JPS6371539A - Controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To reduce the fuel consumption without generating engine stall by setting the aimned idle revolution speed in correspondence with the variation quantity of revolution speed after the operation state change judgement. CONSTITUTION:The state in which the throttle of an internal Combustion engine 2 is perfectly closed, and no driving power is transmitted to wheels is detected by an idle switch 23, clutch sensor 26, and a position sensor 27, and an ECU 3 judges the change from the detected state to the different state. Further, the revolution speed variation quantity of the internal combustion engine 2 is detected by the ECU 3 on the basis of the signal supplied from a revolution speed sensor 25. When the change of state is recognized from the above- described judgement, the aimed idle revolution speed is set in correspondence with the revolution speed variation quantity after the judgement by the ECU 3. Therefore, the suitable aimed idle revolution speed can be set in correspondence with the constitution of the internal combustion engine 2, change through the lapse of time, or the existence of the load of a cooler, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an internal combustion engine control device that is effective in setting a target idle rotation speed in idle speed control of a vehicle internal combustion engine.

[Prior Art] Conventionally, there has been a technology called idle speed control as a measure against machine differences and changes over time in the idle rotation speed of internal combustion engines for vehicles. This is feedback control to a value set as the target idle rotation speed in order to keep the idle rotation speed as low as possible without causing engine stall from the viewpoint of combustion stability and fuel efficiency. be.

As this type of technology, for example, Japanese Patent Application Laid-Open No. 58-19053
Publication No. 4 etc. have been proposed.

[Problems to be Solved by the Invention] In this prior art, the rotational speed drops when transitioning from a state other than idling to an idling state due to engine differences in the internal combustion engine, changes over time, or the presence or absence of a load such as a cooler. There is a problem in that the idle rotation speed is significantly lower than the target idle rotation speed and engine stall is likely to occur. On the other hand, if the target idle speed is set high to avoid engine stalling, there is a problem in that fuel consumption increases.

The purpose of the present invention is to set a target idle rotation speed that reduces fuel consumption without causing an engine stall, depending on internal combustion engine differences, changes over time, or the presence or absence of a load such as a cooler. It is.

[Means for solving the problems] The gist of the present invention, which was made to solve the above problems, is as follows.
As illustrated in FIG. 1, in an internal combustion engine control device that controls the rotational speed of the internal combustion engine M1 based on a target idle rotational speed when the vehicle internal combustion engine M1 is idling, when the throttle of the internal combustion engine M1 is fully closed, and a driving state detecting means M2 that detects a state in which the driving force is not transmitted to the wheels; a rotational speed change amount detecting means M3 that detects the amount of change in the rotational speed of the internal combustion engine M1; and the driving state detecting means M2. The operating state changes to a state where the throttle is fully closed and no driving force is transmitted to the wheels.
A state change determination means M4 determines that the state has changed from a different state, and when the state change determination means M4 determines that the state has changed, a state change determination means M4 determines that the state has changed from a different state, and when the state change determination means M4 determines that the state has changed, the state change determination means M4 determines that the state has changed from a different state. The present invention is characterized by comprising a target idle rotation speed setting means M5 for setting a target idle rotation speed.

Here, the operating state detection means M2 detects the operating state of the internal combustion engine M1, and includes an idle switch that detects the opening/closing state of the throttle, a clutch sensor that detects the engagement/disengagement state of the clutch, and a gear sensor that detects the position of the gear. This can be realized using a position sensor, etc.

Further, the rotational speed change amount detecting means M3 may be a device that determines the amount of change in the rotational speed within a predetermined time, or a device that determines the amount of change in the rotational speed within a predetermined crank angle. This can be achieved by processing signals from sensors, etc.

The state change determining means M4 determines whether the operating state changes from, for example, a state where the throttle is open or a state where the clutch is engaged and the gears are engaged, to a state where the throttle is fully closed and the clutch is disengaged, or This is to determine that the gear has changed to the neutral state.

The target idle rotation speed setting means M5, when it is determined by the state change determining means M4 that the state has changed,
By using the amount of change in rotational speed caused by the state of friction, etc. of each internal combustion engine detected after the state change, it is possible to set a target idle rotational speed adapted to the state of each internal combustion engine. Further, this setting may be based on a map stored in a memory within the electronic control unit, and determine the target idle rotation speed in accordance with the amount of change in rotation speed attitude.

Furthermore, the rotational speed change amount when setting the target idle rotational speed may be an average value of a plurality of past rotations.

