JP4161746B2 - INJECTION CHARACTERISTICS DETECTING DEVICE FOR FUEL INJECTION VALVE AND FUEL INJECTION CONTROL DEVICE FOR INTERNAL COMBUSTION ENGINE EQUIPPED - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an injection characteristic detection device for a fuel injection valve, and a fuel injection control device for an internal combustion engine equipped with the detection device.
[0002]
[Prior art]
In general, a fuel injection valve that supplies fuel to a cylinder of an internal combustion engine has a response delay from when the drive voltage is applied until the valve opens, and from when the drive voltage is cut to when the valve closes There is also a response delay. Therefore, there is a difference between the drive time of the fuel injection valve, which is the time from when the drive voltage is applied to when it is disconnected, and the time when the fuel is actually injected. Therefore, when calculating the fuel injection time, which is the drive time of the fuel injection valve, usually, a basic fuel injection time corresponding to the fuel injection amount calculated based on the engine load or the like is first calculated, and the basic fuel injection time is calculated as described above. The final fuel injection time is obtained by correcting the response delay. During this final fuel injection time, a desired fuel amount is injected and supplied into the cylinder of the internal combustion engine by applying a voltage to the fuel injection valve. For example, the apparatus disclosed in Patent Document 1 detects the time corresponding to the response delay of the fuel injection valve as follows.
[0003]
That is, if there is a deviation between the target fuel injection amount set according to the engine load and the actual fuel injection amount, a deviation also occurs between the target air-fuel ratio and the actual air-fuel ratio at the time of air-fuel ratio feedback control. . The difference between the target fuel injection amount and the actual fuel injection amount that causes such a deviation in the air-fuel ratio is partly due to the response delay. Therefore, in the apparatus described in the above-mentioned document, it is a coefficient calculated at the time of air-fuel ratio feedback control, and corresponds to the response delay based on a feedback correction coefficient reflecting a tendency of deviation between the target air-fuel ratio and the actual air-fuel ratio. I try to detect time.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 9-100732
[0005]
[Problems to be solved by the invention]
Incidentally, the detection of response delay based on the difference between the target air-fuel ratio and the actual air-fuel ratio as described above has the following problems.
[0006]
That is, the actual air-fuel ratio is detected by an oxygen sensor or the like that detects the oxygen concentration in the exhaust gas. The oxygen concentration in the exhaust gas detected at this time is the average value of the oxygen concentration in the exhaust gas discharged from each cylinder. It has become. Therefore, the detection of the response delay based on the difference between the target air-fuel ratio and the actual air-fuel ratio is merely detecting the average value of the response delay of each fuel injector provided for each cylinder, The response delay for each fuel injection valve is not detected. Therefore, in the conventional apparatus, for example, even if it is necessary to precisely control the amount of fuel provided to each cylinder, it is difficult to realize this.
[0007]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a fuel injection valve capable of accurately detecting a deviation between the drive time and the actual fuel injection time for each individual fuel injection valve. An object of the present invention is to provide an ejection characteristic detection device. Another object of the present invention is to provide a fuel injection control device for an internal combustion engine that includes the same detection device and can accurately correct a deviation between the drive time and the actual fuel injection time.
[0008]
[Means for Solving the Problems]
  The means for achieving the above object and the effects thereof will be described below.
  According to the first aspect of the present invention, the input time of the drive signal and the actual fuel injection time for the fuel injection valve that injects the fuel in the fuel supply system to the internal combustion engine by opening the valve body based on the input of the drive signal. In the device for detecting the deviation ofBy measuring the time from when the drive signal is input to when the fuel pressure in the fuel supply system starts to decrease, out of the difference between the input time and the actual fuel injection time, the input timing of the drive signal and the actual The deviation from the start timing of fuel injectionThis is the gist.
[0009]
  When the fuel injection valve is opened and fuel injection is actually started, the fuel pressure in the fuel piping system to which the fuel injection valve is connected decreases. Further, when the fuel injection valve is closed and the fuel injection is actually ended, the decrease in the fuel pressure is stopped. That is, since the fuel pressure changes corresponding to the opening / closing operation of the valve body, the actual fuel injection time can be measured based on the fuel pressure change. According to the configuration of claim 1 focusing on this point,The actual start timing of fuel injection is detected based on the fuel pressure that decreases as fuel injection starts.Therefore, the difference between the drive signal input time, that is, the fuel injection valve drive time and the actual fuel injection time.Among these, the response delay time from when the drive signal is input to when fuel injection is actually started, that is, the response delay time when the valve is openedCan be accurately detected. In addition, the change in the fuel pressure is caused by the individual fuel injection valves.OpeningSince it changes corresponding to the operation, according to the configuration of the first aspect, the deviation can be detected for the individual fuel injection valves.
[0012]
  Claim2The invention described in claim1In the fuel injection valve injection characteristic detection device according to claim 1, when detecting a deviation between the input timing of the drive signal and the actual start timing of fuel injection, the fuel pressure when the drive signal is input is measured. The gist is to store the deviation between the detected input timing and the start timing as a deviation corresponding to the measured fuel pressure.
[0013]
  The response delay time at the time of valve opening described above changes when the drive signal is input, that is, depending on the fuel pressure immediately before the valve is opened. In this regard, the above claims2According to the configuration described in the above, the response delay time at the time of opening the valve detected in association with the fuel pressure immediately before the valve opening is stored. Therefore, the response delay time at the time of valve opening corresponding to the fuel pressure can be stored, and the accuracy of the detected deviation can be improved.
[0014]
  Claim3The invention described inIn a device for detecting a difference between an input time of a drive signal and an actual fuel injection time for a fuel injection valve that injects fuel in a fuel supply system to an internal combustion engine by opening the valve body based on the input of the drive signal,After the input of the drive signal is completed,Fuel supply systemBy measuring the time until the decrease in the fuel pressure is settled, out of the difference between the input time and the actual fuel injection time, the difference between the input end timing of the drive signal and the actual fuel injection stop timing is detected. The gist is to detect.
