JP3327087B2 - Control unit for diesel engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control apparatus for a diesel engine, and more particularly to a control apparatus for shutting off a power supply under a predetermined condition when an electronically controlled fuel injection pump is controlled by a controller which receives a power supply.

[0002]

2. Description of the Related Art In order to perform an emergency stop in a diesel engine, there is one in which the power supply of a fuel metering device and a fuel supply device is cut off (Japanese Patent Laid-Open No. 4-284848,
JP-A-57-210131).

[0003]

In an electronically controlled injection pump for a diesel engine, a microcomputer determines a target injection amount according to operating conditions, and the actual injection amount detected based on the target injection amount and the control sleeve position. The feedback control of the fuel injection amount is performed by giving the control amount to the fuel injection amount control actuator such that the control amount is equal to the control amount. In this case, the difference between the response characteristics of the sensor signal and the actuator and the failure of the sensor signal input circuit, the PID circuit, the microcomputer, etc.
As shown in the above, during the feedback control of the fuel injection amount, the sensor signal or the feedback control signal to the actuator may cross a normal range at a short period (for example, 40 Hz), that is, hunting may occur. In such a case, a device (prior application device) that performs a predetermined fail-safe process is proposed (see Japanese Patent Application No. 7-298436).

At this time, the fail-safe processing includes:
The engine is stopped by shutting off the fuel cut valve 33 (see FIG. 1) provided in the suction port 32 of the plunger barrel 31.

However, in extremely rare cases,
In the event of a hunting failure, the engine continues to run despite the fuel cut valve 33 being closed by the controller 21 and the driver turns the ignition key from ON to OFF.
It has been found during the experiment that the engine may not stop even if it is switched to. According to an analysis of this, when the hunting of the control sleeve and the pumping timing of the high-pressure plunger were synchronized, the engine was continuing to rotate due to the fuel being sucked into the pressurizing chamber from the cutoff port in reverse. all right. The rotation speed at this time is extremely low, but conventionally, the ignition key is
Turns off the power relay of the controller when the power cutoff condition is satisfied when the engine is not rotating and in the FF state.
Therefore, the power relay is not turned off unless the engine rotation is stopped.

Accordingly, the present invention shuts off the power even when a hunting failure is determined and the ignition key is turned off, so that the rotation can be continued very rarely due to the hunting failure. The purpose is not to be.

[0007]

In the first invention, FIG.
As shown in the figure , when the ignition key is OFF and
The power-off condition is that the engine is not running.
In the control device for a diesel engine, an engine control actuator 61 and a control amount given to the actuator 61 are calculated so that a control target value corresponding to an engine operating condition and an actually measured control value detected by the sensor 62 match. Means 63, means 64 for outputting the actuator control amount to the actuator 61, means 65 for setting a failure determination value for the output of the sensor 62.
Means for determining a hunting failure when the sensor output crosses the failure determination value a predetermined number of times within a predetermined time.
And means 67 for judging a hunting failure and shutting off the power supply 68 when the ignition key is turned off.
And provided.

[0008] In the second invention, as shown in FIG. 12, Yi
The ignition key is off and the engine is running
Engine with power-off condition
In the control device, the engine control actuator 61 calculates a control amount given to the actuator 61 such that a control target value corresponding to the operating condition of the engine and an actually measured control value detected by the sensor 62 coincide with each other. A means 63, a means 64 for outputting the actuator control amount to the actuator 61, a means 71 for setting a failure judgment value for the actuator control amount, and a means for setting the failure judgment value to a predetermined number of times within a predetermined time. Means 7 for determining hunting failure when crossing
Means 73 for judging a hunting failure and shutting off the power supply 68 when the ignition key is turned off.
And provided.

In a third aspect based on the first or second aspect, the hunting failure is determined, and the power is shut off when the ignition key has been turned off for a certain period of time.

