JP2008215185A - Fuel injection control unit and fuel injection control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel injection control unit and a fuel injection control system capable of appropriately controlling an engine responding flexibly to more situations even when applied to the engine of an automobile and a like as a moving means. <P>SOLUTION: The fuel injection control unit (ECU for engine control) for controlling the injection-supply of the fuel to an object engine is constituted to comprise a program (step S21) for measuring a fuel residual quantity QT in a fuel tank, and a program (steps S22, S23) for compulsively performing cylinder cut-off control which is the control for operating the object engine through combustion by the remaining cylinders under the state wherein combustion by a part of the cylinders is rested (rest of the injection-supply) when the fuel residual quantity QT is close to starvation (less than "3 liter"). More specifically, it is configured to compulsively perform the cylinder cut-off control under an execution condition that the fuel residual quantity QT in the fuel tank becomes less than "3 liter" during operation of the object engine. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fuel injection control device that controls fuel injection supply to an engine, and a control system used for such fuel injection control.

  As is well known, for example, in an engine (particularly an internal combustion engine) used as a power source of an automobile or the like, an output torque is generated by igniting and burning fuel supplied by a fuel supply system. In a general fuel supply system, fuel pumped up from a fuel tank by a fuel pump and pumped is injected into a predetermined cylinder (strictly speaking, a combustion chamber in the cylinder) of a target engine through a predetermined injector (fuel injection valve). It comes to supply. Incidentally, when there are a plurality of cylinders (in the case of a so-called multi-cylinder engine), fuel is injected and supplied into each cylinder according to a predetermined order.

  In such a fuel supply system, it is important to supply fuel before the fuel in the fuel tank runs out (with some fuel remaining). Specifically, in engine control, the fuel in the fuel tank is empty (more precisely, the fuel level in the fuel tank is lowered until the fuel is completely exhausted, and the piping for sucking up the fuel is not necessary. When the engine continues to run in a state where the fuel is so low that the suction port comes out of the fuel level), the air that was applying pressure to the fuel to pump the fuel during normal operation, It enters into the fuel supply passage (for example, a pipe connecting the fuel tank and the injector) (air mixing). When fuel is supplied to the fuel supply system in which the air has entered (fuel tank is supplied), the fuel supply passage formed as a sealed space in the fuel supply system remains in a state where the air remains. It will be sealed. Normally, in such a state, it is difficult to start the engine quickly. That is, even if the engine is started, only air is supplied into the cylinder (combustion chamber) for a while, and fuel is not supplied until the residual air is discharged. Moreover, in order to start the engine, it is generally necessary to perform a long-time (for example, several minutes) air venting operation using a manual pump or the like.

Such inconvenience (such as an increase in labor associated with the air venting operation) does not occur if fuel is reliably replenished before the fuel in the fuel tank runs out. However, in reality, the operator (operator) is crazy about the work and does not realize that the remaining fuel level is low, or even if he / she notices it, he / she continues the work from the overconfidence based on the convenience and experience of the work. There is a concern that the engine will continue to run without refueling until the fuel runs out. Therefore, conventionally, as described in Patent Document 1, for example, a fuel control device that stops the operation of the engine before the fuel in the fuel tank becomes empty (with some remaining state) has been proposed. Specifically, this document shows an example in which the fuel control device is applied to a diesel engine which is a power source of a hydraulic excavator (so-called excavator car). This device comprises means (remaining limit level position detecting means) for judging whether or not the remaining amount of fuel in the fuel tank is insufficient (whether the fuel level is below a predetermined level). It is. In this device, when it is determined that the remaining amount of fuel is insufficient by the means, the operation of the target engine is stopped (forced stop) by stopping the fuel injection and consequently the fuel discharge by the fuel pump. ) And warn the user to that effect. By doing so, the operation of the engine is stopped before air enters the fuel supply system, and the worker cannot continue even if he wants to continue working. That is, it is possible to prevent inconvenience due to the residual air.
JP-A-11-303701

  However, when this apparatus is applied not to the hydraulic excavator but to an automobile or the like that is generally used as a moving means, the following inconvenience can be considered. That is, for example, when the remaining fuel level decreases while the driver is not aware of the vehicle while traveling on a general road, the engine is stopped as the remaining fuel level decreases, and the drivability of the vehicle (drivability) ) Is significantly worsened and the vehicle must be stopped. When there is no fuel supply facility near the stop location and no spare fuel is provided, it becomes extremely difficult to supply fuel to the fuel supply system (fuel supply) and thus restart the engine.

  The present invention has been made in view of such circumstances, and even when applied to an engine in an automobile or the like as a moving means, the engine is suitably controlled flexibly in response to more situations. The main object of the present invention is to provide a fuel injection control device and a fuel injection control system that can perform the above-described operation.

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

  In the first aspect of the present invention, a fuel injection valve that injects fuel supplied from a predetermined fuel tank, and a fuel that is injected and supplied by the fuel injection valve in a part or all of a plurality of cylinders. And an engine that converts the energy of the fuel combustion into mechanical motion (for example, converts it into rotational motion to rotate the output shaft), and is applied in the fuel tank. A remaining fuel amount acquisition means for actually measuring or estimating the remaining fuel amount, and a part of the plurality of cylinders when the remaining fuel amount acquired by the remaining fuel amount acquisition means is within a predetermined range close to deficiency The cylinder reduction control, which is a control for operating the engine through combustion by the remaining cylinders in a state where the combustion in the cylinders is stopped (for example, injection supply or ignition stop), is forcibly executed. Characterized in that it comprises a cylindrical control execution means.

  According to a fourth aspect of the present invention, a fuel injection valve that injects fuel supplied from a predetermined fuel tank, and a part or all of a plurality of cylinders that inject and supply fuel supplied by the fuel injection valve. An engine system configured to combust in a cylinder and convert energy from the fuel combustion into mechanical motion, and the remaining amount of fuel in the fuel tank during operation of the engine Forced to reduce cylinder control, which is a control for operating the engine through combustion by the remaining cylinders while combustion in some cylinders of the plurality of cylinders is stopped, with the execution condition being short of deficiency The present invention is characterized by comprising a reduced-cylinder control execution means for executing automatically.

  According to the fifth aspect of the present invention, a fuel injection valve that injects fuel supplied from a predetermined fuel tank, and a part or all of a plurality of cylinders that inject and supply fuel supplied by the fuel injection valve. An engine system configured to combust in a cylinder and convert energy from the fuel combustion into mechanical motion, and when the engine is started, the remaining amount of fuel in the fuel tank is almost deficient The engine is started by predetermined start control, and then the engine is operated through combustion by the remaining cylinders in a state where combustion in some cylinders of the plurality of cylinders is stopped. A cylinder reduction control execution means for forcibly executing the cylinder reduction control is provided.

  The inventor performs the reduction-cylinder control as described above, that is, a state in which a certain amount of fuel remains before the actual fuel-deficient state (a state where the amount of fuel necessary for normal operation of the target engine is not reached). Accordingly, the inventors have invented the devices according to claims 1, 4 and 5 by focusing on the point that a state corresponding to the fuel-deficient state can be easily made. That is, when such a device is mounted on, for example, an automobile, the above-described cylinder reduction control is forcibly executed when the remaining amount of fuel in the fuel tank approaches a fuel-deficient state. During execution of this cylinder reduction control, the vehicle is in a state that is in accordance with a fuel-deficient state (so-called gas-deficient state), and the driver feels the same state as in the fuel-deficient state, as if it is in a fuel-deficient state. I get an illusion. In this way, by actually letting the driver experience the fuel-deficient state, the driver's awareness of the crisis is raised in a sense that is different from the case of formal notification by lighting the lamp, etc. You will be encouraged to refuel. That is, according to the configuration of the first, fourth, and fifth aspects, there is a concern (probability) that the engine is continuously operated without replenishment until the fuel in the fuel tank becomes empty by the driver as described above. ) Is suitably suppressed. Moreover, with such reduced cylinder control, the engine output is weakened but does not stop completely. Therefore, even if the reduced cylinder control is executed even if the remaining amount of fuel is reduced at a location away from the refueling facility, It is possible to refuel by driving slowly to the refueling facility. However, in the invention described in claim 4, it is assumed that the engine stopped during execution of the cylinder reduction control is restarted, and the above cylinder reduction control is performed in order to facilitate the start of the engine. Predetermined start control (control suitable for start-up) that is not limited is performed, the engine is started (actuated), and then the above-described cylinder reduction control is executed.

Here, in the apparatus according to claim 1, as the fuel remaining amount acquiring means, for example, as in the invention according to claim 2,
-Measure the remaining amount of fuel in the tank based on the output of the fuel gauge provided in the fuel tank.
Or like invention of Claim 3,
The fuel remaining amount in the fuel tank is determined from a predetermined reference value (for example, the remaining fuel amount when the empty lamp is lit), and the fuel consumption after the fuel remaining amount in the fuel tank reaches the reference value ( For example, the remaining amount of fuel in the fuel tank is estimated based on the subtracted value by subtracting (calculated as an integrated value of the command injection amount for the fuel injection valve).
Etc. are effective. According to these configurations, it is possible to more easily and accurately detect the remaining fuel amount in the fuel tank by monitoring the remaining fuel amount and fuel consumption in the fuel tank as needed.