[0015]
  As described above, when the fuel injection valve is opened and fuel injection is actually started, the fuel pressure in the fuel piping system to which the fuel injection valve is connected decreases. Further, when the fuel injection valve is closed and the fuel injection is actually terminated, the decrease in the fuel pressure is stopped. That is, since the fuel pressure changes corresponding to the opening / closing operation of the valve body, the actual fuel injection time can be measured based on the fuel pressure change. According to the configuration of claim 3 focusing on this point,The actual fuel injection stop timing is detected based on the fuel pressure at which the decrease is suppressed by stopping the fuel injection. Therefore,Of the difference between the drive signal input time, that is, the fuel injection valve drive time and the actual fuel injection time,The response delay time from the end of the drive signal input until the actual fuel injection is stopped, that is, the response delay time when the valve is closedPreciselyCan be detected.Further, since the change in the fuel pressure changes corresponding to the closing operation of the individual fuel injection valve, according to the configuration of the third aspect, the deviation can be detected for the individual fuel injection valve. .
[0016]
  Claim4The invention described in claim3In the fuel injection valve injection characteristic detection device according to claim 1, when detecting a deviation between the input end timing of the drive signal and the actual fuel injection stop timing, the fuel pressure when the drive signal is input is measured. The gist is to store the difference between the detected input end timing and the stop timing as a deviation corresponding to the measured fuel pressure and the input time when the deviation is detected.
[0017]
  The response delay time when the valve is closed changes depending on the fuel pressure at the time when the input of the drive signal is completed. The fuel pressure at the time when the input of the drive signal is completed has a correlation with the fuel pressure at the time when the drive signal is input. In addition, since the fuel pressure decreases when fuel injection is performed, the input time of the drive signal and the fuel pressure at the time when the input of the drive signal is finished have a correlation. Therefore, the above claims4In the configuration described in (1), the detected response delay time when the valve is closed is stored in association with the fuel pressure when the drive signal is input and the input time of the drive signal. Therefore, the response delay time at the time of valve closing corresponding to the fuel pressure and the input time can be stored, and the accuracy of the detected deviation can be improved.
[0018]
  Claim5The invention described inIn a device for detecting a difference between an input time of a drive signal and an actual fuel injection time for a fuel injection valve that injects fuel in a fuel supply system to an internal combustion engine by opening the valve body based on the input of the drive signal,The lowering corresponding to the opening operation of the fuel injection valveFuel supply systemThe gist of the invention is to detect the difference between the input time of the drive signal and the actual fuel injection time by measuring the fuel pressure drop time.
[0019]
  As described above, when the fuel injection valve is opened and fuel injection is actually started, the fuel pressure in the fuel piping system to which the fuel injection valve is connected decreases. Further, when the fuel injection valve is closed and the fuel injection is actually terminated, the decrease in the fuel pressure is stopped. That is, since the fuel pressure changes corresponding to the opening / closing operation of the valve body, the actual fuel injection time can be measured based on the fuel pressure change. According to the configuration of claim 5 focusing on this point,The actual fuel injection time is measured based on the change in fuel pressure. Therefore, the difference between the drive signal input time and the actual fuel injection timePreciselyCan be detected.Further, since the change in the fuel pressure changes corresponding to the opening / closing operation of the individual fuel injection valve, according to the configuration of the fifth aspect, the deviation can be detected for the individual fuel injection valve. .
[0020]
  Claim6The invention described in claim5In the fuel injection valve injection characteristic detection device according to claim 4, when detecting a deviation between the input time of the drive signal and the actual fuel injection time, the fuel pressure when the drive signal is input is measured and the detected fuel pressure is detected. The gist is to store the difference between the input time and the actual fuel injection time as a deviation corresponding to the measured fuel pressure.
[0021]
  The difference between the input time and the actual fuel injection time described above changes depending on the fuel pressure when the drive signal is input, that is, immediately before the valve is opened. In this regard, the above claims6According to the configuration described above, the detected deviation is stored in association with the fuel pressure immediately before the valve is opened.
Therefore, the accuracy of the detected deviation can be improved.
[0022]
  Claim7The invention described in claim 16The gist of the fuel injection valve detection apparatus according to any one of the above is that the deviation is detected when a fuel pump that supplies fuel to the fuel injection valve is stopped.
[0023]
According to this configuration, since the deviation is detected when the fuel pump is stopped, the change in the fuel pressure at this time is basically only the change associated with the opening / closing operation of the valve body of the fuel injection valve. Therefore, the change in the fuel pressure accompanying the opening / closing operation of the valve body can be reliably captured, and the measurement accuracy of the actual fuel injection time can be improved.
[0024]
  Claim8The invention described in claim7In the fuel injection valve injection characteristic detection device according to claim 1, the fuel injection valve is executed a plurality of times when the fuel pump is stopped.
[0025]
  When fuel injection is performed a plurality of times while the fuel pump is stopped, the fuel pressure in the fuel piping system decreases every time fuel injection is performed. Therefore, the above claims8According to the configuration described in (1), the difference between the driving time and the time during which fuel is actually injected is detected at various fuel pressures. Therefore, it is possible to reliably detect the deviation that changes according to the change in the fuel pressure.
[0026]
  Claim9The invention described in claim7Or8The gist of the present invention is to detect the deviation when the fuel pump that is executed during the return of the deceleration fuel cut of the vehicle is stopped.
[0027]
  Normally, stopping the fuel pump during operation of the vehicle will cause deterioration of the engine operating state.9In the configuration described in (4), the deviation is detected during the deceleration fuel cut return when the fuel pump is stopped. Accordingly, the deviation can be detected without deteriorating the engine operating state.
[0028]
  Claim10The invention described in claim7~9The gist of the fuel injector injection characteristic detecting device according to any one of the above is that the fuel is injected within the minimum fuel injection time of the fuel injector.
[0029]
  According to this configuration, it is possible to suppress fuel consumption as much as possible when detecting the deviation.
  Claim11The invention described in claim 110And a fuel injection control device for an internal combustion engine that sets a basic fuel injection amount of the fuel injection valve according to an engine load, using a detection result of the injection property detection device. The gist is to correct the basic fuel injection amount.
