JPS6371534A - Controller for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent the engine stall by setting the restoration revolution speed from fuel cut in correspondence with the variation quantity of revolution speed when a throttle is in perfect closure and the driving power for wheels is in cut state and by starting fuel feed in correspondence with the variation through years. CONSTITUTION:An electronic controller 3 judges the deceleration state when a throttle position sensor 23 denotes the perfect closure of a throttle valve and the controller 3 the number of revolution is over a prescribed value, and the controller 3 executes fuel cut. Therefore, when it is detected from the signal of a clutch sensor 23 that a clutch is in cut-off state or it is judged from the signal of a gear position sensor 26 that a gear is in neutral state, and the cooling water temperature is over a prescribed temperature, the variation quantity of the revolution speed supplied from a revolution speed sensor 2 is calculated at each prescribed time, and the restoration revolution speed for restoring fuel feed is set on the basis of the variation quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an internal combustion engine control device that can set conditions for recovery from a fuel supply cut in a vehicle internal combustion engine that controls a fuel supply cut.

[Prior Art] Conventionally, some control devices for internal combustion engines for vehicles have the function of a fuel supply cup 1. This is a function that stops the fuel supply to the internal combustion engine (hereinafter simply referred to as the engine) for the purpose of improving fuel efficiency and braking effectiveness when decelerating the vehicle by engine braking.
It is activated when conditions such as the engine speed being below a predetermined value and the throttle being fully closed are met. Further, when the fuel supply is stopped, if a predetermined condition such as the speed at which the fuel supply is restarted, so-called return rotational speed, etc., is satisfied, control is performed to return from the fuel supply cut. Further, from the viewpoint of reducing fuel consumption, etc., the return rotation speed has been changed depending on parameters such as the presence or absence of a load such as a cooler and the temperature of the cooling water.

Techniques of this type have been proposed, for example, in Japanese Unexamined Patent Publication No. 58-25527 d3 and Japanese Unexamined Patent Publication No. 61-25934. That is, the fuel supply to the engine is stopped when the engine is being operated at deceleration, and when the fuel supply is stopped, the engine rotational speed falls below a predetermined value;
The fuel supply to the engine is started when at least one of the following occurs: the engine rotational speed decreases by a rotational speed change amount equal to or greater than a predetermined value.

[Problems to be Solved by the Invention] In this prior art, due to machine differences and changes over time in the internal combustion engine, the return rotation speed specified in the conventional specifications may cause a drop in rotation or engine stall. The problem was that it was easy. On the other hand, if the return rotational speed is set high in order to avoid the above-mentioned problems, there is a problem in that fuel consumption increases.

In addition, if the condition for starting fuel supply is that the engine rotational speed decreases by a rotational speed change amount of more than a predetermined value, engine braking with the foot brake may be applied at very high rotational speeds (for example, 50 oorpm or more). Alternatively, if the engine brake is applied when going uphill, the above conditions are met and fuel is supplied. In this case, since the rotational speed is high, the intake pipe has a high negative pressure and little air is supplied to the cylinder, causing the problem that the engine misfires and a large amount of unburned HC gas is discharged.

Furthermore, if the amount of change in engine rotational speed exceeds a predetermined value due to changes over time, etc., if you race without load, the above conditions will be met and fuel will be supplied from a high rotational speed, preventing unnecessary fuel consumption. There was a problem with this.

An object of the present invention is to provide an internal combustion engine control device that can set a suitable return rotation speed.

[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, a fuel cut-off section M2 that stops fuel supply when the operating state of the vehicle internal combustion engine M1 satisfies predetermined operating conditions; When the rotation speed decreases below a predetermined return rotation speed, the internal combustion engine M1
fuel supply starting means M3 for starting fuel supply to the internal combustion engine M3; and a driving state detecting means for detecting a state in which the throttle of the internal combustion engine M1 is fully closed and no driving force is being transmitted to the wheels. M
4, a rotational speed change amount detection means M5 for detecting the amount of change in the rotational speed of the internal combustion engine M1, and a state in which the operating state detected by the operating state detection means M4 is that the throttle is fully closed and no driving force is transmitted to the wheels. a state change determining means M6 for determining that the state has changed from a different state; and when the state change determining means M6 determines that the state has changed, the rotational speed change amount after the state change determination is Correspondingly, the present invention is characterized by comprising a return rotation speed setting means M7 for setting the return rotation speed.