[0010] In the fourth invention, in any one invention of the first to third, a circuit system power supply for the power supply to drive the control amount calculation means 63.

[0011] In the fifth aspect of the invention, in any one invention of the first to third, a power system power supply for the power supply to drive the actuator 61.

According to a sixth aspect of the present invention, in any one of the first to fifth aspects, the actuator 61 is a control sleeve control actuator, and the sensor 62 is a control sleeve position sensor.

In a seventh aspect based on the sixth aspect, a fuel cut valve provided in a suction passage to a plunger pump for feeding fuel is closed when the hunting fails.

[0014]

When the power is turned off under the condition that the ignition key is OFF and the engine is not rotating, fuel is supplied in reverse due to hunting failure (for example, hunting of the control sleeve and high pressure in the distribution type fuel injection pump). When the fuel is sucked into the pressurizing chamber from the cut-off port in synchronization with the plunger pumping timing, in rare cases where the engine continues to rotate, the ignition key is switched to the OFF state to turn off the power. However, in the first and second inventions, since the power is shut off when the hunting failure is determined and the ignition key is turned off, the calculation of the control amount given to the actuator is stopped. Hunting stopped and this caused rotation Reduced the engine is stopped. In this manner, in the first and second aspects of the invention, the rotation is not continued due to the hunting failure on a very rare occasion.

[0015]

FIG. 1 shows the details of a distribution type fuel injection pump 1. In FIG. 1, the fuel injection pump includes a plunger 3 for compressing fuel in a pressurizing chamber 4 while rotating and reciprocating while engaging with a cam roller in an injection pump body 2 forming a pump housing. A cut-off port 3 a formed in the plunger 3 is provided on the outer periphery of the plunger 3.
A control sleeve 5 for adjusting the fuel injection amount by opening and closing the valve is slidably fitted, and an electric governor (for example, a rotary solenoid 6) for driving the control sleeve 5 is provided. As the output voltage to the rotary solenoid 6 increases, the control sleeve 5 moves in the direction in which the plunger 3 enters, so that the fuel injection end timing is delayed and the fuel injection amount increases.

The fuel discharged from the feed pump 7 attached to the pump drive shaft lubricates the inside of the pump and accumulates the pressure in the pump chamber 8.
Is sucked. In addition, the feed pump 7 and the timer piston 9 described later are illustrated in a state of being rotated by 90 ° for the sake of explanation.

In order to control the fuel injection timing, a timer piston 9 is provided as an injection timing control member that moves the phase of the cam roller while engaging with the cam roller that drives the plunger 3. The position of the timer piston 9 is controlled by a timing control valve 10 that controls the flow rate of fuel leaked from the high pressure chamber at one end to the low pressure chamber, thereby advancing or retarding the fuel injection timing.

A controller 21 is provided for controlling the fuel injection amount, injection timing, and the like. The controller 21 includes an accelerator opening sensor 22 for detecting an accelerator opening corresponding to an engine load, a rotation speed sensor 23 for detecting a rotation speed of a fuel injection pump, and a cooling water temperature for detecting operating conditions. A water temperature sensor 24 to be detected,
A signal from the fuel temperature sensor 25 for detecting the fuel temperature is input. Further, the controller 21 includes a control sleeve position sensor 26 for detecting a position of the control sleeve 5 for detecting a fuel injection amount, and a fuel injection nozzle 2.
7, a signal from a nozzle lift sensor 28 as actual injection timing detecting means for actually measuring the injection timing, a key switch 29 for recognizing an engine start command, and the like are also input.

FIG. 2 shows details of the servo circuit in the fuel injection amount control device.

