JPS6040744A - Intake-air vacuum detecting device in cylinder-number controlling engine - Google Patents

Abstract

PURPOSE:To precisely detect the vacuum of intake-air just after the change-over between the all cylinder number operation and the reduced cylinder number operation, by newly initiating the computation of the averaged value of intake-air vacuum values which are obtained by sampling the vacuum of the intake-air after the change-over. CONSTITUTION:During engine-operation, a control unit 28 which receives the outputs signals from sensors 3, 29, 30 for detecting the opening degree of the throttle valve, the temperature of cooling water, the vacuum of intake-air pressure, respectively, and an engine rotational speed signal from the ignition coil 31, judges wherther the engine runs in the reduced cylinder number operating range or not. When it is so judged, the supply of fuel to a part of the cylinders is cut off to change the engine into its reduced cylinder number operating condition. Simultaneously, by controlling an averaged value computing control means for computing the average of sampled vacuum values of intake-air, the computation of the average is newly initiated after the change-over between the all cylinder number operation and the reduced cylinder number operation with the use of vacuum values of intake-air which are sampled after the change-over. Then, the thus obtained averaged intake-air vacuum is used to control the injection amount of fuel.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is capable of switching between all-cylinder operation in which output is output from all cylinders and reduced-cylinder operation in which output is output from only some cylinders, depending on the operating state of the engine. The present invention relates to an intake negative pressure detection device for an engine with cylinder number control.

(Prior Art) In recent years, there has been a desire for a significant improvement in fuel efficiency, especially in automobile engines, and for this reason, for example,
As shown in Japanese Patent No. 338, an engine with cylinder number control has appeared in which the above-mentioned all-cylinder operation and reduced-cylinder operation can be appropriately switched and selected according to the engine operating condition IE. In other words, 1. For example, when the load is high, such as when starting or driving at high speed, fuel is supplied to all cylinders and output is output from all cylinders, while when the load is low, such as when driving at a constant speed or on a steady road, the fuel is supplied to all cylinders. Fuel efficiency is reduced by cutting the fuel supply to some cylinders and increasing the filling efficiency to other cylinders.

Such a cylinder number control engine is equipped with a cylinder number control means for switching to reduced cylinder operation by cutting fuel supply to some cylinders, and also controls engine rotation speed, throttle valve opening, and intake air. The engine is equipped with cylinder reduction determination means for detecting engine operating conditions such as negative pressure and engine temperature to determine whether or not cylinder reduction operation should be performed, and outputting the determination result to the bipedal cylinder number control means.

Incidentally, the intake negative pressure of the engine is used in various ways as data for engine control.For example, it is of course used as data for determining whether or not to perform reduced-cylinder operation, but it is also used as data for electronically controlled fuel injection systems. It is also used as data for determining fuel injection amount. Generally, the average value (moving average value) of a plurality of intake negative pressure values sequentially sampled at predetermined time intervals is used as data for engine control.

However, in engines with cylinder number control, there is a difference in the manner in which intake negative pressure is generated during all-cylinder operation and during reduced-cylinder operation, and it is especially difficult to accurately detect intake negative pressure during reduced-cylinder operation. Measures are required. In other words, the intake negative pressure is different during all-cylinder operation and reduced-cylinder operation even if the engine speed is the same, and therefore the intake negative pressure is different before and after switching between all-cylinder operation and reduced-cylinder operation. Negative pressure changes significantly. Therefore, if multiple intake negative pressure values are simply averaged before and after the above switching, for a while after the switching, the intake negative pressure values sampled before or at the time of switching will be used as data for averaging. As a result, the intake negative pressure used for engine control inevitably becomes inaccurate.

(Object of the Invention) The present invention has been made in consideration of the following two circumstances, and is designed to accurately detect intake negative pressure for a while after switching between full-cylinder operation and reduced-cylinder operation. An object of the present invention is to provide an intake negative pressure detection device for a cylinder number controlled engine.

