JP2007192198A - Fuel supply device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel supply device for an internal combustion engine allowing a worker to grasp its operation condition securely to control supply of fuel to be suitable for the operation condition of the fuel supply device. <P>SOLUTION: An ECU detects a driving current value and a driving voltage value of a DC motor for driving a fuel pump (step S110) and calculates pressure and amount of discharge of fuel fed from the fuel pump under pressure based on the detected driving current value and driving voltage value (step S120). The ECU diagnoses an operation condition of the fuel supply device based on the pressure and the amount of discharge of fuel (step S130). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fuel supply device that injects and supplies fuel to an internal combustion engine.

  2. Description of the Related Art Conventionally, a fuel supply device for an internal combustion engine is configured to pump fuel stored in a fuel tank to a fuel injection valve by a fuel pump and to inject and supply the pumped fuel from the fuel injection valve to the internal combustion engine. . Such a fuel supply device regulates the pressure of the fuel supplied to the fuel injection valve to a predetermined pressure by returning a part of the fuel pumped from the fuel pump to the combustion tank via the pressure regulator, and also the fuel injection valve. The amount of fuel supplied to the internal combustion engine is controlled by the valve opening time.

  By the way, in such a fuel supply device, when the amount of fuel pumped from the fuel pump with respect to the required fuel amount of the engine becomes excessive, the fuel returned from the pressure regulator to the fuel tank increases and the energy for supplying the fuel is increased. Efficiency is reduced. Further, since the fuel returned to the fuel tank is heated by the engine and becomes high in temperature, a large amount of fuel evaporative gas is generated in the fuel tank. For this reason, the amount of fuel supplied to the engine via the fuel evaporative gas treatment device using the canister increases, and the concentration of unburned components contained in the exhaust gas may increase due to the rich air-fuel ratio, which may deteriorate emissions. is there. On the other hand, if the amount of fuel pumped from the fuel pump is too small relative to the required fuel amount of the engine, the fuel injection amount from the fuel injection valve becomes insufficient, and misfiring may occur due to the lean air-fuel ratio. If misfire occurs, the concentration of oxygen contained in the exhaust gas increases and the oxidation of the catalytic converter is promoted, and the catalytic converter may generate heat and melt.

Therefore, in order to adjust the amount of fuel pumped from the fuel pump according to the required fuel amount of the engine, a fuel supply device has been proposed in which the drive voltage value of the fuel pump is controlled according to the engine operating state. (For example, refer to Patent Document 1).
JP-A-7-189843

  By the way, the fuel supply device that controls the drive voltage value of the fuel pump as described above may not supply a desired amount of fuel to the fuel injection valve depending on its operating state. For example, in the case where the flow rate of the fuel returned from the pressure regulator to the fuel tank is lower than the set flow rate due to an abnormality of the pressure regulator, the amount of fuel supplied to the fuel injection valve is excessive. May be. On the other hand, when the flow rate of the fuel returned from the pressure regulator to the fuel tank increases more than the set flow rate, the amount of fuel supplied to the fuel injection valve may be too small.

  As described above, there is a case where the amount of fuel pumped from the fuel pump cannot be adjusted appropriately only by controlling the drive voltage value, and it is difficult to perform fuel supply control in accordance with the operating state of the fuel supply device. For this reason, the problem of exhaust performance, such as the deterioration of the emission resulting from the excessive supply of fuel and the melting damage of the catalytic converter due to the insufficient supply of fuel, still remains. Further, when the amount of fuel supplied to the fuel injection valve becomes too small, the required fuel amount may not be supplied to the internal combustion engine, which may deteriorate the operability of the internal combustion engine.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide an internal combustion engine capable of reliably grasping the operation state in order to perform fuel supply control in accordance with the operation state of the fuel supply device. It is to provide a fuel supply device.

  In order to achieve the above object, an invention according to claim 1 includes a fuel injection mechanism that injects fuel into an internal combustion engine, a fuel pump that pumps fuel stored in a fuel tank to the fuel injection mechanism, and In a fuel supply device for an internal combustion engine comprising a pressure regulating mechanism for regulating the pressure of fuel in a fuel injection mechanism, driving value detecting means for detecting a driving current value and a driving voltage value of the fuel pump, and the detected The fuel pressure and the fuel discharge amount of the fuel pumped from the fuel pump are calculated from the drive current value and the drive voltage value, and the operation state of the fuel supply device is diagnosed based on the fuel pressure and the fuel discharge amount. The gist is to provide diagnostic means.

