JPH0536997Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an electronic governor having an engine protection function.

(Prior Art) Generally, an electronic governor has a rotation detection means for detecting the engine rotation speed, an accelerator detection means for detecting the amount of accelerator depression, and a position detection means for detecting the position of the control member of the fuel injection pump. are doing. The calculating means receives the detection signals from the rotation detecting means and the accelerator detecting means, calculates a target fuel injection amount, calculates the target position of the control member based on this, and controls the control member fed back from the position detecting means. The deviation between the actual position of the member and the target position is calculated, and this deviation signal is output to the drive circuit of the electromagnetic actuator. As a result, the electromagnetic actuator controls the position of the control member to the target position, thereby controlling the amount of fuel injected from the fuel injection pump.

By the way, if the above-mentioned position detection means, drive circuit, etc. are out of order, the drive current to the electromagnetic actuator may flow unlimitedly, causing the control member to be pulled to the maximum in the fuel increasing direction. This may increase abnormally, causing the engine to overrun and cause engine failure.

Therefore, normal electronic governors have overrun prevention means as an engine protection function.
When the rotational speed exceeds the allowable rotational speed, this is detected and the supply of drive current to the electromagnetic actuator is stopped, thereby stopping the engine.

However, with this overrun prevention means, the engine will not be stopped unless the engine speed reaches the allowable speed and an overrun condition occurs, so it cannot prevent the engine from continuing to rotate at high speeds near this allowable speed, which may result in engine failure. The function to prevent this was insufficient.

Therefore, an electronic governor described in Japanese Utility Model Application Publication No. 55-6452 has been developed. That is, the amount of accelerator depression from the accelerator detection means is compared with the reference amount of depression, and the number of rotations obtained from the rotation sensor is compared with the reference number of rotations. Note that this reference rotation speed is lower than the above-mentioned allowable rotation speed for preventing overrun, and is a value within the normal usage range. If the engine rotation speed is higher than the reference rotation speed even though the accelerator depression amount is lower than the reference depression amount, it is assumed that an abnormality has occurred and the engine is stopped.

(Problem that the invention attempts to solve) However, with the electronic governor in the above publication, when going down a slope while applying engine braking, if the engine speed exceeds the above reference speed, there will be no failure and the device will operate normally. Despite this, the engine was stopped and there was a risk that normal operation after engine braking would be hindered.

Also, if you step on the accelerator when the gear is in a neutral state, that is, when the engine and the drive shaft of the vehicle are not connected, the rotation speed will immediately rise to exceed the standard rotation speed, but if you release the accelerator in this state, Immediately after that, the engine speed may not be able to drop below the reference speed, and even in this case, an abnormality has occurred and the engine may be stopped even though the engine is in a normal state.

(Means for solving the problem) The present invention was made to solve the above problem, and its gist is that as an engine protection function,
(b) connection determining means for determining whether or not the engine and the drive shaft of the vehicle are connected; (b) accelerator determining means for comparing the accelerator operation amount obtained from the accelerator detection means with a reference operation amount; ) a rotation speed determination means for comparing the engine rotation speed obtained from the rotation detection means with a reference rotation speed; is not connected to the drive shaft and the accelerator operation amount remains smaller than the standard operation amount, and when the engine speed rises from a state lower than the standard rotation speed and exceeds the standard rotation speed, this occurs. An electronic governor having an engine holding function is characterized by comprising: abnormality detection means for detecting an abnormality; and (e) engine stop means for stopping the engine based on an abnormality detection signal from the abnormality detection means.

(Function) If the engine is not connected to the drive shaft and the accelerator operation amount remains smaller than the standard operation amount, and the engine speed increases after passing through the upper standard rotation speed, this will be detected as an abnormality and the engine will be shut off. make it stop. Since this reference rotation speed can be lower than the standard allowable rotation speed for normal overrun prevention, it is possible to stop the engine before it reaches an overrun state, and the engine can be reliably protected.

As determined by the connection determining means, when the engine and the drive shaft of the vehicle are connected, the engine will not stop, so if you drive down a slope while applying engine braking, the engine will not malfunction and stop. can be prevented.