  In order to more reliably prevent the driver from continuing reckless engine operation as described above, a configuration in which the execution of the reduced cylinder control is not easily canceled by at least the driver (for example, for release from the manufacturer only in an emergency). It is desirable that the password is issued. Ultimately, as in the invention described in claim 6, when the forcible execution of the reduced cylinder control by the reduced cylinder control execution means is performed when a sufficient amount of fuel is supplied into the fuel tank (for example, fuel By setting a threshold for the measured value of the remaining amount, it can be detected directly or estimated from the engine operating conditions etc.). The possibility of emptying is very low.

  By the way, in the cylinder reduction control in the apparatus according to any one of claims 1 to 6, when the cylinder reduction control is performed over a long period of time with a pause cylinder fixed to a specific cylinder, repeated combustion pause processing As a result, a specific cylinder is cooled intensively, and more specifically, by not being heated by combustion, the cylinder is relatively cooled as compared with other cylinders, and the temperature in the cylinder is lowered. And since combustion efficiency falls with such a fall in in-cylinder temperature, it will become a concern about the deterioration of the emission about the cylinder. On the other hand, the invention according to claim 7 is characterized in that the reduced-cylinder control execution means changes the idle cylinder related to the reduced-cylinder control regularly or irregularly (randomly). . With such a configuration, the pause cylinder is not fixed and is appropriately changed, so that the combustion pause process related to the reduced cylinder control is distributed. As a result, the concentration of the combustion stop process for a specific cylinder is also suitably suppressed, and as a result, the emission can be improved.

  Specifically, as in the invention according to claim 8, in the apparatus according to claim 7, the fuel supplied to each cylinder of the engine is supplied to all cylinders except the idle cylinder in one combustion cycle. The reduction cylinder control execution means is configured to include a supply means every time a fuel cycle is performed a predetermined number of times (a fixed value or a variable value corresponding to a predetermined parameter) by the fuel supply means. It is effective to change one or a combination of the stop cylinders related to the control. In order to avoid excessive cooling in the cylinders described above, it is important not to keep the idle cylinders continuous in the same pattern. In this regard, if the pause cylinder pattern (one or a combination) is changed for each unit combustion cycle as in the above configuration, the combustion pause process related to the reduced cylinder control is more dispersed.

  When the degree of dispersion is further increased, as in the invention described in claim 9, in the apparatus described in claim 7 or 8, the reduced-cylinder control execution means controls each cylinder of the engine. It is particularly effective to adopt a configuration in which the cylinders are uniformly used for the cylinder reduction control. By doing so, the concentration of the combustion pause process on the specific cylinder described above is further suppressed. Such a configuration can be realized by setting the stop cylinders according to a predetermined rule that makes each cylinder uniform, or by setting the stop cylinders randomly. However, in order to ensure that the cylinders of the engine are uniformly stopped cylinders (not to be biased) (to achieve averaging of the stopped cylinders), the reduction is performed according to a predetermined rule (defined in a table or the like). A configuration that performs cylinder control is more effective. On the other hand, if this cylinder reduction control is performed by so-called random control (control using a well-known random function), creation of a control program is facilitated.

  According to a tenth aspect of the present invention, in the apparatus according to any one of the first to ninth aspects, the reduced-cylinder control execution unit performs a unit time (for example, according to the remaining amount of fuel in the fuel tank). The cylinder reduction rate indicating the number of idle cylinders per unit combustion cycle (for example, “1%” when the number of idle cylinders per 100 combustion cycles is 1) is variably controlled. .

  With such a configuration, for example, the cylinder reduction rate can be variably controlled in accordance with the remaining amount of fuel in the fuel tank by using a predetermined mathematical formula or a map (for example, a map in which characteristics corresponding to an actual fuel-deficient state are written). The fuel consumption per unit time can be adjusted. In this case, the cylinder reduction rate is increased as the remaining amount of fuel in the fuel tank decreases, so that the fuel consumption can be suppressed as the remaining amount of fuel decreases. This is preferably suppressed for consumption.

  According to an eleventh aspect of the present invention, in the apparatus according to the tenth aspect, the remaining amount of fuel in the fuel tank decreases such that the reduced cylinder control execution means cannot supply fuel to the fuel injection valve. The engine is stopped by stopping combustion in all the cylinders by a predetermined amount before (for example, detecting by setting a threshold value in advance according to the height of the fuel inlet of the fuel tank). And With such a configuration, the engine can be stopped before the fuel can no longer be supplied, that is, in a state where a predetermined amount of fuel remains. Therefore, it is possible to prevent the air from being mixed in (for example, immediately before).

In an engine system such as an automobile, a so-called empty lamp has already been put into practical use and widely used for the purpose of informing the driver of the timing of refueling (fuel supply). 12. The apparatus according to any one of claims 1 to 11, wherein the engine system informs the driver that the notification means such as an empty lamp, that is, the amount of fuel remaining in the fuel tank is approaching a fuel shortage. In the case of being configured with notification means for notification (in addition to an empty lamp, for example, a notification of the fact that fuel shortage is near by voice is also possible), for example, as in the invention according to claim 12,
A configuration in which the reduced-cylinder control execution unit operates the notification unit (for example, turns on an empty lamp) with the execution of the reduced-cylinder control (simultaneously with or before or after the execution).
Or like invention of Claim 13,
A configuration in which the reduced-cylinder control execution unit sets one of the execution conditions of the reduced-cylinder control that the notification unit is operating.
Such a configuration is effective. With such a configuration, during the execution of the cylinder reduction control, the notification means is activated, the vehicle is brought closer to an actual fuel-deficient state (gas-deficient state), and the driver is further reduced by the reduction. The possibility that the cylinder control is mistaken for failure will be reduced.

  If there is an actuator that operates in a fuel-deficient state in normal control other than the notification means (for example, an empty lamp), the vehicle that is executing the reduced-cylinder control is put into an actual fuel-deficient state (gas-deficient state). In order to make it closer, it is more effective to have the actuator actuated in accordance with the execution of the reduced cylinder control.

  According to a fourteenth aspect of the present invention, in the apparatus according to any one of the first to thirteenth aspects, the fuel injection valve includes a first piston and a second piston that allow the inside of the valve body to be displaced in the axial direction. A piston, a fluid filling chamber formed by filling a sealed space sandwiched between the first and second pistons from both sides in the axial direction, and fuel injection that is displaceable in the axial direction And a needle for opening and closing the nozzle hole corresponding to the mouth, and when receiving a predetermined driving force from one end surface side of the first piston, the driving force is supplied to the first piston. The nozzle hole is transmitted to the second piston located on the other end face side of the nozzle through the fluid filling chamber, and the needle is displaced in the axial direction inside the valve body based on the transmitted driving force. At least opening and closing of the valve Characterized in that it is intended to perform one.

  In recent years, injectors having such a structure have been put into practical use in fuel injection control systems for automobile engines. For example, in a diesel engine for an automobile, a piezo injector having the above structure (an injector using the displacement of a piezo (piezoelectric element) as a driving force) has been adopted in order to achieve cleaner exhaust (improvement of emission) and the like. Yes. In such a piezo injector, piezo displacement (driving force) is increased by the first and second pistons and the fluid filling chamber between the pistons, or the difference in material between the valve body and the piezo (details) Absorbs the displacement difference due to the thermal expansion difference).

  According to the piezo injector, there is an advantage that higher responsiveness can be obtained as compared with a general electromagnetic drive type injector (solenoid injector). However, when air mixing occurs due to the excessive continuous operation of the engine described above, the air enters the fluid filling chamber, and the driving force (for example, piezo) to the needle (for example, piezo) (Piezo displacement) is not transmitted properly. That is, in the fuel injection valve having the above structure, the above-described air mixing becomes a problem. In particular, as in the invention described in claim 15, in the device described in claim 14, when the fuel injection valve is supplied with fuel from a common rail for accumulating fuel, a high pressure (for example, “ (1000 atm or more) is likely to cause a fluid (generally fuel) leakage from the fluid filling chamber, and thus air mixing into the fluid filling chamber. If such air contamination occurs, it is usually impossible for ordinary users to cope with it, and it is necessary to replace the fuel injection valve. In this regard, in the inventions described in claims 14 and 15, the invention described in any one of claims 1 to 13 is applied to such a fuel injection valve. By doing so, it is possible to suppress the occurrence of the above-mentioned air mixing. As a result, even when the fuel injection valve having the above-described structure is employed, the possibility of air mixing is reduced, and the restrictions in using the fuel injection valve are reduced.

