JPH041445A - Internal combustion engine power controller - Google Patents

Abstract

PURPOSE:To take a proper countermeasure by lowering the power of an internal combustion engine forcibly and judging whether it is overloaded or not, in the case where an engine power regulating means is in almost maximum power control variable, and engine speed is lowered as far as more than the specified speed. CONSTITUTION:Rotational frequency of an internal combustion engine A is detected by a means B, and engine power is regulated by a means C, while the means B is feedback controlled by a means D so as to be turned to the specified engine speed. In addition, whether the means C is almost in the maximum power control variable or not is detected by a means E. Moreover, when the means C is almost in the maximum power control variable and the rotational speed of the engine A is lowered as far as more than the specified speed, the means C is controlled by a means F so as to forcibly lower the power of the engine A. When a drop in rotational speed corresponding to control over the means F is not generated in the engine A, it is so judged that the engine A goes wrong, thus the specified troubleshooting is performed by a means G.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an output control device for an internal combustion engine, and more particularly to an output control device that determines abnormality in a throttle valve or the like.

[Prior Art] Generally, an internal combustion engine is used as one of the power sources for industrial equipment such as heat pumps, cogeneration systems, or power generators. Inside this internal combustion engine,
There is one in which the actual rotational speed (hereinafter referred to as actual rotational speed) is feedback-controlled to a predetermined target rotational speed. This feedback control is executed, for example, by automatically adjusting the opening degree of the throttle valve so that when the actual rotation speed deviates from the target rotation speed by a predetermined speed, the actual rotation speed approaches the target rotation speed. There is. That is, when the actual rotation speed is lower than the target rotation speed, the throttle valve is driven to the open side to increase the output of the internal combustion engine and increase the actual rotation speed, and conversely, when the actual rotation speed is higher than the target rotation speed, the throttle valve is opened. is driven toward the closed side, thereby lowering the output of the internal combustion engine and lowering the actual rotational speed.

However, if the throttle valve or fuel system used to adjust the output malfunctions (the rotational speed may become extremely low or high, this may cause problems for industrial equipment that requires a stable and appropriate rotational speed).

To solve this problem, a control device is known that automatically detects an abnormality in the internal combustion engine and stops the engine (Japanese Patent Laid-Open No. 60-259735).

In this control device, abnormality detection has been performed, for example, as follows. That is, when the engine rotation speed falls out of a set control range, the rotation speed is forcibly increased. If the actual rotation speed does not increase even after this forced rotation speed increase operation: 1. t.

The internal combustion engine was forcibly stopped due to an abnormality caused by clogging of the fuel filter or air filter. There are disadvantages in determining abnormalities in the internal combustion engine as shown in Table 1 below.

That is, this is a case where the internal combustion engine is overloaded due to some factor. In this case, even though the engine output is set to the maximum (for example, the throttle valve is fully open), the actual rotational speed is significantly lower than the target rotational speed. Even if you try to increase the throttle valve opening, it is already fully open and it is physically impossible to open it any further. Regardless of whether feedback control or forced control is used, it is impossible to achieve the target rotational speed by operating the throttle valve.

Therefore, even though there is nothing abnormal about the internal combustion engine, the conventional control device described above will determine that the internal combustion engine is abnormal. For this reason, the internal combustion engine is forcibly stopped every time an overload occurs, and the manager has to rush in and restart it every time an overload occurs, which is extremely cumbersome and inefficient. do not have.

[Purpose] The present invention has been made with the aim of solving the above-mentioned problems, and is an internal combustion engine that improves the efficiency of management of an internal combustion engine by preventing the internal combustion engine from being judged as abnormal only in an overload state. This provides an engine output control device.

Awesome! [Means for Solving the Problem] As illustrated in FIG. 1, the output control device for an internal combustion engine of the present invention comprises: a rotational speed detection means for detecting the rotational speed of the internal combustion engine; and a rotational speed detection means for adjusting the output of the internal combustion engine. an engine output adjustment means; a rotation speed control means for performing feedback control on the engine output adjustment means so as to achieve a predetermined target rotation speed; and detecting whether or not the engine output adjustment means has reached a substantially maximum output control amount. When the output control amount detection means and the engine output adjustment means are at almost the maximum output control amount and the rotational speed of the internal combustion engine has decreased by a predetermined speed or more from the predetermined target rotational speed, the output of the internal combustion engine is determined. an output reduction means for controlling the engine output adjustment means to forcibly reduce the engine output; If it is determined that there is an abnormality and a predetermined abnormality process is started, and if a decrease in rotational speed occurs in the internal combustion engine corresponding to the control of the output reduction means, it is determined that the internal combustion engine is not abnormal and a normal process is performed. The present invention is characterized by comprising: an abnormality determination processing means for returning to the original state;