In addition, if the engine and the vehicle's drive shaft are not connected, and you press the accelerator to raise the engine speed to a point that exceeds the standard rotation speed, and then release the accelerator, the engine speed will Since the rotation speed will not rise until it is low, even if the rotation speed cannot be lowered to below the reference speed immediately after the accelerator is released, the abnormality detection means will not output an abnormality detection signal, and therefore, in this case, the abnormality detection means will not output an abnormality detection signal. This also eliminates the inconvenience of the engine stopping under normal conditions.

(Example) An example of the present invention will be described below with reference to FIGS. 1 and 2. As shown in FIG. 1, the electronic governor 1 has a position sensor 2 (position detecting means), an accelerator sensor 3 (accelerator detecting means), and a rotation sensor 4.
(rotation detection means), neutral sensor 5 (connection determination means), and these sensors 2 to
A microcomputer 6 receives a detection signal from the microcomputer 5, a drive circuit 7 receives a signal from the microcomputer 6, and a control member for the fuel injection pump 20 driven by the drive circuit 7 (in the case of an in-line fuel injection pump, an electromagnetic actuator 8 that moves the control rack), an engine stop device 9 that is activated by an abnormality detection signal from the microcomputer 6, and an abnormality display device 10.
It has

The position sensor 2 detects the position of the control rack. The accelerator sensor 3 detects the amount of depression (operation amount) of the accelerator. Analog detection signals from these sensors 2 and 3 are converted into digital signals and sent to the microcomputer 6.

The rotation sensor 4 obtains a pulse for each unit angle rotation of the diesel engine, calculates the number of revolutions from this pulse, and outputs the result to the microcomputer 6. Incidentally, it is a matter of course that the rotation speed calculation may be performed by the microcomputer 6.

The above-mentioned neutral sensor 5 is for determining whether the gear is in neutral or not, and outputs an H level signal when the gear is in neutral, and outputs an L level signal when it is not in neutral. It's summery.

In FIG. 1, the microcomputer 6 is shown divided into blocks for each function. To be more specific, the microcomputer 6 has a calculation means 11 for performing normal control. This calculating means 11 calculates a target fuel injection amount based on the accelerator depression amount from the accelerator sensor 3 and the rotation speed from the rotation sensor 4, and determines the target position of the control rack corresponding to this fuel injection amount. calculate. Further, information on the actual position of the control rack is inputted to the calculation means 11 from the position sensor 2, and the deviation between the target position and the actual position is calculated, and this deviation signal is sent to the drive circuit 7. It's getting old. Therefore, the electromagnetic actuator 8 is controlled to the control rack position so that the amount of fuel injected from the fuel injection pump 20 becomes the target amount.

The microcomputer 6 has an accelerator discrimination means 13. In the accelerator determination means 13,
Accelerator depression amount (operation amount) Acc from accelerator sensor 3 is the reference depression amount (using reference operation)
When it is larger than X, an L level signal is output, and when it is smaller, an H level signal is output.

The microcomputer 6 has first to third rotation speed determining means 14 to 16 and an abnormality detecting means 17. Each of the rotational speed determination means 14 to 16 determines whether the engine rotational speed Ne from the rotational sensor 4 is larger than the rotational speed Y ₁ , Y ₂ , Y _{3 ,} respectively, and if larger, outputs an H level signal. This is what is output. Here, Y ₃ > Y ₂ > Y ₁ .

The abnormality detection means 17 outputs an abnormality detection signal as described below based on the signal from the neutral sensor 5, the signal from the accelerator discrimination means 13, and the signals from the rotation speed discrimination means 14, 15, and 16. It is something to do.

The microcomputer 6 further includes overrun detection means 19. The overrun detection means 19 compares the engine rotational speed Ne and the allowable rotational speed _Y4 , and outputs an overrun detection signal when the engine rotational speed is larger. Note that Y ₄ >Y ₃ .

The engine stop device 9 includes, for example, a throttle valve provided in the intake manifold of the engine and an electromagnetic actuator that turns the throttle valve to control opening and closing. When a run detection signal is received, the engine is stopped by closing the throttle valve and reducing the intake air to the engine combustion chamber to zero.

