JPH0445653B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel injection amount control device for a multi-cylinder internal combustion engine, and in particular to a fuel injection amount control device for a multi-cylinder internal combustion engine that performs cylinder reduction operation depending on the operating condition. Regarding a control device.

[Prior art]

In a multi-cylinder internal combustion engine where fuel is injected by a fuel injection pump, the injection pump increases or decreases the amount of fuel injected into each cylinder to control the cylinder output, but the fuel consumption and exhaust gas conditions of the engine depend on the amount of injected fuel. Varies depending on These fuel efficiency and exhaust gas conditions change depending on many conditions such as the internal combustion engine rotation speed, intake temperature, and engine cooling water temperature, so various fuel injection amount controls are required from the viewpoint of improving fuel efficiency and purifying exhaust gas. It has been done. Considering the range of changes in engine output in automobiles, the amount of fuel injection must be varied over a wide range from no-load idling to rapid speed, so the injection amount that achieves the maximum efficiency for the internal combustion engine is determined. I can't keep driving.

Conventionally, in order to increase the amount of fuel injected per cylinder and operate the engine at maximum efficiency, the operation of, for example, three cylinders out of six cylinders is conventionally stopped during low load. So-called reduced cylinder operation has been proposed. Furthermore, as electronic control systems have developed in recent years, methods have also been proposed in which such cylinder reduction operation is performed using an electronic control device. For example, Japanese Patent Laid-Open No. 57-38629 proposes an electronically controlled hydraulically driven diesel injection system, which makes it possible to control fuel injection for each cylinder. Also, Japanese Patent Application Laid-open No. 54-148929,
Japanese Unexamined Patent Application Publication No. 179347/1983 discloses a system that performs cylinder reduction operation depending on the engine operating state and engine temperature.

However, if cylinder reduction operation is performed depending on the operating state of the engine, for example, the engine load, it is possible to reduce the number of operating cylinders and maximize combustion efficiency when the engine load is low, but with this control, Even when the engine is still warmed up and in an idling state, the number of operating cylinders is uniformly set depending on the engine load. Generally, if the fuel injection amounts are equal, the more cylinders are inactive, that is, the fewer cylinders are used for combustion, the faster the warm-up is performed. Therefore, for example, if it is better to deactivate 3 cylinders to promote warm-up, if you reduce the number of cylinders depending on the engine load, 2 cylinders will be deactivated.
There is also the possibility that only the cylinders can be deactivated.

[Purpose of the invention]

The purpose of the present invention is to reduce the number of operating cylinders when the engine load is small compared to when the engine load is large, and in addition to the premise that operation at the maximum combustion efficiency according to the engine load is possible. To provide a fuel injection amount control device for a multi-cylinder internal combustion engine capable of promoting warm-up by reducing the number of operating cylinders as the engine temperature becomes lower.

[Structure of the invention]

As illustrated in FIG. 1, the configuration of the present invention, which has been made to achieve the above object, includes: an operating state detecting means for detecting the engine load including the idling operating state of a multi-cylinder internal combustion engine; and the operating state detecting means. and a first change in the number of active cylinders in which the operation of some cylinders of the multi-cylinder internal combustion engine is stopped so that the number of active cylinders is reduced when the engine load is low compared to when the engine load is high, based on the engine load detected by the above method. temperature detection means for detecting engine temperature; and temperature detection means for detecting engine temperature, and controlling some of the cylinders of the multi-cylinder internal combustion engine to reduce the number of operating cylinders when the engine temperature is low compared to when the engine temperature is high, based on the detected engine temperature. a second operating cylinder number changing means for suspending operation; a determining means for determining that the conditions that the engine temperature is below a predetermined value and the engine is in an idling state are satisfied; and when the above conditions are satisfied; A fuel for a multi-cylinder internal combustion engine, comprising: priority execution control means for giving priority to the operation of the second operating cylinder number changing means over the first operating cylinder number changing means; The gist is the injection amount control device.

According to the fuel injection amount control device of the present invention, when the determination means determines that the engine temperature is below a predetermined value and the engine is in an idling state, the priority execution control means The first means for changing the number of active cylinders based on the load suspends operation of some cylinders of the multi-cylinder internal combustion engine based on the engine temperature so that the number of active cylinders is reduced when the engine temperature is low compared to when the engine temperature is high. The operation by the second operating cylinder number changing means is executed with priority.

Therefore, for example, during warm-up operation, based on the engine temperature, the lower the engine temperature, the lower the number of operating cylinders can be performed.

