiments and the like that the feedback control of the pressure parameter is performed substantially only by the integration operation (substantially only the integration operation) under the pressure stability. The above device was invented based on such an event, and with such a device, the pressure control amount integral term at the time of pressure stabilization (corresponding to the fuel amount compensated by the feedback control of the pressure parameter). It becomes possible to obtain the amount of fuel leak.

In addition, in the apparatus according to any one of claims 1 to 14, as the stability condition, for example, as in the invention according to claim 15,
At least of the fuel injection pressure, the control amount of the pressure parameter in the feedback control, the temperature of the pressurized fuel, and the driving state of the fuel pump that pumps a predetermined fuel to be the pressurized fuel Regarding one or more parameters indicating one, one of the requirements is that the degree of variation is sufficiently small continuously for a predetermined time.
Or like invention of Claim 16,
One of the requirements for establishment is that the deviation between the current value and the target value of the fuel injection pressure is sufficiently small for a predetermined time.
It is effective to adopt such a condition or a combination of both. As a parameter indicating the driving state of the fuel pump, for example, a fuel pump driven by an engine output can use an engine speed or a fuel state such as a fuel temperature.

  Further, regarding the device according to any one of claims 1 to 16, when considering practicality in the present situation, the fuel supply system supplies a fuel pressure corresponding to the fuel pumping amount of the fuel pump to the common rail. It is beneficial to have a configuration that is a common rail fuel injection system that accumulates pressure and injects the accumulated fuel as the pressurized fuel by the fuel injection valve. In the common rail fuel injection system, particularly, the management of the pressure in the common rail is important as the fuel injection pressure. Therefore, in order to further enhance the practicality of such a device, the feedback control is performed as in the invention of claim 17. This is more effective as a configuration in which the fuel injection pressure subject to the above is the pressure in the common rail. In addition, as described above, in the common rail fuel injection system, high pressure fuel (for example, fuel of “1000 atm” or more) is generally injected, and thus the amount of fuel leakage is particularly likely to increase. Therefore, also in this sense, the significance of applying the invention according to any one of claims 1 to 16 to such a configuration is great.

  By the way, depending on the type of business or application, the unit is not a unit of the fuel injection control device, but a larger unit, for example, not only the fuel injection control device but also other related devices (for example, various devices related to control of sensors, actuators, etc.) May be treated as a fuel injection control system constructed by The fuel injection control device according to any one of claims 1 to 17 is also assumed to be used by being incorporated in an engine control system as one of applications. The invention described in claim 18 corresponds to such an application, and has a configuration in which the device described in claim 1 is incorporated in a fuel injection control system. That is, as a fuel injection control system, a fuel pump that pumps up and pumps fuel in a fuel tank, a common rail that accumulates pressurized fuel that is pressurized by the pumping of the fuel pump, and a pressurized fuel that is accumulated by the common rail. A fuel injection valve that injects, an engine that converts the energy generated by burning the fuel supplied by the fuel injection valve into mechanical motion (eg, rotational motion), and a predetermined pressure parameter (eg, pressure itself, or Feedback control means for performing feedback control of the pressure in the common rail to a target value through variable control of other parameters that affect the pressure), and a predetermined stability condition indicating that the pressure in the common rail is stable. During the operation, “fuel consumption = according to the fuel injection valve” regarding the pressurized fuel in the common rail. Based on the relational expression “fuel injection amount + fuel leak amount”, a correction value or a new value corresponding to the fuel leak amount at that time is obtained for at least one of the control amount and the control gain of the pressure parameter used in the feedback control means. Control value deriving means. Similarly, the apparatus according to any one of claims 1 to 17 is particularly useful when incorporated in a fuel injection control system.

  Hereinafter, an embodiment embodying a fuel injection pressure control device according to the present invention will be described with reference to the drawings. In addition, the apparatus of this embodiment is mounted in the common rail type fuel injection control system (high pressure injection fuel supply system) which controlled the diesel engine for motor vehicles, for example. That is, this device, like the device described in the above-mentioned Patent Document 1, directly applies high pressure fuel (for example, injection pressure “1000 atm”) to a combustion chamber (portion where fuel combustion is performed) in a cylinder of a diesel engine (internal combustion engine). This is a fuel injection pressure control device for a diesel engine, which is used for feedback control (PID control) of the fuel injection pressure with respect to a target value when the above light oil) is supplied by injection (direct injection supply). .

  First, an outline of a common rail fuel injection control system according to the present embodiment will be described with reference to FIG. Note that a multi-cylinder (for example, in-line 4-cylinder) engine for automobiles is assumed as the engine of the present embodiment. This engine is a 4-stroke reciprocating engine. Specifically, in this engine, a cylinder discrimination sensor (electromagnetic pickup) provided on the camshaft of an intake / exhaust valve (not shown) sequentially discriminates the target cylinder at that time, and the intake and compression of each of the four cylinders # 1 to # 4 is performed.・ One combustion cycle with four strokes of combustion and exhaust is a “720 ° CA” cycle. Specifically, for example, each cylinder is shifted by “180 ° CA” and sequentially executed in the order of cylinders # 1, # 3, # 4, and # 2. Is done. The injector 20 in the figure is an injector for cylinders # 1, # 2, # 3, and # 4 from the fuel tank 10 side.

  As shown in FIG. 1, in this system, an ECU (electronic control unit) 30 mainly captures sensor outputs (detection results) from various sensors and configures a fuel supply system based on these sensor outputs. It is comprised so that the drive of each apparatus to control may be controlled. The ECU 30 controls the fuel pressure (measured by the fuel pressure sensor 22) in the common rail 16 by adjusting the amount of current supplied to the intake adjustment valve (described later in detail) and controlling the fuel discharge amount of the fuel pump 14 to a desired value. Feedback control (for example, PID control) to a target value (target fuel pressure). Based on the fuel pressure, the fuel injection amount to the predetermined cylinder of the target engine, and thus the output of the engine (the rotational speed and torque of the output shaft) are controlled to a desired magnitude.

  Here, various devices constituting the fuel supply device are arranged in order of the fuel tank 10, the fuel filter 12, the fuel pump 14, the common rail 16, and the injector 20 (fuel injection valve) from the upstream side of the fuel. In this system, the fuel in the fuel tank 10 is pumped by the fuel pump 14 so that the fuel is supplied to the target device in the system. With reference to FIG. 2, the detailed structure of the fuel pump 14 and its operation | movement aspect are demonstrated.

  As shown in FIG. 2, the fuel pump 14 is basically configured to pressurize and discharge the fuel pumped up from the fuel tank 10 by the feed pump 40 with the high-pressure pump 50. . At this time, the amount of fuel sent to the high-pressure pump 50 is adjusted by a suction adjustment valve 60 (SCV: Suction Control Valve) provided on the fuel suction side of the pump 14 (specifically, before the fuel is pumped by the high-pressure pump 50). It has come to be measured.

  Here, the feed pump 40 has an outer rotor on the outer side and an inner rotor on the inner side, and the space created by each of the rotors is increased / decreased according to the rotation of each rotor, and fuel is sucked and discharged according to the increase / decrease. This is a so-called trochoid pump. The pump 40 functions as a so-called low-pressure supply pump that sucks the fuel in the fuel tank 10 from the inlet 42 and sends the fuel to the high-pressure pump 50, and is driven by the rotation of the drive shaft 41. The drive shaft 41 is interlocked with the crankshaft 24 (FIG. 1), and is driven by power from the engine output. That is, the drive shaft 41 is driven (rotation driven) with the rotation of the crankshaft 24 and rotates at a ratio of “1/1” or “½” with respect to one rotation of the crankshaft 24, for example.

