JPS6045738A - Controller for fuel of engine with regulated number of cylinders - Google Patents

Abstract

PURPOSE:To assure the enhancement of fuel efficiency in the deceleration of an engine and prevent the engine from stalling in operating with a reduced number of cylinders, by prescribing such engine revolution speeds corresponding to the reduction of fuel or the return thereof that the speed in th operation with the reduced number of cylinders is higher than that in the operation with all the cylinders. CONSTITUTION:A control unit 26 made of a microcomputer regulates solenoids 24, 25 to operate an engine either with all its cylinders or with a reduced number of them depending on the condition of the engine, and also regulates the injected quantity of fuel, the time of ignition, etc. The control unit 26 receives an engine cooling water temperature signal from a cooling water temperature sensor 27, an intake negative pressure signal from an intake negative pressure sensor 28, an engine rotational frequency signal from an ignition coil 29, a throttle position signal from a throttle sensor 30, a turn-on or turn-off signal sent from an idling switch 31 and indicating whether a throttle valve 9 is in the entirely open position or not, and an intake temperature signal from an intake temperature sensor 32 provided in an intake passage 7, and supplies outputs to the solenoids 24, 25 and a fuel injection valve 8.

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) Recently, it has been desired to significantly improve 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 in which the above-mentioned full-cylinder operation and reduced-cylinder operation can be appropriately switched and selected 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 all cylinders, during low load situations such as when driving at constant speed or on a steady road, fuel supply to some cylinders is cut and output is output from all cylinders. The aim is to save fuel by increasing the filling efficiency of the fuel.

In such a cylinder number control engine, a cylinder number control means is provided to cut fuel supply to some cylinders and switch to reduced cylinder operation, and the engine speed, throttle/help opening, and intake negative pressure are , a cylinder reduction determination means 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.

Incidentally, in recent engines, as part of efforts to improve fuel efficiency, as shown in Japanese Patent Application Laid-Open No. 7021/1983, fuel consumption is often reduced during deceleration until the number of times the engine is reduced to a predetermined number. In other words, during deceleration when no output is required, the amount of fuel is reduced and this reduction aims to improve fuel efficiency, but when the engine speed reaches a level slightly higher than the idle speed, the fuel is supplied as normal again. I am planning on making a comeback.

However, in an engine with cylinder number control, if the engine speed when returning the fuel is set in the same way as a general engine, engine stall is likely to occur during cylinder reduction operation due to the small low-speed torque. Such measures are desired.

(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 an engine with a controlled number of cylinders, which is capable of ensuring improved fuel efficiency by reducing the amount of fuel during deceleration while avoiding engine stall during reduced-cylinder operation due to the reduced amount of fuel.

(Structure of the Invention) In order to achieve the above-mentioned object, in the present invention, the predetermined engine rotation at which the fuel reduction is stopped, that is, the fuel is restored, is made faster during reduced-cylinder operation than during full-cylinder operation. It's also going to get bigger.

Specifically, as shown in FIG. 1, the engine is equipped with cylinder number control means and cylinder reduction determination means, as in the past, and switches between all-cylinder operation and cylinder reduction operation according to the operating state of the engine. .

Further, the fuel is set to a predetermined value by a fuel injection amount control means in, for example, an electronically controlled fuel injection device as a fuel adjustment device, and is injected into the intake negative pressure of the engine from a fuel injection valve. According to the present invention, the fuel reducing means receives the output from the cylinder reduction determining means, and the fuel reducing means receives the output from the rotational speed detecting means and the deceleration detecting means. The fuel injection amount control means is controlled to reduce the amount of fuel until the engine speed drops to a predetermined number of revolutions. Control is performed to increase a predetermined engine speed.

(Example) In Fig. 2, ■ is the engine body, and intake air is supplied to the combustion chamber 6 via the air cleaner 2, throttle chamber 3, intake manifold 4, and intake port 5, and from the air cleaner 2 to the intake port 5. The path up to this point constitutes the intake passage 7. The intake air flowing through the intake passage 7 is mixed with fuel from the fuel injection valve 8, and the amount of intake air is determined by the throttle valve 9.
controlled by Further, the exhaust residue from the fuel chamber 6 passes through the exhaust manifold 11 etc. from the exhaust port 10,
Emitted into the atmosphere.