〔Example〕

The present invention will be described below with reference to drawings and examples.

FIG. 2 is an explanatory diagram showing the relationship between the control rack and actuator of the in-line fuel injection pump according to the embodiment of the present invention.

In the figure, 1 is a camshaft connected to a crankshaft (not shown) and driven by the engine, 2 is a rotation speed sensor that generates one pulse per revolution of the camshaft, and 3 is a known plunger (not shown) that controls the fuel injection amount. 4 is a rack position detector for detecting the position of the control rack 3; 5 is a control rack as a fuel injection adjustment member for controlling the
is a movable iron core linear solenoid as an actuator that controls the position of the control rack 3;
6 each represents an electronic control circuit as an arithmetic control means. The movable iron core type linear solenoid 5 that moves the control rack 3 generates a force that attempts to move the moving core 12 in the direction of arrow a by the current flowing through the coil 11. A return spring 13 is arranged on the collar of the control rack 3 and generates a force that moves the control rack 3 in the direction of arrow b.

The moving core 12 of the linear solenoid 5 and the control rack 3 have a structure in which they come into contact with each other by pressing against each other, and the structure is such that a slight misalignment between the axis of the control rack 3 and the axis of the linear solenoid 5 can be tolerated. There is. The position of the control rack 3 is determined by the balance between the suction force of the linear solenoid 5 (force in the direction a) and the spring force of the return spring 11 (force in the direction b).

In addition, 16 is engine oil that serves as a lubricating oil, and 1
7 is a drain for keeping the oil level constant.

Next, FIG. 3 is an explanatory diagram of a control system centered on an electronic control circuit 6 as an arithmetic control means.
A rotation number counter 42 and a rotation number counter include a built-in microcomputer whose main elements are a read-only memory (ROM) 31 and a random access memory (RAM) 32, and measure the number of rotations based on the output signal from the engine rotation speed sensor 2. an interrupt control unit 43 that generates an interrupt to the CPU 30 every 42 predetermined counts; a timer 44 that counts time;
An input port 47 that inputs signals from a starter switch 45 that operates the starter and an idle switch 46 that detects an idle state, an A/D conversion input port 48 that inputs various analog quantities, converts them to digital quantities, and outputs them to the CPU 30; A drive circuit 4 that drives a linear solenoid 5 that adjusts the position of the control rack 3 based on the control of the CPU 30.
9, a common bus 50 connecting the CPU 30, memories 31, 32, and each port, and a power supply circuit 61 that supplies power from a battery 55 via a key switch 60. Here, the A/D conversion input port 48 includes a rack position sensor 4 that detects the position of the control rack 3, a cooling water temperature sensor 71 that detects the engine cooling water temperature, an accelerator position sensor 72 that detects the accelerator position, Intake pressure sensor 73, intake temperature sensor 74, and fuel temperature sensor 75 for detecting the amount of air taken into the engine
Analog signals from each are input.

FIG. 4 is a flowchart showing the processing of this embodiment in a six-cylinder internal combustion engine. In the figure 1
10 represents a step for determining whether the key switch for starting the engine is turned on. Reference numeral 120 represents a step for reading signals such as engine operating conditions, such as engine cooling water temperature Tw, engine speed Ne, or idle switch ON/OFF. 130 represents a step for determining whether or not to deactivate the cylinder. 140 represents a step for calculating the number of cylinders at rest and the position of the cylinders. 150 is a step for controlling the fuel injection amount; 160
represents a step for reading the engine speed Ne. 170 is a step for determining whether the engine rotation speed Ne is equal to or higher than a preset predetermined rotation speed No, and 180 is a step for reading signals such as the engine operating state, that is, the engine water temperature Tw and the rotation speed Ne. It represents. 190 represents a step for determining whether or not there is a deactivated cylinder in the engine. 2
00 represents a step for calculating the number of deactivated cylinders and the position of deactivated cylinders.