[0030]
  As described above, according to the above-described injection characteristic detection device, it is possible to more accurately detect the drive signal input time, that is, the difference between the drive time of the fuel injection valve and the actual fuel injection time for each individual fuel injection valve. Can do. The basic fuel injection time is corrected using the detection result.11According to the configuration described in (1), it is possible to accurately correct the deviation between the drive signal input time and the actual fuel injection time.
[0031]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A fuel injection control device for a fuel injection valve according to the present invention and a fuel injection control device for an internal combustion engine equipped with the same will be described in detail with reference to FIGS. .
[0032]
FIG. 1 is a schematic configuration diagram showing a fuel injection control device according to the present embodiment, and a peripheral configuration thereof, together with an in-cylinder injection type gasoline engine 1 to which this is applied. The gasoline engine 1 has a plurality of cylinders, and the cylinder block 2 is provided with a plurality of cylinders 4 (only one is shown in FIG. 1 for convenience). A piston 5 is provided in the cylinder 4, and the piston 5 is connected to a crankshaft 7 that is an engine output shaft via a connecting rod 6.
[0033]
A cylinder head 3 is attached to the upper part of the cylinder block 2. In the cylinder 4, a combustion chamber 8 is formed between the upper end of the piston 5 and the cylinder head 3. The cylinder head 3 has a fuel injection valve 35 for directly injecting fuel into the combustion chamber 8 and a spark plug 11 for spark ignition of the air-fuel mixture in the combustion chamber 8 corresponding to each cylinder. Each is provided.
[0034]
The cylinder head 3 is provided with an intake port 9 that is an intake passage to the combustion chamber 8 and an exhaust port 10 that is an exhaust passage from the combustion chamber 8 for each cylinder. ing. These intake port 9 and exhaust port 10 are connected to an intake passage 20 and an exhaust passage 30, respectively. A throttle valve 23 whose opening degree is adjusted by an actuator 22 driven based on an operation of an accelerator pedal is provided in the intake passage 20. By changing the opening of the throttle valve 23, the amount of air taken into the combustion chamber 8 is adjusted.
[0035]
On the other hand, an intake side timing pulley 15 and an exhaust side timing pulley 16 are drivingly connected to the crankshaft 7 via a timing belt 14. An intake camshaft 17 that rotates together with the intake side timing pulley 15 is attached to the intake side timing pulley 15. An exhaust camshaft 18 that rotates together with the exhaust side timing pulley 16 is attached to the exhaust side timing pulley 16.
[0036]
An intake valve 12 and an exhaust valve 13 provided corresponding to the combustion chamber 8 open and close the intake port 9 and the exhaust port 10, respectively. The intake valve 12 and the exhaust valve 13 are opened and closed by cams provided on the intake camshaft 17 and the exhaust camshaft 18, respectively. Therefore, the intake valve 12 and the exhaust valve 13 are driven to open and close at a predetermined timing in synchronization with the rotation of the crankshaft 7, that is, corresponding to the reciprocating movement of the piston 5.
[0037]
A delivery pipe 60 that distributes fuel to the fuel injection valves 35 provided for each cylinder is connected to a high-pressure pump 62 via a high-pressure fuel passage 61.
[0038]
The high-pressure fuel passage 61 is provided with a check valve 63 that restricts fuel from flowing backward from the delivery pipe 60 to the high-pressure pump 62 side. A low pressure pump 65 provided in the fuel tank 66 is connected to the high pressure pump 62 via a low pressure fuel passage 64.
[0039]
The low pressure pump 65 sucks the fuel in the fuel tank 66 and discharges it to the low pressure fuel passage 64, thereby pumping the fuel to the high pressure pump 62.
The high-pressure pump 62 includes a plunger 62a that is reciprocally driven by a cam 68 provided on the intake camshaft 17, and a cylinder 62b that accommodates the plunger 62a in a reciprocable manner. The pressurizing chamber 62c formed in the cylinder 62b is supplied with fuel through the low-pressure fuel passage 64 and is connected to the delivery pipe 60, which is a fuel supply system, through the high-pressure fuel passage 61. The electromagnetic valve 62d blocks communication between the low pressure fuel passage 64 and the pressurizing chamber 62c. In the high-pressure pump 62, when the electromagnetic valve 62d is open, the fuel supplied to the high-pressure pump 62 is returned to the fuel tank 66 side without being pressurized and pressurized to the delivery pipe 60 side. On the other hand, when the electromagnetic valve 62d is closed, fuel is pressurized and sent from the high pressure pump 62 to the delivery pipe 60 side through the high pressure fuel passage 61. The control device 50 described later feedback-controls the opening / closing timing of the electromagnetic valve 62d with reference to the fuel pressure FP detected by the fuel pressure sensor 45 attached to the delivery pipe 60, and pressurizes and pressure-feeds from the high-pressure pump 62 to the delivery pipe 60. Adjust the amount of fuel to be used. Thereby, the fuel pressure in the delivery pipe 60 is adjusted to an appropriate pressure. The return passage 67 is a passage for returning excess fuel in the low-pressure fuel passage 64 to the fuel tank 66.
[0040]
On the other hand, in addition to the fuel pressure sensor 45, the gasoline engine 1 is provided with various sensors for detecting the engine operating state. For example, the crank angle sensor 41 provided close to the crankshaft 7 outputs a pulse signal having a frequency corresponding to the rotation speed of the gasoline engine 1 based on the rotation of the crankshaft 7. Based on this output signal (pulse signal), the rotation speed of the gasoline engine 1 (crankshaft 7), that is, the engine rotation speed NE and the rotation angle (crank angle) of the crankshaft 7 are detected. Further, the cam angle sensor 42 provided in the vicinity of the intake camshaft 17 outputs a pulse signal serving as a reference signal for every predetermined rotation based on the rotation of the intake camshaft 17. Cylinder discrimination is performed based on output signals from the crank angle sensor 41 and the cam angle sensor 42. A throttle opening sensor 43 provided in the vicinity of the throttle valve 23 detects the opening TA (throttle opening TA) of the throttle valve 23. An intake air amount GA flowing through the intake passage 20 is detected by an air flow meter 44 provided on the upstream side of the throttle valve 23.
