JPS6040739A - Fuel controller for cylinder number controlling engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

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

(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, Japanese Patent Application Laid-Open No. 57-338
As shown in the above publication, an engine with a controlled number of cylinders has appeared that can appropriately switch between full-cylinder operation and reduced-cylinder operation as described in L depending on the operating state of the engine. That is,
For example, during high loads such as when starting or driving at high speed,
While fuel is supplied to all cylinders and output is output from the main cylinder, during low load conditions such as when driving at a constant speed or on a steady road, the fuel supply to some cylinders is cut to reduce the charging efficiency of other cylinders. Efforts are being made to save fuel by increasing the fuel consumption.

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

By the way, recently, as part of efforts to improve fuel efficiency,
As shown in Publication No. 7021, there is. However, if the fuel supply is completely cut off, during the next steady run or acceleration after deceleration, the air-fuel ratio will temporarily change because the fuel supplied will not be able to keep up with the increase in the amount of intake air. This causes the problem of poor responsiveness when transitioning to the next run as described above. In other words, during deceleration, the inside of the intake passage becomes high negative pressure, which causes the fuel adhering to the inner wall of the intake passage to peel off and be rapidly sucked into the fuel chamber, but when the engine shifts to driving conditions such as acceleration. While the increasing amount of intake air is quickly supplied to the fuel chamber, a portion of the supplied fuel adheres to the inner wall of the intake passage. This will result in dilution.

Therefore, during deceleration, instead of completely cutting off the fuel supply, it may be possible to supply a small amount of deceleration fuel to keep the inner wall of the intake passage constantly wet.

However, in engines with controlled number of cylinders, there is a difference in the magnitude of intake negative pressure during deceleration, that is, the degree of wetness (also considered as the degree of dryness) of the inner wall of the intake passage, between full-cylinder operation and reduced-cylinder operation. Therefore, some kind of countermeasure is desired in order to reduce the amount of deceleration fuel as much as possible to save fuel and ensure responsiveness when transitioning to the next run.

(Object of the invention) The present invention has been made in consideration of the above circumstances, and
It is an object of the present invention to provide a fuel control device for a cylinder number controlled engine that can obtain appropriate deceleration fuel depending on the operating mode of full-cylinder operation and reduced-cylinder operation.

(Structure of the Invention) In order to achieve the above-mentioned object, the present invention provides that the magnitude of the intake negative pressure during deceleration, that is, the degree of dryness of the inner wall surface of the intake passage, is lower during full-cylinder operation than during reduced-cylinder operation. Taking note of the fact that the engine speed is larger, the amount of deceleration fuel is set to be less during reduced-cylinder operation than during full-cylinder operation.

Specifically, as shown in Fig. 1, it has a cylinder number control means and a reduced-cylinder determination means, as in the past, and switches between all-cylinder operation and reduced-cylinder operation according to the interlocking state of the engine. on the other hand,
The deceleration fuel control means receives outputs from both the deceleration detecting means and the cylinder reduction determining means, and controls a fuel oil adjustment device such as an electronically controlled fuel injection device. In other words, the fuel injection amount is determined by the fuel injection amount control means 14, but during deceleration, the deceleration fuel control means controls the fuel injection amount control means 2, so that the fuel injection amount is determined at full capacity during cylinder reduction operation. This is done so that the amount of deceleration fuel is less than during cylinder operation. Note that the fuel is injected into the intake passage of the engine according to the fuel injection amount.

(Example) In Fig. 2, l is the main body of the engine, and the intake air is
It is supplied to the combustion chamber 7 via the air cleaner 2, throttle chamber 4, intake manifold 5, and intake port 6, and is
A path from the air cleaner 2 to the intake port 6 constitutes an intake passage 8. Fuel from a fuel injection valve 10 is mixed with the intake air flowing through the intake passage 8, and the amount of intake air is controlled by a throttle valve 11. Further, the air gas from the fuel chamber 7 is discharged to the atmosphere from the exhaust port 12 through the υ1 air manifold 13 and the like.