  It should be noted that the target vehicle can be brought into a state that is equivalent to the fuel-deficient state (in other words, a pseudo-gas-out state) not only by the reduced-cylinder control but also by other controls. The fuel injection control device according to claim 16 is applied to an in-vehicle engine system that burns fuel supplied from a predetermined fuel tank to generate energy and travels the vehicle using the energy. Vehicle simulating control means for controlling the operating state of the target vehicle in a pseudo fuel deficient state as if the fuel in the fuel tank is deficient prior to the deficiency when the remaining amount of fuel is close to deficient. Features.

  Here, as the vehicle simulation control means, in addition to the above-described reduction cylinder control, for example, by controlling an in-vehicle device other than the engine, such as a brake device or a power train, together with the engine alone, a pseudo fuel What makes a deficiency state etc. is employable suitably. With such a vehicle simulation control means, it is possible for at least the driver to experience the above-mentioned pseudo fuel deficiency state, and as a result, the driver is aware of the crisis and replenishes fuel potentially (psychologically). Can be encouraged. Thus, the concern (probability) that the engine is continuously operated without replenishment until the fuel in the fuel tank is emptied by the driver as described above is preferably suppressed.

  Further, in this case, as in the invention described in claim 17, the vehicle pseudo control means is more similar to the pseudo fuel deficient state depending on the fuel remaining amount (actually measured value or estimated value) in the fuel tank. It is more effective to adopt a configuration in which the driving state of the target vehicle is variably controlled to a high degree state. In the fuel-deficient state, the driving state of the vehicle usually changes according to the remaining amount of fuel in the fuel tank. For this reason, when convincing the driver that the vehicle is actually in a fuel-deficient state, the driving state of the target vehicle is variably controlled to a state with a higher degree of similarity according to the remaining amount of fuel in the fuel tank, using a predetermined map or the like. It is effective to do. Specifically, for example, a configuration in which the output of the engine is weakened as the remaining amount of fuel in the fuel tank decreases is useful.

  On the other hand, it is possible to urge the driver to refuel based on the difficulty of driving not only by forced execution of the reduced cylinder control but also by limiting the control based on the driving operation of the driver by other controls. The fuel injection control device according to claim 18 is applied to an in-vehicle engine system that burns fuel supplied from a predetermined fuel tank to generate energy and travels the vehicle using the energy. When the remaining amount of fuel is close to deficiency, prior to the deficiency, control of the target vehicle based on the driving operation of the driver is satisfied until a predetermined condition is satisfied (for example, until a sufficient amount of fuel is supplied into the fuel tank) Vehicle control limiting means for limiting is provided.

  Here, as the vehicle control limiting means, in addition to forcing execution of the above-described cylinder reduction control, for example, for adding a certain limit to vehicle control based on operation of a predetermined operation unit (accelerator pedal, etc.) It can be adopted as appropriate. If it is the structure provided with such a vehicle control restriction means, it becomes possible to prompt the driver to refuel based on the difficulty of driving due to the restriction of the vehicle control restriction means.

  In this case, as the vehicle control limiting means, it is effective to perform a control that suppresses the fuel consumption speed associated with engine operation without completely stopping the engine. Specifically, for example, it is effective to provide restrictions (for example, an upper limit) on the vehicle speed (can be replaced by the engine rotational speed), engine torque (for example, fuel injection amount or fresh air amount), and the like. Further, the movement of a predetermined operation unit (accelerator pedal) may be mechanically restricted or suppressed (the pedal may not be depressed or made heavy).

  Further, as in the nineteenth aspect of the present invention, as the vehicle control restriction means, one that variably controls the degree of restriction of the vehicle control according to the remaining amount of fuel (actual value or estimated value) in the fuel tank is used. By doing so, as the remaining amount of fuel in the fuel tank decreases (the fuel tank approaches the sky), the driver can be urged to refuel more strongly. Refueling will take place before it runs out (fuel runs out).

  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 various devices including The fuel injection control device according to any one of claims 1 to 19 is also assumed to be used by being incorporated in an engine control system as one of the applications. The invention described in claim 20 corresponds to such an application, and has a configuration in which the apparatus described in claim 1 is incorporated in a fuel injection control system. That is, as a fuel injection control system, a fuel injection valve that injects fuel supplied from a predetermined fuel tank, and fuel supplied by the fuel injection valve is burned in some or all of the cylinders. An engine that converts the energy of the fuel combustion into a mechanical motion (for example, rotational motion), a fuel remaining amount acquiring unit that measures or estimates the remaining amount of fuel in the fuel tank, and the remaining fuel amount acquiring unit. Combustion by the remaining cylinders in a state where combustion in some cylinders of the plurality of cylinders is stopped (injection supply or ignition stop) when the obtained remaining fuel amount is within a predetermined range close to deficiency And a cylinder reduction control execution means for forcibly executing cylinder reduction control which is control for operating the engine. Similarly, the apparatus according to any one of claims 1 to 19 is particularly useful when incorporated into a fuel injection control system.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, an embodiment embodying a fuel injection control device and a fuel injection control system according to the invention will be described with reference to the drawings. The fuel injection control system of the present embodiment is a common rail fuel that is controlled by, for example, a reciprocating diesel engine (internal combustion engine) as an automobile engine that rotates the output shaft by converting energy from fuel combustion into rotational motion. This is an injection control system (high-pressure fuel supply system), and the fuel injection control device of the present embodiment is mounted on the system and directly into a combustion chamber in a cylinder of a diesel engine (for example, an injection pressure “1000 atm”). This is a so-called fuel injection control device for a diesel engine, which is used when the above light oil) is supplied by injection (direct injection supply).

  First, an outline of a common rail fuel injection control system (vehicle engine system) according to the present embodiment will be described with reference to FIG. Note that a multi-cylinder engine (for example, an in-line four-cylinder engine) for a four-wheel automobile is assumed as the engine of the present embodiment. In FIG. 1, four injectors 20 are injectors for cylinders # 1, # 2, # 3, and # 4, respectively, 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 adjusts the amount of current supplied to the intake adjustment valve 11c to control the fuel discharge amount of the fuel pump 11 to a desired value, thereby allowing the fuel pressure in the common rail 16 (the fuel at each time measured by the fuel pressure sensor 16a). The pressure is controlled to a target value (target fuel pressure) by feedback control (for example, PID control). 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 system are arranged in the order of the fuel tank 10, the fuel pump 11, the common rail 16, and the injector 20 from the upstream side of the fuel. Among these, the fuel tank 10 and the fuel pump 11 are connected by a pipe 10 a via a fuel filter 12.

  Here, the fuel tank 10 is a tank (container) for storing fuel (light oil) of the target engine. Further, the fuel tank 10 is provided with a fuel gauge 10d for detecting the remaining amount of fuel in the fuel tank 10. The fuel gauge 10d detects a position of the arm (corresponding to the remaining amount of fuel) as a change in electric resistance by floating a float with an arm in the fuel tank 10 (fuel liquid). The fuel remaining amount thus detected is displayed on a meter near the driver's seat so that the driver can see it.

  The fuel pump 11 includes a high-pressure pump 11a and a low-pressure pump 11b, and is configured to pressurize and discharge the fuel pumped up from the fuel tank 10 by the low-pressure pump 11b with the high-pressure pump 11a. The amount of fuel pumped to the high-pressure pump 11a, and hence the amount of fuel discharged from the fuel pump 11, is adjusted by a suction control valve (SCV) 11c provided on the fuel suction side of the fuel pump 11. It has become. That is, in this fuel pump 11, the amount of fuel discharged from the pump 11 is desired by adjusting the amount of drive current (and hence the valve opening) of the intake regulating valve 11c (for example, a normally-on type that opens when not energized). The value can be controlled.

  Here, the low-pressure pump 11b is configured as a trochoid feed pump, for example. On the other hand, the high-pressure pump 11a is composed of, for example, a plunger pump, and feeds it to the pressurizing chamber by reciprocating predetermined plungers (for example, three plungers) in the axial direction by eccentric cams (eccentric cams) (not shown). The fuel is sequentially pumped at a predetermined timing. Both pumps are driven by the drive shaft 11d. Incidentally, the drive shaft 11d is interlocked with the crankshaft which is the output shaft of the target engine, and rotates at a ratio such as “1/1” or “1/2” with respect to one rotation of the crankshaft, for example. Yes. That is, the low pressure pump 11b and the high pressure pump 11a are driven by the output of the engine.