[0041]
Various controls such as ignition timing control, fuel injection timing (injection amount) control, and fuel injection pressure control of the gasoline engine 1 are performed by the control device 50. The control device 50 is configured around a microcomputer including a central processing control device (CPU). For example, the control device 50 is provided with a read-only memory (ROM) in which various programs, maps, and the like are stored in advance, and a random access memory (RAM) in which CPU calculation results and the like are temporarily stored. The control device 50 is also provided with a backup RAM, an input interface, an output interface, and the like for storing calculation results and prestored data after the engine is stopped. Output signals from the crank angle sensor 41, the cam angle sensor 42, the throttle opening sensor 43, the air flow meter 44, the fuel pressure sensor 45, and the like are input to the input interface. The operating state of the gasoline engine 1 is detected by these sensors 41 to 45 and the like.
[0042]
On the other hand, the output interface is connected to the fuel injection valve 35 via the drive circuit 51. In addition, they are also connected to an ignition coil for applying a high voltage to the ignition plug 11, an actuator 22 for the throttle valve 23, an electromagnetic valve 62d, and the like via corresponding drive circuits. Then, the control device 50 controls the fuel injection valve 35, the ignition coil, the actuator 22, the electromagnetic valve 62d and the like according to the control program and initial data stored in the ROM based on the signals from the sensors 41 to 45. Control through a drive circuit.
[0043]
Here, as the fuel injection valve 35 in the present embodiment, a general fuel injection valve is used. Therefore, a schematic diagram of the cross-sectional structure of the fuel injection valve 35 is shown in FIG. 2, and the structure and operation mode will be briefly described with reference to this.
[0044]
As shown in FIG. 2, a fuel passage 35 a is formed in the fuel injection valve 35. A fuel injection hole 35b is provided at the tip of the fuel passage 35a. A valve body 35c is disposed in the fuel passage 35a. A core 35e is fixed to the valve body 35c. The core 35e is attracted when a driving voltage is applied to an electromagnetic coil 35f provided in the fuel injection valve 35, and thereby the valve body 35c moves in a direction to open the fuel injection hole 35b. That is, fuel injection is performed. Further, when the drive voltage is cut off, the core 35e is not sucked, and the valve body 35c moves in a direction to close the fuel injection hole 35b by the urging force of the spring 35d. That is, fuel injection is stopped. Thus, the opening / closing operation of the fuel injection valve 35 is performed in response to the application of the drive voltage to the electromagnetic coil 35f. The drive voltage is applied to the electromagnetic coil 35 f while the drive signal output from the control device 50 is input to the drive circuit 51 of the fuel injection valve 35. The time during which the drive signal is input to the drive circuit 51, that is, the fuel injection time, is determined by the control device 50 according to the engine operating state so that the amount of fuel corresponding to the engine operating state is supplied to the combustion chamber 8. Time is set.
[0045]
Here, the fuel injection valve 35 has a response delay after the drive voltage is applied until the valve body 35c opens, and fuel injection is not performed within this response delay time. That is, there is a difference between the input timing of the drive signal and the start timing of fuel injection. Since the fuel injection valve 35 has such an invalid injection time, there is a difference between the drive signal input time (drive time of the fuel injection valve 35) and the actual fuel injection time. Further, as the fuel pressure in the delivery pipe 60 increases, the valve opening operation of the valve body 35c is inhibited, so this invalid injection time also changes depending on the fuel pressure. Therefore, in order to supply the amount of fuel corresponding to the engine operating state to the combustion chamber 8, it is necessary to add the invalid injection time corresponding to the fuel pressure to the fuel injection time.
[0046]
Therefore, the fuel injection control device according to the present embodiment accurately measures the actual fuel injection time at various fuel pressures, and determines the difference between the drive time and the actual fuel time, that is, the invalid injection time of the fuel injection valve 35. An injection characteristic detection device that detects precisely is provided. Then, based on the detection result, the fuel injection time in which the deviation is accurately corrected is set.
[0047]
Next, measurement of actual fuel injection time at various fuel pressures will be described.
FIG. 3 shows the fuel injection time (solid line a) and the fuel pressure in the delivery pipe 60 (solid line b) when the deceleration fuel cut and deceleration fuel cut return processing is executed during deceleration of a vehicle equipped with a gasoline engine. The change mode is shown.
[0048]
First, when the throttle valve 23 is fully closed and the engine rotational speed gradually decreases and reaches a predetermined fuel cut execution speed, the fuel injection from the fuel injection valve 35 is interrupted, that is, the fuel cut during deceleration is performed. Executed. At this time, as shown in FIG. 3, the fuel injection time is set to “0”. Further, since fuel injection is not performed, the fuel pressure in the delivery pipe 60 is maintained at a constant pressure. Thereafter, when the engine rotational speed further decreases and reaches the fuel cut return rotational speed, a deceleration fuel cut return process is performed (time ta to tb). In the deceleration fuel cut recovery process, the fuel injection valve 35 is driven a plurality of times with the minimum fuel injection time. This is to avoid an engine stop due to an excessive decrease in the engine speed NE. Further, in the deceleration fuel cut recovery process, the fuel supply from the high pressure pump 62 to the delivery pipe 60 is stopped. This is because the fuel pressure in the delivery pipe 60 is lowered to the vicinity of the optimum pressure for maintaining the engine rotational speed NE at the idle rotational speed. Thus, during the deceleration fuel cut recovery, the fuel pressure in the delivery pipe 60 decreases rapidly each time fuel injection is executed. Then, when the fuel pressure in the delivery pipe 60 decreases to near the optimum pressure for maintaining the engine rotational speed at the idle rotational speed (time tb), the idle control is started to maintain the engine rotational speed at the idle rotational speed. The feedback control is started. In this idle control, the fuel injection time varies according to the variation of the engine speed. Further, by adjusting the amount of fuel discharged from the high-pressure pump 62, the fuel pressure in the delivery pipe 60 is gradually reduced to an optimum pressure for maintaining the idle rotation speed.
[0049]
FIG. 4 shows the fuel pressure change mode, the drive signal input mode, and the operation mode of the valve body 35c, in other words, the fuel injection valve 35, among the fuel injections executed a plurality of times during the deceleration fuel cut recovery. The change modes of the valve opening are respectively shown.