  The fuel sucked up by the feed pump 40 passes through the fuel filter 42a and is sent to the intake adjustment valve 60. At this time, the discharge pressure (fuel pressure) of the feed pump 40 is limited (adjusted) to a predetermined pressure or less by the regulator valve 43. The regulator valve 43 communicates the discharge side and the supply side of the feed pump 40 when the discharge pressure of the feed pump 40 exceeds a predetermined pressure. Further, the temperature of the fuel sent to the intake adjustment valve 60 can be detected by the fuel temperature sensor 43a.

  The intake adjustment valve 60 is configured to include, for example, a normally-on type linear solenoid solenoid valve that opens when not energized, and adjusts the intake fuel amount of the high-pressure pump 50. The ECU 30 (FIG. 1) controls the energization time (supply current amount) for the intake adjustment valve 60 so that the amount of fuel drawn from the feed pump 40 to the high-pressure pump 50 through the fuel passage 44 can be adjusted. It has become. That is, the fuel sent by the feed pump 40 is adjusted to a required discharge amount (target fuel pressure feed amount) by the suction adjustment valve 60 and enters the high-pressure pump 50 through the suction valve 53 (suction valve).

  The high-pressure pump 50 is a plunger pump that pressurizes the fuel metered by the suction adjustment valve 60 and discharges the fuel to the outside. The high-pressure pump 50 is mainly configured to include a plunger 51 that is driven to reciprocate by a drive shaft 41, and a pressurizing chamber 52a formed between the inner wall 52b of the housing 52 and the top surface of the plunger 51. The volume (volume) of the pressurizing chamber 52a (plunger chamber) changes as the plunger 51 reciprocates in the axial direction.

  The plunger 51 is pressed against a ring cam 56 mounted around an eccentric cam 55 (eccentric cam) by a spring 57. Although not shown, in detail, a cylindrical shaft hole for assembling the drive shaft 41 is formed at the center of the ring cam 56 having a rectangular parallelepiped shape. A cylindrical eccentric cam 55 corresponding to the shape of the shaft hole is attached to the drive shaft 41 so as to be eccentric. Then, the ring cam 56 is assembled on the eccentric cam 55 of the drive shaft 41 in such a manner that the drive shaft 41 passes through the shaft hole of the eccentric cam 55, so that the drive shaft 41 and the ring cam 56 are connected to the eccentric cam 55. It is connected through. In the high-pressure pump 50, when the drive shaft 41 rotates, the eccentric cam 55 rotates eccentrically, and the ring cam 56 displaces following the eccentric cam 55, thereby pushing (or pulling) the plunger 51 in the axial direction. In this way, the two plungers 51 reciprocate between the pumping top dead center and the pumping bottom dead center.

  As described above, on the suction side of the high-pressure pump 50, the suction valve 53 that connects or blocks the pressurizing chamber 52a and the feed pump 40 side is disposed. On the other hand, a discharge valve 54 is also provided on the discharge side of the high-pressure pump 50 to communicate or block the pressurizing chamber 52a and the common rail 16 side. That is, when the volume of the pressurizing chamber 52a increases with the lowering of the plunger 51 and the pressure in the pressurizing chamber 52a decreases, the discharge valve 54 closes and the suction valve 53 opens. As a result, fuel is supplied from the feed pump 40 into the pressurizing chamber 52 a via the suction adjustment valve 60. Conversely, when the volume of the pressurizing chamber 52a decreases as the plunger 51 rises and the pressure in the pressurizing chamber 52a increases, the suction valve 53 is now closed. When the pressure in the pressurizing chamber 52a reaches a predetermined pressure, the discharge valve 54 is opened, and the high-pressure fuel pressurized in the pressurizing chamber 52a is supplied toward the common rail 16. In the fuel pump 14 of the present embodiment, the fuel is pumped and supplied in this way. However, even in this pump 14, the above-described internal leak occurs during such a pumping operation (pressure feeding operation). Specifically, a slight amount of fuel outflow (leakage) occurs at the sliding portion of the plunger 51 (the gap between the inner wall 52b of the housing 52 and the plunger 51) due to the high pressure of the fuel. This increases the machine difference (individual difference) variation regarding the fuel injection pressure control.

  The detailed structure and operation mode of the fuel pump 14 have been described above with reference to FIG. That is, as shown in FIG. 1, the fuel in the fuel tank 10 is pumped up by the fuel pump 14 through the fuel filter 12 and pressurized (suppressed) to the common rail 16.

  The common rail 16 stores the fuel pumped from the fuel pump 14 in a high pressure state and stores the fuel in a high pressure state through a pipe (high pressure fuel passage) 18 provided in each of the cylinders # 1 to # 4. To the injection valve). The common rail 16 is provided with a fuel pressure sensor 22 for detecting the fuel pressure (rail pressure) in the common rail 16, thereby enabling detection and management of rail pressure correlated with the fuel injection pressure of the injector 20. Has been.

  The injector 20 is provided for each combustion chamber in each of the cylinders # 1 to # 4, and is configured as a fuel injection valve for high-pressure fuel that injects high-pressure fuel accumulated and held in the common rail 16. It is what is done. In particular, the injector 20 of the present embodiment is a hydraulically driven fuel injection valve that uses combustion engine fuel (fuel in the fuel tank 10), and transmission of driving power during fuel injection is a hydraulic chamber (command chamber). Is done through. FIG. 3 shows a detailed structure of the injector 20.

  As shown in FIG. 3, this injector 20 is an internal valve opening type fuel injection valve, and is configured as a so-called normally closed type fuel injection valve that is closed when not energized. That is, in the injector 20, the degree of sealing of the hydraulic chamber Cd and the pressure in the hydraulic chamber Cd (the back pressure of the needle 20b) are determined according to the energization state (energized / non-energized) of the solenoid 20a constituting the two-way solenoid valve. The needle 20b reciprocates (up and down) in the valve cylinder (inside the housing 20d) according to or against the extension force of the spring 20c (coil spring). As a result, the fuel supply passage up to the injection holes 20e (as many as necessary) is opened and closed halfway (specifically, a predetermined seat surface on which the needle 20b is seated based on the reciprocating motion). At this time, drive control of the needle 20b is performed through so-called PWM (Pulse Width Modulation) control. That is, a pulse signal (energization signal) is sent from the ECU 30 to the drive unit (the two-way electromagnetic valve) of the needle 20b. The lift amount (the degree of separation from the seat surface) of the needle 20b is variably controlled based on the pulse width (corresponding to the energization time). In this control, the lift amount increases as the energization time increases. As the amount increases, the injection rate (the amount of fuel injected per unit time) increases. Incidentally, the pressure increasing process of the hydraulic chamber Cd is performed by supplying fuel from the common rail 16. On the other hand, the decompression process of the hydraulic chamber Cd is performed by returning the fuel in the hydraulic chamber Cd to the fuel tank 10 through the pipe 28 connecting the injector 20 and the fuel tank 10. The injector 20 of the present embodiment performs the fuel injection supply in this way. However, even in this injector 20, a small amount of fuel outflow (static leak) occurs at the sliding portion of the needle 20b when not in operation, and a fuel outflow (dynamic leakage) due to decompression processing of the hydraulic chamber Cd occurs during operation. This increases the machine difference (individual difference) variation regarding the fuel injection pressure control.