Here, the fuel cup 1 to the control means M2 and the fuel supply start means M3 can be realized, for example, by controlling a fuel injection valve or the like by an electronic control device.

The operating state detection means M4 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 position that detects the position of the gear. This can be realized using sensors, etc.

The rotational speed change amount detecting means M5 may be for determining the amount of change in the rotational speed within a predetermined time, or may be for determining the amount of change in the rotational speed within a predetermined crank angle. For example, it can be put to practical use by processing signals from a rotational speed sensor or the like.

The state change determining means M6 means that the operating state is, for example, slot i.
- When the throttle is idle, such as when the throttle is open or the clutch is engaged and the gears are engaged,
It also determines whether the clutch is disengaged or the gear has changed to the neutral state.

The return rotation speed setting means M7 is the state change determination means M
6, when it is determined that the state has changed, the engine speed can be adapted to the state of each internal combustion engine 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. The return rotation speed can be set. Further, this setting may be based on a map stored in a memory within the electronic control unit, and the return rotational speed may be determined in accordance with the amount of change in rotational speed.

Furthermore, the average value of a plurality of past rotational speeds may be used as the amount of change in rotational speed when setting the above-mentioned return rotational speed.

[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 closed and no driving force is transmitted to the wheels is detected by the operating state detecting means M4, and a state change determining means M6 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 M5.

Next, if a change in the state is recognized by the above determination, the return rotation speed setting means M7 sets the return rotation speed in accordance with the amount of change in rotation speed after the above determination.

Therefore, the internal combustion engine control device of the present invention works to appropriately adjust the return rotational 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 includes an engine 2
and an electronic control unit (hereinafter simply referred to as EC) that controls the engine 2.
Call it U. )3.

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. A fuel injection valve 9, a throttle valve 10, and an air cleaner 11 are arranged in the intake pipe 8. In addition, the intake pipe 8
A bypass passage 12 is provided to bypass 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. Also,
The engine 2 has an igniter 14 that outputs a high voltage necessary for ignition, and a distributor 15 that is linked to a crankshaft (not shown) and distributes the high voltage generated by the igniter 14 to the spark plugs 7a of each cylinder. Roughly speaking, the engine 2 includes a water temperature sensor 21 disposed in the cylinder block 5a to detect the cooling water temperature, and an intake temperature sensor 22 disposed in the air cleaner 11 to measure the intake air temperature.
, a throttle position sensor 23 that detects the opening degree of the throttle valve 10 and has a built-in idle switch.
, an intake pipe pressure sensor 24 that detects the pressure inside the intake pipe 8.
, 1/24 of the camshaft of Disc 1 to Reviewer 15
A rotation angle sensor 25 is provided which also serves as a rotation speed sensor and outputs a rotation angle signal every rotation, that is, every integer multiple of the crank angle O0 to 300. Additionally, a clutch sensor 26 detects the engagement/disengagement state of the clutch, a gear position sensor 27 detects the neutral position of the gear, and a cooler switch 28 detects the ON/OFF state of the cooler.
is also included in the system configuration of this embodiment.

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.

By controlling the fuel injection valve 9, fuel cut control is performed. This control closes the fuel injection valve 9 to stop the fuel supply when the vehicle is being decelerated and the engine speed exceeds a predetermined value, etc., and when the engine speed is stopped, the engine speed When the speed falls below a predetermined value, that is, the return rotation speed, and other conditions are met, the fuel injection valve 9 is opened to resume fuel supply.

The above FCU3 includes CPU3a, ROM3b, RAM3
It is configured as a logical arithmetic circuit centering around G 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 return rotational speed setting process executed by the ECU 3 will be explained based on the flowchart of FIG. 3. This return rotational 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 main return rotational speed setting process is once terminated.