In the above configuration, during normal operation, the electromagnetic actuator 8 is controlled by the calculation means 11 as described above to control the amount of fuel injected from the fuel injection pump 20.

If a malfunction occurs such as the position sensor 2 becoming short or open, the calculation means 11 may output a large deviation signal regardless of the detection signals from the accelerator sensor 3 or rotation sensor 4. If so, an unrestricted current may flow through the electromagnetic actuator 8, pulling the control rack in the direction of maximum injection. When such a failure occurs, if the gear is in neutral and the accelerator is released or the amount of pedal depression is small, the abnormality can be detected and the engine can be stopped.

Specifically, when the gear is in neutral, that is, when the engine is not connected to the drive shaft of the vehicle, the output from the neutral sensor 5 is at H level. Further, when the accelerator is released, the accelerator determining means 13 detects that the accelerator depression amount is smaller than the reference depression amount X, and outputs an H level signal.

In the abnormality detection means 17, the neutral sensor 5
Then, while receiving the H level signal from the accelerator discrimination means 13, a change in the engine speed Ne is detected. In other words, if the engine speed Ne increases from a state lower than the engine speed Y ₁ through the engine speeds Y ₁ , Y ₂ , Y ₃ , or from a state lower than the engine speed Y ₂ to the engine speeds Y ₂ , Y If it increases after passing through ₃ , this is regarded as an abnormality and an abnormality detection signal is output.

When the abnormality detection signal from the abnormality detection means 17 is output, the engine stop device 9 is activated to stop the engine, and the abnormality is displayed on the abnormality display device 10.

In the present invention, when the above-mentioned failure occurs, an abnormality is detected by focusing on the fact that the engine speed increases even when the accelerator is released.

Note that even if the engine speed Ne rises and exceeds the engine speed _Y3 when the accelerator is depressed under normal conditions, the accelerator discrimination means 13 determines that the accelerator depression amount Acc is larger than the reference depression amount X and issues a signal. In order to set the level to L, no engine stopping operation is performed.

In addition, if you step on the accelerator in a neutral state to increase the engine speed Ne until it exceeds the engine speed Y ₃ , and then release the accelerator,
In a normal state, the engine speed Ne is low and does not increase, so even if the engine speed Ne does not drop below _Y3 immediately after the accelerator is released, the abnormality detection signal is output from the abnormality detection means 17. Therefore, it is possible to eliminate the inconvenience of the engine stopping under normal conditions.

Further, when the vehicle descends a slope while applying engine braking, the signal from the neutral sensor 5 is at the L level, so the abnormality detection means 17 does not output an abnormality detection signal. Therefore, inconveniences such as the engine stopping when engine braking is applied can be prevented.

Abnormality detection by the abnormality detection means 17 is actually achieved by executing a program as shown in FIG. First, in step 100, it is determined whether the gear is in neutral. If it is not neutral, the flag is cleared in step 110. If neutral, step
Do 101.

In step 101, it is determined whether the accelerator depression amount Acc is smaller than the reference depression amount X or not.
If they are greater or equal, the flag is cleared in step 110 above. If small, step
Run 102.

In step 102, the engine speed Ne is
Determine whether Y is greater than ₁ . If they are smaller or equal, the flag is cleared in step 110 above. If it is larger, step 103 is executed.

In step 103, the engine rotation speed Ne is the rotation speed
Determine whether Y is greater than ₂ . If they are less than or equal, ie, Y ₂ ≧Ne>Y ₁ , a flag is set in step 120. Engine speed Ne
If the number of revolutions is greater than _Y2 , step 104 is executed.

In step 104, the engine speed Ne is set to
Determine whether Y is greater than ₃ . If they are smaller or equal, that is, if Y ₃ ≧Ne>Y ₂ , the program is terminated. If the engine speed Ne is greater than the engine speed _Y3 , step 105 is executed.

In step 105, it is determined whether the flag is set. Terminate the program when the flag is clear. If the flag is set, Y ₂ ≧Ne>
Y ₁ , which means that Ne > Y ₃ when the program was executed this time, so the engine speed Ne
It is determined that the engine has gone through a rising process and has exceeded _Y3 , and step 106 is executed to activate the engine stop device 9 and abnormality display device 10.