The main microcomputer 41 obtains a basic fuel injection amount by searching a fuel injection amount characteristic (drive Q map) from the engine speed and the accelerator opening, and performs various corrections on the basic fuel injection amount to obtain a target injection amount. The pump characteristic is calculated from the target injection amount and the engine speed to find the microcomputer output target voltage value UASLMS. This UAS
The LMS is converted to a 1.5 KHz duty signal and input to the FV conversion circuit 42, where it is converted to a target rotary solenoid output voltage UAM1, and the PID circuit 43
Is input to The PID circuit 43 also has an input circuit 44
, The actual rotary solenoid output voltage UAIST is input, and the target rotary solenoid output voltage UAM2 is determined such that the UAIST matches UAM1.
This UAM2 is converted into a 250 Hz duty signal UAM3 by the VF conversion circuit 45 and output to the rotary solenoid 6.

On the other hand, the control sleeve position sensor 2
6 (the actual rotary solenoid output voltage UAIST from the input circuit 44) is input to the sub-microcomputer 46, and the sub-microcomputer 46 determines whether the sensor 26 has failed. For example, UAIST
It is determined whether or not the sensor 26 has a failure when a state outside the normal range has elapsed for a predetermined period of time by checking whether or not is within the normal range.

However, when the feedback control of the fuel injection amount is performed by the configuration shown in FIG. 2, the difference between the sensor signal and the response characteristic of the actuator (rotary solenoid 6) or each circuit (FV conversion circuit 42, P
A failure of the ID circuit 43, the input circuit 44, the VF conversion circuit 45) or the main microcomputer 41 may cause a so-called hunting in which the sensor signal crosses the normal range in a short cycle, which is referred to as hunting. With the determination method, it cannot be determined that a failure has occurred.

The hunting will be described in more detail with reference to FIG. 5. The full range of the sensor output is 0.7 V to 3.5 V (the full range of the input circuit 44 is 0.3 V to 4.7 V). U at a cycle equivalent to 40 Hz
The AIST peak exceeds 3.5V.

In order to cope with this, in the present invention, a hunting failure is determined for the actual rotary solenoid output voltage UAIST. It should be noted that the UAIST waveform also becomes periodic due to the periodic depression of the accelerator pedal,
At this time, the UAIST does not exceed 3.5 V which is the upper limit of the full range of the sensor output, and the cycle at this time is 80 m
s, which cannot be confused with the case of hunting.

Since hunting also occurs with respect to the target rotary solenoid output voltage UAM2, a hunting failure is determined also with respect to the target rotary solenoid output voltage UAM2.

The contents of this control executed by the sub-microcomputer 46 will be described with reference to the following flowchart.
Since the failure determination method is the same for UAIST and for UAM2, the UAIST will be described below.

The flowchart of FIG. 3 is for determining a hunting failure of the output of the control sleeve position sensor, and is executed at a period (for example, a period of 4 ms) much shorter than the hunting period.

In S1 and S4, it is checked whether or not an ignition key (abbreviated as IGN KEY in the figure) has been switched from OFF to ON and whether or not a diagnosis permission condition has been met.
When the ignition key is switched from OFF to ON, it is determined that the engine has started, and the process proceeds to S2 and S3, where 0 is entered in the hunting monitor counter value (first integrated value) CSPCHK and the flag G2FLG1 is cleared. S2 and S2 are also set when the diagnosis permission condition is not satisfied although the engine is not started.
Proceed to 3.

When the ignition key is ON and the start switch is OFF, the diagnosis permission condition is satisfied.
At this time, CSPCHK is compared with the maximum value in S5, and if it is not the maximum value, CSPCHK is incremented by 1 in S6.

At S7, a normality determination counter value (second integrated value) GM5CNT is calculated. The operation of the GM5CNT will be described with reference to a subroutine in FIG.

In S21, S22, and S23 of FIG. 4, the hunting determination voltage value is 3.5 V, and the hunting determination voltage value DGHCSP (= 3.5 V) is inserted into the variable ROL in order to provide the hunting determination voltage value with hysteresis. After that, the hysteresis width HYCS
The value obtained by subtracting P (= 0.4 V) is set as the value of ROL again, and the hunting determination voltage values ROH and ROL are determined by putting DGHCSP into the variable ROH. As a result, as shown in FIGS. 5 and 6, the position at 3.5 V is at ROH, and the position at 0.4 V below is at RO.
It becomes L.