  According to this configuration, the fuel pressure and the fuel discharge amount of the fuel pumped from the fuel pump are calculated from the drive current value and the drive voltage value of the fuel pump detected by the drive value detecting means, and the calculated fuel The operating state of the fuel supply device is diagnosed based on the pressure and the fuel discharge amount. By detecting the drive current value and drive voltage value of the fuel pump in this way, it is possible to determine the load applied to the fuel pump and the rotational speed thereof, so that the fuel pressure corresponding to the load and the fuel discharge amount corresponding to the rotational speed And can be calculated. Since the fuel pressure and the fuel discharge amount can be grasped, it is possible to diagnose the operating state of the pressure regulating mechanism, the fuel pump, and the like. For example, in a state where the fuel pressure is decreasing despite the increase in the fuel discharge amount, the pressure regulation value becomes low due to the valve closing operation failure of the pressure regulator constituting the pressure regulation mechanism. Abnormalities such as being can be diagnosed. Further, if the fuel pressure is rising despite the decrease in the fuel discharge amount, an abnormality such as clogging of a pipe for supplying fuel can be diagnosed. In this way, the fuel pressure decreases even though the fuel discharge amount increases, and the fuel pressure increases and the fuel pressure increases despite the fuel discharge amount decreasing. Thus, it is possible to diagnose an abnormal operation of the fuel supply apparatus from a state where the fuel is excessively supplied.

  In the case of detecting either the drive current value or the drive voltage value, it is impossible to grasp both the fuel pressure and the fuel discharge amount. I can't. In this regard, by calculating the fuel pressure and the fuel discharge amount from the drive current value and the drive voltage value as described above, it is possible to reliably diagnose the operating state of the fuel supply device. For this reason, it is possible to suitably diagnose an abnormal operation of the fuel supply apparatus in which the fuel pumped from the fuel pump is undersupplied or oversupplied.

  According to a second aspect of the present invention, in the fuel supply apparatus for an internal combustion engine according to the first aspect, when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal, the fuel by the fuel injection mechanism The gist of the invention is to further include a control means for stopping the injection.

  According to this configuration, when it is diagnosed that the operating state of the fuel supply device is abnormal, the fuel injection by the fuel injection mechanism is stopped and the internal combustion engine is stopped, so that the fuel is undersupplied or oversupplied. It is possible to avoid the internal combustion engine from being operated in such a state. For this reason, while suppressing the deterioration of the operability of the internal combustion engine due to the fact that the required fuel amount is not supplied to the internal combustion engine, the deterioration of the emission due to the excessive supply of fuel, the melting damage of the catalytic converter due to the insufficient supply of fuel, etc. The deterioration of the exhaust performance can be suppressed.

  According to a third aspect of the present invention, in the fuel supply apparatus for an internal combustion engine according to the first aspect, when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal, the fuel of the fuel injection mechanism The gist of the invention is that it further comprises a control means for correcting the injection time.

  According to this configuration, when the operating state of the fuel supply device is diagnosed to be abnormal, the fuel injection time of the fuel injection mechanism is corrected. The fuel supply device can be controlled so as to obtain an appropriate fuel injection amount by shortening the fuel injection time in a state where the fuel is excessively supplied in a state where the fuel is excessively supplied.

  According to a fourth aspect of the present invention, in the fuel supply apparatus for an internal combustion engine according to the first aspect, when the diagnostic means diagnoses that the operating state of the fuel supply apparatus is abnormal, the drive voltage of the fuel pump The gist of the invention is to further include a control means for correcting the value.

  According to this configuration, when the operating state of the fuel supply device is diagnosed to be abnormal, the drive voltage value is increased in a state where the fuel supply is insufficient in order to correct the drive voltage value of the fuel pump. Thus, in a state where the fuel discharge amount from the fuel pump is increased and the fuel is excessively supplied, the drive voltage value can be lowered to reduce the fuel discharge amount from the fuel pump. For this reason, even when the operation of the fuel supply device is abnormal, the fuel supply device can be controlled so that the amount of fuel supplied to the fuel injection mechanism becomes an appropriate amount of fuel.

  According to a fifth aspect of the present invention, in the fuel supply device for an internal combustion engine according to the first aspect, when the diagnosis means diagnoses that the operating state of the fuel supply device is abnormal, the intake air amount of the internal combustion engine The gist of the invention is that it further comprises a control means for correcting the opening of the throttle valve for adjusting the opening.

  According to this configuration, when it is diagnosed that the operating state of the fuel supply device is abnormal, the opening of the throttle valve that adjusts the intake air amount of the internal combustion engine is corrected. For this reason, in the case where the fuel supply is insufficient and the fuel injection amount is insufficient, by reducing the intake air amount by reducing the opening of the throttle valve, the lean air-fuel ratio is suppressed and the catalyst is reduced. It is possible to suppress melting damage of the converter.

  According to a sixth aspect of the present invention, in the fuel supply device for an internal combustion engine according to any one of the third to fifth aspects, the operating means of the fuel supply device is controlled by the diagnostic means even by the correction. When diagnosing an abnormality, the gist is to stop fuel injection by the fuel injection mechanism.

  According to this configuration, when it is diagnosed that the operating state of the fuel supply device is abnormal by correcting the fuel injection time of the fuel injection mechanism, correcting the drive voltage value of the fuel pump, or correcting the opening of the throttle valve. Then, the fuel injection by the fuel injection mechanism is stopped to stop the internal combustion engine. For this reason, when it is not possible to avoid an abnormal operation of the fuel supply device, it is possible to suppress adverse effects on exhaust performance and the like due to insufficient supply or excessive supply of fuel.