The intake valve 14 that opens and closes the intake port 6 and the exhaust valve 15 that opens and closes the υ1 air port 12 are opened and closed at predetermined timing by a valve mechanism. In addition to the turn spring 16.17 that urges the IA valve j14.15 in the valve closing direction, a camshaft 18 rotationally driven by a crankshaft (not shown), a cam 19 provided on the camshaft, and a rocker arm 20
．． 21, and a tappet 22.23 that constitutes a pivot point for the rocker arm 20.21. In Example 1, the engine body l is for 4 cylinders,
If the ignition order is set to 1-3-4-2, the first and fourth cylinders are inactive during direct cylinder operation, that is, the fuel F1 supply is cut off, and therefore, For tappets 22 and 23 for cylinders 1 and 4,
A drive control device 24.25 is provided.

The valve drive control devices 24 and 25 are respectively switched and driven by solenoids 26 and 27, and when the solenoids 26 and 27 are demagnetized, the openings of the tappets 22 and 23 and the swinging fulcrums for the lever arms 20 and 21 are used. is in a position displaced downward in the figure, and the rocker arms 20 and 21 swing in response to the rotation of the camshaft 18, opening and closing all the cylinders.
This results in an all-cylinder operation in which the exhaust valves 14 and 15 are opened and closed. vice versa,
When the solenoids 26 and 27 are energized, the above-mentioned swing fulcrum is shown in the figure. The interlocking relationship between the camshaft 18 and the intake/exhaust valves 14.15 was cut off, and the intake/exhaust valves 14.15 of the first and fourth cylinders remained closed. It will continue to operate with fewer cylinders.

Note that the valve drive control device 24, 25 itself described above is
Since it is already well known, for example, as shown in Japanese Unexamined Patent Publication No. 52-56212, detailed explanation thereof will be omitted.

Reference numeral 28 in FIG. 2 is a control unit consisting of a microcomputer, and the control unit 28 controls the solenoid 26.
27, as well as the fuel injection amount, ignition timing, etc., but in the following explanation, explanation of parts that are not directly related to the present invention, such as ignition timing, will be omitted. do.

The control unit 28 includes information such as the position of the throttle valve 11 from the throttle sensor 3, the engine cooling water temperature as the engine temperature from the cooling water temperature sensor 29, the intake air temperature from the intake air temperature sensor 30 provided in the intake passage 8, and the intake air temperature from the intake air temperature sensor 30 provided in the intake passage 8. intake negative pressure detected by the negative pressure sensor 31;
The engine rotational speed from the ignition coil 32 and the ignition coil 32 are respectively inputted, while outputs are outputted from the control unit 28 to both the solenoids 26, 27 and the fuel injection valve IO.

In FIG. 2, numeral 33 is a destroyer, numeral 34 is a spark plug, and numeral 35 is a battery.

Next, the content of control by the control unit 28 will be explained based on the flowchart shown in FIG. 3. The flowchart is roughly divided into a routine for cylinder discrimination and a routine for fuel calculation. In order to
In the following explanation, we will break down each of these routines.

Effort/Imperation Determination Routine (Steps 36-47) First, the routine is initialized in step 36, and the cylinder number flag is set to 1. When this cylinder number flag is rlJ, it means all-cylinder operation, and when it is "0", it means reduced-cylinder operation.

Next, in step 37, each data of intake air temperature, engine cooling water temperature, intake negative pressure, engine speed, and throttle position is input.

Thereafter, based on the data input in step 37, it is sequentially determined in steps 38 to 40 whether the engine operating state satisfies the conditions for reduced-cylinder operation. That is,
The cooling water temperature is higher than the setting (tTo (for example, 60'C) (38 steps, and the engine speed is the set value N).
o (e.g. 2000 rpm) or less (steel speed)
If all the conditions are met, ie, the vehicle is not in an accelerated state (step 40), and the vehicle is in a steady or decelerated state (step 40), the process proceeds to step 41. Note that whether or not the vehicle is in the acceleration state is determined by calculating the amount of change in the throttle position per intermediate time to obtain acceleration, and determining whether or not this acceleration is greater than the set acceleration.