In step 110, it is determined based on the signal from the taradry sensor 26 whether the clutch is in a disengaged state. If the determination is negative, the process proceeds to step 120, while if the determination is affirmative, the process proceeds to step 130. In step 120,
Based on the signal from the gear position sensor 27, it is determined whether the gear is in the neutral 1 to 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 water temperature sensor 21
It is determined whether the cooling water temperature is equal to or higher than a predetermined temperature TH'C (for example, 70° C.) based on a signal from the controller. If an affirmative determination is made, the process proceeds to step '140, whereas if a negative determination is made, this process is temporarily terminated. In step 140, it is determined whether or not a predetermined period of time less than 12- (for example, 2 SeC) has elapsed since it was determined that the state has changed to proceed to step 14.0. This predetermined time T means that after the conditions for proceeding to step 130 are met, the engine rotational speed begins to decrease, and when NE becomes approximately constant, the engine rotational speed change decreases to the rotational speed change amount. This is for detecting NE. 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. In step 145, it is determined whether or not this step has been proceeded to for the first time after the predetermined time T has elapsed. As a result, the return 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, this process is temporarily terminated. Step 150
Then, it is determined based on the signal from the cooler switch 28 whether or not the cooler is in the ON state. 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, the return rotational speed 13 corresponding to the rotational speed change amount NE is determined based on the map Con when the cooler is ON. In step 170, similarly to step 160, the return rotational speed corresponding to the rotational speed change amount ΔNE is determined based on the map C0ff when the cooler is OFF. In addition,
In this map, for the same rotational speed change amount ΔNE,
The return rotation speed when the cooler is ON is set higher than when the cooler is OFF.

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

FIG. 5 is a flowchart showing the rotational speed change amount detection process for determining the rotational speed change amount ΔNF.

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 NF detected by the signal from the rotational speed sensor 25 is substituted into NFl. In step 210, NEl and the previous time (for example, 40m5
The difference between the rotational speed NEO and the rotational speed NEO detected before ec) is calculated, and this value is substituted into ΔNE as the amount of rotational speed change between ΔT. In step 220, NEl is substituted into NEO and the process is temporarily terminated.

Returning to FIG. 3, in step 180, the determined return rotational speed is stored in the backup RAM 3d and set as the return rotational speed. Thereafter, the setting of the return rotational 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 processes executed by the fuel injection valve 9 and the ECu3 include the idle switch 23 and the clutch sensor 26 as the fuel cup 1 to control means M2 and fuel supply start means M3. The gear position sensor 26 serves as the driving state detection means M4, steps 200, 210, and 220 of the processes executed by the rotation speed sensor 25 and the FCU 3 serve as the rotation speed change amount detection means M5, and the rest of the processes executed by the ECU 3. Steps 100, 110, and 120 each function as state change determination means M7.

As explained in the first embodiment, the amount of change in rotational speed after a predetermined time T after the throttle is fully closed and the clutch is disengaged or the gear is in neutral indicates a value specific to the internal combustion engine. Become. 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 NEA is large for the amount of rotational speed change, indicating that friction is significant, while the graph for internal combustion engine B shows the amount of rotational speed change Δ
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 and changes over time.

If NE is reflected in the rotational speed change amount on the return rotational speed, that is, when NE becomes large in the rotational speed change amount, the drop in rotational speed is large, so the return rotational speed is increased.
Conversely, if the return rotation speed is lowered, it is possible to set the optimum return rotation speed for the engine, that is, the return rotation speed that does not cause engine stall and reduces fuel consumption. Furthermore, if the engine rotational speed decreases by more than a predetermined value, the fuel supply will not be restarted, so the fuel supply will not be restarted when the engine is at high rotational speed and idle, making it unnecessary. Fuel consumption and unburned HC gas emissions due to fuel injection can be reduced. That is, with the return rotation speed set as described above, the fuel supply can be restarted at an appropriate time in the fuel cut control.