(First embodiment)
Hereinafter, a first embodiment in which a fuel supply device for an internal combustion engine according to the present invention is embodied will be described with reference to FIGS.

  FIG. 1 is a configuration diagram of a gasoline engine (hereinafter simply referred to as an engine) equipped with a fuel supply device. An engine 11 as an internal combustion engine includes a cylinder block 13 having a plurality of cylinders 12, and a piston 14 is provided in each cylinder 12 so as to be capable of reciprocating. The piston 14 is connected via a connecting rod 15 to a crankshaft 16 provided at the lower part of the engine 11. The reciprocating motion of the piston 14 is converted into the rotational motion of the crankshaft 16 by the connecting rod 15.

  A cylinder head 17 is provided on the top of the cylinder block 13. A combustion chamber 18 is formed by a space surrounded by the bottom surface of the cylinder head 17 and the upper end surface of the piston 14. An intake port 20 and an exhaust port 21 are formed in the cylinder head 17 so as to communicate with the combustion chamber 18. Further, the cylinder head 17 is provided with an intake valve 22 and an exhaust valve 23 for opening and closing the intake port 20 and the exhaust port 21, respectively, so as to be able to reciprocate. By opening and closing the intake valve 22 and the exhaust valve 23, the intake port 20, the exhaust port 21 and the combustion chamber 18 are communicated and blocked.

  An intake passage 25 having a throttle valve 24 is connected to the intake port 20. Air outside the engine 11 is sucked into the combustion chamber 18 through the intake port 20, the intake passage 25, and the like. The throttle valve 24 is rotatably provided in the intake passage 25 and is driven by an actuator 26 formed of an electric motor or the like. The amount of intake air flowing through the intake passage 25 is adjusted according to the opening of the throttle valve 24. An exhaust passage 27 is connected to the exhaust port 21, and a catalytic converter 28 for purifying harmful components in the exhaust is provided in the middle of the exhaust passage 27. Exhaust gas generated in the combustion chamber 18 is discharged to the outside of the engine 11 through the exhaust port 21, the exhaust passage 27, and the like.

  The cylinder head 17 is provided with an electromagnetic fuel injection valve 29. The fuel injection valve 29 is opened by energization and injects and supplies fuel to the intake port 20. The fuel injected from the fuel injection valve 29 is mixed with air to become an air-fuel mixture and is sucked into the combustion chamber 18. The cylinder head 17 is provided with a spark plug 30 that ignites the air-fuel mixture in the combustion chamber 18.

  The fuel supply device 31 includes a fuel injection mechanism 32 that injects and supplies fuel to the intake port 20, a fuel pump 34 that pumps fuel stored in the fuel tank 33 to the fuel injection mechanism 32, and fuel in the fuel injection mechanism 32. And a pressure adjusting mechanism 35 that adjusts the pressure.

  The fuel tank 33 stores fuel supplied to the intake port 20. The fuel pump 34 is provided in the fuel tank 33, draws fuel in the fuel tank 33, and is a fuel injection composed of a delivery pipe 38 and a fuel injection valve 29 via a supply path 37 provided with a filter 36. Fuel is pumped to mechanism 32. The fuel pump 34 is driven by a DC motor 39 such as a DC brush motor. The DC motor 39 is connected to the battery 41 via the driver 40 and is driven and controlled via the driver 40.

  A pressure regulator 42 is connected to the downstream side of the delivery pipe 38. The pressure regulator 42 returns the fuel in the delivery pipe 38 to the fuel tank 33 through the return passage 43 when the pressure of the fuel in the delivery pipe 38 reaches a certain value or more. The pressure of the fuel in the delivery pipe 38 is regulated by the pressure regulating mechanism 35 constituted by the pressure regulator 42 and the reflux passage 43.

  The engine 11 is provided with various sensors for detecting the engine operating state. For example, the rotational speed sensor 51 detects the rotational speed of the crankshaft 16, and the throttle sensor 52 detects the opening of the throttle valve 24. Further, the amount of air sucked into the combustion chamber 18 is detected by an intake air amount sensor 53 provided in the intake passage 25, and the air-fuel ratio state is detected by an oxygen concentration sensor 54 provided in the exhaust passage 27. Further, a drive current value and a drive voltage value of the DC motor 39 that drives the fuel pump 34 are detected by a fuel pump drive value sensor 55 as a drive value detection means provided in the driver 40.

  Various controls of the engine 11 are performed by the ECU 61. The ECU 61 is configured around a microcomputer, and the detection signals of the respective sensors of the engine 11 are taken in, respectively. Based on these detection signals, the central processing unit of the ECU 61 performs arithmetic processing according to programs, control data, and the like stored in the memory, and performs various controls based on the calculation results. For example, the driving of the spark plug 30 and the fuel injection valve 29 is controlled based on the engine operating state detected by the sensors and the like. Further, the target opening value of the throttle valve 24 is set based on the depression amount of the accelerator pedal, and the opening degree control of the throttle valve 24 is performed so as to become the set target opening value.