  In the above, the various apparatuses of the fuel supply system in the common rail fuel injection system of the present embodiment have been described. Hereinafter, referring to FIG. 1 again, the configuration of the system will be further described.

  That is, in this system, a vehicle (not shown) is further provided with various sensors and actuators for vehicle control. For example, on the outer peripheral side of the crankshaft 24 that is the output shaft of the target engine, a crank angle sensor 24 a that outputs a crank angle signal at every predetermined crank angle (for example, at a cycle of 30 ° CA) has a rotational angle position of the crankshaft 24. And a rotational speed (engine rotational speed). In addition, an accelerator sensor 26 that outputs an electric signal corresponding to a state (displacement amount) of the pedal to the accelerator pedal (driving operation unit) detects an operation amount (accelerator depression amount) of the accelerator pedal by the driver. Is provided.

  In such a system, the ECU 30 functions as the fuel injection pressure control device of the present embodiment and performs engine control mainly as an electronic control unit. The ECU 30 includes a known microcomputer (not shown), grasps the operating state of the target engine and user requirements based on the detection signals of the various sensors, and accordingly the fuel pump 14 and the injector 20. By operating various actuators such as the above, various controls related to the engine are performed in an optimum manner according to the situation at that time. The microcomputer mounted on the ECU 30 basically includes a CPU (basic processing device) that performs various calculations, and a RAM (main memory that temporarily stores data and calculation results during the calculation) ( Random Access Memory (ROM), ROM (program only memory) as program memory, EEPROM (electrically rewritable non-volatile memory) as data storage memory and backup RAM (backup power source such as in-vehicle battery) Backup memory), signal processing devices such as A / D converters and clock generation circuits, input / output ports for inputting / outputting signals to / from the outside, various arithmetic devices, storage devices, signal processing devices And a communication device. The ROM stores various programs and control maps related to engine control including a program related to the fuel injection pressure control, and the data storage memory (for example, EEPROM) includes design data of the target engine. Various control data to be stored are stored in advance.

  Next, the operation of the common rail fuel injection control system according to this embodiment, that is, the operation of the system (FIG. 1) will be described.

  As described above, in this embodiment, the fuel injection pressure control is performed based on the pump control (control of the fuel pump 14). First, the basic procedure of this pump control will be described with reference to FIG. FIG. 4 is a flowchart showing a pump control processing procedure corresponding to the main part of the fuel injection pressure control. The series of processing shown in FIG. 4 is basically a program stored in the ROM by the ECU 30. Is executed sequentially at predetermined processing intervals (for example, at predetermined crank angles or at predetermined time intervals). The values of various parameters used in this processing are stored as needed in a storage device such as a RAM, EEPROM, or backup RAM mounted on the ECU 30 and updated as necessary.

  As shown in FIG. 4, in this series of processing, first, in step S101, the engine speed (NE) is calculated based on the output of the crank angle sensor 24a, and the accelerator is based on the output of the accelerator sensor 26. The pedal operation amount (accelerator opening) is calculated.

  Next, in step S102, the target common rail pressure PP is acquired (calculated) based on the engine rotation speed and the accelerator pedal operation amount acquired in step S101. Specifically, for example, a predetermined map (for example, stored in a ROM or a mathematical expression) in which an appropriate value (optimum value) of the target common rail pressure PP is written for each engine rotation speed and each accelerator pedal operation amount by an experiment or the like is used. Get.

  In step S103, the current common rail pressure NP is acquired (calculated) based on the output of the fuel pressure sensor 22. In the subsequent step S104, based on the current common rail pressure NP and the target common rail pressure PP acquired in step S102, a pressure deviation DP (= PP−NP) as a difference between the two is calculated.

  Next, in step S105, based on the pressure deviation DP calculated in step S104 and the engine speed (NE) at that time, the gain related to the feedback control of the fuel injection pressure performed through the processing (pump control) of FIG. (PID constant) GP0, GI0, and GD0 are calculated. Specifically, this gain calculation is performed with reference to a map, for example. FIG. 5 shows an example of the map.

  As shown in FIG. 5, in the present embodiment, a plurality of types of gains G11 to G14 are selectively used according to the situation (pressure deviation DP and engine speed). These gains G11 to G14 all increase the pressure control amount as the pressure deviation DP increases, but the sensitivity to the pressure deviation DP (corresponding to the slope of the graph) is different for each gain. In the present embodiment, due to such a difference in characteristics, the use gain is switched based on the threshold values TH1 and TH2 in FIG. 5 in detail according to the magnitude of the pressure deviation DP. That is, for example, when the pressure deviation DP is large, the gain G12 (DP> TH1) or the gain G13 (DP <TH2) having high sensitivity to the pressure deviation DP is used, and the pressure deviation DP is small (TH2 ≦ DP ≦ TH1). Uses a gain G14 having a small sensitivity to the pressure deviation DP. On the other hand, in the idling state where the engine is rotating at a low speed, for example, the gain G11 having a smaller sensitivity is used.

  In the subsequent step S106, the correction coefficient K1 (KP1, KI1, KD1) updated by a separate learning process (described later in detail) is read from the EEPROM in the ECU 30, and the previous correction coefficient K1 is used based on the read correction coefficient K1. The gains GP0, GI0, and GD0 calculated in step S105 are corrected (GP = GP0 × KP1, GI = GI0 × KI1, GD = GD0 × KD1).

  In subsequent step S107, pressure control amounts (PID control amounts) QP, QI, and QD are calculated based on the corrected gains GP, GI, and GD calculated in step S106. In further subsequent step S108, these pressures are calculated. The total pressure control amount QPID of the control amount is calculated.

  Specifically, according to a well-known control expression related to the PID operation, the control amount P term (proportional term) is “QP = KP1 × DP”, and the control amount I term (integral term) is “QI = KI1 × ∫ (DP). The control amount D term (derivative term) is calculated as “QD = KD1 × (DP (current value) −DP (previous value)) / Δt”, and the total pressure control amount QPID is “QPID = QP + QI + QD”. It is calculated as follows.

  In the subsequent step S109, the volume elastic modulus K2 is calculated based on the fuel temperature (detected by the fuel temperature sensor 43a) and the fuel pressure (detected by the fuel pressure sensor 22) at that time. Here, the volume elastic modulus is “ΔPFL = K2 · ΔV / V” (K2: volume elastic modulus, ΔPFL: pressure change amount associated with volume change of fluid, V: volume, ΔV: volume for pressure change in a predetermined fluid. (Volume change amount from V) is a coefficient that satisfies the relational expression, and the reciprocal of this coefficient corresponds to the compression ratio. This parameter (coefficient K2) is important in pump control. Particularly in the control of a high-pressure pump for high-pressure fuel, the bulk modulus of the fuel in the high-pressure portion is important. The bulk modulus is affected by the fuel properties, fuel temperature, fuel pressure (base pressure), and the like.

  In the subsequent step S110, the required discharge amount PQ of the fuel pump 14 is calculated based on the bulk modulus K2 calculated in step S109. Specifically, the ratio “K2 / KV” between the volume elastic modulus K2 and the volume KV (constant based on design data) of the fuel high-pressure portion (the common rail 16 and the injector 20 downstream from the high-pressure pump 50) is the total pressure control amount. The required discharge amount PQ is calculated by multiplying QPID (PQ = QPID × K2 / KV).