FIG. 7 shows a flowchart of the return rotation speed setting process according to the second embodiment of the present invention, and is a flowchart from step 300 to step 3.
/1. Step 100.11 of the first embodiment until O
0,120,130. 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 adding the previous rotational speed change amount ΔNF, even if the state change determining means determines that the state has changed.
This is for not adding the rotational speed change amount ΔNF if the time ec has not passed. This is done to obtain accurate statistical values by spacing data sampling. In step 360, it is determined whether the cooler is ON. If the determination is affirmative, the process proceeds to step 370, while if the determination is negative, the process proceeds to step 380. In step 370, it is determined whether the flag FC is ]. If affirmative judgment is made, step 38
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 the determination is affirmative, the process proceeds to step 400, while if the determination is negative, the process proceeds to step 1.10. In step /1.10, the integrated value ΣΔ of NE is added to the rotational speed change amount.
Find NF. In step 4.20, N is incremented and the - amount water treatment is ended. In step 4.00, as shown in Figure 4 above, the map Q when the cooler is ON is
Average value of rotational speed change △NE based on On ΣΔN F
/N Find the return rotation speed corresponding to 1. Step 4
In 30, the calculated return rotation speed is stored in the backup RAM3d.
and set it as the return rotation speed. Step 4.
4.0, the values of the number counter N and the integrated value ΣΔNE are set to O, and this process is temporarily terminated. In step 390, a value set in advance corresponding to the cooler ON state is determined as the return rotation speed. In step 450, the flag FC is set to 1, and the - amount water treatment is completed through steps 430 and 440 described in the previous step. In step 380, the flag F
Determine whether C is O. If a positive determination is made, the process proceeds to step 460, while if a negative determination is made, the process proceeds to step 47.
Go to 0. Here, when the flag FC is O, the cooler is OFF.
Indicates that the state is In step 4-60, 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 490. In step 4.90, the integrated value Σ of the rotational speed change amount △NE
Find △NE. In step 500, N is incremented, and the water treatment ends. In step 480,
The return rotation speed corresponding to the average value ΣΔN E/N 1 of the rotation speed change amount ΔNE is determined based on the map Coff when the cooler is OFF, and the process is temporarily terminated through steps 430 and 440. In step 470, the cooler O
[The value set corresponding to the state at F is determined as the return rotation speed. In step 510, the flag FC is set to O, and the process is temporarily terminated via step 430.4.40.

In addition, in steps 390 and 4.70, the return rotation speed was set to a preset value, but as another method, in step 390, when Σ
The value obtained from map C0n and used from ΔN E/N 1 may be used as the return rotation speed, and in step 470, ΣΔNE/
The value obtained and used from NIJ=remap Coff may be used as the return rotational speed.

In the second embodiment, the return rotation speed is determined by using the average value of the rotation speed change amount ΔNF detected each time the condition is satisfied over a predetermined number of times N1, which is more preferable because it is less influenced by errors in individual detected values. It is difficult to set an accurate return rotation speed.

In addition, in the first and second embodiments, the cooling water temperature is lower than 1'', the predetermined time T, T1. What is Δdou and the predetermined number of times N1?

The values are not limited to those in these embodiments, and arbitrary values may be adopted as necessary.

Further, in steps 160 and 170 of the first embodiment and steps 410 and 4.20 of the second embodiment, the amount of rotational speed change Δ
When determining the return rotational speed corresponding to NF, a calculation formula may be used instead of using a map.

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

Also, step 130 of the first embodiment. In step 330 of the second embodiment, the engine cooling water temperature is used as the determination condition to perform the return rotation speed setting process only for warm-up recovery. In addition, by setting the cooling water temperature as a parameter and calculating the return rotation speed using a two-dimensional map of the cooling water temperature and the rotation speed change amount ΔNF (or its average value ΣΔNE/N1), it is possible to calculate the return rotation speed even during warm-up. The return rotation speed can be set. In this case, the first
Example step 130. Step 330 of the second embodiment
becomes unnecessary.