In S24 and S25, UAIST and ROL,
By comparing with ROH, <1> when UAIST is less than ROL, <2> when UAIST is greater than or equal to ROL and less than ROH, and <3> when UAIST is greater than or equal to ROH. Proceeds to S26, S27 and S28, and only when the flag G2FLG3 is in the set state, 0 is set to the normality determination counter value GM5CNT (0 at startup) and the flag G2FLG3 is cleared. <3>
In the case of, the process proceeds to S29, S30, S31 and the flag G
Only when the 2FLG3 is in the clear state, 0 is set to the normality determination counter value GM5CNT and the flag G2FLG is set.
Set 3 In the case of <2>, the current state is maintained.

In S32 and S33, the GM5CNT is compared with the maximum value.
Increment NT by one.

Referring specifically to FIG. 5, how the flag G2FLG3 and the normality determination counter value GM5CNT change, as shown, the UAIST hunts across the ROL and ROH up and down with a short period of about 40 Hz. are doing. Now, one cycle of UAIST (for example, from point A to D
4) at point A in FIG.
G2FLG3 is kept in a clear state because the flow flows through S28, S32, and S33, and GM5CNT is incremented. If point B has not been reached after 4 ms, FIG.
At S26, S28, S32, S33 and G2
GM5CNT is incremented while FLG3 is kept in the clear state. This state continues until immediately before point B, and when point B is reached, S29, S30, S31, S32,
Since it flows with S33, G2FLG3 is switched to the set state, and GM5CNT is returned to 0. After that, until just before the point C, S29, S31, S32, and S33 flow and G2
FLG3 is held in the set state, and GM5CNT increases. At point C, S26, S27, S28, S
32 and S33, G2FLG3 is switched to the clear state, and GM5CNT is returned to 0. After that, up to the point D, S26, S28, S32, and S33 flow and G2F
LG3 is kept in the clear state, and GM5CNT increases.

Thus, the GM5CNT has a UAI
Since ST is returned to 0 (cleared) at the timing of crossing ROH and ROL, the value cannot be increased when hunting occurs. On the other hand, when hunting has not occurred, the UAIST does not cross ROL and ROH as shown in FIG.
Will only increase and will not be returned to zero. That is, in FIG. 4, S24 to S26, S27 to S29,
S31 is a part for comparing the UAIST with ROH and ROL to determine whether or not the condition for clearing the GM5CNT is satisfied.

After calculating the GM5CNT in this way, returning to FIG. 3, the GM5CNT is compared with the normal-time counter clear judgment value (the second judgment value, for example, 7) CSPCNT in S8. CCSPNT is a determination value for clearing the counter value CSPCHK when it is normal, and as shown in FIGS. 5 and 6, the counter value GM5CN
It is determined that T does not reach only during hunting. Therefore, the counter value GM5CNT is equal to the judgment value CSP.
When it becomes CNT or more, it is determined that it is normal and S
Proceeding to 11, the counter value CSPCHK is returned to 0 to prepare for the next hunting failure determination.

On the other hand, GM5CNT is
If it is less than T, there is a possibility of a hunting failure, so the process proceeds to S9, where the counter value CSPCHK and the hunting determination value (the second determination value, for example, 27) CSP
Compare with CNG. If CSPCHK is equal to or greater than CSPCNG, it is determined that a hunting failure has occurred, and the flag G2FLG1 is set in S10. Setting the flag G2FLG1 to the set state indicates that a hunting failure has occurred in the control sleeve position sensor output.

Note that the CSPCNG is replaced by the CSPCNT.
The reason for making the hunting failure larger is to prevent a hunting failure from being determined before the GM5CNT is returned to 0 several times (that is, before experiencing hunting).