From step 41 above, since the cylinder number flag is initialized to be 1 in step 37, the process first moves to step 42, where it is determined whether the intake negative pressure is equal to or higher than the set value 24. Ru. If the intake negative pressure is a low load equal to or less than the set value P4, the process moves to step 43, where the number of cylinders flag is set to 0.

” - The transition to step 43 is when all the conditions for 1g cylinder operation are satisfied, so in step 44 an output is made indicating that cylinder reduction operation (in the embodiment, 2 cylinder operation) is to be performed, that is, the solenoid 26.27 is excited, the intake and exhaust of the 1st and 4th cylinders, f? 4.1
5 becomes a cylinder reduction operation in which the valve is maintained in the closed state.

After this, fuel calculation processing is performed in steps 48 to 52, which will be described later, and the process returns to step 37.
If the operating state of the engine is the same as described above, the process moves to step 41 as described above. and,
In step 41, since the cylinder number flag is set to O as described above in step 43, the process moves to step 45, where it is determined whether the intake negative pressure is greater than the set value P2 or not, and whether the engine speed is the same. Even if there is, it is different during reduced-cylinder operation and during all-cylinder operation, and therefore, the intake negative pressure P2, which is the condition 1 for switching to all-cylinder operation during reduced-cylinder operation, is the same as that during reduced-cylinder operation. Intake negative pressure P4, which is a condition for switching to reduced-cylinder operation during full-cylinder operation, is the one used during full-cylinder operation (P2>P4). This prevents frequent switching between reduced-cylinder operation and full-cylinder operation in response to intake negative pressure in a short period of time (hunting prevention +I: ).

Here, the cooling water temperature is the set value T. If the engine speed is higher than the set value No., if the engine speed is accelerated, if the intake negative pressure is greater than the set value P2 (during reduced-cylinder operation) or P4 (during all-cylinder operation), any one of the following will occur. If the conditions are met, the process moves to step 46, where the cylinder number flag is set to 1, and then, in step 47, an output indicating that all-cylinder operation is to be performed is made. That is, solenoid 26
．． 27 is demagnetized and all cylinder intake and exhaust valves 14.1
5 is an all-cylinder operation in which opening and closing movements are performed.

II Fuel Calculation Routine (Steps 48 to 57) First, during cylinder reduction operation, the process moves from step 44 to step 48, where it is determined whether or not the engine is in a deceleration state. Note that whether or not this is the deceleration is determined based on, for example, the throttle position and the engine rotation speed.

If it is determined in step 48 that the deceleration is not occurring, the process moves to step 49, where a basic map for cylinder reduction operation consisting of a function of intake negative pressure and engine speed is selected, and the basic map is selected. A fuel injection amount is determined. After this, step 5
After the pulse width corresponding to the basic fuel injection amount is calculated at step 51, the calculated pulse r is calculated at step 51.
tJ is corrected based on the engine cooling water temperature and intake air temperature. Then, in step 52, the fuel 11 is injected from the injection box 10 with the corrected pulse width.

If it is determined in step 48 that the vehicle is in a deceleration state, the process proceeds to step 53, where it is determined whether the engine speed is greater than Nl. This rotational speed N is determined by supplying a very small amount of quick fuel, or by supplying a normal amount of fuel that is larger than this reduced speed fuel, since the very low speed torque is small during cylinder reduction operation, which tends to cause engine stalling. This is set as a boundary point as to whether or not to supply fuel (generally idle fuel), and if the rotational speed is less than N1, the process moves to step 49 described above and processes in steps 50, 51, and 52 are performed. In addition, the number of revolutions N1 at the two-legged step 53
If it is determined that the above is the case, the process moves to step 54,
The deceleration fuel for reduced-cylinder operation is determined, and then steps 50, 51, and 52 are performed.

On the other hand, during full-cylinder operation, the process moves from step 47 to step 55, and if the engine is not in a deceleration state, the process goes to step 56, and if it is in a deceleration state, the process goes to step 57.