[Effect] The internal combustion engine control device of the present invention operates as follows.

A state in which the throttle of the internal combustion engine M1 is fully closed and no driving force is transmitted to the wheels is detected by the operating state detecting means M2, and a state change determining means M4 determines that the detected state has changed from a different state. do.

Further, the rotational speed change amount of the internal combustion engine M1 is detected by the rotational speed change amount detection means M3.

Next, if a change in the state is recognized by the above judgment, the target idle rotation speed setting means M5 sets a target idle rotation speed in accordance with the amount of rotation speed change after the above judgment.

Therefore, the internal combustion engine control device of the present invention functions to appropriately adjust the target idle rotation speed. The technical problems of the present invention are solved by each component of the present invention acting as described above.

[Example] Next, a preferred example of the present invention will be described in detail based on the drawings. FIG. 2 shows a system configuration of an internal combustion engine control device according to a first embodiment of the present invention.

As shown in the figure, the internal combustion engine control device 1 controls the internal combustion engine (
The engine is comprised of an electronic control unit (hereinafter simply referred to as ECU) 3 that controls the engine 2 (hereinafter simply referred to as an engine) 2.

The engine 2 includes a cylinder 5 and a piston 6 to form a combustion chamber 7, and the combustion chamber 7 is equipped with a spark plug 7a.
It communicates with the intake pipe 8 via the intake valve 7b. The intake pipe 8 includes a fuel injection valve 9 and a throttle valve 10i!
'3 and an air cleaner 11 are provided. The intake pipe 8 is provided with a bypass passage 12 that bypasses the throttle valve 10, and an idle speed control valve (hereinafter simply referred to as 15CV) 13 is interposed in the bypass passage 12 to adjust the air flow rate. equipped.

The engine 2 also includes an igniter 14 that outputs high voltage necessary for ignition, and a high voltage generated by the igniter 14 in conjunction with a crankshaft (not shown) to the spark plugs of each cylinder.
It has a distributor 15 that distributes and supplies to a. Furthermore, the engine 2 includes a water temperature sensor 21 disposed in the cylinder block 5a to detect the cooling water temperature, and an air cleaner 1.
1, an intake air temperature sensor 22 that measures the intake air temperature, a throttle position sensor 23 that detects the throttle valve 100 opening degree and has a built-in idle switch, and an intake pipe internal pressure that detects the pressure inside the intake pipe 8. Sensor 24, 1/1 of the camshaft of the distributor 15
Every 24 revolutions, the crank angle changes from 0° to 30'
A rotation angle sensor 25 is provided which also serves as a rotation speed sensor that outputs a rotation angle signal for every integer multiple of . Also included in the system configuration of this embodiment are a clutch sensor 26 that detects the disengaged state of the clutch, a gear position sensor 27 that detects the neutral position of the gear, and a cooler switch 28 that detects the ON-OFF state of the cooler. .

The output signals of each sensor and switch mentioned above are sent to FCU3.
and the ECU 3 inputs the fuel injection valve 9, l5CV1
3 and the igniter 14.

The control of l5CV13 by ECU3 is called idle speed control (ISC), which means that if the engine rotation speed at idle is lower than the target idle rotation speed, l5CV13 is opened (
Alternatively, if the engine speed is high, close l5CV13 (or reduce the opening) to reduce the amount of inflow air to reach the target engine speed. Feedback control is performed on the idle rotation speed.

The above ECU3 includes CPU3a, ROM3b, RAM3C
It is configured as a logic operation circuit centering around iB and backup RAM 3d, and is connected via a common bus 3e to an input section 3f equipped with an A/D converter and an output section 3q equipped with an output circuit, thereby allowing input/output with the outside. Let's do it.

Next, the target idle rotation speed setting process executed by the FCU 3 will be explained based on flowchart 1 in FIG. This target idle rotation speed setting process is repeatedly executed at predetermined time intervals after the ECU 3 is started.

First, in step 100, based on a signal from the throttle position sensor 23, it is determined whether the engine 2 is in a fully closed throttle state.

If an affirmative determination is made, the process proceeds to step 110, whereas if a negative determination is made, the present target idle rotation speed setting process is once terminated. In step 110, it is determined based on the signal from the clutch sensor 26 whether the clutch is in a disengaged state. If a negative determination is made, the process proceeds to step 120, and on the other hand,
If an affirmative determination is made, the process proceeds to step 130. Step 12
0, it is determined based on the signal from the gear position sensor 27 whether the gear is in the neutral state.