  In the subsequent step S111, a drive amount necessary for causing the pump 14 to discharge fuel corresponding to the required discharge amount PQ, that is, a drive current amount PI of the intake adjustment valve (SCV) 60 is calculated. Specifically, for example, a control map (I-Q map) as indicated by a solid line Q0 in FIG. 6, that is, a suitable value (equivalent value) of the drive current amount PI is written for each required discharge amount PQ by, for example, experiments in advance. It is acquired using a predetermined map (for example, stored in a ROM or the like, may be a mathematical expression). In a further subsequent step S112, a current corresponding to the drive current amount PI is supplied to the intake adjustment valve 60, whereby the drive amount of the fuel pump 14 is controlled so that the required discharge amount PQ is satisfied. To do.

  In the present embodiment, the series of processes in FIG. 4 are repeatedly executed, so that the pressure in the common rail 16 (corresponding to the fuel injection pressure) is successively feedback controlled (PID control) to the target common rail pressure PP. Moreover, in the present embodiment, as the pressure deviation DP increases, the convergence of the control is improved by setting a value for increasing the control amount for the gain related to feedback control of the fuel injection pressure ( FIG. 5).

  Further, in addition to such pump control, injection control for supplying high-pressure fuel in the common rail 16 into each cylinder of the target engine, that is, drive control of the injector 20 is also performed. However, since the control mode of the injector 20 related to this injection control conforms to a known control mode, the description thereof is omitted here.

  In the present embodiment, at the time of this injection control, the amount of fuel consumed by fuel injection by the injector 20 (fuel injection amount) is determined based on a command signal for controlling the drive of the injector 20, and the determined fuel The high pressure fuel in the common rail 16 is supplemented by the injection amount. In addition to the feedback control shown in FIG. 4 (in a separate routine), the fuel supply is basically performed by always controlling the drive amount of the fuel pump 14 (the drive current amount PI of the intake adjustment valve 60) at all times. To do. In the present embodiment, the program for obtaining the fuel injection amount based on the command signal of the injector 20 is “fuel injection amount deriving means”, and the program for supplementing the fuel by the obtained fuel injection amount is “injected fuel supplementing means”. Respectively.

  Further, in the present embodiment, based on these pump controls and while the fuel injection pressure is stable, “fuel consumption in the entire system = fuel injection amount by the injector 20 + fuel leak amount in the fuel supply system” The above-described control gain correction value (step S106 in FIG. 4) corresponding to the fuel leak amount at that time of the actual machine (this system) is used for the above-described fuel leak amount with machine difference variation. The correction coefficient K1) is obtained. Hereinafter, the fuel injection pressure control, that is, the control parameter (control gain) correction process used for the pump control shown in FIG. 4 will be described in detail with reference to FIGS. Note that the series of processes shown in these drawings is also executed sequentially at predetermined processing intervals by executing a program stored in the ROM by the ECU 30. The values of various parameters used in the processes of FIGS. 7 to 9 are also stored as needed in a storage device such as a RAM or an EEPROM, and are updated as needed.

The control parameter correction process in this fuel injection pressure control is largely
A process of determining whether or not the learning execution condition is satisfied (success determination of learning execution condition, FIG. 7 and FIG. 8). In this process, it is determined whether or not the characteristic correction of the fuel pump is completed and whether or not the fuel injection pressure is stable. If both are satisfied, the execution of the learning process is permitted.
A learning process of the correction coefficient K1 executed while the learning execution condition is satisfied (FIG. 9). In this process, a correction coefficient K1 corresponding to the actual fuel leak amount is learned.
Control gain correction processing using the learning value (correction coefficient K1) (step S106 in FIG. 4). This process has already been described.
It consists of three types of processing.

  FIG. 7 and FIG. 8 are flowcharts showing a processing procedure of processing for determining whether or not the execution condition (learning execution condition) of the learning process is successful.

  In the process of FIG. 7, first, in step S21, it is determined whether or not the learning process related to the “current-discharge amount” characteristic (map shown in FIG. 6) of the fuel pump 14 has already been completed. If it is determined in step S21 that learning has not yet been completed, in step S22, the pump learning completion flag indicating whether or not the characteristic correction of the fuel pump 14 has been completed is set to OFF. At the same time, the learning process of the fuel pump 14 is executed in the subsequent step S23. Hereinafter, this learning process will be briefly described. This learning process is performed, for example, in the manner shown in FIG. In the present embodiment, as the main map error, the drive current amount PI (horizontal axis) of the intake adjustment valve 60 and the required discharge amount PQ of the fuel pump 14 with respect to the regular map fit value indicated by the solid line Q0 in FIG. Assuming a case where the relationship with (vertical axis) is offset in parallel to the direction (horizontal axis) of the drive current amount PI as it is and errors as shown by broken lines Q1 and Q2 occur, learning for the error is performed. To do.

  In this learning process, for example, a deviation of the drive current amount PI (FIG. 4) between the solid line Q0 and the broken line Q1 (or broken line Q2) in FIG. 6 is calculated and used as a learning value. Specifically, for example, by feedback control (PID control) as shown in FIG. 4, for example, the drive current is gradually increased so that the actual discharge amount (for example, converted from the rail pressure) approaches the required discharge amount PQ indicated by the solid line Q0. The amount PI is changed, and the amount of change (e.g., calculated as an integral value) from before the change until the discharge amount matches is used as the learning value. For example, when feedback control is performed on the discharge amount to the discharge amount PQ0 in the figure, if the drive current amount PI has values as indicated by the points P1 and P2 in the figure, the errors ΔP1 and ΔP2 in the figure are used as the learning value. And The learning value obtained in this way is stored in a nonvolatile manner in, for example, an EEPROM or a backup RAM. By doing so, even if the ECU 30 is disconnected once and restarted when the engine is stopped, the data stored therein remains without being erased.

  Returning to the description of the processing in FIG. If such a learning process is executed in the previous step S23 and it is determined in step S21 that learning is completed, in step S24, the pump learning completion flag is set to “ON”.

  The learning process related to the discharge characteristics of the fuel pump 14 can be performed at an arbitrary timing by setting the pump learning completion flag to OFF under a predetermined condition. For example, a configuration in which the learning process is executed again by setting the pump learning completion flag to OFF periodically (for example, every time the engine is started) or at the time of pump replacement is effective.

On the other hand, in the process of FIG. 8, through steps S31 to S37,
The difference between the target common rail pressure PP and the current common rail pressure NP is sufficiently small (absolute value | PP-NP | <judgment value (predetermined value), step S31).
The pressure change over time is sufficiently small (absolute value | NP (current value) −NP (previous value) | <determination value (predetermined value), step S32).
The time change of the fuel temperature NT is sufficiently small (absolute value | NP (current value) −NP (previous value) | <determination value (predetermined value), step S33).
The time change of the engine speed NE is sufficiently small (absolute value | NE (current value) −NE (previous value) | <determination value (predetermined value), step S34).
The time change of the pressure control amount I term (integral term) QI0 calculated in a manner similar to the processing of steps S105 to S107 in FIG. 4 is sufficiently small (absolute value | QI0 (current value) −QI0 (previous value) ) | <Determination value (predetermined value), steps S35 and S36).
-The five conditions of steps S31, S32, S33, S34, and S36 are continuously satisfied for a predetermined time or more (step S37).
The success or failure of each condition is determined. If it is determined in steps S31 to S37 that all the above conditions are satisfied at the same time, it is determined that the fuel injection pressure is stable, and in step S381, the pressure stabilization flag is set to “ON” (pressure After the stability flag = ON), the series of processes in FIG. On the other hand, if it is determined in steps S31 to S37 that any one of the above conditions is not satisfied, the fuel injection pressure is not stable, and “OFF” is set to the pressure stabilization flag in step S382 ( After the pressure stabilization flag = OFF), the series of processes in FIG.