Next, a description will be given of the fuel injection amount control process for the multi-cylinder internal combustion engine in this embodiment. This processing routine for controlling the fuel injection amount is indicated by A in FIG.
Step 110 is first performed to start the engine, that is, to determine whether the key switch is on or off.
If the key switch is off in step 110, the determination is "NO" and the process repeats itself. If the determination in step 110 is "YES", that is, the key switch is on, then in the subsequent step 120, the operating state of the engine, for example, the engine cooling water temperature Tw is determined from the cooling water temperature sensor 71, the engine rotational speed Ne is determined from the rotational speed sensor 2, The idle state is read from the idle switch 46.
In step 130, if the idle switch is turned on, it is determined whether or not to deactivate the cylinders based on the engine cooling water temperature Tw. The determination of the deactivated cylinder in step 130 is made based on whether the engine cooling water temperature Tw is lower than a preset water temperature _Tw2 . If the determination at step 130 is "YES", the process proceeds to step 140, where the number of deactivated cylinders and the position of the deactivated cylinders are calculated. The determination of the number of idle cylinders in step 140 can be read as a map of the engine cooling water temperature Tw and the number S of idle cylinders, as shown in FIG. This will be explained in detail with reference to the map shown in FIG. In this example, when the engine water temperature is Tw ₂ or less, it becomes the rest area, and the water temperature Tw ₀
In the following, the number of idle cylinders S=3, the number S of idle cylinders is set to S=2 when the water temperature is Tw ₀ to Tw ₁ , and the number S of idle cylinders is set to S=1 when the water temperature is Tw ₁ to Tw ₂ . In this way, if the fuel injection amount is the same, the warm-up will be faster as the number of cylinders inactive is larger, that is, the fewer cylinders are used for combustion. As the aircraft progresses, processing is performed to reduce the number of idle cylinders. Furthermore, the control of the position of the deactivated cylinders in step 140 can be performed, for example, if combustion proceeds in the order of the 1st cylinder → 4th cylinder → 2nd cylinder → 6th cylinder → 3rd cylinder → 5th cylinder in a 6-cylinder internal combustion engine. The cylinders to be deactivated may be determined according to a predetermined algorithm, such as the first cylinder in the first cycle, the fourth cylinder in the next cycle, and the second cylinder in the next cycle.

If the determination in step 130 is "NO", or in step 140
After completion of step 150, the process proceeds to step 150, where fuel injection is controlled using a fuel amount corresponding to the operating state of the internal combustion engine read in step 120. In step 150, the control rack 3 of the in-line injection pump is controlled by the linear solenoid 5 uniformly for all cylinders if there are no idle cylinders, or according to the number of idle cylinders and the position of the idle cylinders determined in step 140 if there are idle cylinders. control to control fuel injection. The position of the control rack 3 is detected by a rack position sensor 4 and subjected to feedback control.
In the following step 160, the rotational speed Ne of the engine is read, and in step 170 it is determined whether the rotational speed Ne is larger than a preset rotational speed No.
Here, No is the number of rotations at which it can be determined whether or not the engine has started. If the determination at step 170 is "NO" and the engine is not started, the process returns to step 110. On the other hand, if the determination in step 170 is ``YES'', that is, the engine has started, then in the following step 180, the process of reading the operating state of the engine is performed again. The operating conditions read in step 180 include engine cooling water temperature Tw and engine speed.
In addition to Ne, there is an intake pressure Q for detecting the amount of air taken into the engine, an intake air temperature Ta, and a fuel temperature Tf. The intake pressure Q is determined by the intake pressure sensor 73, the intake temperature Ta is determined by the intake temperature sensor 74, and the fuel temperature Tf is determined by the fuel temperature sensor 7.
5, respectively.

In the next step 190, the step 180
According to the engine operating state read in, it is determined whether there are any cylinders inactive or not. When the intake air temperature Ta and the fuel temperature Tf are within predetermined ranges and the engine load Q/Ne is below a predetermined value, it may be determined that there is a deactivated cylinder. If there is no deactivated cylinder, the process returns to step 150. On the other hand, if it is determined that there is a deactivated cylinder, the process moves to step 200, where the number of deactivated cylinders and the position of the deactivated cylinder are calculated. Step 2
The calculation of the number of idle cylinders and the position of idle cylinders at 00 may be set in a region where the fuel efficiency of the engine is maximized, taking into consideration the relationship between the engine speed and the fuel injection amount, as shown in FIG. 6, for example. . 6th
In the figure, for example, if the engine load is 75%, the relationship between the engine speed and the injection amount is expressed as A-B in the figure. Looking at the fuel injection amount in the region A-B, it is found that the fuel injection amount is between about 4/6 and 5/6 of the maximum injection amount.
In other words, in this case, rather than operating all six cylinders, it is better to deactivate one cylinder and operate the remaining five cylinders, which increases the amount of fuel injected per cylinder and achieves maximum efficiency for the engine. This shows that you can drive.