  The fuel pumped up by the fuel pump 11 from the fuel tank 10 through the fuel filter 12 is pressurized and supplied (pressure fed) to the common rail 16. The common rail 16 stores the fuel pumped from the fuel pump 11 in a high pressure state and stores the fuel in a high pressure state through the pipe 20a (high pressure fuel passage) provided for each cylinder. To each fuel injection valve). Here, the common rail 16 is provided with a fuel pressure sensor 16a for detecting the fuel pressure (rail pressure) in the common rail 16, thereby detecting and managing the rail pressure correlated with the fuel injection pressure of the injector 20. It is possible. Further, a pipe 20b is connected to each fuel discharge port of each injector 20, and this pipe 20b is integrated into one, and the fuel is returned to the fuel tank 10 via the pressure reducing valve 18 (back pressure valve). Is connected to the piping 10b. The pressure reducing valve 18 is for lowering the fuel pressure when the vehicle is decelerated.

  In this system, the fuel pumped by driving the fuel pump 11 passes through each of the cylinders # 1 to # 4 through the injectors 20 (# 1) to (# 4) provided for the cylinders # 1 to # 4. Each is directly supplied with an injection (direct injection supply). This engine is a 4-stroke engine. That is, 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 above-mentioned four cylinders # 1 to # 4 are respectively suctioned and compressed. -One combustion cycle by four strokes of combustion and exhaust is sequentially executed at a "720 ° CA" cycle.

  Here, with reference to FIG. 2, the structure of the injector 20 and the operation and control mode of the injector 20 will be described in detail. FIG. 2 is an internal side view schematically showing the internal structure of the injector 20.

  As shown in FIG. 2, the injector 20 is formed by mounting a separate nozzle (nozzle portion 21a) at the tip of a body 21 (valve body) made of, for example, a cylindrical metal. Further, at the tip of the nozzle portion 21a, for example, as many as (for example, 6 to 8) injection holes 21b (micro holes) having a diameter of about “0.15 mm” are formed as fuel injection ports communicating with the inside and outside of the valve. It is installed. The nozzle portion 21a accommodates a cylindrical nozzle needle 22 that opens and closes a fuel passage to the nozzle hole 21b. The needle 22 is urged to the valve front end side by a spring 22a (coil spring) provided on the valve rear end side and is pressed against the tapered seat surface ST1, and the injector according to or against this urging force. 20 is slid in the axial direction (longitudinal direction of the body 21). However, a stopper (not shown) is provided to prevent (regulate) the needle 22 from moving upward in the axial direction (valve rear end side) at a predetermined position for the purpose of preventing abnormal operation.

  High pressure fuel is sent to the nozzle portion 21a from the common rail (pressure accumulation pipe) 16 through the pipe 20a (see also FIG. 1). Then, the fuel is injected to the outside of the valve tip through the nozzle hole 21b. When the fuel is injected, the amount of fuel supplied to the nozzle hole 21b according to the amount of upward displacement (lift amount) of the needle 22 in the axial direction, and hence per unit time injected from the nozzle hole 21b. The amount of fuel (injection rate) changes. In the state where the needle 22 is seated on the seat surface ST1 (lift amount = “0”), the fuel injection is stopped.

  As described above, the fuel injection amount (injection rate) by the injector 20 is basically variably controlled based on the amount of displacement (lift amount) of the needle 22. A drive device (actuator) for displacing the needle 22, that is, a needle 22 is provided on the valve rear end side of the needle 22.

  Specifically, a back pressure chamber RM1 is provided on the valve rear end side of the needle 22 as a compartment space inside the body 21 (compartment on the inner peripheral surface of the body). The back pressure chamber RM1 is connected to the pipe 20a (high pressure fuel passage) so that the high pressure fuel from the common rail 16 is supplied. Further, the back pressure chamber RM1 is connected to the pipe 20b (low pressure fuel passage) via the control valve 23, so that the back pressure chamber RM1 communicates with the pipe 20b depending on whether the control valve 23 is driven or It is cut off (blocked by the valve 23). The control valve 23 is urged toward the valve rear end side by a spring 23a provided on the valve front end side, whereby the opposing surface formed in a tapered shape is pressed against the seat surface ST2. However, when the control valve 23 is driven, the control valve 23 receives a force (a force corresponding to the drive amount) opposite to the urging force of the spring 23a and is displaced toward the valve tip side. As a result, the tapered facing surface is separated from the seat surface ST2, and the back pressure chamber RM1 and the pipe 20b are communicated with each other.

  On the valve rear end side of the control valve 23, as an actuator for displacing (driving) the control valve 23, a piezoelectric stack comprising a piezoelectric laminate in which a plurality of plate-like piezoelectric elements (for example, ceramics such as PZT) are laminated. 25a is provided (specifically, it is fixed to the body 21). The piezo stack 25a expands and contracts (displaces) in the axial direction of the injector 20 using the inverse piezoelectric effect of the piezo. Specifically, the piezo stack 25a expands when charged and contracts when discharged. To do. The displacement (driving force) of the piezo stack 25a is transmitted to the control valve 23 via a hydraulic driving force transmitting portion.

  Here, the hydraulic drive force transmission section is defined by two pistons having different diameters (large diameter and small diameter pistons 25b and 25c) and sandwiched between the pistons (specifically, the body inner peripheral surface and the upper and lower two pistons). The oil-tight chamber RM2 (sealed space filled with fuel) and the spring 25d. That is, the displacement (small displacement) of the piezo stack 25a is enlarged by a predetermined magnification (for example, 2 times) based on the difference in the diameters of the pistons 25b and 25c and the difference in pressure receiving area in the pistons, and is transmitted to the control valve 23. It has come to be. By providing such a hydraulic driving force transmitting portion, it becomes possible to suppress the displacement (distortion) of the piezo stack 25a to be small, and as a result, the reliability of the injection is enhanced. In addition, during injection, the hydraulic driving force transmission part absorbs a displacement difference caused by a thermal expansion difference between the piezoelectric stack 25a made of ceramics and the body 21 made of metal, and in that sense, further reliability is achieved. The improvement of the property will be achieved. A circuit for controlling charging / discharging of the piezo stack 25a, a program for performing injection control through this circuit, and the like are mounted on the ECU 30 and the EDU 40 (driver unit).

  That is, the ECU 30 and the EDU 40, for example, control the energization / non-energization of the piezo stack 25a in a binary manner (through a pulse signal) to make the lift amount of the needle 22 variable according to the energization time, and from the common rail 16 to the pipe 20a. The high-pressure fuel sequentially supplied through the nozzles is injected through the nozzle holes 21b.

  Specifically, the control valve 23 receives a force toward the rear end side of the valve by the high-pressure fuel from the pipe 20a (and thus the common rail 16), and reverses by the extension force (extension force along the axial direction) of the spring 25d. The force to the valve tip side is also received. In a state where the piezo stack 25a is not energized (discharge state), the piezo stack 25a contracts, and the control valve 23 is seated on the seat surface ST2 against the extension force of the spring 25d. As a result, the passage connecting the pipe 20b (low pressure fuel passage) and the back pressure chamber RM1 is closed, and the back pressure chamber RM1 is maintained at a high pressure. Due to the pressure, the needle 22 is seated on the seat surface ST1 while being urged by the spring 22a. When the power is not supplied, the passage connecting the pipe 20a (high-pressure fuel passage) and the injection hole 21b is blocked, and fuel is not supplied to the injection hole 21b. This is the valve closed state.

  On the other hand, when the piezo stack 25a is energized (charged), the piezo stack 25a extends, and the control valve 23 separates from the seat surface ST2 against the fuel pressure. As a result, the pipe 20b (low pressure fuel passage) and the back pressure chamber RM1 are communicated with each other, and the fuel pressure in the back pressure chamber RM1 decreases. As the pressure decreases, the needle 22 moves away from the seat surface ST1 against the extension force of the spring 22a. When energized, the pipe 20a (high pressure fuel passage) and the injection hole 21b are thus communicated, and fuel is injected and supplied into the cylinder (combustion chamber) of the target engine through the injection hole 21b. This is the valve open state. The injector 20 is a so-called normally closed type fuel injection valve that is in a closed state when not energized.

  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, a crank angle sensor 30a that outputs a crank angle signal at every predetermined crank angle (for example, in a cycle of 30 ° CA) is provided on the outer peripheral side of the crankshaft that is an output shaft of the engine. It is provided for detecting the like. In addition, the accelerator sensor 30b that outputs an electric signal corresponding to the state (displacement amount) of the pedal to the accelerator pedal (driving operation unit) detects the operation amount (accelerator opening degree) of the accelerator pedal by the driver. Is provided. Also, in the vicinity of the driver's seat of the vehicle (for example, the instrument panel section), an empty light is turned on when the remaining amount of fuel (detected by the fuel gauge 10d) in the fuel tank 10 falls below a predetermined amount (for example, “10 liters”). A lamp 30c (fuel remaining warning light) is installed to notify the driver that the remaining amount of fuel in the fuel tank 10 is close to fuel shortage ("lights on the lamp 30c" = "close to fuel shortage"). ing.