  Next, an operation in which the fuel supply device 31 supplies the fuel in the fuel tank 33 to the intake port 20 will be described. The operation of the fuel supply device 31 is controlled by the ECU 61. The ECU 61 controls the amount of fuel supplied from the fuel tank 33 to the fuel injection mechanism 32 according to the engine operating state, and performs valve opening control of the fuel injection valve 29.

  The ECU 61 calculates the required fuel amount to be injected from the fuel injection valve 29 based on the detected value of the intake air amount by the intake air amount sensor 53 and the detected value by the rotational speed sensor 51 that detects the rotational speed of the crankshaft 16. . The ECU 61 controls the drive of the fuel pump 34 so that the pressure of the fuel in the delivery pipe 38 becomes a desired pressure from the calculated required fuel amount. For example, when the required fuel amount of the engine is large, the drive voltage value applied to the DC motor 39 that drives the fuel pump 34 is set high to increase the fuel discharge amount pumped from the fuel pump 34, and the delivery pipe The fuel pressure in 38 is maintained. The pressure of the fuel in the delivery pipe 38 is also regulated by the pressure regulating mechanism 35, and when the fuel pressure becomes excessive, the fuel is recirculated to the fuel tank 33. Therefore, the ECU 61 has an excessive amount of fuel to be recirculated. The drive of the fuel pump 34 is controlled so as not to occur. Then, the ECU 61 controls the valve opening time of the fuel injection valve 29, that is, the fuel injection time, according to the required fuel amount, and injects and supplies the fuel corresponding to the fuel injection time to the intake port 20.

  In this manner, the ECU 61 controls the drive voltage value of the DC motor 39 and the fuel injection time of the fuel injection valve 29, and supplies an appropriate amount of fuel from the fuel tank 33 to the fuel injection valve 29 according to the engine operating state. While supplying, an appropriate amount of fuel is injected and supplied from the fuel injection valve 29.

  By the way, in the fuel supply device 31 controlled as described above, when the fuel pressure adjustment function by the pressure adjustment mechanism 35 does not work normally, or when the fuel supply capability by the fuel pump 34 is reduced, etc., delivery is performed. There are times when the fuel pressure in the pipe 38 cannot be controlled to a desired pressure. For example, if the valve closing operation of the pressure regulator 42 becomes defective and the amount of fuel recirculated to the fuel pump 34 through the recirculation passage 43 increases, the delivery pipe can be increased even if the amount of fuel discharged from the fuel pump 34 is increased. The fuel pressure in 38 does not increase. In such a case, since the pressure applied to the fuel injection mechanism 32 is too low, there is a possibility that a sufficient amount of fuel supplied from the fuel injection valve 29 to the intake port 20 cannot be secured. Therefore, the ECU 61 grasps the operating state of the fuel supply device 31 and performs the following control in order to supply fuel according to the operating state.

  The flowchart in FIG. 2 shows a fuel supply control routine performed by the ECU 61. The ECU 61 repeats this fuel supply control routine at every predetermined timing when the engine 11 is in operation.

  When the fuel supply control routine is started, the ECU 61 acquires each sensor value (step S110). In this step, the ECU 61 detects the drive current value and drive voltage value of the DC motor 39 detected from the fuel pump drive value sensor 55, the intake air amount detected from the intake air amount sensor 53, and the rotation speed sensor 51. The rotation speed of the crankshaft 16 to be obtained is acquired.

  Next, the ECU 61 as diagnostic means calculates the fuel pressure P and the fuel discharge amount Q of the fuel pumped from the fuel pump 34 from the detected drive current value and drive voltage value of the DC motor 39. (Step S120). FIG. 3 is a characteristic diagram showing the relationship between the torque and the rotational speed of the DC motor 39 (TN characteristic) and the relationship between the torque and the drive current (TI characteristic). The torque T of the DC motor 39 is substantially proportional to the drive current I, and the rotational speed N of the DC motor 39 increases with the drive voltage V and decreases with the increase of the torque T. That is, using this characteristic diagram, the torque T of the DC motor 39 can be obtained from the drive current I, and the rotational speed N of the DC motor 39 can be obtained from the drive voltage V. For example, when the drive current value A and the drive voltage value B of the DC motor 39 are detected, the torque value C is obtained from the drive current value A. Then, a corresponding characteristic diagram of the TN characteristic is selected from the drive voltage value B, and the rotational speed D is obtained from the torque value C. The ECU 61 converts the fuel pressure P of the fuel pumped from the fuel pump 34 from the torque value C, that is, a load applied to the fuel pump 34, and converts the fuel discharge amount Q from the fuel pump 34 into the rotational speed D, that is, the fuel pump 34. Convert from the number of rotations. Then, the fuel pressure P and the fuel discharge amount Q of the fuel pumped from the fuel pump 34 are calculated. Further, the ECU 61 calculates a required fuel amount to be injected from the fuel injection valve 29 from the intake air amount sucked into the combustion chamber 18 and the rotational speed of the crankshaft 16.