After determining the number of deactivated cylinders and the position of deactivated cylinders in step 200, the process returns to step 150, where fuel injection control is performed, and the above-described processes are repeated from step 160 onwards.

FIG. 7 is an explanatory diagram showing how fuel is injected into each cylinder when the internal combustion engine is operated with one of the six cylinders inactive. In the figure, Rw ₁ and Rw ₀ indicate the position of the control rack 3. If control rack 3 is in Rw ₁ , fuel injection is performed by a predetermined amount q, and control rack 73 is in Rw 1.
If Rw is ₀ , the injection amount of the fuel injection pump is 0. Control rack 3 is linear solenoid 5
According to a predetermined algorithm, one cylinder is stopped one after another in one cycle, as shown in FIG.

In this embodiment, since the operating state of the internal combustion engine is detected and the number of cylinders inactive is determined based on the engine load, etc., the combustion efficiency of the internal combustion engine can be increased.
Fuel efficiency and exhaust gas conditions can be improved. In addition, when controlling the idle cylinders, the control rack 3 of the in-line fuel injection pump is directly controlled by the linear solenoid 5, so there is no need for a new device for controlling the idle cylinders, and the entire system can be made smaller. It can also be converted into On the other hand, during warm-up operation, the number of idle cylinders is increased depending on the engine cooling water temperature, so warm-up can be performed quickly. Furthermore, since the position of the idle cylinders is successively changed according to a predetermined algorithm, the problem of injection pump seizure caused by continuing to idle the same cylinder is also solved.

In this embodiment, the deactivated cylinders are controlled independently one by one, but the series of processes such as determining the number of deactivated cylinders in the electronic control circuit takes a long time compared to the processing time determined by the rotational speed of the internal combustion engine. If the response speed of the control rack 3 is not sufficient, or if the response speed of the control rack 3 is not sufficient, it is also possible to carry out control to deactivate two cylinders at the same time. This situation is shown in FIG. Also, when the number of idle cylinders changes, for example, when the number of idle cylinders changes from 2 to 1, the proportion of the number of idle cylinders being 2 and the proportion of the number of idle cylinders being 1 within a predetermined time is changed as appropriate. Therefore, smoothly varying the rotation speed is more suitable in terms of engine operating performance.

[Effects of the Invention] According to the fuel injection amount control device for a multi-cylinder internal combustion engine of the present invention, it is assumed that the lower the engine load, the lower the number of operating cylinders to maximize combustion efficiency.
During warm-up operation, the number of operating cylinders can be reduced as the engine temperature is lower, based on the engine temperature, and this has the special effect of promoting warm-up.

[Brief explanation of drawings]

Fig. 1 is a basic configuration diagram of the present invention, Fig. 2 is an explanatory diagram showing the connection between a control rack and a linear solenoid according to an embodiment of the present invention, and Fig. 3 is an explanatory diagram showing a control system centered on an electronic control circuit. 4 is a flowchart of the embodiment, FIG. 5 is an explanatory diagram showing the relationship between engine cooling water temperature and the number of idle cylinders, FIG. 6 is an explanatory diagram showing the relationship between engine speed and fuel injection amount, and FIG. Figure 7 is an explanatory diagram showing the state of fuel injection in each cylinder when controlling the number of cylinders inactive.
Each figure shows an explanatory diagram when cylinders are deactivated. 3...Control rack, 5...Linear solenoid, 6...Electronic control circuit, 30...CPU, 71...Cooling water temperature sensor, 73...Intake pressure sensor.

Claims (1)

[Scope of Claims] 1. Operating state detection means for detecting the engine load including the idle operating state of the multi-cylinder internal combustion engine, and based on the engine load detected by the operating state detection means, when the engine load is small, , first operating cylinder number changing means for suspending operation of some cylinders of the multi-cylinder internal combustion engine so as to reduce the number of operating cylinders compared to when the number of operating cylinders is large; and temperature detecting means for detecting engine temperature; a second operating cylinder number changing means for suspending operation of some cylinders of the multi-cylinder internal combustion engine so as to reduce the number of operating cylinders when the engine temperature is low compared to when the engine temperature is high, based on the engine temperature; determining means for determining that the conditions that the temperature is below a predetermined value and the idling state are satisfied; and when the conditions are satisfied, the second operating cylinder number changing means A fuel injection amount control device for a multi-cylinder internal combustion engine, comprising: priority execution control means for giving priority to execution of the operation by the operating cylinder number changing means;