(Structure of the Invention) In order to achieve the above-mentioned objective, in the present invention, after switching between full-cylinder operation and reduced-cylinder operation, the intake negative pressure value sampled up to the time of switching is used. Instead, the intake negative pressure value sampled after the switching is used as data, and its averaging (moving average operation 3'I) is newly started.

Specifically, as shown in FIG. 1, the cylinder reduction determining means determines whether cylinder reduction operation should be performed depending on the operating state, and the cylinder number control means is controlled based on the result of this determination. While switching to reduced-cylinder operation as appropriate, the average calculation control means is also controlled, and after switching between all-cylinder operation and reduced-cylinder operation, the intake negative pressure is calculated without using the intake negative pressure value sampled up to the time of switching. This will cause the averaging to start anew. Of course, the intake negative pressure averaging means usually calculates the intake negative pressure average value based on the intake negative pressure value detected by the intake negative pressure detection means,
This intake negative pressure average value is used for engine control.1 For example, it is used manually in the fuel injection amount control means of an electronically controlled fuel injection device to determine the amount of fuel to be injected from the fuel injection valve. Used as data.

(Example) In Fig. 2, l is the engine body, and intake air is supplied to the combustion chamber 7 via the air cleaner 2, throttle chamber 4, intake manifold 5, and intake port 6. 6 constitutes an intake passage 8. Fuel from the fuel injection valve 10 is mixed with the intake air flowing through the intake passage 8.
The intake air amount is controlled by a throttle valve 11. Moreover, the exhaust gas from the fuel chamber 7 is
12, passes through the exhaust manifold 13, etc., and is exhausted to the atmosphere.

The intake valve 14 that opens and closes the intake port 6 and the exhaust valve 15 that opens and closes the exhaust port 12 are opened and closed at predetermined timing by a valve mechanism. In this embodiment, this valve mechanism includes a crankshaft (not shown) in addition to a turn spring 16.17 that urges the intake/exhaust valve 14.15 in the valve closing direction.
The camshaft 18 is rotationally driven by a camshaft 18, a cam 19 provided on the camshaft, Lonca arms 2o, 21, and tappets 22.23 that constitute the swinging fulcrum of the Lonca arms 20.21. In the embodiment, the engine main body l is for four cylinders, and the ignition order is set to 1-3-4-2, and during cylinder reduction operation, the first cylinder and the fourth cylinder are appropriately stopped, i.e., the fuel It is a dormant cylinder where the supply is cut off, and therefore, valve drive control devices 24, 25 are installed for the tappets 22, 23 for the 1st and 4th cylinders. .

The valve drive control devices 24, 25 are respectively switched and driven by solenoids 26, 27, and when the solenoids 26, 27 are demagnetized, the swinging fulcrum of the tappets 22, 23 relative to the rocker arms 2o, 21 is The rocker arms 20 and 21 swing in response to the rotation of the camshaft 18, and the rocker arms 20.
This is an all-cylinder operation in which exhaust valves 14 and 15 are opened and closed. Conversely, when the solenoid 26.27 is energized, the swing fulcrum shown in -■- can be displaced upward in the figure, and the interlocking relationship between the camshaft 18 and the intake/exhaust valves 14.15 is interrupted. The cylinder reduction operation is performed with the intake and exhaust valves 14 and 15 of the first and fourth cylinders maintained in the closed state.

Note that the valve drive control device 24, 25 itself described above is
For example, it is already well known as disclosed in Japanese Patent Application Laid-Open No. 5Z-5E2X2+3, so a detailed explanation thereof will be omitted.

Reference numeral 28 in FIG. 2 denotes a control unit consisting of a microcomputer, and the control unit 28 selects and controls either full-cylinder operation or reduced-cylinder operation according to the operating condition of the engine, and also controls all-cylinder operation. This control unit 28 controls the detection (processing) of the intake negative pressure when switching between the cylinder reduction operation and the cylinder reduction operation.
The fuel injection ff't, ignition timing, etc. are also controlled, but in the following description, description of parts that are not directly related to the present invention will be omitted.