  Next, the ECU 61 as a diagnosis unit diagnoses the operating state of the fuel supply device 31 from the fuel pressure P, the fuel discharge amount Q, and the required fuel amount calculated in step S120 (step S130). In this step, an appropriate fuel discharge amount is pumped from the fuel pump 34 with respect to the required fuel amount to be supplied to the fuel injection mechanism 32, and the fuel pressure in the delivery pipe 38 becomes an appropriate pressure. The operating state of the fuel supply device 31 is diagnosed from the point of whether or not

  FIG. 4 shows a relationship diagram between the fuel discharge amount Q pumped from the fuel pump 34 and the fuel pressure P. The fuel discharge amount Q and the fuel pressure P basically have a proportional relationship, and the fuel pressure P increases as the fuel discharge amount Q increases. When the operating state of the fuel pump 34 is in the region X, it indicates that the fuel supply device 31 is operating normally because the fuel discharge amount Q and the fuel pressure P have a substantially proportional relationship. That is, when in the region X, an appropriate fuel discharge amount is pumped from the fuel pump 34 in accordance with the required fuel amount, and the fuel pressure in the delivery pipe 38 is controlled to an appropriate pressure. .

  On the other hand, when the operating state of the fuel pump 34 is in the region Y, the driving current value of the DC motor 39 is relatively low and the driving voltage value is relatively high. This shows a state where the fuel pressure P is low. That is, when in the region Y, since the fuel pressure P is decreasing despite the increase in the fuel discharge amount Q, the fuel pumped to the fuel injection mechanism 32 is undersupplied. It shows that. As a cause of the excessive supply of fuel in this way, there are a case where the valve closing operation of the pressure regulator 42 is abnormal, a case where the fuel supply capacity of the fuel pump 34 is lowered, and the like. When the valve closing operation of the pressure regulator 42 is abnormal, for example, when the pressure regulator 42 is kept open, even if the fuel discharge amount Q from the fuel pump 34 is increased, the fuel pump 34 via the return passage 43 is increased. Therefore, the fuel that is recirculated also increases, so that the required fuel pressure cannot be maintained by the delivery pipe 38, and the fuel is undersupplied. Further, when the fuel supply capacity of the fuel pump 34 is reduced, the fuel discharge amount Q is insufficient with respect to the rotation speed of the fuel pump 34, so that the required fuel pressure cannot be maintained by the delivery pipe 38. , The fuel is undersupplied.

  The operating state of the fuel pump 34 is in the region Z when the driving current value of the DC motor 39 is relatively high and the driving voltage value is relatively low, and the fuel pressure with respect to the fuel discharge amount Q. The state where P is high is shown. That is, when in the region Z, the fuel pressure P is increasing despite the fuel discharge amount Q being decreased, so the fuel pumped to the fuel injection mechanism 32 is excessively supplied. It shows that. As a cause of excessive supply of fuel in this way, there are a case where the valve opening operation of the pressure regulator 42 is abnormal, a case where the recirculation passage 43 is clogged, or the like. When the valve opening operation of the pressure regulator 42 is abnormal, for example, when the pressure regulator 42 is kept closed or when the recirculation passage 43 is clogged, the fuel discharge amount Q from the fuel pump 34 can be reduced. Further, the fuel recirculated to the fuel pump 34 through the recirculation passage 43 further decreases. For this reason, fuel exceeding the required fuel amount is supplied to the delivery pipe 38, and the fuel is in an excessive supply state.

  As described above, the ECU 61 diagnoses the operation state of the fuel supply device 31 based on the operation state of the fuel pump 34. When the operation state of the fuel pump 34 is in the region X, it is diagnosed that the fuel supply control is normally performed. When the operation state of the fuel pump 34 is in the region Y or the region Z, the fuel supply is insufficient. Or diagnose that there is an oversupply.

  Next, the ECU 61 determines whether or not the operating state of the fuel supply device 31 is abnormal from the diagnosis result of step S130 (step S140). That is, when the operating state of the fuel pump 34 is in the region Y or the region Z, it is determined that the operating state of the fuel supply device 31 is abnormal because the fuel is under-supplied or over-supplied, and the fuel pump 34 When the operating state is in the region X, it is determined that the operating state of the fuel supply device 31 is normal.

  When it is determined that the operating state of the fuel supply device 31 is abnormal, the ECU 61 serving as the control unit stops fuel injection by the fuel injection valve 29 (step S150). When the operating state of the fuel supply device 31 is abnormal, the ECU 61 stops the fuel injection and stops the engine in order to prevent the operation of the engine 11 from being continued in a state where the fuel is insufficiently supplied or excessively supplied. 11 is stopped. Then, processing such as notifying that the fuel supply device 31 is abnormal by a warning light is performed, and this routine is terminated. In step S140, when it is not determined that the operating state of the fuel supply device 31 is abnormal, this routine is ended as it is.