The intake valve 12 that opens and closes the intake port 6 and the exhaust valve 13 that opens and closes the exhaust port 10 are opened and closed at predetermined timing by a valve mechanism. In this embodiment, this valve mechanism includes a turn spring 14.15 that biases the intake/exhaust valve 12.13 in the valve closing direction, and a crankshaft (not shown).
It is generally composed of a camshaft 16 that is rotationally driven by a camshaft 16, a cam 17 provided on the camshaft, a long arm 18.19, and a tappet 20.21 that constitutes a pivot point for the long arm 18.19. In the embodiment, the engine body 1 is for four cylinders, and the ignition order is 1. -3-4-2, and the 1st and 4th cylinders are the cylinders that are stopped, that is, the fuel supply is cut off, during cylinder reduction operation. Therefore, the 1st and 4th cylinders are For tappets 20 and 21, valve drive control device 2
2.23 is the old version.

The valve drive control devices 22, 23 are respectively switched and driven by solenoids 24, 25, and when the solenoids 24, 25 are demagnetized, the swinging fulcrum of the tappet 20, 21 relative to the rocker arm 18, 19 is The rocker arms 18 and 19 swing in response to the rotation of the camshaft 16, and the rocker arms 18.
This results in an all-cylinder operation in which the exhaust valves 12 and 13 are opened and closed. vice versa,
When the solenoids 24 and 25 are energized, the above-mentioned swing fulcrum can be displaced upward in the figure, and the camshaft 16 and suction
The interlocking relationship with the exhaust valves 12.13 is cut off, and reduced-cylinder operation is performed with the intake and exhaust valves 12.13 of the first and fourth cylinders maintaining their closed states.

Note that the valve drive control device 22, 23 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 26 in FIG. 2 is a control unit consisting of a microcomputer, and the control unit 26 controls the solenoids 24 and 25 to perform either full-cylinder operation or reduced-cylinder operation depending on the operating state of the engine. Of course, it also controls the fuel injection amount, ignition timing, etc., but in the following explanation, explanations of parts that are not directly related to the present invention, such as ignition timing, will be omitted. do.

The control unit 26 includes engine cooling water temperature as the engine temperature from the cooling water temperature sensor 27;
The intake negative pressure detected by the intake negative pressure sensor 28, the engine rotation speed from the ignition coil 29, the throttle position from the throttle sensor 30, the ON status of whether the throttle/help 9 is in the full open position from the idle switch 31,
While the OFF signal and the intake air temperature from the intake air temperature sensor 32 provided in the intake passage 7 are inputted, the control unit 26 inputs the two solenoids 24
．． 25 and the fuel injection valve 8.

In addition, in the figure t52, 33 is a destroyer, 34 is a spark plug, and 35 is a battery.

Next, the content of control by the control unit 26 will be explained based on the flowcharts shown in FIGS. 3 to 5. The flowcharts include a routine for cylinder discrimination, a routine for fuel calculation, Since the routines are broadly divided into injection routines, the following explanation will be divided into these routines.

Equipped Cylinder Determination Routine (Steps 36 to 47) First, the routine is initialized in step 36, where the cylinder number flag is set to 1 and the reduction flag is set to O. When this cylinder number flag is "1", it means all-cylinder operation, and when it is rQJ, it means reduced-cylinder operation.
When it is "1", it means when the fuel is reduced, and when it is "0", it means when it is not when the fuel is reduced.

Next, in step 37, each data of intake air temperature, engine cooling water temperature, intake negative pressure, engine speed, throttle position, and idle switch signal 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,
Cooling water temperature set value T. (for example, 60°C) or higher (step 38), and the engine speed is at the set value N. (
If all conditions are met, such as low speed (for example, 2000 rpm) or less (step 39), and steady or decelerated running without acceleration (step 40), the process moves to step 41. Note that whether or not the vehicle is in an acceleration state is determined by differentiating the change in throttle position with respect to time to obtain acceleration, and determining whether or not the acceleration is greater than a set acceleration.

From step 41 above, since the cylinder number flag is initialized to be 1 in step 36, 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 the reduced-cylinder operation are satisfied, so step 44 outputs an output indicating that the reduced-cylinder operation (in the embodiment, 2-cylinder operation) is to be performed, i.e. The solenoids 24 and 25 are energized, resulting in reduced-cylinder operation in which the intake and exhaust valves 12 and 13 of the first and fourth cylinders are maintained in the closed state.

After this, the fuel calculation process described later is performed, and the process returns to step 37. However, if the operating state of the engine is the same as described above, the process proceeds to step 41 as described above. Then, in step 41, the number of cylinders flag is set to O in step 43 as described above.
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, the intake negative pressure is different during reduced-cylinder operation and during full-cylinder operation, even if the engine speed is the same, and therefore, the conditions for switching to full-cylinder operation during reduced-cylinder operation are different. The intake negative pressure P2 used is that during reduced-cylinder operation, and the intake negative pressure P, which is the condition for switching to reduced-cylinder operation during all-cylinder operation, is used during all-cylinder operation ( P 2 >
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).