If the determination is affirmative, the process proceeds to step 130, and if the determination is negative, the process is temporarily terminated. In step 130, the cooling water temperature reaches a predetermined temperature TH based on a signal from the water temperature sensor 21.
'C (for example, 70'C) or higher. If an affirmative determination is made, the process proceeds to step 140, whereas if a negative determination is made, this process is temporarily terminated. Step 1=1.
0, it is determined whether a predetermined time T (for example, 2 seconds) or more has elapsed since it was determined that the state has changed to proceed to step 140.
After the conditions for advancing to 0 are met, the engine rotation speed begins to decrease, and the engine rotation speed change amount △N
When E becomes almost constant, the rotational speed change amount △NE
The purpose is to detect

If an affirmative determination is made here, the process proceeds to step 145, whereas if a negative determination is made, this process is temporarily terminated. Step 145
Then, after the predetermined time T has elapsed, it is determined whether or not the process has proceeded to this step. As a result, the target idle rotational speed is set only once each time the above conditions are satisfied. If an affirmative determination is made here, the process proceeds to step 150, and if a negative determination is made, the water volume treatment is terminated. Step 150
Now, it is determined whether the cooler is in the ON state based on the signal from the cooler switch 2B. If the determination is affirmative, the process proceeds to step 160, and if the determination is negative, the process proceeds to step 170. In step 160, as shown in FIG. 4, a target idle rotational speed corresponding to the rotational speed change amount NE is determined based on the map Con when the cooler is ON.

In step 170, as in step 160, the cooler O
Based on the FF map Co"f"f', a target idle rotational speed corresponding to the rotational speed change amount ΔNF is determined. In addition, in this map, for the same amount of rotation speed change NE, the target idle rotation speed when the cooler is ON is
It is set higher than when it is FF.

Next, a method for calculating NE will be described below.

FIG. 5 is a flowchart showing the rotational speed change amount detection means for determining the rotational speed change amount ΔNE.

This rotational speed change amount detection process is repeatedly executed every predetermined time period Δ (for example, 4Qmsec) after the ECU 3 is started.

First, in step 200, the rotational speed N'F@NE1 detected by the signal from the rotational speed sensor 25 is substituted. In step 210, NE'l and the previous time (for example,
Find the difference between the rotational speed NEO detected at
Substitute into F. In step 220, NEl is assigned to NFO and the process is temporarily terminated.

Returning to FIG. 3, in step 180, the obtained target idle rotation speed is stored in the backup RAM 3d and set as the target idle rotation speed. Thereafter, the setting of the target idle rotation speed is repeatedly executed every time the above-described conditions are met.

In this embodiment, the engine 2 corresponds to the internal combustion engine M1, and the idle switch 23, the clutch sensor 26, and the gear position sensor 26 serve as the driving state detection means M2, and the rotational speed sensor 25 and the ECU 3 perform step 200 of the processing executed by the rotational speed sensor 25 and the ECU 3. .210 and 220 are the rotational speed change detection means M3, and among the processes executed by the ECU 3, steps 100, 110.120 are the state change determination means M4, and steps '160, 170.180 are the target idle rotational speed setting. Each functions as means M5.

As explained in the first embodiment, the rotational speed change amount ΔNE after a predetermined time T after the throttle is closed and the clutch is disengaged or the gear is in neutral shows a value specific to the internal combustion engine. . This situation is shown in FIG. 6, which illustrates the temporal changes in the rotational speeds of different internal combustion engines A and B. Here, the graph for internal combustion engine A shows that the amount of rotational speed change ΔNEA is large and the friction is large, while the graph for internal combustion engine B shows the amount of rotational speed change ΔNEA.
This shows that NFB is small and friction is also small. Such differences in friction occur even if the engine type is the same, due to machine differences during manufacturing, changes over time, etc.

If this rotational speed change amount ΔNE is reflected in the target idle rotational speed, that is, when the rotational speed change amount ΔNE is large, the drop in rotational speed is large, so the target idle rotational speed is increased, and when it is small, the target idle rotational speed is increased. Conversely, if the target idle rotation speed is lowered, it is possible to set the optimum idle rotation speed for the engine, that is, the target idle rotation speed that does not cause engine stall and reduces fuel consumption.