  As described above, the ECU 61 diagnoses the operating state of the fuel supply device 31 based on the drive current value and drive voltage value of the DC motor 39 detected from the fuel pump drive value sensor 55. When the operating state of the fuel supply device 31 is abnormal, the fuel injection by the fuel injection mechanism 32 is stopped and the engine 11 is stopped. Thus, the operating state of the fuel supply device 31 is accurately diagnosed, and the operation of the engine 11 is prevented from being continued in a state where the fuel is undersupplied or excessively supplied.

According to the fuel supply device of the first embodiment, the following effects can be obtained.
(1) In the first embodiment, the fuel pressure P and the fuel discharge amount Q of the fuel pumped from the fuel pump 34 from the drive current value and drive voltage value of the DC motor 39 detected from the fuel pump drive value sensor 55. And the operating state of the fuel supply device 31 is diagnosed based on the calculated fuel pressure P and fuel discharge amount Q. When the drive current value and the drive voltage value of the fuel pump 34 are detected in this way, the load applied to the fuel pump 34 and the number of rotations thereof can be obtained. Therefore, the fuel pressure P of the fuel pumped from the fuel pump and the fuel The discharge amount Q can be calculated. Based on the relationship between the fuel pressure P and the fuel discharge amount Q, the pressure control function of the pressure control mechanism 35 and the operation state such as the fuel supply capacity of the fuel pump 34 can be diagnosed. For this reason, the operation state of the fuel supply device 31 can be diagnosed more accurately than in the case where either one of the drive current value and the drive voltage value is detected.

  Further, in order to diagnose the operation state of the fuel supply device 31 from the fuel pressure P and the fuel discharge amount Q, an abnormal operation of the fuel supply device 31 such that the fuel pumped from the fuel pump 34 is undersupplied or oversupplied. Diagnosis can be suitably performed.

  Further, since the operating state of the fuel supply device 31 can be diagnosed based on the drive current value and the drive voltage value of the DC motor 39, a fuel pressure sensor for detecting the fuel pressure in the delivery pipe 38 becomes unnecessary, and the fuel supply device. The configuration of 31 can be simplified and the cost can be reduced.

  (2) In the first embodiment, when it is determined that the operating state of the fuel supply device 31 is abnormal, the fuel injection by the fuel injection valve 29 is stopped and the engine 11 is stopped. It can be avoided that the engine 11 is operated in a state of excessive supply. For this reason, it is possible to suppress the deterioration of the operability of the engine 11 due to the required fuel amount not being supplied to the combustion chamber 18. Further, it is possible to suppress the deterioration of the exhaust performance such as the deterioration of the emission caused by the excessive supply of fuel and the melting damage of the catalytic converter 28 caused by the insufficient supply of fuel.

(Second Embodiment)
Next, a second embodiment in which the internal combustion engine fuel supply apparatus according to the present invention is embodied will be described with reference to FIG. This second embodiment differs from the first embodiment only in the process of the fuel supply control routine shown in FIG. In the embodiments described below, the same components as those in the first embodiment are denoted by the same reference numerals, and redundant descriptions thereof are omitted or simplified.

  FIG. 5 shows a flowchart of the fuel supply control routine. The processing from step S110 to step S140 in the flowchart of FIG. 5 is the same as the flowchart of FIG. Here, processing after step S140 different from the flowchart of FIG. 2 will be described.

  When it is determined that the operating state of fuel supply device 31 is abnormal (YES in step S140), ECU 61 as the control means corrects the drive voltage value of DC motor 39 (step S210). In this step, when the fuel supply device 31 is in an operation state in which the fuel is undersupplied or oversupplied, a process for correcting the drive voltage value of the DC motor 39 so that the fuel discharge amount Q approaches an appropriate amount. I am doing. That is, when the fuel supply is insufficient, the drive voltage value is corrected so as to increase. As a result, the TN characteristic shown in FIG. 2 moves in the direction in which the rotational speed N increases, so that the fuel discharge amount Q of the fuel pump 34 increases. On the other hand, when the fuel is excessively supplied, the drive voltage value is corrected so as to decrease, and the fuel discharge amount Q of the fuel pump 34 is decreased. If the fuel is excessively supplied, a period for stopping the fuel pump 34 by setting the drive voltage value to 0 may be provided. Then, the ECU 61 diagnoses the operating state of the fuel supply device 31 again (step S220). The diagnosis in step S220 is performed by the same method as in step S130.

  Next, the ECU 61 determines whether or not the operating state of the fuel supply device 31 is abnormal from the diagnosis result of step S220 (step S230). The voltage value that can be applied to the DC motor 39 is limited in terms of the power supply conditions of the battery 41 and the like and the reliability of the DC motor 39. For this reason, even when the drive voltage value of the DC motor 39 is corrected, when the fuel is undersupplied or excessively supplied, it is determined that the operating state of the fuel supply device 31 is abnormal. If it is not determined that the operating state of the fuel supply device 31 is abnormal, it is assumed that the retreating from the abnormal operation can be performed by correcting the driving voltage value of the DC motor 39, and this routine is continued. Exit.