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 If the conditions are met, the process moves to step 46, where the generous 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 24
．． 25 is demagnetized and all cylinder intake valves 12.1
3 is an all-cylinder operation in which opening and closing movements are performed.

II deceleration determination and fuel calculation routine (step 48~
61) First, in step 48, idle switch 7ch 31 is turned on.
It is determined whether the throttle is ON or OFF, and if the throttle is ON but the throttle is fully closed, the process moves to step 49. In this step 49, the engine cooling water temperature is set to the set value TI.
(For example, 45°C, T.

< T o ), and if it is larger than the revised value T1, the process moves to step 50.

Then, in step 50, the cylinder number flag is determined, and if the cylinder number flag is 1 during full cylinder operation, the process proceeds to step 51, and if it is 0 during reduced cylinder operation, the process proceeds to step 54.

In step 51, it is determined whether the intake negative pressure is greater than a set value Pa (for example, -160 mmHg) during all-cylinder operation, and if it is smaller than the set value Pa, step 5
Move to 2. In this step 52, the engine speed is a set value N which is the fuel return speed during all-cylinder operation.
It is determined whether or not the value is greater than 4, and if it is greater than the set value N4, the process moves to step 53'\. Then, in this step 53, the reduced deceleration fuel η, (a constant value in the embodiment) during all-cylinder operation is set, and the F/CFuel
After that, the weight loss flag is set to 1 in step 57.

Further, in step 54, the intake negative pressure is set to a set value Pb' (for example, -21'OmmHg, Pa>Pb
), and if it is smaller than the set value Pb, the process moves to step 55. In this step 55, it is determined whether the engine speed is larger than a set value N2 (N2 > N4), which is the fuel return speed during cylinder reduction operation, and if it is larger than the set value N4, the engine speed is The process moves to section 56. Then, in this step 56, the reduced deceleration fuel η, (in the embodiment, a constant value η4>η7) during cylinder reduction operation is set, and the F/CFuel
, the weight loss flag is set to 1 in step 57.
It is said that

In this way, it is determined whether or not it is in a deceleration state, and the deceleration fuel for full-cylinder operation or reduced-cylinder operation is set.
The reason for the difference in b is that, as mentioned above, there is a difference in the magnitude of the intake negative pressure that occurs even at the same engine speed, so the intake negative pressure value is one of the factors that determines whether or not it is in a deceleration state. This is to make it compatible with full-cylinder operation and reduced-cylinder operation. Also, the reason why the rotational speeds are made different such as N 4 and N 2 is to make the fuel return rotational speed, which is a feature of the present invention, higher when the cylinders are reduced than when they are full. Of course, N 2 > N 4. In addition, the reason why the cooling water temperature is used as a determination factor in step 49 is as follows.
This is because combustion is unstable when the engine is sufficiently warmed up, so in this case the fuel should not be reduced.

On the other hand, when the idle switch 31 is OFF, if the cooling water temperature is smaller than the set value T, the intake negative pressure is lower than the set value Pa(
(during all-cylinder operation) or Pb (during reduced-cylinder operation), the engine speed is N4 (during all-cylinder operation) or N2.
(during cylinder reduction operation), if any one of the conditions is met, the process moves to step 58.

The flow from steps 58 to 60 is a normal fuel determination route, and first, in step 58, a basic fuel injection amount is calculated from the engine speed and intake negative pressure. Of course, in this step 58, the above basic information is calculated from the map for reduced cylinder operation or the map for full cylinder operation, depending on the output from steps 44 and 47 for reduced cylinder operation or full cylinder operation. This is to calculate the fuel injection amount τ.

Next, in step 59, the correction coefficient C based on the cooling water temperature is multiplied by the basic fuel injection amount τ to correct the fuel injection amount (with the corrected fuel injection amount). In step 6o, the corrected fuel injection amount obtained by this correction is multiplied by a correction coefficient 02 based on the intake air temperature to obtain a corrected fuel injection amount of 2, which is Fu
Stored as el.

After that, the process moves to step 61, and the weight loss flag is set to 0.

■Fuel injection routine (Figures 4 and 5) First, let us explain about Figure 4, which shows the normal fuel injection routine other than during deceleration.The flowchart in Figure 4 is different from the flowchart in Figure 3. For example, the interruption is performed at regular fuel injection timings such as every TDC' (top dead center) timing. First, in step 62, it is determined whether the reduction flag is 1 or O. When the reduction flag is 1, that is, when the engine is decelerating and the engine rotation speed is greater than the predetermined rotation speed N4 at which fuel is restored, the normal Since this is the time when the deceleration fuel for deceleration should be supplied instead of the fuel for the engine, the engine is returned to normal operation.