FIG. 7 shows a flowchart 1 of the target idle rotation speed setting process according to the second embodiment of the present invention, and steps 300 to 340 are steps 100 and 1 of the first embodiment.
10,120,130. and 140. In step 350, it is determined whether a predetermined time T1 (for example, 200 SeC) has elapsed since the previous affirmative determination was made in this step. end.

Here, the predetermined time T1 is a certain period of time, for example 200 seconds, after the previous tightening of the rotational speed change amount ΔNF, even if the state change determining means determines that the state has changed.
If ec has not elapsed, the rotational speed change amount ΔNE is not tightened. This is done to obtain accurate statistical values by spacing data sampling. In step 360, it is determined whether the cooler is ON. If a positive determination is made, the process proceeds to step 370, while if a negative determination is made, the process proceeds to step 3.
Proceed to 80. In step 370, it is determined whether the flag FC is set to 1 or not. If affirmative judgment is made, step 380
On the other hand, if the determination is negative, the process advances to step 390. Here, when the flag FC is 1, it indicates that the cooler is in an ON state. In step 380, it is determined whether the number of times counter N is equal to a predetermined number of times N1 (for example, 4). If a positive determination is made, the process proceeds to step 400, while if a negative determination is made, the process proceeds to step 4.10. Step 4
In step 10, the integrated value ΣΔNE of the rotational speed change amount ΔNF is determined. In step 420, N is incremented and -
Finish water treatment. In step 400, as shown in FIG. 4, a target idle rotational speed corresponding to the average value ΣΔNF/N1 of the rotational speed change amount ΔNE is determined based on the map CON when the cooler is ON. In step 430, the obtained target idle rotation speed is stored in the backup RAM 3d.
and set it as the target idle rotation speed. In step 440, the values of the number counter N and the integrated value ΣΔNF are set to O, and the process is temporarily terminated.

In step 390, a value set in advance corresponding to the cooler ON state is determined as the target idle rotation speed. In step 450, the flag FC is set to 1, and the above-mentioned steps 430 and 440 are performed, and the water treatment is completed. In step 380, it is determined whether the flag FC is O. If an affirmative determination is made, the process proceeds to step 460,
On the other hand, if the determination is negative, the process proceeds to step 470. Here, when the flag FC is O, it indicates that the cooler is in an OFF state. In step 460, it is determined whether the number of times counter N is equal to a predetermined number of times N1 (for example, 4). If the determination is affirmative, the process proceeds to step 480, while if the determination is negative, the process proceeds to step 4.90.

In step 490, the integrated value Σ of the rotation speed change amount ΔNF
Find ΔNE. In step 500, N is incremented, and the water treatment ends. In step 480,
The target idle rotation speed corresponding to the average value Σ△N F/N 1 of the rotation speed change amount ΔNF is determined based on the map Cof when the cooler is OFF, and the target idle rotation speed is determined in step 430 described above.
．． After passing through step 440, the process ends once. Step 470
Now, a value set in advance corresponding to the state when the cooler is OFF is determined as the target idle rotation speed. In step 510, flag FC is set to O, and in step 430
．． 4=! 1.0 and then the process ends once.

In addition, in steps 390 and 470, the target idle rotation speed 1 degree was set as a preset value, but as another method, in step 390 d3, the target idle rotation speed 1 degree is calculated from the map QOn from ΣΔNE/N1 when the cooler was turned on last time. The value previously used may be used as the target idle rotation speed.
In some cases, a value obtained from the map C0ff using ΣΔNF/N1 and used may be used as the target idle rotation speed.

In the second embodiment, the target idle rotation speed is determined by using the average value of the predetermined number of times N1 of NE to the rotation speed change amount detected every time the condition is satisfied, so that it is less influenced by errors in individual detected values. A more suitable target idle rotation speed can be set.

In addition, the cooling water temperature TH1 predetermined time T in the first and second embodiments
, T1. The Δt and the predetermined number of times N1 are not limited to the values of these embodiments, and arbitrary values can be adopted as necessary.

Further, in steps 160 and 170 of the first embodiment and steps 410 and 420 of the second embodiment, the amount of change in rotational speed is
When determining the target idle rotation speed corresponding to E, a calculation formula may be used instead of using a map.

Furthermore, the first. In the second embodiment, the target idle rotation speed may be corrected for loads other than the cooler before setting the target idle rotation speed.