  In step S230, when it is determined that the operating state of the fuel supply device 31 is abnormal, the ECU 61 as the control unit corrects the fuel injection time of the fuel injection valve 29 (step S240). In this step, even when the drive voltage value of the DC motor 39 is corrected, when the fuel is undersupplied or oversupplied, the fuel injection time of the fuel injection valve 29 is corrected so that the fuel injection amount approaches an appropriate amount. Is doing the right thing. That is, when the fuel is undersupplied, correction is made so that the fuel injection time becomes long, and when the fuel is oversupplied, correction is made so that the fuel injection time becomes short. Then, the ECU 61 diagnoses the operating state of the fuel supply device 31 again (step S250). The diagnosis in step S250 is performed by the same method as in step S130.

  Next, the ECU 61 determines whether or not the operating state of the fuel supply device 31 is abnormal from the diagnosis result of step S250 (step S260). There is a limit to the fuel injection time of the fuel injection valve 29 that can be corrected, and this limit also varies depending on the engine operating state such as the engine speed. For this reason, even when the fuel injection time is corrected, when the fuel is insufficiently supplied or excessively supplied, it is determined that the operating state of the fuel supply device 31 is abnormal. Then, when it is not determined that the operation state of the fuel supply device 31 is abnormal, it is assumed that the retreating operation from the operation abnormality can be performed by correcting the fuel injection time, and this routine is ended as it is.

  When it is determined in step S260 that the operating state of the fuel supply device 31 is abnormal, the ECU 61 as the control means corrects the opening of the throttle valve 24 (step S270). In this step, even when the fuel injection time is corrected, when the fuel is undersupplied or excessively supplied, the opening of the throttle valve 24 is corrected so that the air-fuel mixture in the combustion chamber 18 approaches the stoichiometric air-fuel ratio. I am doing. For example, when the fuel supply is insufficient and the fuel injection amount is insufficient, the opening of the throttle valve 24 is decreased to reduce the intake air amount. Thereby, leaning of the air-fuel ratio is suppressed, and melting loss of the catalytic converter 28 is suppressed.

  Then, the ECU 61 corrects the opening degree of the throttle valve 24 to determine whether or not the air-fuel ratio detected from the oxygen concentration sensor 54 is within an allowable range (step S280). When the air-fuel ratio falls within the allowable range, the exhaust performance can be prevented from deteriorating, so this routine is terminated as it is.

  If it is determined in step S280 that the air-fuel ratio is not within the allowable range, the fuel injection by the fuel injection valve 29 is stopped (step S290). If the air-fuel ratio does not fall within the allowable range even by correcting the opening of the throttle valve 24, the fuel injection is stopped and the engine 11 is stopped in order to suppress adverse effects on the exhaust performance. Then, processing such as notifying that the fuel supply device 31 is abnormal by a warning light is performed, and this routine is terminated.

  As described above, the ECU 61 diagnoses the operating state of the fuel supply device 31 based on the drive current value and drive voltage value of the DC motor 39 detected from the fuel pump drive value sensor 55. When the operating state of the fuel supply device 31 is abnormal, the correction of the drive voltage value of the DC motor 39, the correction of the fuel injection time of the fuel injection valve 29, and the opening of the throttle valve 24 are corrected. Perform evacuation procedure. When the operating state of the fuel supply device 31 and the operating state of the engine 11 cannot be improved even by these evacuation measures, the fuel injection is stopped and the engine 11 is stopped.

According to the fuel supply device of the second embodiment, in addition to the effect (1) of the first embodiment, the following effects can be obtained.
(3) In the second embodiment, when it is determined that the operating state of the fuel supply device 31 is abnormal, the drive voltage value of the DC motor 39 is corrected. For this reason, the drive voltage value is increased to increase the amount of fuel discharged from the fuel pump 34 in a state where the fuel is undersupplied, and the drive voltage value is decreased to reduce the fuel in a state where the fuel is excessively supplied. The amount of fuel discharged from the pump 34 can be reduced. Therefore, even when the operation of the fuel supply device 31 is abnormal, the fuel supply device 31 can be controlled so that the amount of fuel supplied to the fuel injection mechanism 32 becomes an appropriate amount of fuel.

  (4) In the second embodiment, the fuel injection time of the fuel injection valve 29 is corrected when it is determined that the operating state of the fuel supply device 31 is abnormal. For this reason, the fuel injection time is increased in a state where the fuel is undersupplied, and the fuel injection time is shortened in a state where the fuel is excessively supplied, so that an appropriate fuel injection amount is obtained. The fuel supply device 31 can be controlled.

  (5) In the second embodiment, the opening degree of the throttle valve 24 is corrected when it is determined that the operating state of the fuel supply device 31 is abnormal. For this reason, in the case where the fuel supply is insufficient and the fuel injection amount is insufficient, the opening of the throttle valve 24 is reduced to reduce the intake air amount, thereby suppressing the lean air-fuel ratio. The melting loss of the catalytic converter 28 can be suppressed.