FIG. 8 shows a flowchart of the return rotation speed setting process according to the third embodiment of the present invention, from step 600 to step 6.
Steps up to step 20 are the same as steps 100 to 120 in the first embodiment.

Furthermore, steps 630 and 640 are the same as steps 140 and 145 in the first embodiment. In step 650, the return rotational speed MW corresponding to the cooling water temperature is determined from the map. In step 660,
The correction addition amount ΔMW corresponding to the rotational speed change amount 8NF is determined from the map shown in FIG. In step 670, it is determined whether the cooler is ON. If the determination is affirmative, the process proceeds to step 680, while if the determination is negative, the process proceeds to step 690. In step 680, the return rotation speed is determined by adding the correction addition amount ΔMW corresponding to ΔNE to the return rotation speed MW corresponding to the chilled water temperature and adding the cooler correction amount AMC. In step 700, the determined return rotational speed is stored in the backup RAM 3d, set as the return rotational speed, and the -quantity water treatment is ended. In step 690, the return rotation speed is determined by adding the correction addition amount ΔMW corresponding to 8NE to the return rotation speed MW corresponding to the cooling water temperature, and the process is temporarily terminated via step 700.

In the third embodiment, since the return rotation speed MW corresponding to the cooling water temperature is used, the return 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 △NE determined for the predetermined time Δc@, the rotational speed change amount detection process shown in FIG.
As an interrupt process for each θ, the rotational speed change amount Nθ may be determined and this value may be used to set the return rotational speed.

[Advantageous Effects of the Invention 1] As detailed above, the internal combustion engine control device of the present invention adjusts 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 return rotational speed. In other words, a suitable return rotation speed can be set depending on the internal combustion engine difference, aging, or the presence or absence of a load such as a cooler.

As a result, fuel consumption can be reduced without causing engine failure.

Furthermore, if the engine rotational speed decreases by more than a predetermined value, the fuel supply will not be restarted, so the fuel supply will not be restarted when the engine is at high rotational speed and idle, making it unnecessary. It is possible to reduce fuel consumption and discharge of unburned 1-IC gas due to fuel injection.

[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.
The figure is a flowchart showing the return rotation speed setting process.
The figure is a graph showing a map for determining the return rotation speed from the rotation speed change amount or its average value, Figure 5 is a flowchart showing the rotation speed change detection process, and Figure 6 is the difference in the rotation speed change amount of individual internal combustion engines. FIG. 7 is a flowchart 1 to 1 showing the return rotational speed setting process according to the second embodiment of the present invention, and FIG. 8 is a flowchart showing the return rotational speed setting process according to the third embodiment of the present invention. FIG. 9 is a graph showing a map for determining the amount of correction addition from the amount of change in rotational speed. Ml...Internal combustion engine M2...Fuel cut control means M3...Fuel supply control means M4...Operating state detection means M5...Rotational speed change amount detection means M6...State change determination means Ml. ...Return rotation speed setting means 1...Internal combustion engine control device 2...Internal combustion engine = 25-3...Electronic control unit (FCU) 3a...CPU 9...Fuel injection valve 21... Water temperature sensor 23...Throttle position sensor 25...Rotation angle sensor (rotation speed sensor) 26...Tallage sensor 27...Gear position sensor 28...Cooler switch

Claims (1)

[Scope of Claims] Fuel cut control means for stopping fuel supply when the operating state of a vehicle internal combustion engine satisfies predetermined operating conditions; and a fuel supply start means for starting fuel supply to the internal combustion engine when the internal combustion engine has a throttle fully closed and driving force is not being transmitted to the wheels. a rotational speed change detection means for detecting a change in the rotational speed of the internal combustion engine; and a rotational speed change amount detection means for detecting a change in the rotational speed of the internal combustion engine; a state change determination means for determining that the state has changed from a different state to a state that is not transmitted; and when the state change determination means determines that the state has changed, the rotational speed after the state change determination; An internal combustion engine control device comprising: return rotation speed setting means for setting the return rotation speed in accordance with the amount of change.