On the other hand, in step 62, when the reduction flag is O, that is, when the engine rotation speed is smaller than the number N2 or N4, which is not the case during deceleration, the process moves to step 63. , the cylinder number flag is determined. During all-cylinder operation when the cylinder number flag is 1, a fuel injection pulse with a pulse width corresponding to the fuel injection amount of 2 in step 60 is output, and fuel is injected from the fuel injection valve 8 for 2 minutes. be done. Further, during cylinder reduction operation when the cylinder number flag is 0, the process moves to step 65, where it is determined whether or not it is the TDC timing of the active cylinder.If it is the TDC timing of the active cylinder, the process moves to step 64, and the above In the same way as in the case of , if only 2 minutes is injected from fuel injection valve 8 and the TDC timing of the idle cylinder is,
It is restored without injecting fuel.

Next, we will explain about FIG. 5, which shows the routine of reduced fuel injection during deceleration. The flowchart in FIG. 5 is such that the flowchart in FIG. First, in step 66, a weight loss flag is determined. Then, when the weight loss flag is O, the operation returns as is, and when the weight loss flag is 1, in step 67, step 53 or step 5
Fuel injection amount F / CF u e set in 6
A fuel injection pulse with a pulse width corresponding to 1 is output, and fuel corresponding to 1 F/CFue is injected from the fuel injection valve.

The above-mentioned control contents are summarized and diagrammatically shown in FIG.

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

■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 limited to half of the total number of cylinders, but can be set to an appropriate number (e.g. In a 6-cylinder engine, 2 or 4 cylinders can be stopped, etc.).

4> To configure the idle cylinder, a valve drive control device 22, 23 is provided in the valve mechanism to control the camshaft 16 and the intake/exhaust valve 1.
2.13, for example, a shutoff valve may be provided in the intake passage corresponding to the cylinder to be deactivated to cut the supply of air-fuel mixture to the cylinder to be deactivated. good. In addition, in the case where a fuel supply device such as a fuel injection valve is provided for each cylinder individually, it is also possible to cut the fuel supply from the fuel injection valve to the cylinder that should be deactivated. Often, in this case, intake air may be supplied to the cylinder to be deactivated, or it may be possible to supply no intake air at all. However, it is also necessary to reduce the intake air supply to the cylinders that should be stopped.
It is preferable to reduce the so-called pumping loss and further improve fuel efficiency.

(2) The control unit 26 can be configured by either an analog or digital computer.

■A carburetor may be used as the fuel adjustment device.

(2) The fuel reduction during deceleration operation may be zero, that is, a fuel cut.

(, 0 The reduced fuel amount may not be a constant value, but may be adjusted depending on the engine speed, for example, or the reduced fuel amount may be the same during full-cylinder operation and during reduced-cylinder operation.

■ To adjust the amount of reduced fuel or regular fuel, it may be done by changing the pulse period instead of the pulse IJ.

(Effects of the Invention) As is clear from the above description, the present invention reduces fuel consumption during deceleration, thereby making it possible to improve fuel costs. Since it is made larger during operation than during full-cylinder operation, it is possible to prevent engine stall during reduced-cylinder operation due to the fuel reduction.

[Brief explanation of drawings]

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. 3 to 5 are flowcharts showing an example of control contents of the present invention. FIG. 6 is a diagram schematically showing an example of control contents of the present invention. 1...Fist・φEngine body 7...Intake passage 8...Fuel injection valve 9...e...Throttle valve 12.9-...Intake valve 13... ...Exhaust valve 22.23...Valve drive control device 26...Fist...Control unit 31...e...
number idle switch

Claims (1)

[Claims] (1) A cylinder reduction determining means for determining whether or not the cylinder reduction operation region is in which fuel supply to some cylinders is canted, depending on the engine motion state; and receiving an output from the cylinder reduction determination means. a cylinder number control means that is operated to cut the fuel supply to some of the cylinders, a fuel oil adjustment device that supplies fuel to the intake passage of the engine, and a rotational speed that detects the engine rotational speed. a detection means; a deceleration detection means for detecting a deceleration state of the engine; and +iii) rotational speed rotational speed detection means; receiving the output of the deceleration detection means, controls the fuel adjustment device to reduce the engine rotational speed to a predetermined twin engine rotational speed during deceleration; a fuel reduction means for reducing the amount of fuel until the fuel is reduced; and a fuel return means for receiving the output of the cylinder reduction determination means and increasing the predetermined engine speed during cylinder reduction operation than during full cylinder operation. A fuel control device for an engine with cylinder number control.