  (6) In the second embodiment, the operating state of the fuel supply device 31 is also abnormal by correcting the driving voltage value of the DC motor 39, correcting the fuel injection time of the fuel injection valve 29, and correcting the opening of the throttle valve 24. When a diagnosis is made, the fuel injection by the fuel injection valve 29 is stopped and the engine 11 is stopped. For this reason, when the abnormal operation of the fuel supply device 31 cannot be avoided, it is possible to prevent the engine 11 from being operated in a state where the fuel is insufficiently supplied or excessively supplied. Therefore, it is possible to suppress the deterioration of the exhaust performance such as the deterioration of the emission caused by the excessive supply of fuel and the melting damage of the catalytic converter 28 caused by the insufficient supply of fuel.

In addition, you may change the said embodiment as follows.
In the first and second embodiments, the fuel injection mechanism 32 is configured to inject and supply fuel to the intake port 20. However, the fuel is directly injected into the combustion chamber 18 or the fuel is supplied to the combustion chamber 18. And a fuel injection mechanism of a type that supplies fuel to both the intake port 20 and the intake port 20.

  In the first and second embodiments, the fuel stored in the fuel tank 33 is pumped to the fuel injection mechanism 32 by one fuel pump 34, but fuel is injected using a plurality of fuel pumps. You may make it pressure-feed to a mechanism. A fuel supply device using a plurality of fuel pumps can also perform fuel supply control by diagnosing the operating state of the fuel supply device using the same principle as in the above embodiment.

  In the first and second embodiments, the operating state of the fuel supply device 31 is diagnosed based on the drive current value and drive voltage value of the DC motor 39 detected from the fuel pump drive value sensor 55. The operation state of the fuel supply device 31 may be diagnosed by using a sensor such as a fuel pressure sensor for detecting the pressure of the fuel in the delivery pipe 38.

  In the first and second embodiments, the fuel pump 34 is driven by the DC motor 39, but the fuel pump 34 may be driven by an actuator other than the DC motor. Even if an actuator other than a DC motor is used, the fuel supply control can be performed by diagnosing the operating state of the fuel supply device using the same principle as in the above embodiment.

  In the second embodiment, when it is determined that the operation state of the fuel supply device 31 is abnormal, the correction of the drive voltage value of the DC motor 39, the correction of the fuel injection time of the fuel injection valve 29, the throttle valve 24 Although the fuel supply control is performed so as to correct the opening, the fuel supply control may be performed so that only one or two of these corrections are performed.

The block diagram of the engine carrying a fuel supply apparatus. The flowchart of a fuel supply control routine. The characteristic diagram which shows the relationship between the torque of a DC motor, and rotation speed, and the relationship between a torque and a drive current. The relationship figure of the fuel discharge amount and fuel pressure pumped from a fuel pump. The flowchart of the fuel supply control routine in 2nd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Engine, 18 ... Combustion chamber, 24 ... Throttle valve, 28 ... Catalytic converter, 29 ... Fuel injection valve, 31 ... Fuel supply device, 32 ... Fuel injection mechanism, 33 ... Fuel tank, 34 ... Fuel pump, 35 ... Adjustment Pressure mechanism, 38 ... delivery pipe, 39 ... DC motor, 40 ... driver, 42 ... pressure regulator, 51 ... rotational speed sensor, 52 ... throttle sensor, 53 ... intake air amount sensor, 54 ... oxygen concentration sensor, 55 ... fuel pump Drive value sensor, 61... ECU.

Claims (6)

A fuel injection mechanism that injects fuel into the internal combustion engine, a fuel pump that pumps fuel stored in a fuel tank to the fuel injection mechanism, and a pressure adjustment mechanism that regulates the pressure of the fuel in the fuel injection mechanism In a fuel supply device for an internal combustion engine comprising:
Drive value detection means for detecting a drive current value and a drive voltage value of the fuel pump;
A fuel pressure and a fuel discharge amount of fuel pumped from the fuel pump are calculated from the detected drive current value and drive voltage value, and an operation of the fuel supply device is performed based on the fuel pressure and the fuel discharge amount. A fuel supply device for an internal combustion engine, comprising: a diagnosis unit that diagnoses a state. The fuel supply device for an internal combustion engine according to claim 1,
A fuel supply apparatus for an internal combustion engine, further comprising: a control means for stopping fuel injection by the fuel injection mechanism when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal. The fuel supply device for an internal combustion engine according to claim 1,
A fuel supply apparatus for an internal combustion engine, further comprising a control means for correcting a fuel injection time of the fuel injection mechanism when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal. The fuel supply device for an internal combustion engine according to claim 1,
A fuel supply apparatus for an internal combustion engine, further comprising control means for correcting the drive voltage value of the fuel pump when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal. The fuel supply device for an internal combustion engine according to claim 1,
The internal combustion engine further comprising a control unit that corrects an opening degree of a throttle valve that adjusts an intake air amount of the internal combustion engine when the diagnostic unit diagnoses that the operating state of the fuel supply device is abnormal. Fuel supply system. The fuel supply apparatus for an internal combustion engine according to any one of claims 3 to 5,
The control means stops the fuel injection by the fuel injection mechanism when the diagnosis means diagnoses that the operating state of the fuel supply apparatus is abnormal also by the correction. .

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