  In such a system, the ECU 30 functions as the fuel injection control device of this embodiment and performs engine control mainly as an electronic control unit. The ECU 30 (engine control ECU) includes a known microcomputer (not shown), grasps the operating state of the target engine and the user's request based on the detection signals of the various sensors, and responds accordingly. By operating various actuators such as the injector 20, 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) RAM), signal processing devices such as A / D converters and clock generation circuits, various arithmetic devices such as input / output ports for inputting / outputting signals to / from the outside, storage devices, signal processing devices, And a communication device or the like. The ROM stores various programs related to engine control including a program related to the fuel injection control, a control map, and the like, 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.

  The EDU 40 (driver unit) applies a high voltage to the injector 20 based on a command signal from the ECU 30. By applying such a high voltage, the injector 20 operates at high speed. Specifically, the EDU 40 has a high voltage generator (for example, a DC / DC converter), and converts the battery voltage applied from the vehicle-mounted battery into a high voltage by the high voltage generator. Then, the high voltage (drive signal) is applied to a predetermined injector based on a command from the ECU 30. At this time, if the circuit operation of the EDU 40 and the operation of the injector 20 are good, an injection confirmation signal indicating that is output to the ECU 30. On the other hand, if there is any problem, this injection confirmation signal is not output. ECU30 monitors the malfunction of EDU40 and the injector 20 at any time by the presence or absence of this injection confirmation signal.

  The configuration of the fuel injection control system according to this embodiment has been described in detail above. That is, a vehicle (for example, a four-wheel passenger car or a truck) on which a diesel engine to be controlled is mounted is controlled by such a control system. In this system, the ECU 30 calculates the fuel injection amount (engine control amount) on the basis of various sensor outputs (detection signals) inputted as needed, and based on the fuel injection amount, The illustrated torque (generated torque) generated through fuel combustion in the chamber), and in turn, the shaft torque (output torque) actually output to the output shaft (crankshaft) is controlled. That is, the ECU 30 calculates a fuel injection amount in accordance with, for example, the engine operating state from time to time or the accelerator pedal operation amount by the driver, and injects fuel at that fuel injection amount in synchronization with a desired injection timing. An instructing injection control signal is output to the injector 20. As a result, the output torque of the engine is controlled to the target value based on the drive amount (for example, valve opening time) of the injector 20. In the control system of this embodiment as well as the well-known diesel engine system, during steady operation, an intake throttle valve (throttle valve) provided in the intake passage of the engine is used for the purpose of increasing the amount of fresh air and reducing pumping loss. ) Is maintained in a substantially fully open state. Therefore, control of the fuel injection amount is mainly used as combustion control during steady operation (particularly combustion control related to torque adjustment). Hereinafter, the basic procedure of the fuel injection control according to the present embodiment will be described with reference to FIG. Note that the values of various parameters used in the processing of FIG. 3 are stored as needed in a storage device such as a RAM, EEPROM, or backup RAM mounted in the ECU 30 and updated as necessary. The series of processes in these figures is basically executed once per combustion cycle for each cylinder of the engine by executing a program stored in the ROM by the ECU 30 (for example, each cylinder). (Sequentially shifted by “180 ° CA”). By this program (fuel supply means), fuel is supplied to all the cylinders except the idle cylinder in one combustion cycle.

  As shown in FIG. 3, in this series of processing, first in step S11, for example, engine operation such as engine speed (detected by the crank angle sensor 30a), rail pressure (detected by the fuel pressure sensor 16a), etc. Various parameters indicating the state and the accelerator operation amount (detected by the accelerator sensor 30b) at that time by the driver are read. In the subsequent step S12, an injection pattern is set based on the engine operating state, the accelerator operation amount, etc. read in step S11 (calculating the required engine operating state separately if necessary).

  The injection pattern is determined by parameters such as the number of injection stages (the number of injections in one combustion stroke), the injection timing, the injection time (corresponding to the injection amount), the injection interval (the injection interval in the case of multistage injection), and the like. For example, it is acquired based on a predetermined map (which may be a mathematical expression) stored and held in the ROM. Specifically, for example, an optimum pattern (adapted value) is obtained by experiments or the like for each engine operating state assumed in advance and written in the map. Thus, the map shows the relationship between the engine operating state and the optimum pattern.

  In subsequent step S13, a correction coefficient updated by a separate learning process (for example, a learning process related to aging of the injector 20) is read from the EEPROM, and in subsequent step S14, based on the read correction coefficient, the previous step S12 is performed. The command value (command signal) corresponding to the injection pattern set in step 1, that is, the command value for the injector 20 is corrected. Then, in the following step S15, based on the corrected command value (command signal), the injection pattern, that is, the command value related to the number of injection stages, the injection timing, the injection time, the injection interval, etc. is determined, and the command value Based on the above, the drive of the injector 20 is controlled.

  In the present embodiment, fuel is supplied to the target engine through such fuel injection control. When the fuel in the fuel tank 10 is consumed as the fuel is supplied, the remaining amount of fuel in the fuel tank 10 falls below “10 liters” and the empty lamp 30c is lit. Here, if the fuel is consumed until the fuel in the fuel tank 10 runs out, air (air) enters from the pipe 10a (FIG. 1) connected to the fuel pump 11 and causes various inconveniences. Just as you did. In particular, in the present embodiment, since the injector 20 having the structure as shown in FIG. 2 is employed, when such air mixing occurs, for example, the high pressure of the oil tight chamber RM2 sealed with a force of about “1000 N” is used. There is a high possibility that fuel leaks from a gap (for example, a gap of about “3 μm” on the sliding surfaces of the pistons 25b and 25c), and air (air) enters the oil-tight chamber RM2 instead. In this regard, in the present embodiment, when the remaining amount of fuel in the fuel tank 10 is nearly deficient during engine operation, combustion in some of the cylinders # 1 to # 4 is suspended. In a state (specifically, in a state where fuel injection supply by the injector 20 is stopped), control for operating the target engine through combustion in the remaining cylinders, that is, so-called reduced-cylinder control is forcibly executed. By this control, the remaining amount of fuel in the fuel tank 10 (FIG. 1) is deficient (the fuel level L11 in the fuel tank 10 is lowered so that the suction port of the pipe 10a for sucking up the fuel comes out from the fuel level. This is preferably suppressed with respect to the consumption of fuel until the amount of fuel is reduced).

  Hereinafter, with reference to FIG. 4, a process related to the cylinder reduction control that is started when the empty lamp 30 c is turned on will be described. The process of FIG. 4 is sequentially executed at predetermined crank angles or at predetermined time intervals until the fuel is replenished and the empty lamp 30c is turned off. Also in the processing of FIG. 4, the values of various parameters are stored as needed in a storage device such as a RAM, EEPROM, or backup RAM mounted on the ECU 30, for example, and updated as needed.

  As shown in FIG. 4, in this series of processes, first, in step S21, the fuel remaining amount QT in the fuel tank 10 is measured (measured) by the fuel gauge 10d. Next, in step S22, based on the measured remaining fuel amount QT, a cylinder reduction rate GEN indicating the number of idle cylinders per unit time (for example, one combustion cycle) is acquired. In a further subsequent step S23, a reduced cylinder operation pattern (combination cylinder combination) is determined (variably set) based on the acquired reduced cylinder rate GEN. Hereinafter, with reference to FIG. 5 and FIG. 6, the process related to the determination (variable setting) of the reduced cylinder operation pattern will be described in more detail. FIG. 5 is a graph showing an example of a mathematical expression (relational expression GEN = f (QT) between the cylinder reduction ratio GEN and the remaining fuel amount QT) used in step S22, and FIG. 6 is a table used in step S23. An example (for example, stored in a ROM, an EEPROM, or the like) is shown. Here, the cylinder reduction ratio GEN is set to “1%” when the number of idle cylinders per 100 combustion cycles is one. By the way, when creating the mathematical formula used in step S22 as a mathematical formula that defines the characteristics according to the actual fuel-deficient state, the actual operating state at the time of idling is used as a reference (cylinder reduction rate “0%”). A method is effective in which the ratio of cylinders that are deactivated within a predetermined time (for example, “1 minute”) in the fuel-deficient state (gas-deficient state) is sequentially set to the cylinder reduction rate with the remaining fuel amount.