The overrun detection means 19 of the microcomputer 6 outputs an overrun detection signal when the engine exceeds the allowable rotation speed _Y4 , regardless of whether the engine is in neutral or how much the accelerator is depressed. Stop the engine.

In addition to the failure of the position sensor 2, the drive circuit 7, the electromagnetic actuator 8, and the fuel injection pump 2
An abnormal increase in engine speed caused by a failure in the engine is detected in the same way, and the engine can be stopped.

The present invention is not limited to the above embodiments and can be modified in various ways. For example, it is of course possible to replace each function of the microcomputer with ordinary circuits.

As connection determination means for determining whether or not the engine and the drive shaft of the vehicle are connected, a clutch sensor may be used instead of the neutral sensor, or both may be used. The clutch sensor outputs, for example, an L level signal when the clutch is in a connected state, and an H level signal when the clutch is in a disengaged state.

The engine stop device may be a relay switch that opens and closes the drive circuit of the electromagnetic actuator. In addition, in the distribution type fuel injection pump, a solenoid valve placed in the fuel supply passage from the low pressure chamber where fuel is stored to the fuel pressurizing chamber is used as an engine stop device, and the solenoid valve is closed in the event of an abnormality. The engine may be stopped by reducing the fuel injection amount to zero.

In the case of distributed fuel injection pumps, a control sleeve is used as the control element. In this case, the sleeve position is fed back by a position sensor.

Recently, distribution type fuel injection pumps have been developed in which the fuel pressurization chamber and the low pressure chamber are communicated through a relief passage, and fuel injection is controlled by opening and closing a solenoid valve provided in the relief passage. However, this solenoid valve may be used as an electromagnetic actuator. In this case no control member is required.

When the accelerator depression amount is smaller than the _reference depression amount It may be detected as an abnormality.

(Effects of the invention) As explained above, with the present invention, even if the electronic governor becomes unable to control the speed, the engine can be stopped before the engine goes into overrun state, and the engine can be reliably operated. can be protected. What's more, when the engine and the vehicle's drive shaft are not connected, the accelerator is pressed to increase the engine speed to a point that exceeds the standard speed.
When the accelerator is released after this, or when engine braking is applied, there is no misjudgment that an abnormality has occurred, and unnecessary engine stoppage can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of an electronic governor according to the present invention, and FIG. 2 is a flowchart of processing in a microcomputer. 1... Electronic governor, 3... Accelerator detection means (accelerator sensor), 4... Rotation detection means (rotation sensor), 5... Connection judgment means (neutral sensor), 7... Drive circuit, 8... Electromagnetic Actuator, 9...Engine stop means (engine stop device), 11...Calculation means, 13...Accelerator discrimination means, 14-16...Rotational speed discrimination means, 17...
Abnormality detection means, 20...Fuel injection pump, Acc...
...Accelerator operation amount, X...Reference operation amount, Ne...
Engine rotation speed, Y ₃ ...Reference rotation speed.

Claims (1)

[Scope of claim for utility model registration] Rotation detection means for detecting the rotation speed of the engine;
an accelerator detection means for detecting an accelerator operation amount;
An electronic governor comprising a calculating means for performing calculations in response to the rotation detecting means and the accelerator detecting means, and an electromagnetic actuator for controlling the fuel injection amount from the fuel injection pump by operating based on the calculation results, Furthermore, as an engine protection function, (a) a connection determination means for determining whether or not the engine and the drive shaft of the vehicle are connected; and (b) a comparison of the accelerator operation amount obtained from the accelerator detection means with a reference operation amount. (c) a rotation speed determination means for comparing the engine rotation speed obtained from the rotation detection means with a reference rotation speed; and (d) information from the connection determination means, the accelerator determination means, and the rotation speed determination means. Calculation is performed based on An engine protection function characterized by comprising: an abnormality detecting means for detecting this as an abnormality when the number exceeds the number, and (e) an engine stopping means for stopping the engine based on an abnormality detection signal from the abnormality detecting means. Electronic governor with.