The two-legged control unit 28 receives the opening degree of the throttle valve 11 from the throttle sensor 3, the engine coolant temperature as the engine temperature from the coolant temperature sensor 29, and the intake air from the intake negative pressure sensor 30 provided in the intake passage 8. The negative pressure and the engine speed from the ignition coil 31 are output from the human control unit 28 to the solenoids 26 and 27, respectively.

In addition, in FIG. 2, 32 is a destroyer, 33 is a spark plug, and 34 is an octagon.

Next, regarding the contents of control by the control unit 28, first, the portion for determining and switching between full-cylinder operation and reduced-cylinder operation will be explained based on flowchart 1 in FIG. 3.

First, in step 35, the engine is initialized, and the number of cylinders flag is set to 1, and the remaining cylinder flag and cylinder reduction flag in the flowchart of FIG. 4, which will be described later, are set to O. This cylinder number flag means all-cylinder operation when it is rlJ, and reduced-cylinder operation when it is "O", and the after-resistance flag means that all-cylinder operation continues when it is "l". When it is "0", it means switching from reduced-cylinder operation to full-cylinder operation, and when the reduced-cylinder flag is rlJ, the reduced-cylinder operation is #! When the value is "0", it means that the all-cylinder operation is switched to the reduced-cylinder operation.

Next, in step 36, each data of engine cooling water temperature, intake negative pressure, engine speed, and front and center valve opening is input.

Thereafter, it is sequentially determined in steps 37 to 39 whether or not the engine operating state IE satisfies the conditions for reduced-cylinder operation based on the data manually entered in step 36 described in -. That is, the cooling water temperature is high above the set value TO (for example, 60'C) (step 37), and the engine speed is low below the set value No (for example, 2oo0 rpm) (
Step 38), if it is determined that the vehicle is not in an acceleration state but in a steady or decelerated state (step 39), step 40
leading to. Note that whether or not the vehicle is in the acceleration state is determined by differentiating the change 0 in the throttle opening with respect to time t, determining the acceleration α, and determining whether or not this acceleration α is larger than a set value α0.

From step 40, since the cylinder number flag is initialized to be 1 in step 35, the process moves to step 41, where it is determined whether the intake negative pressure is less than or equal to the set value P4. It is determined. Then, if the intake negative pressure is a low load below the set value P4, the process moves to step 42,
Here, the cylinder number flag is set to O.

” When the step 42 is reached, all the conditions for cylinder reduction operation are satisfied, so an output is output from step 43 indicating that cylinder reduction operation (in the embodiment, two cylinder operation) is to be performed. Solenoids 26 and 27 are energized,
The cylinder reduction operation is performed in which the intake/exhaust valves r14.15 of the No. 1 and No. 4 cylinders are maintained in the closed state. Then, the process moves to step 44, where the fuel injection amount is determined, and the determined amount of fuel is injected from the fuel injection valve 10. Note that the fuel injection process itself in step 44 is basically the same as in the case of the conventional electronically controlled fuel injection system #I, so a detailed explanation thereof will be omitted.

After this, the process returns to step 36, but if the engine operating condition remains the same as described above,
The process moves to step 40 as described above. Then, in step 40, the cylinder number flag is set to O in step 42.
As a result, the process moves to step 45, where it is determined whether the intake negative pressure is greater than the set value P2. In other words, as mentioned above, the intake negative pressure is different during reduced-cylinder operation and during full-cylinder operation, even if the engine speed is 500 rpm. The intake negative pressure P2, which is the condition for switching to reduced-cylinder operation, is the one used during reduced-cylinder operation, and the intake negative pressure P4, which is the condition for switching to reduced-cylinder operation during all-cylinder operation, is the one used during all-cylinder operation. be(
P2 > P4).