[0050]
As shown in FIG. 4, when a drive signal is input to the drive circuit 51 of the fuel injection valve 35 (time t1), the valve body 35c starts to open after the invalid injection time, and actual fuel injection starts. (Time t2). The fuel pressure in the delivery pipe 60 begins to decrease due to the actual fuel injection. Thereafter, when the drive signal is disconnected (time t3), the valve body 35c is gradually closed, and the valve body 35c is completely closed with a slight delay from the disconnection of the drive signal (time t4). . That is, fuel injection is actually stopped. Then, the fuel pressure drop in the delivery pipe 60 is reduced due to the actual stop of the fuel injection. Further, since the high-pressure pump 62 is stopped during the deceleration fuel cut recovery, the lowered fuel pressure is not returned to the original fuel pressure. Therefore, the fuel pressure in the delivery pipe 60 rapidly decreases as shown in FIG. 3 by executing the fuel injection during the deceleration fuel cut recovery multiple times.
[0051]
As described above, during deceleration fuel cut recovery, the fuel pressure decreases corresponding to one fuel injection, and the fuel pressure decrease time corresponds to the actual fuel injection time. Therefore, in the injection characteristic detection process according to the present embodiment, the invalid injection time is detected by measuring the time from when the drive signal is input until the fuel pressure starts to decrease.
[0052]
Next, the invalid injection time detection processing procedure executed by the control device 50 will be described with reference to FIG. This process is repeatedly executed every predetermined time.
[0053]
When this process is started, first, it is determined whether or not the current engine operation state is returning to the deceleration fuel cut (S100). This determination is made based on whether or not a deceleration fuel cut recovery process that is performed separately is being performed. If the deceleration fuel cut recovery is not in progress (NO in S100), this process is temporarily terminated.
[0054]
On the other hand, when the deceleration fuel cut recovery is in progress (YES in S100), the fuel pressure FP before the drive signal is input to the fuel injection valve 35 to be injected among the plurality of fuel injection valves 35 is read. (S110).
[0055]
Next, the time from when the drive signal is input to the fuel injection valve 35 to be injected until the fuel pressure FP starts to decrease, that is, the invalid injection time TV of the fuel injection valve 35 to be injected is measured ( S120). Then, the invalid injection time TV at the measured fuel pressure FP is stored in the RAM of the control device 50 in association with the identification flag representing the fuel injection valve 35 that is the current injection target (S130), and this process is terminated. The After that, if the deceleration fuel cut is being recovered, the above detection process is repeatedly executed. Therefore, the invalid injection time TV at the fuel pressure FP that gradually decreases with fuel injection is continuously measured for each of the plurality of fuel injection valves 35, and the various fuel pressures and the invalid injection time TV at the individual fuel injection valves 35 are measured. It is stored in RAM.
[0056]
Next, FIG. 6 shows a calculation process procedure of the fuel injection time using the invalid injection time TV stored in the RAM. This process is also repeatedly executed by the control device 50 every predetermined time.
[0057]
When this process is started, an identification flag representing the fuel injection valve 35 to be subjected to fuel injection is read (S200).
Next, the fuel injection amount Q is calculated based on the intake air amount GA and the engine rotational speed NE (S210).
[0058]
Next, the basic fuel injection time TAU is calculated based on the fuel injection amount Q (S220).
Next, the current fuel pressure FP is measured, and the invalid fuel injection time TV corresponding to the fuel injection valve 35 represented by the measured fuel pressure FP and the identification flag is read from the RAM (S230).
[0059]
Next, the read invalid injection time TV is added to the basic fuel injection time TAU to obtain the final fuel injection time TAU (S240). Thereafter, a drive signal corresponding to the final fuel injection time TAUF is input to the drive circuit 51 of the fuel injection valve 35 represented by the identification flag, and the electromagnetic coil 35f receives a drive voltage during the final fuel injection time TAUF. Is applied. Thus, since the invalid injection time TV detected in the invalid injection time detection process is added to the basic fuel injection time TAU, the amount of fuel corresponding to the engine load from the fuel injection valve 35 toward the combustion chamber 8 is individually determined. The fuel injection valve 35 is supplied precisely.
[0060]
As described above, according to the fuel injection valve injection characteristic detection device and the internal combustion engine fuel injection control device including the detection device according to the present embodiment, the following effects can be obtained.
[0061]
(1) Since the fuel pressure FP in the delivery pipe 60 changes corresponding to the opening / closing operation of the valve body 35c, the actual fuel injection time can be measured based on the change in the fuel pressure. According to the embodiment focusing on this point, the actual fuel injection time can be surely known when detecting the deviation between the actual fuel injection time and the drive signal input time. In particular, in the above-described embodiment, the timing at which the valve body 35c is actually opened is detected based on the decrease in the fuel pressure due to the start of fuel injection. Therefore, the response delay time from when the drive signal is input to when fuel injection is actually started, that is, the invalid injection time TV can be accurately detected.
[0062]
(2) The invalid injection time TV changes according to the fuel pressure FP immediately before the valve is opened. Therefore, the fuel pressure FP at the time when the drive signal is inputted and the invalid injection time TV at the fuel pressure FP at that time are associated with each other and stored in the RAM of the control device 50. Accordingly, the invalid injection time TV corresponding to various fuel pressures can be stored, and the accuracy of the invalid injection time TV can be improved.
[0063]
(3) The fuel pressure FP changes when any one of the plurality of fuel injection valves 35 connected to the delivery pipe 60 is subjected to fuel injection. According to the above-described injection characteristic detection device that detects such a shift by detecting such a change in fuel pressure, each invalid injection time TV can be detected for each individual fuel injection valve 35.
[0064]
(4) The invalid injection time TV precisely detected for each fuel injection valve 35 is stored in this way, and the basic fuel injection time TAU is corrected using the stored invalid injection time TV. Accordingly, the deviation between the drive time of the fuel injection valve 35 and the actual fuel injection time is accurately corrected, so that a fuel amount corresponding to the engine load can be supplied to the combustion chamber 8.