Here, the operation at the time of a hunting failure according to the present invention will be described with reference to FIGS.

As long as the diagnosis permission condition is satisfied, as shown in FIG. 6, two counter values CSPCHK, GM5
Both CNTs increase by one every 4 ms from the start. In this case, if hunting does not occur in the UAIST, the second counter value GM5CNT is equal to the second determination value C
At the timing when SPCNT is reached, the first counter value CS
PCHK is returned to 0, and thereafter, the second counter value GM
Since 5CNT is equal to or greater than the second determination value CCSPNT,
The first counter value CSPCHK remains at 0. The second counter value GM5CNT continues to increase thereafter, and is maintained at the maximum value after reaching the maximum value.

On the other hand, if hunting suddenly occurs at the point E during the feedback control of the fuel injection amount as shown in FIG. 5, the UAIST crosses the hunting determination voltage value ROH. GM5C
NT is returned to 0, and thereafter, the counter values GM5CNT and CSPCHK both increase by one every 4 ms.

In this case, the second counter value GM5CNT
UAIST indicates that the hunting determination voltage values ROH, ROL
Is reset to 0 every time the vehicle crosses the second counter value G
While M5CNT does not exceed the second determination value CCSPNT, the first counter value CSPCHK increases steadily to reach the first determination value CSPCNG, at which timing the flag G2FLG1 changes from the clear state to the set state. Is switched. That is, a hunting failure is determined after CSPCNG × 4 ms from the timing at which the UAIST crosses the hunting determination voltage value ROH due to the occurrence of hunting, and a predetermined fail-safe process is performed.

As described above, according to the present invention, the sensor output is sampled at a period of 4 ms shorter than the hunting period, and the first counter value CSP is sampled every 4 ms period from the start.
While the CHK is incremented by one, the second counter value GM5CNT is incremented by one every 4 ms period, and only the second counter value GM5CNT is set to 0 every time the sampling value crosses the hunting determination voltage values ROH and ROL. And the second counter value GM5CN
When the second counter value GM5CNT is equal to or greater than the second determination value CCSPNT, it is determined that the state is normal and the first counter value CS is determined by comparing T with the second determination value CCSPNT.
PCHK is returned to 0, and the second counter value GM5
If the first counter value CSPCHK is greater than or equal to the first determination value CSPCNG when the CNT is less than the second determination value CSPCNT, it is determined that a hunting failure has occurred. Therefore, the failure mode in which the sensor output hunts is determined. Can be.

It is not essential to provide hysteresis in the hunting determination voltage value, and ROL = ROH may be set. However, in this case, a hunting failure may be erroneously determined due to a bit error. Therefore, the embodiment provides hysteresis. The hunting determination voltage value is the upper limit value of the full range of the sensor output.
Instead of 5V, a voltage value within a normal range may be used. However, in the embodiment, for safety, it is the limit value of the normal range.
5V. In the embodiment, the hunting determination is performed by the sub-microcomputer, but may be performed by the main microcomputer.

As a fail-safe process when a hunting failure occurs, a fuel cut valve 33 (see FIG. 1) provided in the suction port 32 of the plunger barrel 31 is closed to shut off fuel supply and stop the engine. Let me. In the case of a hard failure of the fuel injection system such as clogging of the fuel injection nozzle, the engine is almost stopped even without the fuel cut valve 33. Therefore, the fuel cut valve 33 is provided for a small case where the engine may not stop, but in the case of a hunting failure, the fuel cut valve is closed as it corresponds to this slight case. is there.