[Operation] The output reduction means checks the detected values of the output control amount detection means and the rotational speed detection means. As a result, the engine output adjustment means is at almost the maximum output control amount, and if it is found that the rotational speed of the internal combustion engine has decreased by a predetermined speed or more from the predetermined tank rotational speed, the output of the internal combustion engine is adjusted. The engine output adjustment means is controlled to forcefully reduce the engine output.

If the cause is simply overload, it should be possible to further reduce the rotational speed by controlling the output in the direction of decreasing it. Therefore, even if the output reduction control is executed, if the rotational speed does not decrease, it can be determined that the internal combustion engine is abnormal. If it is determined that an abnormality has occurred, processing will be carried out in the event of an abnormality, such as forcibly stopping the internal combustion engine.

On the other hand, if a decrease in rotational speed occurs in the internal combustion engine due to control in the direction of decreasing output, it can naturally be determined that the internal combustion engine is not abnormal, but merely overloaded, for the above reasons. Therefore, it is sufficient to return to normal processing such as normal feedback processing.

[Example] Next, an example of the present invention will be described based on the drawings. Second
The figure shows the system configuration of the output control device. The output control device includes an electronic control circuit 1, a rotation angle sensor 3, an ignition coil 5, an intake pipe negative pressure sensor 7, a stepping motor 9, and a fuel cutoff valve 11.

The electronic control circuit 1 includes a CPU 1a, a ROM 1b, and a RAM 1.
It is configured as a microcomputer equipped with input/output circuits (Ilo), ld, etc. CPLJla is ROM1
The detection values of the rotation angle sensor 3 and the intake pipe negative pressure sensor 7 or the ROM 1b are stored in accordance with the program stored in the ROM 1b.
various setting values in , and stepping motor 9 in RAM1c.
The operating state of the internal combustion engine 3 is detected based on stored values such as control values. And the ignition timing suitable for the operating condition,
Performs various calculation processes to calculate throttle valve opening, fuel cutoff area, etc. The result of this arithmetic processing is sent to the ignition coil 5.
, stepping motor 9, and fuel cutoff valve 1], thereby controlling the operating state of the internal combustion engine]3.

The rotation angle sensor 3 detects a rotation signal having a period corresponding to the rotation speed of the internal combustion engine 3 based on the rotation of a crankshaft pulley 17 attached to the crankshaft 15.

The ignition coil 5 generates a high voltage based on the ignition signal output from the electronic control circuit 1 and supplies it to the ignition plug 19 .

The intake pipe negative pressure sensor 7 detects the negative pressure within the intake pipe 13a of the internal combustion engine 13. The stepping motor 9 drives the throttle valve 2 based on a control signal corresponding to the calculated throttle valve opening correction value to adjust its opening. The fuel cutoff valve] is controlled to close in order to stop the operation of the internal combustion engine when the present output control device determines that there is an abnormality.

Note that the internal combustion engine 13 is a normal gasoline engine or a gas engine, and sucks outside air from an air cleaner 23.
Gasoline or gas is atomized and mixed from a nozzle 27 of a carburetor in a venturi 25, and is introduced into a combustion chamber 29 through a throttle valve 21. When the air-fuel mixture is ignited and combusted by the spark plug 19 in the combustion chamber 29, the energy rotates the crankshaft 5 via the piston 3. As a result, the crankshaft pulley 1
7 rotates, and the rotation angle sensor 3 detects its rotation speed, that is, the rotation speed NE of the internal combustion engine.

Note that during normal control, the electronic control circuit 1 controls the opening degree of the throttle valve 21 in order to control the internal combustion engine 13 to a predetermined target rotational speed.

During this control, changes in the load applied to the internal combustion engine 13 are as follows:
This can be determined from the opening degree of the throttle valve 21 (the number of steps of the stepping motor 9) and the detected value of the intake pipe negative pressure sensor 7. The larger the number of steps of the stepping motor 9 or the smaller the negative pressure (closer to atmospheric pressure), the larger the load.

Flowcharts of the processing executed by the electronic control circuit are shown in FIGS. 3 to 5, and a timing chart of a specific example thereof is shown in FIG. 6.7.