[0065]
(5) The invalid injection time TV is detected during deceleration fuel cut recovery. Therefore, the following effects can be obtained.
(5.1) The invalid injection time TV is detected when the high-pressure pump 62 is stopped. Therefore, basically, only the change in the fuel pressure FP accompanying the opening operation of the valve body 35c can be detected, that is, the opening operation of the valve body 35c can be reliably captured. Therefore, the measurement accuracy of the actual fuel injection start time can be improved.
[0066]
(5.2) Normally, stopping the high-pressure pump 62 during operation leads to deterioration of the engine operating state. However, in the above embodiment, during the deceleration fuel cut recovery in which the high-pressure pump 62 is originally stopped, The invalid injection time TV is detected. Therefore, the invalid injection time TV can be detected without deteriorating the engine operating state.
[0067]
(5.3) Multiple fuel injections are performed during deceleration fuel cut recovery. As described above, when the fuel injection is performed a plurality of times while the high-pressure pump 62 is stopped, the fuel pressure FP in the delivery pipe 60 decreases every time the fuel injection is executed, and therefore the invalid injection time TV at various fuel pressures FP. Can be detected. Therefore, the invalid injection time TV corresponding to the change in the fuel pressure FP can be reliably detected.
[0068]
(5.4) With respect to the fuel injection required for detecting the invalid injection time TV, the injection time at that time is set to the minimum fuel injection time. Therefore, fuel consumption can be suppressed as much as possible when detecting the invalid injection time TV.
[0069]
(6) The invalid injection time TV of the fuel injection valve 35 attached to the gasoline engine 1 is detected. Therefore, even if the invalid injection time TV changes due to secular change or the like, the invalid injection time TV can be accurately detected, and the change can be dealt with.
[0070]
(Second Embodiment)
Next, a description will be given of a second embodiment of an injection characteristic detecting device for a fuel injection valve according to the present invention and a fuel injection control device for an internal combustion engine equipped with the same.
[0071]
In the first embodiment, the time from the input of the drive signal to the actual start of fuel injection from the fuel injection valve 35, that is, the invalid injection time TV (FIG. 4), which is the response delay time at the time of valve opening. The time between the time t1 and the time t2 shown) is detected. On the other hand, in this embodiment, of the difference between the input time of the drive signal and the actual fuel injection time, the shift time between the input end timing of the drive signal and the actual fuel injection stop timing, that is, at the time of valve closing. Response delay time (time between time t3 and time t4 shown in FIG. 4) is detected.
[0072]
Further, when calculating the final fuel injection time TAUF, not only the invalid injection time but also the response delay time when the valve is closed is taken into consideration.
This valve closing response delay time can be detected by changing the procedure after S110 in the invalid injection time detecting process shown in FIG. 5 as shown in FIG.
[0073]
That is, when the valve closing response delay time process shown in FIG. 7 is started by the control device 50, it is first determined whether or not the deceleration fuel cut is being restored (S100). The process in S100 is the same as the process in S100 described in the first embodiment.
[0074]
Next, when the deceleration fuel cut recovery is in progress (YES in S100), the fuel pressure FP before the drive signal is input to the fuel injection valve 35 to be injected among the plurality of fuel injection valves 35 is read. (S110).
[0075]
Next, it is determined whether or not the drive signal is input to the drive circuit 51 of the fuel injection valve 35 to be injected (S300). If no drive signal is input (NO in S300), that is, if fuel injection is not currently being performed, this process is temporarily terminated.
[0076]
On the other hand, when the drive signal is input (YES in S300), that is, when fuel injection is currently being performed, the time from when the input of the drive signal is completed until the decrease in the fuel pressure FP is stopped, that is, closed. The valve response delay time TC is measured (S310).
[0077]
Next, the measured valve closing response delay time TC is stored in the RAM of the control device 50 as follows. That is, at the measured fuel pressure FP, as the valve closing response delay time TC when the fuel injection is executed at the basic fuel injection time TAU set according to the engine load, the fuel injection valve that is the current injection target It is stored in correspondence with the identification flag representing 35 (S320). Then, this process ends. After that, if the deceleration fuel cut is being recovered, the above detection process is repeatedly executed. Therefore, the valve closing response delay time TC at various fuel pressures and basic fuel injection times TAU is stored in the RAM for each of the plurality of fuel injection valves 35.
[0078]
Next, FIG. 8 shows a calculation process procedure of the fuel injection time using the valve closing response delay time TC stored in the RAM. This process is also repeatedly executed by the control device 50 every predetermined time. Further, only the procedure after S230 in the fuel injection time calculation process shown in FIG. 6 is different in the first embodiment.
[0079]
When this process is started, an identification flag representing the fuel injection valve 35 to be subjected to fuel injection is read (S200).
Next, the fuel injection amount Q is calculated based on the intake air amount GA and the engine rotational speed NE (S210).
[0080]
Next, the basic fuel injection time TAU is calculated based on the fuel injection amount Q (S220).
Next, the current fuel pressure FP is measured, and the invalid injection time TV corresponding to the fuel injection valve 35 represented by the measured fuel pressure FP and the identification flag is read (S230). Further, the valve closing response delay time TC is read based on the fuel pressure FP, the basic fuel injection time TAU, and the identification flag of the fuel injection valve 35 (S400).
[0081]
Next, a value obtained by subtracting the valve closing response delay time TC from the invalid injection time TV is added to the basic fuel injection time TAU to obtain the final fuel injection time TAUF (S410). Thereafter, a drive signal corresponding to the final fuel injection time TAUF is input to the drive circuit 51 of the fuel injection valve 35 represented by the identification flag, and the electromagnetic coil 35f receives a drive voltage during the final fuel injection time TAUF. Is applied. Thus, the basic fuel injection time TAU is corrected by the invalid injection time TV detected in the invalid injection time detection process and the valve closing response delay time TC detected in the valve closing response delay detection process. A fuel amount corresponding to the engine load is precisely supplied from the fuel injection valve 35 to the combustion chamber 8 for each individual fuel injection valve 35.
[0082]
As described above, according to the fuel injection valve injection characteristic detection device and the internal combustion engine fuel injection control device including the detection device according to the present embodiment, the following as compared with the first embodiment: An effect comes to be acquired.