  As shown in FIG. 5, in this mathematical expression, even after the empty lamp 30c is turned on, the normal operation pattern (without the above-described cylinder reduction control) is performed until the remaining fuel amount QT falls below (below) “3 liters”. The above-described fuel injection control (FIG. 3) is performed at a reduced cylinder rate GEN “0%”). Then, after the lamp 30c is turned on, when the fuel is consumed by the engine operation and the remaining fuel amount QT in the fuel tank 10 falls below "3 liters", the first reduced cylinder operation pattern (the reduced cylinder rate GEN "25%"). ), But when the fuel is further consumed and the remaining fuel amount QT falls below “2 liters”, the second reduced-cylinder operation pattern (reduced-cylinder rate GEN “50%”) is set in step S23 of FIG. It is set as a reduced-cylinder operation pattern. That is, in this case, the above-described fuel injection control (FIG. 3) is performed based on the injection pattern (set in step S12 of FIG. 3) reflecting these first or second reduced-cylinder operation patterns. . Further, when the fuel consumption further proceeds and the remaining fuel amount QT falls below “1 liter”, an operation pattern with the reduced cylinder rate GEN “100%” is set. That is, in this case, fuel cut (fuel injection supply pause processing by the injector 20) is performed for all cylinders # 1 to # 4 of the target engine. In other words, fuel injection is not performed by the above-described fuel injection control (FIG. 3), and the operation of the target engine is stopped (forced stop). The threshold value “1 liter” of the remaining fuel amount QT related to the engine stop is obtained in advance by experiments or the like as a value immediately before the remaining fuel amount in the fuel tank 10 decreases so that fuel cannot be supplied to the injector 20. It is a thing. Specifically, the value of “1 liter” indicates that the intake port of the pipe 10a for sucking up the fuel by lowering the fuel level L11 (FIG. 1) in the fuel tank 10 comes out of the fuel liquid level and the air is sucked in. This is obtained as the fuel level L11 (remaining amount of fuel) immediately before the amount of fuel decreases as the fuel level becomes lower (in other words, the fuel level L11 becomes lower than the suction port height L21 of the pipe 10a).

  In step S22 of FIG. 4, the reduced cylinder ratio GEN is set as a function of the remaining fuel amount QT (GEN = f (QT)) according to such a mathematical expression. In the subsequent step S23, a predetermined operation pattern corresponding to the reduced cylinder ratio GEN is set. At that time, the table shown in FIG. 6 is used (referenced) for setting the operation pattern.

  As shown in FIG. 6, in the normal operation pattern in this table (cylinder reduction ratio GEN “0%”), fuel supply (in order of cylinders # 1, # 3, # 4, and # 2) for each cylinder ( Fuel injection), and consequently fuel combustion (combustion stroke). On the other hand, in the first reduced-cylinder operation pattern (cylinder reduction rate GEN “25%”), the fuel is not supplied to the cylinder # 1. In the second reduced-cylinder operation pattern (cylinder reduction rate GEN “50%”), fuel is not supplied to cylinder # 2 in addition to cylinder # 1. Further, as described above, in the operation pattern of the cylinder reduction rate GEN “100%”, fuel is not supplied to any cylinder of the target engine, that is, fuel cut (fuel supply) for all cylinders # 1 to # 4. (Pause processing) is performed.

  In step S23 of FIG. 4, the operation pattern corresponding to the value of the cylinder reduction rate GEN (“0%”, “25%”, “50%”, “100%”) is set according to such a table. And the driving | operation pattern set here is reflected in the injection pattern acquired by step S12 of FIG. That is, if a reduced cylinder operation pattern in which one of the cylinders is a pause cylinder is set in step S23, fuel injection is not performed for that cylinder and only for the remaining cylinders in step S15 of FIG. Fuel injection supply is performed. However, if the above-described reduced-cylinder operation is suddenly started during high-speed operation of the engine (injection pattern is switched), a large torque shock occurs, and there is a concern about drastic deterioration of drivability. For this reason, in the present embodiment, a well-known gradual change process (a process for gradual torque change) is appropriately performed in a transient state (transition period) in which the torque change is large. By doing so, the deterioration of the drivability is suppressed.

  In this embodiment, the above-described cylinder reduction control is forcibly performed regardless of the driving operation of the driver as the remaining fuel amount decreases. The forcible execution of the cylinder reduction control is canceled only when a sufficient amount of fuel (for example, an amount exceeding “10 liters”) is supplied into the fuel tank 10. When the engine is stopped during the execution of the cylinder reduction control and then the engine is started again, predetermined start control (control suitable for starting) is performed and the engine is started and then the above reduction is performed. The cylinder control is executed. This makes it easier to start the engine.

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

  (1) As a fuel injection control device (ECU 30 for engine control) that controls fuel injection supply to a target engine (not shown), a program (fuel remaining amount acquisition means, FIG. 4 and step S21) and when the remaining fuel amount QT is within a predetermined range (less than "3 liters") that is short of deficiency, a part of the cylinders (cylinders # 1 to # 4) A program for forcibly executing reduced cylinder control, which is a control for operating the target engine through combustion by the remaining cylinders in a state where combustion of the engine is stopped (injection supply is stopped) (reduced cylinder control execution means, vehicle simulation control means, vehicle Control limiting means, step S23 in FIG. 4 and step S12 in FIG. 3). Specifically, during the operation of the target engine, the above-described cylinder reduction control is forcibly executed on the condition that the remaining fuel amount QT in the fuel tank 10 is nearly deficient (less than “3 liters”). . By executing the above-mentioned cylinder reduction control with such a configuration, when the remaining fuel amount QT in the fuel tank 10 is close to being deficient, it is simulated that the fuel in the fuel tank 10 is deficient prior to the deficiency. Thus, the driving state of the target vehicle is controlled in a fuel deficient state. Furthermore, control of the target vehicle based on the driver's driving operation (accelerator pedal operation) is limited. That is, during execution of the above-mentioned cylinder reduction control, the vehicle is in a state that is in accordance with a fuel-deficient state (so-called gas-deficient state), and the driver feels the same state as that in the fuel-deficient state, as if it is in a fuel-deficient state. I get an illusion. In addition to notifying informally by turning on the lamp, etc., the driver's crisis consciousness can be further enhanced by actually letting the driver experience the condition, and the driver can be a potential (psychological) Will be prompted to refuel. Further, the vehicle control (specifically, torque control) based on the accelerator pedal operation is restricted during execution of the cylinder reduction control, and the driver is also encouraged to refuel early because it becomes difficult to drive. Thereby, the concern (probability) that the engine is continuously operated without replenishment until the fuel in the fuel tank 10 is emptied by the driver as described above is preferably suppressed (reduced). Become.

  (2) Moreover, with such reduced cylinder control, the engine output will weaken, but it will not stop completely, so even if the remaining amount of fuel decreases at a location away from the fueling facility and the reduced cylinder control is executed. It is possible to refuel by driving slowly to the nearest refueling facility.

  (3) If the remaining amount of fuel in the fuel tank 10 is already near deficiency (less than “3 liters”) when the target engine is started, the cylinder reduction control is performed after the engine is started by predetermined start control. Was forcibly executed. By doing so, it is possible to avoid a situation in which the engine start continues to fail in the reduced cylinder control and the engine life is shortened.

  (4) In step S21 of FIG. 4, the remaining fuel amount QT in the tank 10 is actually measured based on the output of the fuel meter 10d provided in the fuel tank 10. More specifically, the remaining fuel amount QT in the tank 10 is monitored (monitored) by sequentially executing the processing of step S21 at predetermined processing intervals. By doing so, the remaining fuel amount QT in the fuel tank 10 can be detected more easily and accurately.

  (5) The cylinder reduction control executed in step S23 of FIG. 4 is canceled only when a sufficient amount (“10 liters” or more) of fuel is supplied into the fuel tank 10. By doing so, the above-mentioned cylinder reduction control is not stopped by the driver's hand, and the possibility of emptying the fuel by continuing the engine operation becomes extremely low.

  (6) In step S22 of FIG. 4, the cylinder reduction ratio GEN is variably controlled in accordance with the remaining fuel amount QT in the fuel tank 10. Specifically, the cylinder reduction ratio GEN is increased as the remaining fuel amount QT decreases according to a predetermined mathematical formula (FIG. 5). By doing so, the fuel consumption amount can be suppressed as the remaining fuel amount QT decreases, and as a result, the fuel consumption until the remaining fuel amount becomes empty is suitably suppressed.

  (7) In addition, by the processing of step S22, the driving state of the target vehicle is variably controlled to a higher similarity state as a pseudo fuel deficiency state according to the remaining fuel amount QT in the fuel tank 10. did. Specifically, the output of the target engine is weakened as the remaining fuel amount QT in the fuel tank 10 decreases. By doing so, the pseudo fuel deficiency state can be brought closer to an actual fuel deficiency state in response to a change in the remaining fuel amount QT.

  (8) Similarly, by the process of step S22, the vehicle control limit degree is variably controlled in accordance with the remaining amount of fuel in the fuel tank 10. In this way, the fuel remaining amount QT in the fuel tank 10 decreases (the fuel tank approaches the empty state), and the driver can be urged to refuel more strongly. Refueling will take place before is empty (no fuel).

  (9) Further, in step S22, the combustion in all the cylinders is performed before the remaining amount of fuel QT in the fuel tank 10 decreases so that fuel cannot be supplied to the injector 20 (a predetermined amount before, in other words, just before). Was suspended and the target engine was stopped (forced stop). By doing so, it is possible to prevent the air from being mixed (immediately before).