However, as a very rare case,
During testing, it was found that the engine could not stop due to a hunting failure. According to an analysis of this, when the hunting of the actual rotary solenoid output voltage UAIST (that is, the hunting of the control sleeve) and the pumping timing of the plunger 3 are synchronized, fuel is sucked into the pressurizing chamber 4 from the cutoff port 3a in reverse. As a result, it was found that the engine rotation continued. Although the rotation speed at this time is extremely low, the engine does not stop even if the driver turns off the ignition key. Conventionally, the power supply relay is turned off under the condition that the ignition key is in the OFF state and the engine is not rotating, so that the power supply relay is not turned off unless the rotation of the engine stops.

To cope with this, in the present invention, when a hunting failure is determined and the state in which the ignition key is turned off has passed for a predetermined time, the power supply relay OF
Change to F. The contents of this control will be described with reference to the electric circuit diagram of FIG. 7 and the flowchart of FIG.

FIG. 7 shows a circuit including the power supply relay 51. The power supply relay 51 has two normally open contacts 51a and 51b arranged in parallel. The normally open contact 51a for the power system power supply has one end connected to the plus terminal of the battery 52 and the other end connected to the emitter of the transistor 53 for driving the fuel cut valve inside the controller 21. Grounded through the solenoid coil 33a of the fuel cut valve. The rotary solenoid 6 connected to the point P is connected to the collector of the electric governor driving transistor 54, and the emitter of the transistor 54 is connected to the ground.

The normally open contact 51b for the circuit power supply has one end connected to the plus terminal of the battery 52 and the other end connected to an internal circuit of the controller 21 (for example, a PID circuit constituting a part of a fuel injection amount feedback control system). 43).

The electromagnetic coil 51c of the power supply relay 51 has one end connected to the plus terminal of the battery 52, the other end connected to the collector of the power supply relay driving transistor 55, and the emitter of the transistor 55 connected to the ground. The power relay driving transistor 55 is connected to the main microcomputer 44.
Driven by the ignition switch 56
Is in the OFF state, the base current is cut off and the transistor 55 is de-energized. However, when the ignition switch 56 is switched from OFF to ON, the base current is passed to the transistor 55 in response to this, and the transistor 55 is energized. When the transistor 55 is energized, a current flows through the electromagnetic coil 51c of the power supply relay, and the normally open contact 51
Both a and 51b are closed.

It is the main microcomputer 41 that drives the transistor 53 for driving the fuel cut valve.
When the ignition switch 56 is switched to ON, the base current is not flowing, but after the initialization process is completed, the base current is flowed to turn on the transistor 53. At this time, current flows from the battery 52 to the solenoid coil 33a of the fuel cut valve 33, and the fuel cut valve 33 is opened against the return spring. When the hunting failure is determined, the base current to the fuel cut valve driving transistor 53 is cut off, and the fuel cut valve 33 is closed.

The flowchart shown in FIG. 8 is for realizing the cutoff of the power supply, and is executed every 10 ms by the main microcomputer 41 or the sub microcomputer 46 (see FIG. 2).

Steps S41, S42 and S43 are for checking whether or not the power-off condition is satisfied. First, in S41, the ignition key flag IGSW is checked. IGS
W is clear when ignition key is OFF, O
This flag is set when N is set. Accordingly, if the ignition key is ON, the process proceeds to S4 8, S4 9, together with the shut-off flag SSOFF set state, keep back the delay counter EGITM to 0.

Here, the self-shutoff flag SSO
The FF instructs that the power supply relay 51 be turned on (base current flows through the transistor 55) when the FF is in the set state, and turns off the power supply relay 51 (when the transistor 55 has the base current) when it is in the clear state. This flag indicates that no current flows. Further, the delay counter EGITM is for measuring the time from when the power-off condition is satisfied.

When the ignition key 56 is turned off, the process proceeds to S42 and S43, where the hunting failure determination flag GE0 and the engine stall determination flag FENST are checked to determine the next <1.
1) When the hunting failure judgment flag is set,
<12> If any one of the conditions when the hunting failure determination flag is in the clear state and the engine stall determination flag is in the set state is satisfied, it is determined that the power cutoff condition is satisfied, and the process proceeds to S44.