[0083]
(1) The fuel pressure FP in the delivery pipe 60 changes corresponding to the opening / closing operation of the valve body 35c. Therefore, the timing at which the valve body 35c actually closes is detected based on the change in the fuel pressure FP, more specifically, the decrease in the fuel pressure due to the stop of fuel injection. For this reason, it is possible to accurately detect the response delay time from when the input of the drive signal is completed to when the fuel injection is actually stopped, that is, the response delay time TC during valve closing.
[0084]
(2) The valve closing response delay time TC changes according to the fuel pressure FP at the time when the input of the drive signal is completed. The fuel pressure FP at the time when the input of the drive signal is completed has a correlation with the fuel pressure FP at the time of input of the drive signal. Further, since the fuel pressure FP decreases when fuel injection is performed, the length of the basic fuel injection time TAU and the fuel pressure FP at the time when the input of the drive signal is completed have a correlation. Therefore, the valve closing response delay time TC is stored in the RAM of the control device 50 in association with the fuel pressure FP at the time when the drive signal is input and the basic fuel injection time TAU. Accordingly, the valve closing response delay time TC corresponding to various fuel pressures FP and the basic fuel injection time TAU can be stored, and the accuracy of the valve closing response delay time TC can be improved.
[0085]
(3) The basic fuel injection time TAU is corrected using the invalid injection time TV and the valve closing response delay time TC precisely detected for the individual fuel injection valves 35. Therefore, the deviation between the drive time and the actual fuel injection time is corrected more precisely, so that the fuel amount corresponding to the engine load can be supplied to the combustion chamber 8 more accurately.
[0086]
It should be noted that each of the above embodiments can be modified as follows.
In each of the above embodiments, the invalid injection time TV of the fuel injection valve 35 and the valve closing response delay time TC are detected. In addition to this, the basic fuel injection time TAU corresponding to the drive signal input time and the actual fuel injection time are detected by detecting the actual fuel injection time (the time between the times t2 and t4 shown in FIG. 4). You may make it detect the shift | offset | difference between time.
[0087]
This actual fuel injection time, that is, the actual fuel injection time TAUR is detected by changing the procedure after S110 in the invalid injection time detection process shown in FIG. 5, as shown in the detection process procedure in FIG. can do.
[0088]
That is, when the actual fuel injection time detection process shown in FIG. 9 is started by the control device 50, it is first determined whether or not the deceleration fuel cut is being recovered (S100). The process in S100 is the same as the process in S100 described in the first embodiment.
[0089]
Next, when the deceleration fuel cut recovery is in progress (YES in S100), the fuel pressure FP before the drive signal is input to the fuel injection valve 35 to be injected among the plurality of fuel injection valves 35 is read. (S110).
[0090]
Next, a decrease time of the fuel pressure FP when fuel injection is executed at the basic fuel injection time TAU, that is, the actual fuel injection time TAUR is measured (S500), and the difference between the basic fuel injection time TAU and the actual fuel injection time TAUR is measured. ΔT is calculated (S510).
[0091]
Next, the difference ΔT in the fuel pressure FP measured this time is stored in the RAM of the control device 50 in association with the identification flag representing the fuel injection valve 35 that is the current injection target (S520), and this process is terminated. . After that, if the deceleration fuel cut is being recovered, the above detection process is repeatedly executed. Therefore, the actual fuel injection time TAUR at various fuel pressures FP is detected for each of the plurality of fuel injection valves 35, and the above differences ΔT at the various fuel pressures FP and the individual fuel injection valves 35 are stored in the RAM.
[0092]
Thus, instead of detecting the invalid injection time TV and the valve closing response delay time TC individually, the actual fuel injection time (actual fuel injection time TAUR) including these is detected. Also good. In this case as well, the actual fuel injection time TAUR varies depending on the fuel pressure FP immediately before the valve is opened. However, in this modified example, the actual fuel injection time TAUR is related to the fuel pressure FP immediately before the valve is opened. Is remembered. Therefore, the accuracy of the actual fuel injection time TAUR can be improved.
[0093]
In calculating the final fuel injection time TAUF described above, the basic fuel injection time TAU is corrected by the difference ΔT corresponding to the fuel pressure FP and the individual fuel injection valve 35, whereby the individual fuel injection valve 35 and the combustion chamber 8 are corrected. As for the amount of fuel injected and supplied toward the vehicle, the amount of fuel corresponding to the engine load can be precisely supplied.
[0094]
In each of the above-described embodiments, the case where the fuel injection valve injection characteristic detection device according to the present invention is applied to the fuel injection control device of the gasoline engine 1 has been described. In addition to this, for example, the above-described injection characteristic detection process may be performed in an experimental apparatus or the like that detects the injection characteristic of an individual fuel injection valve. In this case as well, it is possible to detect a difference between the drive signal input time and the actual fuel injection time for each individual fuel injection valve.
[0095]
In each of the above embodiments, the injection characteristic of the fuel injection valve is detected during deceleration fuel cut recovery. However, since the correspondence between the fuel pressure change and the opening / closing operation of the valve body 35c is established to some extent even during normal operation, the above-described injection characteristic detection processing may be performed during normal operation.
[0096]
In each of the above-described embodiments, the case where the fuel injection valve fuel injection control device according to the present invention and the fuel injection control device of the internal combustion engine including the detection device are applied to the direct injection gasoline engine 1 has been described. In addition, the present invention can be similarly applied to an internal combustion engine in which fuel is injected into an intake port, a common rail type diesel engine, and the like.
[0097]
In each of the above embodiments, the actuator that opens the valve body 35c of the fuel injection valve 35 is the electromagnetic coil 35f. However, the present invention is not limited to this. For example, an actuator that is driven by application of a drive voltage, such as a piezo element, may be used.
[0098]
The fuel injection valve 35 in each of the above embodiments is a type in which the valve body 35c is directly opened and closed by the electromagnetic coil 35f. In addition to this, an actuator (such as an electromagnetic coil 35f) for opening and closing the valve body of the fuel injection valve is separately provided outside the fuel injection valve, for example, the fuel pressure in the fuel injection valve is increased by driving the actuator. The present invention can be similarly applied when detecting the injection characteristics of a fuel injection valve whose body is opened.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an internal combustion engine to which an injection characteristic detection device for a fuel injection valve according to a first embodiment and a fuel injection control device for an internal combustion engine equipped with the detection device are applied.