This prevents frequent switching between reduced-cylinder operation and full-cylinder operation in a short period of time depending on the negative or positive intake air (hunting prevention).

Here, when the cooling water temperature is lower than the set value -r, when the engine speed is higher than the set value No, when accelerating, the intake negative pressure is set at P2 (during cylinder reduction operation) or P4 (
If any one of the following conditions is met, the number of cylinders flag is set to 1, and then step 47 indicates that all-cylinder operation is to be performed. The following output is produced. i.e. solenoid 2
6.27 and demagnetize all cylinder intake and exhaust valves 14.1.
5 is an all-cylinder operation in which opening and closing are delayed.

Next, the content of the control for detecting the intake negative pressure will be explained based on FIG. 4. The flowchart in FIG.
At the sampling interval of the intake negative pressure, such as j5, the third
An interruption is made to flowchart 1 in the figure. In addition, in this embodiment, maps are created separately for all-cylinder operation and reduced-cylinder operation to calculate fuel injection amount using engine speed and intake negative pressure as data. When switching to reduced cylinder operation (switching transition period),
Of the above maps, only the map for all-cylinder operation is used. Therefore, in the following explanation, we will explain during all-cylinder operation, during reduced-cylinder operation, when switching between all-cylinder operation and reduced-cylinder operation,
We will separately discuss how to detect (process) the intake negative pressure for the three cases. Note that during the above 1iIJ change (transition period), the response after the output from step 43.47 in FIG. and
This is the range indicated by time T or T2 (seconds) in FIGS. 5 and 6.

During the idle operation, first, in step 48, the cylinder number flag is determined,
If the number of cylinders flag is 1 indicating all-cylinder operation,
In step 49, the cylinder reduction flag in step 61, which will be described later, is set to 0, and then the process moves to step 50.

In step 50, a predetermined period of time T
(seconds) has elapsed, and if the specified time TI has elapsed, the process moves to step 51 (after point β in Figure 5) and a map for calculating the fuel injection amount is determined. As such, one for all-cylinder operation is selected. Next, in step 52, the margin flag is determined, and if the margin flag is 0, which means switching from reduced-cylinder operation to full-cylinder operation (this point will be described in detail later), step 53 Move to.

In step 53, since it is immediately after switching from reduced-cylinder operation to full-cylinder operation as described above, the moving average value up to now is first cleared (the intake negative pressure value sampled up to now is cleared). After this clearing, a moving average is started in step 54 based on the newly sampled intake negative pressure value. Then, in step 55,
It is determined whether the number of samplings of intake negative pressure values to be subjected to the moving average has reached a predetermined number n, and if the number has not reached the predetermined number n, in step 56, a predetermined number of samples sampled after the start of the moving average is determined. A moving average of a number of intake negative pressure values less than n is calculated to obtain an intake negative pressure average value Pa. After step 56, step 55 is performed again.
Pa is calculated in the same manner as described above until the number of intake negative pressure samplings for the moving average reaches the predetermined number n.

In this way, when the intake negative pressure sampling number reaches n, the process moves from step 55 to step 57, and the margin flag is set to 1.

After this, when the process returns from step 48 to step 52, the room flag in step 52 is -1, and the step 52 described above is set to -1.
7 is set to 1, so step 52 to step 5
8, a moving average of a predetermined number n of intake negative pressure samplings is calculated, and an intake negative pressure average value Pb is determined.