  FIG. 9 is a flowchart showing the processing procedure of the learning process of the correction coefficient K1 (KP1, KI1, KD1) executed while the learning execution condition is satisfied.

  As shown in FIG. 9, in this series of processing, first, in steps S41 and S42, whether or not the learning execution condition is satisfied, that is, whether or not the pump learning completion flag and the pressure stabilization flag are set to “ON” is determined. to decide. When it is determined in these steps S41 and S42 that both flags are set to “ON”, the process proceeds to the next step S43. In this series of processes, while “OFF” is set in any of the flags and it is determined in any of the above steps S41 and S42 that the execution condition is not satisfied, in the first steps S41 and S42, The success or failure of the learning execution condition is determined repeatedly at a predetermined processing interval.

  In step S43, the static leak amount LK1 and the dynamic leak amount LK2 of the injector 20 are calculated based on predetermined fuel supply conditions (for example, engine speed, fuel temperature, rail pressure, etc.). In the subsequent step S44, the internal leak amount LK3 of the fuel pump 14 is calculated based on predetermined fuel supply conditions (for example, engine speed, fuel temperature, rail pressure, etc.). Specifically, these leak amounts LK1 to LK3 are prepared by, for example, a map as shown in FIG. 10, for example, by experiments in advance, and leaks for each predetermined fuel supply condition (engine speed, fuel temperature, and rail pressure). It is obtained using a predetermined map (for example, stored in a ROM or a mathematical expression) in which estimated values (reference leak amount indicated by the solid line L11) of the amounts LK1 to LK3 are written. In order to improve the estimation accuracy, it is effective to prepare a map for each type of leak (static leak, dynamic leak, internal leak).

  In the subsequent step S45, the deviation degree (equipment difference variation ratio) LKD1 of the actual fuel leak amount (actual device leak amount) when the reference leak amount (= LK1 + LK2 + LK3) consisting of the sum of these leak amounts LK1 to LK3 is used as a reference. calculate.

  Here, the actual machine leak amount is shown as a point P11 in FIG. 10, for example, and is calculated with high accuracy based on the pressure control amount I term (integral term) QI0 calculated in step S35 of FIG. be able to. Specifically, when the pressure feedback control is performed so that the fuel supply amount and the fuel consumption amount are equal to each other by the processing of FIG. 4 under the stable fuel pressure (pressure stabilization flag = ON), the rail pressure (fuel pressure sensor 22 The fuel consumption corresponding to the pressure fluctuation amount (decrease amount) detected at (1) is compensated. Therefore, under the stable fuel pressure, the relational expression “fuel consumption in the entire system = fuel injection amount by the injector 20 + fuel leakage amount in the fuel supply system” is established. Further, as described above, in the present embodiment, in addition to the pressure feedback control of FIG. 4, only the amount of high-pressure fuel in the common rail 16 consumed by the fuel injection by the injector 20 (detected from the command signal for the injector 20). Compensation is made sequentially (pump control by open control). In addition, under the stable pressure, the pressure feedback control is performed substantially only by the integral operation (substantially only the integral operation). Therefore, the actual machine leak amount can be accurately calculated based on the relational expression “actual machine leak amount = pressure control amount I term (integral term) QI0”. This actual machine leak amount is stored in the EEPROM (or backup RAM is also acceptable) in the ECU 30 in association with, for example, the calculation time (derivation time) and the fuel supply conditions at the time of calculation (pump operating conditions, fuel pressure, fuel temperature, etc.). Is done. These data are stored without being automatically deleted so that data analysis can be performed, and the latest data is used in the subsequent steps. In addition, as described above, by storing in a non-volatile storage device (EEPROM), the data remains without being erased even after the ECU 30 is disconnected.

  In step S45, the ratio between the pressure control amount I term (integral term) QI0 (point P11 in FIG. 10) corresponding to the actual machine leak amount and the reference leak amount (solid line L11 in FIG. 10), that is, the machine difference variation ratio. LKD1 is calculated as “LKD1 = QI0 / (LK1 + LK2 + LK3)”.

  In the subsequent step S46, the difference between the machine difference variation ratio LKD1 calculated in step S45 this time and the previous ratio LKD0 (initial value is arbitrarily set) is compared (see “difference” in this case). The leakage amount change is calculated (leak amount change = absolute value | LKD1-LKD0 |). Then, it is determined whether or not the leak amount change is larger than a predetermined determination value (leak amount change> determination value).

  Here, it is determined that the leak amount change is large (leak amount change> judgment value) in step S46 because the current process is the first learning or a secular change or the like has occurred since the previous learning. In this case, it is necessary to update the correction coefficient K1, and the process proceeds to step S47 and subsequent steps. On the other hand, if it is determined that the leak amount change is not large (leak amount change ≦ determination value), it is not necessary to update the correction coefficient K1, and the process is terminated without executing the processes after step S47.

  In step S47, the parameter used to calculate a new correction coefficient K1, that is, the ratio LKD0 (stored in a nonvolatile storage device such as the EEPROM) is updated with the current ratio LKD1. Specifically, this is updated by an operation “LKD0 = LKD1”.

  In step S48, a new correction coefficient K1 (KP1, KI1, KD1) corresponding to the current fuel leak amount is calculated based on the machine difference variation ratio LKD0 updated in step S47. Specifically, the correction coefficient K1 is created in advance by experiment or the like, for example, and a predetermined map (for example, stored in a ROM or the like, which is written in a suitable value (optimum value) of the correction coefficient K1 for each machine difference variation ratio LKD0 is also expressed by an equation. Acquired using FIG. 11 shows an example of a map used for calculating the correction coefficient K1 in this embodiment.

  As shown in FIG. 11, according to this map, the larger the machine difference variation ratio LKD0 (horizontal axis), that is, the larger the actual machine leak amount, the larger the correction coefficient K1 (vertical axis) is set. . That is, for example, as shown in FIG. 12, when a convergence delay ΔT (decrease in response speed) occurs due to the actual machine leak amount becoming larger than the reference leak amount (solid line L21) (broken line L22a). Thus, a larger value is set for the correction coefficient K1 than when “actual machine leak amount = reference leak amount (LKD0 = 1)”. As a result, the control gain is corrected to a larger value through the processing of step S106 in FIG. 4 (solid line L22), and the convergence delay ΔT is compensated by this gain increase. Thus, by using the map shown in FIG. 11, a high response speed with respect to a change in the target value (target common rail pressure PP) is maintained in the fuel injection pressure control shown in FIG.