FIG. 3 shows a throttle drive routine for opening and closing the throttle valve 21 to detect overload operation, and FIG. 4 shows an overload determination routine for determining overload operation based on the rotational speed deviation.
FIG. 5 shows a flowchart of a general NE abnormality determination routine.

In addition, as a normal control, throttle valve 2]
Rotational speed feedback processing is executed to achieve the target rotational speed by opening and closing the , but since such processing is well known, illustration and explanation will be omitted.

First, the throttle drive routine shown in FIG. 3 will be explained. This process is repeatedly executed at predetermined time intervals.

When the process starts, it is first determined whether JNE, which is the deviation between the preset target rotation speed NETARG and the actual rotation speed NE checked in a routine (not shown), is smaller than the NE abnormality judgment value. Determined (step 11
0). If an affirmative determination is made, it becomes clear that the actual rotational speed NE is within a normal range, and the NEE normal determination is canceled (step 120). For example, the NEE normal determination flag is reset. If the NEE normal determination is already in the canceled state, that state will be maintained.

Next, the overload determination counter C0VL is cleared (step 130), the overload flag X0VL is reset (step 40), and the throttle valve opening/closing cycle counter CJUD is cleared (step 15o).

Next, it is determined whether the overload flag ×○VL is set (=1) (step) 60. Currently, ×○VL is reset (=O
), it is assumed that the overload condition is not satisfied, and the rotational speed control is set to normal feedback control (step 170). That is, the normal feedback processing of the throttle valve 2 continues without being stopped.

On the other hand, if a negative determination is made in step 110, 5, JN
Since E is smaller than α (ANE≧α), it is determined that the rotational speed NE cannot be maintained near the target rotational speed NETARG, and it is determined that the rotational speed is abnormal (Step) 8
0). Here, for example, a NEE normal determination flag is set. In FIG. 6, this corresponds to the state at time t1.

Next, it is determined whether the throttle valve opening value C3TEP stored in the RAM 1c as a control value for the stepping motor 9 is a fully open value (step 190). If the value indicates full open, the two conditions of "rNE abnormality determination" and "throttle valve opening = fully open" are satisfied, so there is a possibility of overload operation.

In other words, this indicates that there is a possibility that a load exceeding the maximum output of the internal combustion engine 13 is applied, and that even if the throttle valve 2 is fully opened, the actual rotational speed NE may not reach the target rotational speed. There is.

However, in order to prevent control hunting, in practice,
Using the overload determination counter C0VL, only when this state continues for a predetermined time TI, a process for determining overload is started. That is, step 190
When an affirmative determination is made, first, an overload determination counter C0VL is incremented (step 200).
. Next, it is determined whether C0VL is less than the set time T1 (step 210). If C0VL has not yet reached T1, an affirmative determination is made and the processes from step 140 onwards are executed. In other words, it is processed as a state in which no overload judgment processing is performed.The feedback state continues (
Step] 70).

In FIG. 6, this corresponds to the state from time t1 to time t2.

Negative determination is made in step 110.If the state in which the affirmative determination is made in step 110 continues, and C0VL becomes lower than 1 for the set time by incrementing C0VL in step 200 (time t2), negative determination is made in step 2]0. It will be judged. Next, overload flag X0VL is set (step 220). Furthermore, to prevent overflow of the memory storing the C0VL value, C0VLI:T
A value of l+1 is set (step 230).

Next, in the determination process of step 160, the previous step 22
Since X0VL=1 at 0, an affirmative determination is made.Next, it is determined whether the throttle opening/closing cycle counter CJUD exceeds "1" (step 240). Initially, since CJUD is "0", a negative determination is made and the feedback control process is stopped. The following open loop control is performed (step 250). Therefore, from time t2, feedback control is switched to open loop control.

Next, interval counter C0VL2 is incremented (step 260). In addition, C0vL2 is initially “
0'', therefore, C0VL2=1 in this process.

Next, it is determined whether C0VL2 is equal to or longer than throttle opening/closing cycle time T2 (step 270).

Initially, since C0VL2<T2, a negative determination is made and the process is temporarily terminated.

If the state where the negative determination is made in step 270 continues and C0VL2≧T2 is established by the increment in step 260 (time t3), the affirmative determination is made in step 270. Next, the throttle opening/closing control flag XJUD is set to rO
J or not is determined. Since the first instruction is to drive the stepping motor in the closing direction (X JUD = 0), an affirmative determination is made and the throttle valve opening degree C3TEP = fully open - Δ
Set the throttle control target value to the 5tep position (
Step 290). Due to this, [Full-open-/s t
In order to realize e pJ , the stepping motor 9 rotates in the closing direction. In this way, if there is no abnormality in the throttle valve 2], the opening degree of the throttle valve 2] is "fully open - Δ
It becomes 5tepJ.