II During cylinder reduction operation In this case, the cylinder number flag at step 48 is 0, and until the predetermined intake negative pressure sampling number n is obtained, from step 48 to step 5.
8, 59, 60, 61, 62, 63, 64, 65, and finally step 66. The flow of the steps described above is as follows: Step 4 during all-cylinder operation
8, 49.50.51.52.53.54.55.56
．． Since the flow is basically the same as that of 57, all-cylinder operation I'j
To explain only the differences from the flow, in step 58 corresponding to step 49, the margin flag is set to 0, and in step 59, corresponding to step 50, the margin flag is set to 0, taking into account the difference in response time for switching, the margin flag is set to 0. (See Fig. 6) It is determined whether or not the elapsed time has elapsed, and in step 60 corresponding to step 51, a map for reducing cylinders is selected since it is the time of cylinder reduction operation, and the step corresponding to step 52 In 61, the reduced cylinder flag will be set, and the
In step 66 corresponding to pump 57, the cylinder reduction flag is set to 1.
It is said that

After the number of samples reaches the predetermined number n in step 64, the process moves from step 61 to step 67, and a moving average for the predetermined number n is calculated.

Note that the predetermined number n of intake negative pressure samplings during reduced-cylinder operation may be different from those during full-cylinder operation.

■When switching between all-cylinder operation and reduced-cylinder operation (switching transition period) When switching from reduced-cylinder operation to all-cylinder operation, the process moves from step 50 to step 68, and when switching from all-cylinder operation to reduced-cylinder operation The process moves from step 59 to step 68.

In step 68, after the map for all-cylinder operation is selected as the map for fuel injection ♀ calculation, the process moves to step 69. The average final value Pc is now used as the intake negative pressure value in the engine control law.

Here, to add a little bit to the explanation of I to ■ above, the reason why the cylinder reduction flag is set to 0 in step 49 is that when switching from all-cylinder operation to cylinder reduction operation, the cylinder reduction flag in step 61 is set to 0. At the beginning of the cylinder reduction operation, the predetermined value is O!
! [Even if the number of intake negative pressure samplings is less than n,
This is because the moving averages are calculated in steps 62 to 65. Similarly, the reason why all flags are set to O in step 58 is that when switching from reduced-cylinder operation to full-cylinder operation, all flags in step 52 are set to O, and at the beginning of full-cylinder operation, This is because even if the number of intake negative pressure samplings is less than the predetermined number n, the moving average is expanded in step 52 to step 53 and subsequent steps. Also, set all flags (Seitsutsu flags) to 1 with Ste Tsubu 57 (66).
Step 52 (61) to step 58 (
67) in order to be able to calculate the moving average of a predetermined number n of intake negative pressure sampling numbers.

Further, in step 50 or 59, until the response delay time T1 or T2 from when the switching signal is generated to when the forward rotation mode is actually switched has elapsed, the processing in steps 68 and 69 is carried out, respectively, and this switching II. ! The map for all-cylinder operation is selected for j, and the moving average of the previous time (before switching) @H(p'i) is used as the intake negative pressure.

Note that after the above-mentioned steps 58 and 67, although not shown, the oldest sampled intake negative pressure value is replaced with the newest one, and the data is rearranged. .

The above explanation is diagrammatically shown in fJ't5, Figure 6.
The diagram shows the transition from reduced-cylinder operation to full-cylinder operation! , lJ, the intake negative pressure value used for engine control is the moving average value Pb at step 67 (this may also be the moving average value at step 65) before time α in FIG. When converting !ilJ between time α and time β (between "1-1"), it is the value Pc at step 69, and immediately after β, it is the moving average value Pa at step 56.
After that, for a predetermined period of time (intake negative pressure sampling is 5 m
If it is every s e c, after 5m5ecXn) has elapsed from the β time point.

This is the moving average value Pb at step 58.

Conversely, when switching from all-cylinder operation to reduced-cylinder operation, the intake negative pressure value for engine control is the moving average value Pb at step 58 (the moving average value at step 56 before time γ in FIG. 6). Pa), and when switching between γ and δ time points (during T2), it is the value Pc at step 69, and immediately after the δ time point has passed, the moving average 4Q P at step 65. a, and the moving average value Pb at step 67 after a certain amount of time has elapsed from the point δ.