  In step S48, the correction coefficient K1 calculated in the above-described manner is stored in an EEPROM (or backup RAM) in the ECU 30 so that it can be used in step S106 of FIG. Specifically, the value of the correction coefficient K1 is stored in association with, for example, the calculation time (derivation time) and the fuel supply conditions (pump operating conditions, fuel pressure, fuel temperature, etc.) at the time of calculation (however, These associations are not mandatory). These data are stored without being automatically deleted so that data analysis or the like is possible, and the latest data is used in step S106 in FIG. In addition, as described above, by storing in a non-volatile storage device (EEPROM), the data remains without being erased even after the ECU 30 is disconnected. Then, the series of processes shown in FIG. 9 ends in step S48.

  As described above, in this embodiment, the machine difference variation ratio LKD0 of the actual actual machine leak amount due to machine difference variation, characteristic change with time, etc., and thus the correction coefficient K1 are sequentially obtained by the learning process shown in FIG. We decided to learn (update). Then, the control gain related to the feedback control of the fuel injection pressure is corrected by executing the correction processing (step S106) shown in FIG. 4 based on the learning value (correction coefficient K1). In this way, the control gain is set to a value corresponding to the current fuel leak amount of the actual machine (this system), and as a result, the fuel by the injector 20 in a manner suitable for the fuel leak amount at that time. The injection pressure is accurately controlled.

  As described above, according to the fuel injection pressure control device and the fuel injection pressure control system according to the present embodiment, the following excellent effects can be obtained.

  (1) This is a part in which pressurized fuel (high-pressure fuel in the common rail 16) that is pressurized by the pumping of the fuel pump 14 is subjected to fuel combustion of the target engine by a predetermined fuel injection valve (injector 20). This is applied to a fuel supply system (FIG. 1) that directly injects and supplies fuel into a cylinder, and the fuel injection pressure (rail pressure) of the injector 20 is controlled through variable control of a predetermined pressure parameter (a driving current amount PI of the intake adjustment valve 60). Feedback control to the target value. In such a fuel injection pressure control device (engine control ECU 30), while the predetermined stability condition (FIG. 8) indicating that the fuel injection pressure is stable is satisfied (pressure stability flag = ON), A program (leak amount deriving means, step of FIG. 9) for obtaining a fuel leak amount (actual machine leak amount) based on a relational expression of “fuel consumption = fuel injection amount by fuel injection valve + fuel leak amount” relating to pressurized fuel S43 to S45). Specifically, in step S45 of FIG. 9, when the fuel injection pressure is stable (pressure stabilization flag = ON), the fuel leak amount (actual machine leak amount) is determined as the pressure control amount I term (integral term) QI0 ( The pressure control amount is obtained on the basis of the part related to the integral operation). Further, a program for obtaining a correction value (correction coefficient K1) corresponding to the fuel leak amount at that time for the control gain of the drive current amount PI in the pressure feedback control (rail pressure feedback control) based on the actual machine leak amount ( Control value deriving means, FIG. 9), and a program (control value setting means, step S106 in FIG. 4) for setting the control gain based on the correction coefficient K1. As a result, even if there is an individual difference regarding the amount of fuel leak described above, it is easier to create a pressure map for each target system without creating a control map or control formula that takes into account the individual differences for each target system. (Control amount and control gain) can be acquired, and as a result, the fuel injection pressure can be controlled in a manner suitable for the pressure characteristics.

  (2) A program (fuel injection amount deriving means) for obtaining a fuel injection amount by the injector 20 based on a command signal for controlling the drive of the injector 20, and control of a pressure parameter (drive current amount PI) in pressure feedback control And a program (fuel consumption deriving means, step S45 in FIG. 9) for obtaining the fuel consumption based on the pressure control amount I term (integral term) QI0, which is a part related to the integral operation of the quantity. . In step S48 of FIG. 9, a correction value (correction coefficient K1) corresponding to the fuel leak amount at that time is obtained based on the fuel injection amount and the fuel consumption amount. Specifically, the amount of fuel leakage and thus the correction coefficient K1 is obtained in consideration of the fuel compensation by the open control. With such a configuration, the correction value (correction coefficient K1) corresponding to the fuel leak amount can be obtained more easily and accurately.

  (3) A program (injected fuel supplementing means) for supplementing the high-pressure fuel in the common rail 16 by the amount of fuel consumed by the fuel injection by the injector 20 (detected based on the command value) separately from the feedback control of the fuel injection pressure. It was set as the structure provided with. In the process of FIG. 9, while the fuel consumption is compensated, the correction coefficient K1 is obtained based on the relational expression “fuel leakage amount = pressure control amount integral term”. With such a configuration, the correction value (correction coefficient K1) corresponding to the fuel leak amount can be obtained more easily and accurately.

  (4) Feedback control of the rail pressure (fuel pressure in the common rail 16) is performed using parameters related to the discharge amount of the fuel pump 14, more specifically, the drive current amount PI of the intake adjustment valve 60. With such a configuration, the controllability when controlling the fuel injection pressure is high.

  (5) Prior to the derivation (learning execution) of the correction coefficient K1, a configuration (correction means, FIG. 7) for correcting the discharge characteristics of the fuel pump 14 is provided. This makes it possible to accurately perform feedback control of the fuel injection pressure.

  (6) In the process of FIG. 9, the correction value (correction coefficient K1) of the control gain integral term indicating the strength of the integral operation relating to the feedback control of the fuel injection pressure (rail pressure) is obtained. Under the stable fuel injection pressure, the rail pressure feedback control is performed substantially only by the integral operation. Therefore, this configuration is effective for performing pressure control more easily and accurately.

  (7) The correction value (correction coefficient K1) obtained through the processing of FIG. 9 is determined in a predetermined manner according to the derivation time (calculation time) and the fuel supply conditions at that time, and in detail each data (correction coefficient K1) is associated with both, and a program (control value storage means, step S48 in FIG. 9) is stored in a predetermined storage device (EEPROM). With such a configuration, it is possible to grasp the pressure characteristics (control gain) from time to time for each fuel supply condition. Thus, for example, data analysis by data accumulation, correction of the pressure characteristics (control gain), failure diagnosis of the fuel supply system, and the like can be performed more easily and accurately.

  (8) In step S106 in FIG. 4, the correction coefficient K1 is increased as the fuel leak amount (actual machine leak amount) obtained through steps S43 to S45 in FIG. 9 increases (FIGS. 11 and 12). The gains GP, GI, and GD are set to larger values as the actual machine leak amount increases. By doing so, a high response speed with respect to a change in the target value (target common rail pressure PP) in the fuel injection pressure control is maintained.

  (9) The fuel leak amount (actual machine leak amount) obtained through the processing of steps S43 to S45 in FIG. 9 is described in detail in a predetermined manner according to the derivation time (calculation time) and the fuel supply conditions at that time. Is configured to include a program (fuel leak amount storage means, step S45 in FIG. 9) for storing each data (actual machine leak amount) in association with both in a predetermined storage device (EEPROM). With such a configuration, it is possible to grasp the pressure characteristics (leak characteristics) from time to time for each fuel supply condition. As a result, for example, data analysis by data accumulation, correction of the pressure characteristics (control amount and control gain), failure diagnosis of the fuel supply system, and the like can be performed more easily and accurately.