  (10) One of the execution conditions of the cylinder reduction control is that the empty lamp 30c is in operation (lighted) (the remaining fuel amount QT is less than "10 liters"). By doing so, the vehicle comes closer to an actual fuel-deficient state (gas-deficient state), and thus the possibility that the driver misunderstands the above-mentioned reduced cylinder control as a failure or the like is reduced.

  (11) An injector 20 having a structure as shown in FIG. 2 is employed as a fuel injection valve for supplying fuel to the target engine. That is, a large-diameter piston 25b (first piston) and a small-diameter piston 25c (second piston) that can displace the body 21 (valve body) in the axial direction, and a large-diameter and small-diameter piston 25b from both sides in the axial direction. , 25c, an oil-tight chamber RM2 (fluid filling chamber) formed by filling a predetermined fluid (specifically, light oil as fuel of the target engine) into a sealed space, and a fuel injection port that can be displaced in the axial direction And a needle 22 that opens and closes the nozzle hole 21b corresponding to the above, and receives a predetermined driving force (displacement of the piezo stack 25a) from one end surface side (valve rear end side) of the large-diameter piston 25b. In this case, the driving force is transmitted to the small-diameter piston 25c located on the other end surface side (valve tip side) of the large-diameter piston 25b via the oil-tight chamber RM2, and the body is based on the transmitted driving force. 21 is a fuel injection valve that opens the nozzle hole 21b by displacing the needle 22 in the axial direction. More specifically, the fuel injection valve has such a structure and receives supply of high-pressure fuel from the common rail 16 so-called high-pressure fuel. A fuel injection valve was adopted. By performing the above-described cylinder reduction control, even when such a fuel injection valve is used, it is possible to suppress the occurrence of air mixing described above. The piezo injector having the above-described structure is a fuel injection valve that greatly contributes to emission improvement in an automobile engine or the like, and this structure is significant in realizing an environmentally friendly clean diesel vehicle.

  (12) On the other hand, the fuel injection control system includes an injector 20 (fuel injection valve) that injects fuel (light oil) supplied from a predetermined fuel tank 10 and a plurality of cylinders that are supplied with fuel supplied by the injector 20 And an engine (not shown) that burns in some or all of the cylinders and converts the energy of the fuel combustion into mechanical motion (rotational motion), and the engine control ECU 30. . As described above, the ECU 30 has a program for actually measuring the fuel remaining amount in the fuel tank 10 (fuel remaining amount acquisition means) and the acquired fuel remaining amount within a predetermined range close to deficiency. And a program for forcibly executing the reduced cylinder control (reduced cylinder control execution means). According to such a fuel injection control system, a more reliable fuel supply system can be realized.

  (13) By applying the fuel injection control system to an automobile (a four-wheel automobile in the present embodiment), an automobile that is less likely to fail is realized. In general, automobiles are frequently used as a means of transportation, and become a daily necessities in areas where traffic is inconvenient, so it is important to reduce the probability of failure.

  The above embodiment may be modified as follows.

  In order to further increase the driver's risk awareness, the remaining fuel amount QT may be less than “10 liters” and the empty lamp 30c may be blinked, and the blinking speed may be increased as the remaining fuel amount QT decreases. When the remaining amount of fuel QT falls below a predetermined amount (“1 liter”) and the target engine is forcibly stopped, immediately before that (for example, several seconds to several tens of seconds) the driver is notified that the engine will be stopped. A warning sound may be sounded a second before or when the remaining fuel amount QT approaches “1 liter”.

  In the operation pattern illustrated in FIG. 6, the idle cylinder is fixed to a specific cylinder (cylinder # 1 or cylinder # 2). However, it is not limited to this operation pattern, and instead of this, for example, the operation pattern shown in FIG. 7 (for example, stored as a table in ROM, EEPROM, or the like) may be used.

  As shown in FIG. 7, in this operation pattern, the pause cylinder pattern is not fixed, and the pause cylinder according to the cylinder reduction control is performed every time one combustion cycle (fuel supply) is performed by the process of FIG. The pattern (one or a combination) is changed. In addition, each cylinder of the target engine is uniformly set as the idle cylinder (averaged). In this example, in the first reduced-cylinder operation pattern, all cylinders become idle cylinders at a rate of “once every 5 combustion cycles”, and in the second reduced-cylinder operation pattern, all cylinders become “1 per 3 combustion cycles”. It becomes a pause cylinder at the rate of “times”. According to such an operation pattern, the combustion pause process related to the reduced cylinder control is uniformly distributed. For this reason, it is possible to prevent or suppress the deterioration of the emission caused by the intensive decrease in the in-cylinder temperature in the specific cylinder caused by the concentration of the combustion pause process.

  -It is not restricted to what changes a stop cylinder regularly, You may comprise so that a change of a stop cylinder may be performed irregularly. For example, with respect to the operation pattern illustrated in FIG. 6, the idle cylinders of the first and second reduced cylinder operation patterns are randomly selected (for example, a well-known random function) corresponding to each cylinder reduction rate (“25%” “50%”). Use). By doing this as well, the idle cylinders are approximately averaged by a random function, and each cylinder can be made uniformly idle cylinders (without being biased).

  However, the operation pattern used for the cylinder reduction control is basically arbitrary as long as the cylinder reduction control can be performed. And if it is an operation pattern which makes the cylinder reduction rate GEN larger as the remaining fuel amount QT decreases, it is possible to obtain the same effects as the effects (6) to (8) or effects equivalent thereto.

  A plurality of types of reduced-cylinder operation patterns (operation patterns used for reduced-cylinder control) may be held according to conditions, and any one may be selected (switching usage patterns) according to the conditions. For example, a plurality of types of patterns (for example, two patterns for high speed and low speed) may be held according to the vehicle speed, the engine rotation speed, and the like. Such a configuration is also effective in improving drivability when executing the reduced cylinder control.

  In the above embodiment, the execution condition of the cylinder reduction control is that the empty lamp 30c is in operation (lighting), but is not limited thereto, and the cylinder reduction control is executed before the empty lamp 30c is lit. You may do it. In this case, it is possible to obtain an effect according to the effect (10) by turning on the empty lamp 30c with the execution of the above-described cylinder reduction control (simultaneously or before and after the execution). Further, when there is an actuator that operates in a fuel-deficient state (so-called gas-deficient state) in normal control other than the empty lamp 30c, in order to bring the vehicle in which the cylinder reduction control is being executed closer to the actual fuel-deficient state, A configuration in which the actuator is also activated in accordance with the execution of the reduced cylinder control (for example, before or after a predetermined time before the execution of the control) is more effective.

  In the above embodiment, the fuel remaining amount QT in the tank 10 is actually measured based on the output of the fuel gauge 10d in step S21 of FIG. However, the fuel remaining amount QT in the fuel tank 10 is not limited to this, and the fuel remaining in the fuel tank 10 is determined from a predetermined reference value (which can be arbitrarily set, for example, the remaining fuel amount “10 liters” when the empty lamp 30c is lit). By subtracting the fuel consumption after the remaining amount QT reaches the reference value, estimation may be performed based on the subtraction value. The fuel consumption after reaching the reference value is, for example, a command injection amount for the injector 20 (or an estimated value or an actual measurement value of the injection amount) from when the remaining amount of fuel becomes “10 liters” which is the reference value. Can be calculated as an integrated value of the injection amount.

  In the above embodiment, in order to more reliably prevent the driver from continuing reckless engine operation, the reduced cylinder control is released only when a sufficient amount of fuel is supplied into the fuel tank 10. However, even if the cancellation of the cylinder reduction control is not strictly prohibited so far, the effect equivalent to the effect (5) can be obtained as long as at least the execution of the cylinder reduction control is not easily released. For example, a configuration may be adopted in which a password for canceling the reduced cylinder control is issued from a manufacturer (company or person responsible for the product) only in an emergency.

  -Even if it is the structure which does not perform cylinder reduction control, it is possible to make the object vehicle into a state (in other words, a pseudo gas deficient state) according to the fuel deficient state. A similar effect can be obtained. For example, a pseudo fuel-deficient state may be created by controlling a vehicle-mounted device other than the engine such as a brake device and a power train, without performing the cylinder reduction control, alone or alone.

  -Reduced cylinder control is not performed, and vehicle speed (can be replaced with engine speed) or engine torque (for example, fuel injection) to apply certain restrictions to vehicle control based on the operation of a predetermined operation unit (accelerator pedal, etc.) (E.g., amount or fresh air amount) or the like may be provided with restrictions (for example, an upper limit). This also makes it possible to prompt the driver to refuel based on the difficulty of driving, and the effect according to the effect (1) can be obtained. Further, the movement of a predetermined operation unit (accelerator pedal) may be mechanically restricted or suppressed (the pedal may not be depressed or made heavy).

  -As an alerting | reporting means which alert | reports to a driver | operator that the fuel remaining amount in the fuel tank 10 is nearing fuel shortage, the arbitrary vehicle-mounted apparatuses not restricted to the empty lamp 30c (warning light) are employable. For example, a device that informs that a fuel shortage is approaching by voice through a car navigation system or the like may be used instead of the empty lamp 30c.