Note that the basic fuel injection amount is calculated from the map for all-cylinder operation at the time of overturning, and from the map for all-cylinder operation at the time of reduced-cylinder operation.
As the intake negative pressure value as a function of this map, the one for engine control described above is used. After calculating the basic fuel injection amount, the predetermined fuel is injected from the fuel injection valve IO after correction is made based on the engine temperature Ji, etc., if necessary. Of course, the intake negative pressure value to be compared with the setting (lri P 4 ) in step 41 in FIG.
The value at step 56, 58 or 69 in FIG. 4 is used, and similarly, the intake negative pressure value to be compared with the set value P2 at step 45 in FIG. The count in step 65.67 or 69 is used.

Although one embodiment has been described below, the present invention is not limited to this, and includes, for example, the following case.

■It can be applied not only to 4-cylinder engines but also to other multi-cylinder engines such as 6-cylinder engines, and the number of cylinders to be deactivated is not necessarily half of the total number of cylinders, but an appropriate number (
For example, in a 6-cylinder engine, 2 or 4 cylinders can be stopped! 'I).

■To configure the idle cylinder, a valve drive control device 24, 25 is installed in the valve machine, and the camshaft 18 and intake cylinder F1 are
4.15, and for example, a shutter valve may be provided in the intake passage corresponding to the cylinder to be deactivated to cut off the supply of air-fuel mixture to the cylinder to be deactivated. In addition, in the case where a fuel supply device such as a fuel injection valve is provided individually for each cylinder,
The fuel supply to the cylinder to be deactivated may be cut, and in this case, intake air may be supplied to the cylinder to be deactivated, or intake air may not be supplied at all to the cylinder to be deactivated. However, it is preferable to also cut the intake air supply to the cylinders to be deactivated in order to reduce so-called pumping loss and further improve fuel efficiency.

(2) The control unit 28 can be configured by either an analog or digital computer.

(ΦWhen switching as shown in T in Fig. 5 or T2 in Fig. 6,
Instead of using the final value of the previous moving average, this TI or the intake negative pressure 4fi itself sampled during 12 times, or the moving average during this period may be used for engine control.

At the time of switching indicated by T1 or T2 in tΦL, a map for cylinder reduction may be used as a map for calculating the fuel injection amount.

(Effects of the Invention) As is clear from the above description, the present invention, after switching between all-cylinder operation and reduced-cylinder operation, converts the intake negative pressure values sampled before and at the time of switching into the moving average value after switching. Since the calculation of the moving average is newly started using the newly sampled intake negative pressure value after switching, the detection of the intake negative pressure immediately after switching is particularly accurate.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is a system diagram showing one embodiment of the present invention. FIG. 3 and FIG. 4 are flowcharts I. showing an example of the control contents of the present invention. FIGS. 5 and 6 are diagrams showing the relationship between changes in intake negative pressure caused by switching between all-cylinder operation and reduced-cylinder operation, the cylinder number switching signal, and the map selection signal for fuel precalculation. L...III・Engine body 8...Φ・Intake passage 14...Intake valve 15...Exhaust valve 24.25...J"Drive control device 26.27...Solenoid 281 Fist: Control unit 30: Intake negative pressure sensor

Claims (1)

[Claims] (1) A cylinder reduction determination means for determining whether or not the cylinder reduction operation region is in which fuel supply to some cylinders is cut in accordance with the operating state of the engine, and receiving an output from the cylinder reduction determination means; cylinder number control means that is activated to cut fuel supply to some of the cylinders; and intake negative pressure detection means that detects intake negative pressure of the engine. Intake negative pressure averaging means receives the output from the intake negative pressure detection means, samples the intake negative pressure, and calculates an average of the sampled intake negative pressure values; and receives the output from the reduced cylinder determination means. , after switching between all-cylinder operation and reduced-cylinder operation by controlling the intake negative pressure averaging means, the intake air sampled after the switching is calculated without using the intake negative pressure 4+fi sampled up to the switching time. An intake negative pressure detection device for an engine with a controlled number of cylinders, comprising: average calculation control means for newly starting calculation of the average using a negative pressure value.