  (10) As a requirement for establishing a predetermined stability condition indicating that the fuel injection pressure is stable, that is, a condition for setting “ON” in the pressure stabilization flag (FIG. 8), the fuel injection pressure (step S32 in FIG. 8) is set. ), The control amount of the pressure parameter (drive current amount PI) (step S36 in FIG. 8), the temperature of the injected fuel (step S33 in FIG. 8), and the drive state of the fuel pump 14, more specifically the engine rotation Regarding the speed (step S34 in FIG. 8), the degree of fluctuation is continuously sufficiently small for a predetermined time (step S37 in FIG. 8), and the value of the fuel injection pressure at that time (current common rail pressure NP) And the target value (target common rail pressure PP) (step S31 in FIG. 8) is continuously small for a predetermined time (step S37 in FIG. 8). It was. By adopting such conditions, it becomes possible to accurately detect the period during which the fuel injection pressure (rail pressure) is stable.

  (11) The fuel injection pressure control device (ECU 30) is applied to a common rail fuel injection system. In general, a common rail fuel injection system is known as a technology for purifying exhaust (such as reducing PM) of a diesel engine by increasing the pressure of fuel. If such a high-pressure technique is combined with the apparatus of the present embodiment, as described above, the high-pressure injection pressure can be controlled with high accuracy, and the exhaust gas can be exhausted according to the application. It is possible to further enhance the effect of cleaning. Therefore, the configuration in which the apparatus (ECU 30) of the present embodiment is incorporated in the common rail fuel injection system as described above is a diesel vehicle having a low diffusion rate (especially a low diffusion rate in Japan) due to problems such as emissions. It is a major advance in diffusion.

  (12) On the other hand, the fuel injection control system includes a fuel pump 14 that pumps up the fuel in the fuel tank 10 and pumps it, a common rail 16 that accumulates pressurized fuel pressurized by the pumping of the fuel pump 14, An injector 20 (fuel injection valve) that injects pressurized fuel accumulated by the common rail 16 and an engine that converts energy generated by burning the fuel supplied by the injector 20 into mechanical motion (rotational motion). (Not shown) and the engine control ECU 30 are provided. As described above, the pressure in the common rail 16 (corresponding to the fuel injection pressure of the injector 20) is fed back to the target value through the variable control of a predetermined pressure parameter (the drive current amount PI of the intake adjustment valve 60) inside the ECU 30. While the program to be controlled (feedback control means, FIG. 4) and the predetermined stability condition (FIG. 8) are established, “fuel consumption = fuel by fuel injection valve” regarding the injected fuel (high pressure fuel) in the common rail 16 Based on the relational expression “injection amount + fuel leak amount”, a correction value (correction coefficient K1) corresponding to the fuel leak amount at that time is obtained for the control gain of the drive current amount PI of the intake regulating valve 60 related to the feedback control. And a program (control value deriving means, FIG. 9). According to such a fuel injection control system, a fuel supply system that enables high-pressure fuel injection control with higher accuracy is realized.

  The above embodiment may be modified as follows.

  In the above embodiment, the correction coefficient K1 is basically increased as the fuel leak amount (actual machine leak amount) increases (FIG. 11). However, the present invention is not limited to this. For example, in the map shown in FIG. 11, only when the fuel leak amount is larger than the reference leak amount (reference value “LKD0 = 1”), the pressure feedback control is performed as the fuel leak amount increases. The control gain may be increased (for example, the correction coefficient K1 is fixed to “1” in the region where LKD0 is “1” or less). By doing so, the calculation of the control gain can be efficiently performed only in a region where the response speed is significantly reduced.

  -Fuel replenishment by the above open control is not an essential configuration. Even when such fuel compensation is omitted, the fuel injection amount can be obtained by a method such as actual measurement based on a fuel pressure sensor, a fuel flow sensor, etc., or estimation based on a command signal for the fuel injection valve, etc. By calculating the fuel consumption amount based on the I term (integral term) QI0, the fuel leakage amount and the control gain are calculated based on the relational expression “fuel consumption = fuel injection amount by the fuel injection valve + fuel leakage amount”. Can be requested. It is also possible to determine the amount of fuel supplied to the common rail 16 (amount of fuel supplemented by a fuel pump or the like) by measuring the fuel flow rate. That is, for example, a fuel flow rate sensor for measuring the fuel flow rate may be provided in the fuel passage, and the fuel consumption amount may be obtained based on the sensor output. Such sensors (sensors for measuring fuel flow rate) are not put into practical use at present, but will be put into practical use for the purpose of improving the accuracy of fuel injection control in the future (mounted on commercial automobiles, etc.) )there is a possibility.

  The accumulation of data on the fuel leak amount and control gain acquired through the processing of FIG. 9 and the association of the fuel supply conditions with the data are not essential. If these configurations are not required depending on the application, the configuration can be changed as appropriate. For example, old data (for example, other than the newest data) may be automatically and sequentially deleted, or only the value at that time may be stored in the storage device without association.

  The fuel leak amount, control gain, etc. acquired through the processing of FIG. 9 are not used for control of the fuel injection pressure, but may be used only for data analysis by data accumulation, failure diagnosis of the fuel supply system, etc. Good.

  A control value correction value may be obtained instead of the control gain correction value.

  Instead of the correction value, a new value of the control gain or control amount may be obtained, and this new value may be set sequentially.

  In the above embodiment, the drive current amount PI of the intake adjustment valve 60 is used as a pressure parameter related to feedback control of the fuel injection pressure. However, the present invention is not limited to this, and pressure (for example, rail pressure) itself or other parameters that affect the pressure (for example, the driving amount of the fuel pump, the opening of the pressure reducing valve, etc.) may be used.

  The predetermined stability condition related to the learning execution condition is not limited to that shown in FIG. 8, and may be any that indicates that the fuel injection pressure (for example, rail pressure) is stable.

  -The type and system configuration of the engine to be controlled can be changed as appropriate according to the application. For example, the present invention can be applied to a fuel injection system that is not a common rail fuel injection system. Further, the present invention is not limited to a compression ignition type diesel engine, but can be applied to a spark ignition type gasoline engine or the like. Furthermore, the present invention is not limited to a reciprocating engine but can be applied to a rotary engine or the like. The apparatus and system according to the present invention is not limited to a fuel injection valve that directly injects fuel into a cylinder, but also controls a fuel injection pressure for a fuel injection valve that injects fuel into an intake passage or an exhaust passage of an engine. Can be used for.

  In the embodiment and the modification, it is assumed that various kinds of software (programs) are used. However, similar functions may be realized by hardware such as a dedicated circuit.

The block diagram which shows the outline of this system about one Embodiment of the fuel injection pressure control apparatus and fuel injection pressure control system which concern on this invention. The block diagram which shows the detailed structure of the fuel pump used for the system. The block diagram which shows the detailed structure of the fuel injection valve used for the system. The flowchart which shows the process sequence of the pump control which concerns on fuel injection pressure control. The graph which shows the setting aspect of the control gain used for the pump control. The graph which shows the discharge characteristic of a fuel pump. The flowchart which shows the process sequence about each process of the characteristic correction of a fuel pump, and the judgment whether the correction is completed. The flowchart which shows the process sequence of the process which judges whether fuel-injection pressure is stable. The flowchart which shows the process sequence about the learning process of the gain correction value performed while learning execution conditions are satisfied. Map used to calculate the actual fuel leak amount (actual device leak amount). A map used to calculate gain correction values. The graph which shows the correction | amendment aspect of control gain. The graph which shows typically the outline | summary about an example of the conventional fuel injection pressure control apparatus.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 14 ... Fuel pump, 16 ... Common rail, 20 ... Injector, 30 ... ECU (electronic control unit), 50 ... High-pressure pump, 60 ... Suction adjustment valve (SCV).