  -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 not only to a compression ignition type diesel engine but also to a spark ignition type gasoline engine (including both an intake passage injection type and an in-cylinder injection type), and is not limited to a reciprocating engine, and is a rotary engine. The present invention is also applicable to the above. Furthermore, the present invention may be applied to an engine for a hydraulic excavator as in the apparatus described in Patent Document 1 above. Moreover, in the said embodiment, although the injector 20 of a structure as shown in FIG. 2 was employ | adopted, the structures of the fuel injection valve of an object engine can select arbitrary things according to a use etc. That is, instead of the hydraulically driven piezo injector that is binary-controlled by the pulse signal described above, the needle lift amount, and hence the injection rate, are continuously set according to the supply amount of the drive current (piezo charge amount). Further, a direct-acting piezo injector that is directly variable may be employed. Further, the present invention is not limited to a piezo injector using a piezoelectric element as a needle actuator, and a more general fuel injection valve using an electromagnetic solenoid as an actuator may be employed. The type of fuel gauge used to detect the remaining amount of fuel in the fuel tank 10 is also arbitrary, and is not limited to the above-described float detection type, for example, a device that detects the remaining amount of fuel based on a change in electric capacity, etc. is appropriately adopted. Is possible.

  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 control system about one Embodiment of the fuel-injection control apparatus and fuel-injection control system which concern on this invention. The internal side view which shows typically the internal structure of the fuel injection valve used for the system. The flowchart which shows the basic procedure of the fuel-injection control process which concerns on this embodiment. The flowchart which shows the process sequence of the process which concerns on cylinder reduction control. The graph which shows an example of the numerical formula used by reduced cylinder control. The figure which shows an example of the table used by reduced cylinder control. The figure which shows the modification of the same table.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Fuel tank, 10d ... Fuel gauge, 11 ... Fuel pump, 16 ... Common rail (accumulation piping), 20 ... Injector, 30 ... ECU (electronic control unit), 30c ... Empty lamp.

Claims (20)

A fuel injection valve that injects fuel supplied from a predetermined fuel tank, and the fuel that is supplied by the fuel injection valve is burned in some or all of a plurality of cylinders, and the energy resulting from the fuel combustion Is applied to an engine system configured to include an engine that converts to mechanical motion,
Fuel remaining amount obtaining means for actually measuring or estimating the fuel remaining amount in the fuel tank;
When the remaining amount of fuel acquired by the remaining fuel amount acquiring means is within a predetermined range close to deficiency, the combustion in the remaining cylinders is stopped while the combustion in the remaining cylinders is stopped. Reduced-cylinder control execution means for forcibly executing reduced-cylinder control that is control for operating the engine;
A fuel injection control device comprising:   2. The fuel injection control device according to claim 1, wherein the remaining fuel amount acquiring unit measures the remaining fuel amount in the tank based on an output of a fuel gauge provided in the fuel tank.   The fuel remaining amount acquisition means subtracts a fuel consumption amount after the fuel remaining amount in the fuel tank reaches the reference value from a predetermined reference value, and based on the subtracted value, The fuel injection control device according to claim 1, wherein the remaining fuel amount is estimated. A fuel injection valve that injects fuel supplied from a predetermined fuel tank, and the fuel that is supplied by the fuel injection valve is burned in some or all of a plurality of cylinders, and the energy resulting from the fuel combustion Is applied to an engine system configured to include an engine that converts to mechanical motion,
While the engine is in operation, the remaining cylinders are in a state where combustion in some cylinders of the plurality of cylinders is stopped with an execution condition that the remaining amount of fuel in the fuel tank is nearly deficient. A fuel injection control device comprising a reduction-cylinder control execution means for forcibly executing reduction-cylinder control that is control for operating the engine through combustion by means of combustion. A fuel injection valve that injects fuel supplied from a predetermined fuel tank, and the fuel that is supplied by the fuel injection valve is burned in some or all of a plurality of cylinders, and the energy resulting from the fuel combustion Is applied to an engine system configured to include an engine that converts to mechanical motion,
If the remaining amount of fuel in the fuel tank is close to being deficient when the engine is started, the engine is started by predetermined start control, and combustion is performed in some of the plurality of cylinders. A fuel injection control device, comprising: a reduced-cylinder control execution means for forcibly executing reduced-cylinder control, which is control for operating the engine through combustion by the remaining cylinders in a stopped state.   The fuel injection according to any one of claims 1 to 5, wherein the forced execution of the reduced cylinder control by the reduced cylinder control execution unit is canceled only when a sufficient amount of fuel is supplied into the fuel tank. Control device.   The fuel injection control device according to any one of claims 1 to 6, wherein the reduction cylinder control execution unit changes a pause cylinder related to the reduction cylinder control regularly or irregularly. A fuel supply means for supplying fuel to each cylinder of the engine to all cylinders except the idle cylinder in one combustion cycle;
8. The fuel injection according to claim 7, wherein the reduction cylinder control execution means changes one or a combination of the idle cylinders related to the reduction cylinder control every time a predetermined number of combustion cycles are performed by the fuel supply means. Control device.   The fuel injection control device according to claim 7 or 8, wherein the cylinder reduction control execution unit uniformly sets each cylinder of the engine as a stop cylinder related to the cylinder reduction control.   The said cylinder reduction control execution means variably controls the cylinder reduction rate which shows the number of idle cylinders per unit time according to the fuel remaining amount in the said fuel tank. The fuel injection control device described.   The cylinder reduction execution means stops the combustion in all the cylinders and stops the engine by a predetermined amount before the remaining amount of fuel in the fuel tank decreases so that the fuel cannot be supplied to the fuel injection valve. The fuel injection control device according to claim 10, which is to be stopped. The engine system includes an informing means for informing a driver that a fuel remaining amount in the fuel tank is approaching a fuel shortage,
The fuel injection control device according to any one of claims 1 to 11, wherein the reduced-cylinder control execution unit activates the notification unit in accordance with the execution of the reduced-cylinder control. The engine system includes an informing means for informing a driver that a fuel remaining amount in the fuel tank is approaching a fuel shortage,
The fuel injection control device according to any one of claims 1 to 11, wherein the reduced-cylinder control execution unit sets one of execution conditions for the reduced-cylinder control that the notification unit is in operation. The fuel injection valve has a first piston and a second piston that can displace the inside of the valve body in the axial direction, and a sealed space sandwiched between the first and second pistons from both sides in the axial direction. A fluid filling chamber formed by being filled with a predetermined fluid, and a needle for opening and closing a nozzle hole corresponding to a fuel injection port that is displaceable in the axial direction,
When a predetermined driving force is received from one end surface side of the first piston, the driving force is transmitted to the second piston located on the other end surface side of the first piston via the fluid filling chamber. 14. The valve according to claim 1, wherein at least one of opening and closing of the nozzle hole is performed by transmitting and displacing the needle in the axial direction inside the valve body based on the transmitted driving force. The fuel injection control device according to any one of claims.   The fuel injection control device according to claim 14, wherein the fuel injection valve receives supply of fuel from a common rail that accumulates fuel. Applied to an in-vehicle engine system that generates energy by burning fuel supplied from a predetermined fuel tank, and that drives the vehicle with the energy,
Vehicle pseudo control for controlling the operating state of the target vehicle in a pseudo fuel deficient state in which the fuel in the fuel tank is deficient prior to the deficiency when the remaining amount of fuel in the fuel tank is close to deficient A fuel injection control device comprising means.   The vehicle simulation control means variably controls the driving state of the target vehicle to a higher similarity state as the pseudo fuel deficiency state according to the fuel remaining amount in the fuel tank. The fuel injection control device described. Applied to an in-vehicle engine system that generates energy by burning fuel supplied from a predetermined fuel tank, and that drives the vehicle with the energy,
Vehicle control limiting means for limiting control of the target vehicle based on the driving operation of the driver until a predetermined condition is satisfied prior to the shortage when the remaining amount of fuel in the fuel tank is short of shortage, A fuel injection control device.   The fuel injection control device according to claim 18, wherein the vehicle control restriction unit variably controls a restriction degree of the vehicle control in accordance with a remaining amount of fuel in the fuel tank. A fuel injection valve for injecting fuel supplied from a predetermined fuel tank;
An engine that burns fuel supplied by the fuel injection valve in a part or all of a plurality of cylinders and converts energy generated by the fuel combustion into mechanical motion;
Fuel remaining amount obtaining means for actually measuring or estimating the fuel remaining amount in the fuel tank;
When the remaining amount of fuel acquired by the remaining fuel amount acquiring means is within a predetermined range close to deficiency, the combustion in the remaining cylinders is stopped while the combustion in the remaining cylinders is stopped. Reduced-cylinder control execution means for forcibly executing reduced-cylinder control that is control for operating the engine;
A fuel injection control system comprising:

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