FIG. 2 is a schematic diagram of a cross-sectional structure of a fuel injection valve.
FIG. 3 is a timing chart showing how fuel injection time and fuel pressure change during deceleration fuel cut and during deceleration fuel cut return.
FIG. 4 is a timing chart showing changes in fuel pressure, drive signal, and valve opening during deceleration fuel cut recovery.
FIG. 5 is a flowchart showing the invalid injection time detection processing procedure according to the embodiment;
FIG. 6 is a flowchart showing a fuel injection time calculation processing procedure according to the embodiment;
FIG. 7 is a flowchart showing a detection processing procedure of a valve closing response delay time according to the second embodiment.
FIG. 8 is a flowchart showing a procedure for calculating a fuel injection time according to the embodiment.
FIG. 9 is a flowchart showing a processing procedure for detecting an actual fuel injection time according to a modification of each of the embodiments.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Gasoline engine, 2 ... Cylinder block, 3 ... Cylinder head, 4 ... Cylinder, 5 ... Piston, 6 ... Connecting rod, 7 ... Crankshaft, 8 ... Combustion chamber, 9 ... Intake port, 10 ... Exhaust port, 11 ... Ignition Plug, 12 ... Intake valve, 13 ... Exhaust valve, 14 ... Timing belt, 15 ... Intake side timing pulley, 16 ... Exhaust side timing pulley, 17 ... Intake camshaft, 18 ... Exhaust camshaft, 20 ... Intake passage, 22 ... Actuator, 23 ... Throttle valve, 30 ... Exhaust passage, 35 ... Fuel injection valve, 35a ... Fuel passage, 35b ... Fuel injection hole, 35c ... Valve body, 35d ... Spring, 35e ... Core, 35f ... Electromagnetic coil, 41 ... Crank Angle sensor 42 ... Cam angle sensor 43 ... Throttle opening sensor 44 ... Air flow meter 45 ... Fuel pressure sensor 50 ... Control device 51 ... Drive circuit 60 ... Delivery pipe 61 ... High pressure fuel passage 62 ... High pressure pump 62a ... Plunger 62b ... Cylinder 62c ... Pressure chamber 62d Solenoid valve 63 ... Check valve 64 ... Low pressure fuel passage, 65 ... Low pressure pump, 66 ... Fuel tank, 67 ... Return passage, 68 ... Cam.

Claims (11)

In a device for detecting a difference between an input time of a drive signal and an actual fuel injection time for a fuel injection valve that injects fuel in a fuel supply system to an internal combustion engine by opening the valve body based on the input of the drive signal,
By measuring the time from when the drive signal is input to when the fuel pressure in the fuel supply system starts to decrease, out of the difference between the input time and the actual fuel injection time, the input timing of the drive signal and the actual A fuel injection valve injection characteristic detection device for detecting a deviation from the start timing of fuel injection . When detecting the deviation between the input timing of the drive signal and the actual start timing of fuel injection, the fuel pressure when the drive signal is input is measured, and the difference between the detected input timing and the start timing is measured. The injection characteristic detecting device for a fuel injection valve according to claim 1, wherein the deviation is stored as a deviation corresponding to the measured fuel pressure . In a device for detecting a difference between an input time of a drive signal and an actual fuel injection time for a fuel injection valve that injects fuel in a fuel supply system to an internal combustion engine by opening the valve body based on the input of the drive signal,
  By measuring the time from the end of the input of the drive signal until the decrease in the fuel pressure of the fuel supply system is settled, the input of the drive signal is completed out of the difference between the input time and the actual fuel injection time. Detecting the difference between the timing and the actual fuel injection stop timing
  An injection characteristic detecting device for a fuel injection valve, characterized in that: When detecting a deviation between the input end timing of the drive signal and the actual fuel injection stop timing, the fuel pressure when the drive signal is input is measured, and the detected input end timing and stop timing are The difference between the values is stored as a difference corresponding to the measured fuel pressure and the input time when the difference is detected.
  4. An injection characteristic detecting device for a fuel injection valve according to claim 3. In a device for detecting a difference between an input time of a drive signal and an actual fuel injection time for a fuel injection valve that injects fuel in a fuel supply system to an internal combustion engine by opening the valve body based on the input of the drive signal,
  By measuring the time during which the fuel pressure of the fuel supply system that decreases in response to the opening operation of the fuel injection valve is measured, a deviation between the input time of the drive signal and the actual fuel injection time is detected.
  An injection characteristic detecting device for a fuel injection valve, characterized in that: When detecting the difference between the input time of the drive signal and the actual fuel injection time, the fuel pressure when the drive signal is input is measured, and the difference between the detected input time and the actual fuel injection time is determined. Memorize as deviation corresponding to this measured fuel pressure
  6. An injection characteristic detecting device for a fuel injection valve according to claim 5. The deviation is detected when a fuel pump that supplies fuel to the fuel injection valve is stopped.
  The injection characteristic detection apparatus of the fuel injection valve in any one of Claims 1-6. Multiple fuel injections are performed when the fuel pump is stopped
  8. An injection characteristic detecting device for a fuel injection valve according to claim 7. A vehicle comprising the fuel injection valve injection characteristic detection device according to claim 7 or 8, wherein the deviation is detected when the fuel pump is stopped while the vehicle is decelerated and fuel cut is restored.
  An injection characteristic detecting device for a fuel injection valve, characterized in that: The fuel is injected with the minimum fuel injection time of the fuel injection valve.
  The injection characteristic detection device for a fuel injection valve according to any one of claims 7 to 9. A fuel injection control device for an internal combustion engine, comprising the fuel injection valve detection device according to claim 1, wherein a basic fuel injection amount of the fuel injection valve is set according to an engine load.
  The basic fuel injection amount is corrected using the detection result of the injection characteristic detection device.
  A fuel injection control device for an internal combustion engine.

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