Claims (18)

A fuel supply system that injects and supplies pressurized fuel, which is fuel pressurized in a predetermined manner, into a cylinder, which is a portion that performs fuel combustion of a target engine, or an intake passage or an exhaust passage thereof, by a predetermined fuel injection valve In a fuel injection pressure control apparatus that is applied and feedback-controls the fuel injection pressure of the fuel injection valve to a target value through variable control of a predetermined pressure parameter,
While a predetermined stability condition indicating that the fuel injection pressure is stable is satisfied, a relational expression “fuel consumption = fuel injection amount by the fuel injection valve + fuel leakage amount” related to the pressurized fuel. And a control value deriving means for obtaining a correction value or a new value corresponding to the fuel leak amount at the time of at least one of the control amount and the control gain of the pressure parameter in the feedback control based on Pressure control device. Fuel injection amount deriving means for determining a fuel injection amount of the pressurized fuel by the fuel injection valve based on a command signal for controlling the drive of the fuel injection valve;
Fuel consumption amount deriving means for obtaining a fuel consumption amount of the pressurized fuel based on a pressure control amount integral term that is a part related to an integral operation of the control amount of the pressure parameter in the feedback control;
And the control value deriving means obtains a correction value or a new value corresponding to the fuel leak amount at that time based on the fuel injection amount and the fuel consumption amount at that time obtained by each means. 2. The fuel injection pressure control device according to 1. Injected fuel compensation means for supplementing the pressurized fuel separately from the feedback control of the fuel injection pressure by the amount of fuel consumed by fuel injection by the fuel injection valve,
The control value deriving means sets a correction value or a new value corresponding to the fuel leak amount as “fuel leak amount = pressure control amount” at least while the fuel consumption by the fuel injection is compensated by the injected fuel compensation means. The fuel injection pressure control device according to claim 1 or 2, wherein the fuel injection pressure control device is obtained based on a relational expression "integral term". The fuel supply system is configured to include a fuel pump that pumps predetermined fuel into the pressurized fuel,
The fuel injection pressure control apparatus according to any one of claims 1 to 3, wherein one of the pressure parameters used for the feedback control is a parameter related to a discharge amount of the fuel pump. The fuel supply system includes an intake adjustment valve that varies a fuel intake amount to the fuel pump according to a drive amount,
The fuel injection pressure control device according to claim 4, wherein the parameter related to the discharge amount of the fuel pump is a parameter related to the drive amount of the suction adjustment valve.   6. The fuel injection pressure control device according to claim 4, further comprising a correction unit configured to correct a discharge characteristic of the fuel pump prior to execution of control value derivation by the control value derivation unit.   The control parameter required by the control value deriving means is at least one of a control gain integral term indicating the strength of the integral operation related to feedback control of the fuel injection pressure and a control amount integral term that is a control amount related to the integral operation. The fuel injection pressure control device according to any one of claims 1 to 6, which is a correction value or a new value.   Control value storage means for storing the control value obtained by the control value deriving means in a predetermined storage device in a predetermined manner according to at least one of the derivation time and the fuel supply condition at that time. Item 8. The fuel injection pressure control device according to any one of Items 1 to 7. A fuel supply system that injects and supplies pressurized fuel, which is fuel pressurized in a predetermined manner, into a cylinder, which is a portion that performs fuel combustion of a target engine, or an intake passage or an exhaust passage thereof, by a predetermined fuel injection valve In a fuel injection pressure control apparatus that is applied and feedback-controls the fuel injection pressure of the fuel injection valve to a target value through variable control of a predetermined pressure parameter,
While a predetermined stability condition indicating that the fuel injection pressure is stable is satisfied, a relational expression “fuel consumption = fuel injection amount by the fuel injection valve + fuel leakage amount” related to the pressurized fuel. A fuel injection pressure control device comprising: a leak amount deriving unit for determining a fuel leak amount at that time based on the above.   The fuel according to claim 9, further comprising a control value setting unit that sets at least one of a control amount and a control gain of a pressure parameter in the feedback control based on the fuel leak amount obtained by the leak amount deriving unit. Injection pressure control device.   The control value setting means sets the value of at least one of the control amount and the control gain of the pressure parameter in the feedback control to a larger value as the fuel leak amount obtained by the leak amount deriving means increases. The fuel injection pressure control device according to claim 10.   When at least the fuel leak amount obtained by the leak amount deriving unit is larger than a predetermined reference value, the control value setting unit determines the value of the control gain of the pressure parameter in the feedback control as the fuel leak amount. The fuel injection pressure control device according to claim 10, wherein the larger the value is, the larger the value is set.   Fuel leak amount storage means for storing the fuel leak amount obtained by the leak amount deriving means in a predetermined storage device in a predetermined manner according to at least one of the time of derivation and the fuel supply condition at that time The fuel injection pressure control device according to any one of claims 9 to 12. A fuel supply system that injects and supplies pressurized fuel, which is fuel pressurized in a predetermined manner, into a cylinder, which is a portion that performs fuel combustion of a target engine, or an intake passage or an exhaust passage thereof, by a predetermined fuel injection valve In a fuel injection pressure control apparatus that is applied and feedback-controls the fuel injection pressure of the fuel injection valve to a target value through variable control of a predetermined pressure parameter,
Leakage amount deriving means for obtaining a fuel leak amount when the fuel injection pressure is stable based on a part relating to an integral operation in a control amount of a pressure parameter relating to the feedback control at that time, A fuel injection pressure control device.   The stable condition includes the fuel injection pressure, the control amount of the pressure parameter in the feedback control, the temperature of the pressurized fuel, and the driving of a fuel pump that pumps a predetermined fuel to be the pressurized fuel. The one or more parameters indicating at least one of the states is one of the requirements for establishing that the degree of variation is sufficiently small continuously for a predetermined time. The fuel injection pressure control device according to Item.   The stability condition is that the deviation between the value of the fuel injection pressure at that time and the target value is sufficiently small continuously for a predetermined time, as one of the requirements for establishment. The fuel injection pressure control device according to claim 1.   The fuel supply system is a common rail fuel injection system in which a fuel pressure corresponding to a fuel pumping amount of a fuel pump is accumulated in a common rail, and the accumulated fuel is injected by the fuel injection valve as the pressurized fuel. The fuel injection pressure control device according to any one of claims 1 to 16, wherein the fuel injection pressure to be subjected to feedback control is a pressure in the common rail. A fuel pump that pumps up the fuel in the fuel tank and pumps it;
A common rail for accumulating pressurized fuel pressurized by the pumping of the fuel pump;
A fuel injection valve for injecting pressurized fuel accumulated by the common rail;
An engine for converting energy generated by burning fuel supplied by the fuel injection valve into mechanical motion;
Feedback control means for feedback-controlling the pressure in the common rail to a target value through variable control of a predetermined pressure parameter;
While a predetermined stability condition indicating that the pressure in the common rail is stable is satisfied, “fuel consumption = fuel injection amount by the fuel injection valve + fuel leakage amount” regarding the pressurized fuel in the common rail. A control value deriving unit for obtaining a correction value or a new value corresponding to the fuel leak amount at that time for at least one of the control amount and the control gain of the pressure parameter used in the feedback control unit based on the relational expression
A fuel injection pressure control system comprising:

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