In step 56, a basic map for all-cylinder operation consisting of intake negative pressure and engine speed is selected, and the failure fuel injection amount is determined. Furthermore, when the process moves to step 57, the deceleration fuel during full-cylinder operation is determined. After step 56 or 57, the above-described steps 50, 51, and 52 are performed. Of course,
The deceleration fuel for reduced-cylinder operation determined in step 54 is smaller than the deceleration fuel for full-cylinder operation determined in step 57.

Here, in Fig. 4, the region where reduced-cylinder operation is required is indicated by α, the region where all-cylinder operation is required is indicated by β, the region where deceleration fuel is supplied during reduced-cylinder operation is indicated by γ, and the region during all-cylinder operation is indicated by γ. The region where deceleration fuel supply is performed is indicated by δ. In FIG. 4, N is the set engine speed at step 39, N is the set engine speed at step 53, and point A is the boundary point of whether or not the deceleration state is in progress. This indicates the throttle position. In addition, in this Figure 4, the determination of the fuel to be supplied and the above α
The relationship between the region of ~δ is that the region of α is at step 49, and the region of β is at step 49.
The area of γ is at step 56, the area of γ is at step 54,
The area of δ is determined in step 57, respectively.

Although the embodiments have been described above, the present invention is not limited thereto, and includes, for example, the following cases.

(j) 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 can be adjusted as appropriate. (for example, deactivating two or four cylinders in a six-cylinder engine).

■In order to configure a paused cylinder, a valve drive control device 24, 25 is provided in the valve mechanism, and the camshaft 18 and intake/exhaust valve 14 are
．． 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 from the fuel injection valve 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 also be supplied to the cylinder to be deactivated. You can also choose not to. However, it is preferable to also cut the intake air supply to the cylinders to be deactivated in order to reduce the so-called pumping loss and further improve fuel efficiency.

The control and roll unit 28 can be configured by either an analog or digital computer.

(2) A carburetor may be used as the fuel adjustment device, and in this case, the deceleration fuel can be adjusted by changing the diameter of the main jet or main air jet, for example.

(2) The amount of deceleration fuel may not be set fixedly, but may be made variable depending on, for example, the engine speed. In this case, a map for this purpose may be selected in step 57.

(2) In step 50, instead of calculating the pulse width, especially during deceleration, the period of the pulse may be changed to adjust the amount of injected fuel.

(Effects of the Invention) As is clear from the above description, the present invention can obtain an appropriate amount of deceleration fuel suitable for full-cylinder operation and reduced-cylinder operation, so that unnecessary excess deceleration fuel is not supplied. This makes it possible to save fuel and ensure good responsiveness when transitioning from slow speed driving to the next accelerated driving.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram of the present invention. FIG. 2 is an overall system diagram showing one embodiment of the present invention. FIG. 3 is a flowchart showing an example of control contents of the present invention. FIG. 4 is a diagram showing the area classification for determining the amount of fuel to be supplied depending on the operating condition.・ 19 tatami...Fist engine body 8--Life...Intake passage 10--...Fuel injection valve 1l11111Iφ・War throttle valve 14 War...
・・Intake valve 15・φ・・φφexhaust valve 24.25−・・Valve drive control device 28・eΦ・・Control unit Fig. 3

Claims (1)

[Claims] (1) A cylinder reduction determination means for determining whether the fuel supply to some cylinders is cut off or not in a cylinder reduction operation region according to the interlocking state of the engine, and 1) Output from the stated cylinder cylinder determination means. a cylinder number control means that is activated in response to a signal and cuts fuel supply to some of the cylinders; a fuel efficiency adjustment device that supplies fuel to an intake passage of the engine; and a deceleration detection means that detects a deceleration state. In response to the outputs from the deceleration detecting means and the cylinder reduction determining means, the fuel adjustment device is controlled to supply a small amount of deceleration fuel during deceleration, and to reduce the amount of deceleration fuel to the full amount during cylinder reduction operation. 1. A fuel control device for a cylinder number controlled engine, comprising: deceleration fuel control means for reducing fuel consumption compared to during cylinder operation;