Here, in the present invention, the case of <11> is newly added when the power cutoff condition is satisfied. The case of <12> is the same as the conventional case. The hunting failure determination flag (initial setting to a clear state) is a flag that is set when a hunting failure is determined. The engine stall determination flag is a clear state if the engine is rotating due to detection of the engine speed, and is not rotating. This flag is set to the set state at the time. The hunting failure includes not only the hunting failure of the control sleeve position sensor output, but also
Needless to say, a hunting failure of the target rotary solenoid output voltage UAM2 is included.

Steps S44 and S45 are sections for delaying the engine stop signal. At S44, the delay counter value EGITM (initial setting to 0) and the delay time TMEGI
(For example, 1.28 seconds). When the process proceeds to S44 for the first time after the ignition key is switched from ON to OFF, since EGITM <TMEGI, the delay counter value EGITM is incremented in S45. If the process proceeds to S44 even after 10 ms, S45
Execute If the delay counter value EGITM eventually becomes equal to or longer than the delay time TMEGI by repeating S45, the process proceeds to S46.

In steps S46 and S47, the hunting failure determination flag QE0 is cleared and the power supply relay is turned off.
The self-shut-off flag SSOFF is cleared in order to set the state, and the power cutoff process ends. Since the hunting failure flag GE0 is stored in the volatile memory, it is cleared when the power supply relay is turned off. On the other hand, since the flag G2FLG1 is stored in the backup memory (non-volatile memory), the presence or absence of a hunting failure can be determined from this flag.

[0059] Incidentally, hunting failure determination flag S42, S43, when both the engine stall judgment flag clear state, the process proceeds to S4 8, S4 9.

Here, the operation of the present invention when the power is turned off will be described with reference to FIGS. FIG. 9 shows a case where no hunting failure has occurred, and its operation is the same as that of the conventional case. When the ignition key 56 is switched to OFF, the fuel cut valve 33 is closed, the rotation is reduced, and the engine is stopped at the timing t1, a predetermined time (for example, one second) from the stop timing.
Later, engine stall determination flag is switched to the set state, and power supply relay 51 is switched off after a predetermined time from the timing at which the engine stall determination flag is switched.

On the other hand, FIG. 10 shows that although the fuel cut valve 33 is closed at the timing t11, the hunting of the control sleeve 5 and the pumping timing of the plunger 3 are synchronized with each other due to the hunting failure to cut the fuel. Conventionally, the driver switches the ignition key 56 from ON to OFF at the timing of t12 in a case of an extremely rare case where the engine rotation continues due to the reverse suction from the off port 3a into the pressurizing chamber 4. Also, the rotation was not stopped (see the solid line in the second row in FIG. 10).

In this case, according to the present invention, when a hunting failure is determined and the ignition key 56 is turned off, the power supply relay 51 is turned off at a timing t13 after a predetermined time. When the power supply of the circuit system in the controller 21 is cut off by turning off the power supply relay 51, the operation of the PID circuit 43 (which constitutes a part of the servo circuit in the fuel injection amount control device) in FIG. 7 is stopped. Therefore, the hunting of the control sleeve 5 stops. As a result, the fuel supply from the cutoff port 3a is cut off, so that the rotation eventually decreases and the engine stops (see the dashed-dotted line at the second stage in FIG. 10).

As described above, according to the present invention, the case where the hunting failure is determined and the ignition key is kept OFF for a certain period of time is added when the power cutoff condition is satisfied, so that the fuel is cut due to the hunting failure. Even in the extremely rare case where the engine rotation continues by being supplied to the high pressure plunger pump by flowing backward from the off port, as long as the ignition key is turned off,
The engine can be stopped.