Next, X J U [) = 1 is set (step 300)
, the interval counter C0VL2 is cleared (step 310), and the process ends.

Next, in step 190, in step 290, rc
Since sTEP=fully opened-astepJ, a negative determination is made. Next, an affirmative determination is made in step 160, and a negative determination is made in step 240. next step 250
After that, increment from C0VL2=0 is executed again in step 260. Therefore, at step 270, since C0VL2<T2, a negative determination is made and the process is temporarily terminated.

Repeat step 260 increment and C0VL
If 2≧T2 (time t4), since 2XJUD=1 has already been set, a negative determination is made in step 280 this time. Next, set the throttle control target value to the throttle valve opening C3TEP=fully open position (step 3
20). As a result, the stepping motor 9 rotates in the opening direction, and if normal, the throttle valve 2 opens fully.

Next, XJUD=O is set (step 330), and the throttle valve opening/closing cycle counter CJUD is incremented to become CJUD=1 (step 340).
). Furthermore, the interval counter C0VL2 is cleared (step 310), and the process ends on -1.

When another 12 hours have passed (time t5), step 280
If the determination is made in the affirmative, the process of step 290 is executed, and the opening degree of the throttle valve 21 becomes [fully open - dstepJ] again.

Then, when another 12 hours have passed (time t6), a negative determination is made in step 280, step 320 is executed, and the opening degree of the throttle valve 21 is returned to "fully open". At this time, CJUD=2 (step 340)
. Therefore, when this process is executed again, step 240
An affirmative determination is made in , and the feedback control is returned to (
Step] 70).

After that, if the overload disappears (t7), the actual rotational speed NE
gradually increases to the target rotational speed N by feedback control.
Approaching ETARG.

Although not shown, during the above processing (tl to t6)
, /NEh<NE abnormality determination value α, which indicates that the rotational speed can be controlled to near the target rotational speed NETARG. Therefore, an affirmative determination is made in step ]]0, and the NE abnormality determination is made. It is released (step 120).

Therefore, step]40 is executed and X0VL=O
Therefore, a negative determination is made in step 160. Therefore,
The process returns to feedback control even before time t6 (step 170).

In the processing of steps 290 and 320 above, in order to detect an abnormality in the throttle valve 2,
] is controlled to fluctuate by a predetermined opening width Jstep using open loop control. Whether or not the throttle valve 2 has actually fluctuated by the degree width A s t e p during this time is determined by whether or not the rotational speed of the internal combustion engine 3 has actually fluctuated by Δ5tep. be able to. From this, you can determine whether there is an overload or a problem with the throttle valve.

Next, an overload determination routine that implements this function will be explained with reference to FIG. This process is an interrupt process that is repeatedly executed at predetermined time intervals.

First, it is determined whether the above-mentioned overload flag X0VL=1 (step 4] 0). x.

If VL=0, a negative determination is made, the NEOVL setting rotation speed during NE abnormality is cleared (step 420), and the overload detection operation deviation NEOLJ (=NEOV
L-NE) is cleared (step 430) and NEOL
The peak value NE○LJBF of the J data is cleared (step 44o). That is, since there is no overload or the overload cannot be determined, no special processing is performed.

When ×○VL21 is set in step 220 of the process, an affirmative determination is made in step 410 in this process,
It is determined whether or not it is the rising timing of the overload flag X0VL (the first X0VL21 detection timing after time t2 in FIG. 6) (step 450). If it is the rising timing, the actual rotational speed NE at that time is NE
The abnormality setting rotation speed is set as NEOVL (step 460).

This process is started again, and when the determination in step 450 is reached, a negative determination is made because it is not the rising timing of X0VL, and the deviation between the above-mentioned NE abnormality settling rotational speed NEOVL and the actual rotational speed NE is determined.

Overload detection operation (opening/closing operation by throttle valve open loop explained in Fig. 3) time deviation NE
Set as OLJ (step 470). Next, it is determined whether this deviation NEOLJ is negative or not in step 48.
0), if not negative, NEOLJ is the peak value NEO
LJBFI) and it is determined whether it is below (step 490
), if it is not less than NEOLJB as the new peak value
NEOLJ is set in F (step 500).