Also, step 130 of the first embodiment. In step 330 of the second embodiment, the engine cooling water temperature is determined and used as a constant condition, and the target idle rotation speed setting process is performed only after warm-up.
When calculating the target idle rotation speed from ff, add the cooling water temperature to the parameters, and calculate the target idle rotation speed by a two-dimensional map of the cooling water temperature and rotation speed change amount with NE (or its average value ΣΔNE/N1>). For example, the target idle rotation speed can be set even during warm-up. In this case, step 130 of the first embodiment and step 330 of the second embodiment are unnecessary.

FIG. 8 shows a flowchart of the target idle rotation speed setting process according to the third embodiment of the present invention, and steps 600 to 620 are the same as steps 100 to 120 in the first embodiment. Further step 63
0 and step 640 are step 14 of the first embodiment.
0 and step 145. step 650
Then, the target idle rotation speed MW corresponding to the cooling water temperature
is determined from a map in which the lower the cooling water temperature, the higher the target idle rotation speed. In step 660, the correction addition amount ΔMW corresponding to NE to the rotational speed change amount is determined from the map shown in FIG. In step 670, it is determined whether the cooler is ON. If it is determined to be blue, the process proceeds to step 680, while if it is determined to be negative, the process proceeds to step 690.

In step 680, a correction addition amount ΔMW corresponding to ΔNE is added to the target idle rotation speed MW corresponding to the cooling water temperature.
The target idle rotation speed is determined by adding the cooler correction amount AMC. In step 700,
Back up the obtained target idle rotation speed in RAM3d
, set it as the target idle rotation speed, and end the water treatment. In step 690, the target idle rotation speed is determined by adding the correction addition amount ΔMW corresponding to ΔNE to the target idle rotation speed MW corresponding to the cooling water temperature, and the process is temporarily terminated via step 700.

In the third embodiment, since the target idle rotation speed MW corresponding to the cooling water humidity is used, the target idle rotation speed can be set even during warm-up.

Note that in this embodiment, correction of loads other than the cooler, such as electric loads caused by power steering, lights, etc., may be performed in the same way as correction by the cooler. In addition, instead of the rotational speed change amount ΔNF obtained every six teeth for a predetermined period of time, the rotational speed change amount detection process shown in FIG.
The amount of change in rotational speed ΔNθ may be obtained as an interrupt process for each θ, and this value may be used to set the target idle rotational speed.

[Effects of the Invention] As described in detail above, the internal combustion engine control device of the present invention changes the amount of change in rotational speed when it is determined that the operating state of the internal combustion engine falls under the conditions for changing the target idle rotational speed. A suitable target idle rotation speed can be set according to the corresponding target idle rotation speed, that is, the engine difference of the internal combustion engine, aging, or the presence or absence of a load such as a cooler. This makes it possible to reduce fuel consumption without causing engine stall.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram conceptually illustrating the contents of the present invention, FIG. 2 is a system configuration diagram of the first embodiment of the present invention, and FIG.
FIG. 4 is a graph showing a map for determining the target idle rotation speed from the amount of change in rotation speed or its average value; FIG. 5 is a flow chart showing the process for detecting the amount of change in rotation speed; FIG. 6 is a graph showing differences in the amount of change in rotational speed of individual internal combustion engines, FIG. FIG. 9 is a flowchart showing the target idle rotational speed setting process of the third embodiment of the invention, and is a graph showing a map for determining the correction addition amount from the rotational speed change amount. Ml...Internal combustion engine M2...Operating state detection means M3...Rotational speed change amount detection means M4...State change determination means M5...Target idle rotational speed setting means T...Internal combustion engine control device 2 ...Internal combustion engine 3...Electronic control unit (ECU) 3a...CPU 13...Idle speed control valve 21.
・・Water temperature sensor 23...Slot]-ru position sensor 25...Rotation angle sensor (rotation speed sensor) 26...Taratsunasen 1 large 27...Gear position sensor 28...Cooler switch

Claims (1)

[Scope of Claims] 1. In an internal combustion engine control device that controls the rotational speed of a vehicle internal combustion engine with reference to a target idle rotational speed when the internal combustion engine is idle, the internal combustion engine is configured to drive wheels while the throttle is fully closed. an operating state detection means for detecting a state in which no force is being transmitted; a rotational speed change amount detection means for detecting the amount of change in the rotational speed of the internal combustion engine; and a state change determination means for determining that the state has changed from a different state to a state in which no driving force is transmitted to the wheels; and when the state change determination means determines that the state has changed, the state change is determined by the state change determination means. An internal combustion engine control device comprising: target idle rotation speed setting means for setting a target idle rotation speed in accordance with the determined rotation speed change amount.