In order to continue rotation due to a hunting failure,
In FIG. 7, since the main microcomputer 41 and the PID circuit 43 driven by the circuit system power supply and the rotary solenoid 6 driven by the power system power supply are involved, both the circuit system power supply and the power system power supply are shut off in the embodiment. However, it is also possible to shut off only one of the power supplies. Further, as shown in FIG. 2, the servo circuit is composed of many circuit elements, and therefore, it is not necessary to shut off the power of all the circuits but to shut off the power of at least one of them. I don't care.

[0065]

According to the present invention, when the ignition key is OFF and the engine is not running, the power is turned off, and the fuel is supplied in a reverse flow due to a hunting failure. When the ignition key is turned off, the power cannot be cut off by switching the ignition key to the OFF state. However, in the first and second inventions, the hunting failure is determined and the power is turned off when the ignition key is turned off. Therefore, even in rare cases, the rotation is not continued due to the hunting failure.

[Brief description of the drawings]

FIG. 1 is a detailed view of a fuel injection pump.

FIG. 2 is a control block diagram of a fuel injection amount.

FIG. 3 is a flowchart for explaining determination of a hunting failure of a sensor output.

FIG. 4 is a flowchart for explaining the calculation of a normality determination counter value GM5CNT.

FIG. 5 is a waveform chart at the time of a hunting failure of a sensor output.

FIG. 6 is a waveform diagram of a sensor output in a normal state.

FIG. 7 is an electric circuit diagram.

FIG. 8 is a flowchart for explaining power shutoff.

FIG. 9 is a waveform diagram for explaining power cutoff when a hunting failure has not occurred.

FIG. 10 is a waveform diagram for explaining power supply interruption when a hunting failure occurs.

FIG. 11 is a diagram corresponding to claims of the first invention.

FIG. 12 is a diagram corresponding to claims of the second invention.

[Explanation of symbols]

 Reference Signs List 1 injection pump 5 control sleeve 6 rotary solenoid (actuator) 21 controller 26 control sleeve position sensor 51 power relay 52 battery

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F02D 41/22 380 F02D 1/02 311 F02D 45/00 345 F02N 11/08

Claims (7)

(57) [Claims] (1) When an ignition key is in an OFF state and
The power shutdown condition is that the engine is not rotating.
A control device for a diesel engine, an engine control actuator, and a means for calculating a control amount given to the actuator such that a control target value corresponding to an engine operating condition and an actually measured control value detected by a sensor coincide with each other. Means for outputting the actuator control amount to the actuator; means for setting a failure determination value for the sensor output; determining that the hunting failure has occurred when the sensor output has crossed the failure determination value a predetermined number of times within a predetermined time. Means for determining a hunting failure and turning the ignition key off.
Means for shutting off the power supply when the state becomes the F state. The ignition key is turned off and
The power shutdown condition is that the engine is not rotating.
A control device for a diesel engine, an engine control actuator, and a means for calculating a control amount given to the actuator such that a control target value corresponding to an engine operating condition and an actually measured control value detected by a sensor coincide with each other. A means for outputting the actuator control amount to the actuator; a means for setting a failure determination value for the actuator control amount; and a hunting failure when the actuator control amount crosses the failure determination value a predetermined number of times within a predetermined time. Means for determining that a hunting failure has occurred and the ignition key is OFF
Means for shutting off the power supply when the state becomes the F state. 3. The control apparatus for a diesel engine according to claim 1, wherein the power supply is cut off when the hunting failure is determined and the ignition key is turned off for a predetermined time. . Wherein said power supply control apparatus for a diesel engine according to any one of claims 1 to 3, characterized in that the circuit system power source for driving the control amount calculation means. 5. A control device for a diesel engine according to any one of the power supply from claim 1, characterized in that the power system power supply for driving the actuator to 3. 6. The diesel engine control device according to claim 1, wherein the actuator is a control sleeve control actuator, and the sensor is a control sleeve position sensor. 7. The control system for a diesel engine according to claim 6, wherein a fuel cut valve provided in a suction passage to a plunger pump for pumping fuel is closed when the hunting fails.