In this way, the peak value NEOLJBF is determined, and
It is determined whether the peak value NEOLJBF exceeds the normality determination value β (step 510).

If the normality determination value β is exceeded, it is determined that the opening/closing degree operation of the throttle valve 21 by z steps has actually caused a change in the opening degree. That is, it is clear that there is no abnormality in the throttle valve 21 and that the operation is under overload. Therefore, when an affirmative determination is made, the NE abnormality determination is canceled (step 520). If an NE abnormality flag exists, the flag is reset (time ts).

On the other hand, as shown in FIG. 7, in step 510, the state in which the peak value NEOLJBF does not exceed the normality determination value β continues (it is determined that there is an abnormality in the throttle valve 21, etc.).

A flowchart of the NE abnormality determination routine will be explained in FIG. This process is interrupted every predetermined time. When the process starts, it is first determined whether or not an NE abnormality determination has been made (step 610). For example, the determination is made by looking at the state of the NE abnormality flag. If the determination is negative, the NE abnormality determination counter CNEF is cleared (step 62).
0), this process ends once. Therefore, especially internal combustion engine 1
3, no abnormality processing is performed and normal processing is executed as is.

If the NE abnormality determination has been made, an affirmative determination is made in step 610, and the NE abnormality determination counter CNEF is incremented (step 630). Next, CNEF is N
It is determined whether E abnormality processing determination time 3 has been exceeded (step 640). Initially, since CNEF has not reached T3, a negative determination is made and the process is temporarily terminated.

If the NE abnormality determination is canceled before CNEF>T3 (time ts in FIG. 6), a negative determination is made in step 610, step 620 is executed, and CNEF is cleared. Therefore, the abnormality process is not executed, and the internal combustion engine 3 continues to operate according to the normal process (here, a continuation of the open loop process or feedback process).

On the other hand, if the CNEF increment in step 630 continues with the NE abnormal, as shown in FIG.
F>T3, and an affirmative determination is made in step 640 (time te in FIG. 7). This NE abnormality processing determination time 3 is defined as the set time TI and the throttle opening/closing cycle 12 hours, for example, T3≧TI +4
It is related to XT2. Therefore, CNEF>T3 (Friend: This is not an overload, but an abnormality such as sticking to the throttle valve 21 drive mechanism, or the internal combustion engine)
This indicates that there is an abnormality in other parts of 3 and the output does not decrease.

Since the internal combustion engine 13 whose output cannot be controlled in this manner must be stopped, the next step 650 is to stop the output of the ignition signal as an abnormality process, and output a fuel cutoff signal to the fuel cutoff valve 1. By doing so, fail-safe processing is performed.

This prevents the internal combustion engine ] 3 from continuing to operate after time te.

It should be noted that if the negative determination at step ]90 in FIG.
i Without executing open loop control, an affirmative determination is made in step 640 of FIG. 5, and step 650,
In the process of 660, the internal combustion engine 13 is stopped.

This actual flow side method As mentioned above, under feedback control, the control value C3TEP of the throttle valve 2 is fully open, and the actual rotation speed NE is equal to the target rotation speed NETARG.
If the abnormality determination value α has decreased from 1: 1, it is further confirmed whether the abnormality is due to overload. That is,
It is checked whether the output of the internal combustion engine 3 is reduced in response to the operation of the throttle valve 2 in the closing direction.

In this way, since the internal combustion engine 13 is not immediately determined to be abnormal only due to the inability to control the actual rotational speed NE, the operation of the internal combustion engine 13 will not be stopped even if there is a simple overload.

Therefore, it becomes easy to manage the engine generator, etc. to which this internal combustion engine 13 is applied, and its operation becomes efficient.

In the above embodiment, the overload determination routine shown in FIG. 4 (confirming whether or not there has been a decrease in output due to open loop control) is based on the peak value NEOLJBF indicating the maximum decrease amount of the actual rotational speed NE. However, in addition to the rotational speed NE, the output of the internal combustion engine] 3 is calculated based on, for example, the intake pipe negative pressure detected by the intake pipe negative pressure sensor 7 or the actual opening degree of the throttle valve 21 detected by the throttle position sensor. The presence or absence of a decrease may also be detected.

FIG. 8 shows an example of an overload determination routine performed based on the intake pipe negative pressure. What is different from Fig. 4 is that the actual rotation speed NE, the set rotation speed NEOVL at the time of NE abnormality, the deviation NE○LJ during overload detection operation, the peak value NEOLJBF of NEOLJ data, and the normality judgment value β are replaced by the intake pipe negative pressure. Detection value PM of sensor 7, Negative pressure setting PM○VL when NE is abnormal, Deviation P during overload detection operation
MOLJ.

The point is that the peak value PMOLJBF of PMOLJ data and the normality judgment value βp are used.

Further, FIG. 9 shows an example of an overload determination routine performed based on the detected value of the throttle position sensor. In this case (Table: A throttle position sensor is installed on throttle valve 2], and the throttle opening is controlled by an electronic control circuit)
The configuration is such that direct detection is performed. What is different from Fig. 4 (actual rotational speed NE).

In place of the NE abnormal setting rotation speed NEOVL, the deviation NEOLJ during overload detection operation, the peak value NEOLJBF of NEOLJ data, and the normality judgment value β, the throttle position sensor detection value PTR, the NE abnormal setting position TR0VL.

Deviation during overload detection operation TR0LJ, TR0LJ
The point is that the data peak value TR0LJBF and the normality determination value βt are used.

Therefore, in both FIGS. 8 and 9, each step is functionally the same as in FIG. 4, so the same numbers are given and explanations are omitted.

Note that in the above embodiment, in step 240, the rc
JIJD) As IJ, the opening/closing operation of the throttle valve 21 by open loop control is limited to two times, but the number of opening/closing operations may be increased by setting a value of "2" or more instead of "1". Also rCJLJD>OJ
The opening/closing operation may be performed only once.

In addition, instead of setting the time T3 [;L from when NE abnormality determination is performed until abnormality processing is performed, T3 > TI + 3XT2 may be used, and the end time of open loop control of the throttle valve 21 may be set. You can set it appropriately depending on the situation.

In this embodiment, the process of stopping the operation of the internal combustion engine 13 is executed as the abnormality process, but it may also be only a process of issuing a warning signal such as turning on a warning light.

Effects of the Invention The output control device for an internal combustion engine according to the present invention (in the case where the engine output adjustment means is at almost the maximum output control amount and the rotational speed of the internal combustion engine is lower than a predetermined speed from a predetermined target rotational speed) l2 Forcibly reduce the output of the internal combustion engine,
Changes in rotational speed are checked to determine whether the internal combustion engine is overloaded or abnormal. Based on this determination, appropriate measures are taken.

Therefore, it is no longer determined that there is an abnormality between the internal combustion engines even though the internal combustion engine is overloaded, and the various types of equipment to which this internal combustion engine is applied become easier to manage, and their operation becomes more efficient.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating the configuration of the present invention, FIG. 2 is a schematic configuration diagram of an embodiment thereof, and FIG. 3 is a flow chart of a throttle drive routine executed by the electronic control circuit. Flowcharts: Figure 5 is a flowchart of the NE abnormality determination routine Figure 6 is a timing chart showing the contents of the above process when there is an overload, Figure 7 is a timing chart showing the contents when the throttle valve is abnormal 8 and 9 are flowcharts of other examples of the overload determination routine. 1...Electronic control circuit 3...Rotation angle sensor 5.
...Ignition coil 7...Intake pipe negative pressure sensor 9.
...Stepping motor 11...Fuel cutoff valve 13
... Internal combustion engine 15 ... Crankshaft 17
...Crankshaft pulley 19...Spark plug 2]...Throttle valve Fig. 1

Claims (1)

[Scope of Claims] 1. A rotational speed detection means for detecting the rotational speed of the internal combustion engine; an engine output adjustment means for adjusting the output of the internal combustion engine; and feedback control of the engine output adjustment means to achieve a predetermined target rotational speed. a rotational speed control means for detecting whether the engine output adjustment means is at a substantially maximum output control amount; and an output control amount detection means for detecting whether the engine output adjustment means is at a substantially maximum output control amount; output reducing means for controlling the engine output adjusting means to forcibly reduce the output of the internal combustion engine when the rotational speed of the internal combustion engine has decreased by a predetermined speed or more from a predetermined target rotational speed; If the rotational speed of the internal combustion engine does not decrease in response to the control of the output reduction means, it is determined that the internal combustion engine is abnormal, and a predetermined abnormality process is started to respond to the control of the output reduction means. An output control device for an internal combustion engine, comprising: abnormality determination processing means for determining that the internal combustion engine is not abnormal and returning to normal processing when a decrease in rotational speed occurs in the internal combustion engine.