JPS6155610B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-cylinder engine control device that controls the operation of each cylinder of an engine having a plurality of cylinders using pulse signals.

In an engine with multiple cylinders, in order to perform appropriate control taking into account variations between each cylinder and transient changes in engine conditions, it is necessary to control the fuel supply amount, injection start timing, and intake and exhaust openings. It is known that it is good to independently control valve time, valve opening start timing, ignition timing, etc. for each cylinder. In order to do this, conventionally, as shown in the block diagram of FIG. 12, various information signals such as a cylinder discrimination signal 13 and an engine rotation angle signal 14 are input, and based on these various input information, the arithmetic processing unit 1
Pulse generators 10-1 to 10-4 perform calculation processing to calculate a control amount for each cylinder according to the engine operating state, and provide the calculated control amount for each cylinder.
(This figure assumes a 4-cylinder engine), each pulse generator 10-1 to 1
0 to 4 generate pulses corresponding to respective input control amounts as output pulses 71 to 74, and these output pulses 71 to 74 cause fuel injection valves, intake valves,
Operates actuators such as exhaust valves and ignition systems.

Figure 2 shows any one of the pulse generators in Figure 1.
201 is a clock signal, 202, 203, and 204 are data signals, address signals, and control signals sent from the arithmetic processing unit 1, respectively, 205 is a counter, 206 is a comparator, and 207 is a detailed block configuration diagram. register, 208
209 represents a timing controller, and 209 represents a flip-flop.

In this way, the pulse generators 10-1 to 10-4
Each of these has a circuit configuration that incorporates a large number of integrated circuits, and the conventional device shown in Figure 1 has a configuration in which such a pulse generator is installed for each cylinder, making the device complex and economical. There were problems in that it was expensive and had a high failure rate.

This invention was made by focusing on the above-mentioned problems with the prior art, and by providing a simple output distribution device consisting of a gate circuit for each cylinder and reducing the number of pulse generators installed. , aims to solve the above problems.

In order to achieve the above object, the features of the present invention are as follows:
The input information includes at least an engine load signal, a cylinder discrimination signal synchronized with engine rotation, and an engine rotation angle signal having a period obtained by dividing the period of this cylinder discrimination signal by the number of cylinders, and an arithmetic processing device that calculates and outputs data corresponding to the amount of fuel to be injected into the cylinder and an output distribution signal indicating that the cylinder will be in the next intake stroke;
A common pulse generating means generates a pulse having a pulse width according to the data and synchronized with the engine rotation angle signal, and a signal obtained by logically multiplying this generated pulse and the output distribution signal for each cylinder. output distribution means having a first control means for outputting the generated pulse as an output pulse; a second control means for outputting the generated pulse as a common output pulse to a plurality of cylinders; and switching determination means for switching from the first control means to the second control means.

The present invention will be explained below based on the drawings.

FIG. 8 is a block diagram showing a configuration corresponding to the present invention. In FIG. 8, the arithmetic processing unit 2 has an intake air amount signal 11 and an engine coolant temperature signal 1.
2, cylinder discrimination signal 13, engine rotation angle signal 1
4. Information signal 1 indicating other engine operating conditions
5 to 17 as input, a time-series data signal 3 corresponding to the amount of fuel to be injected to each cylinder according to the engine operating state, and an output distribution signal 30 to 30 indicating which cylinder will undergo the next intake stroke. 33 (takes the case of a 4-cylinder engine as an example) and outputs it. Pulse generator 4 commonly provided for multiple cylinders
generates a time-series pulse signal 5 having a pulse width corresponding to the data signal 3 and synchronized with the engine rotation angle signal 14. The output distribution unit 6 includes a first control unit that outputs a logical product of the pulse signal 5 and the output distribution signals 30 to 33 as output pulses 70 to 73 for each cylinder; and second control means for outputting a common output pulse to the cylinders. The switching determination unit 8 determines the difference between the pulse width of the data signal 3 from the arithmetic processing unit 2 corresponding to the amount of fuel to be injected into each cylinder or the pulse signal 5 from the pulse generator 4 and the time width of the engine rotation angle signal 14. The magnitude is compared, and depending on the comparison result, the output distribution unit 6 selects the first control means that performs individual control for each cylinder, or performs common control that shares the data to be injected to multiple cylinders. A signal is sent to instruct a switch to select the second control means that performs the operation. Whether the data signal 3 or the pulse signal 5 is used for the determination depends on whether the engine rotation angle signal 14 is a digital signal or an analog signal.

FIG. 3 is a block diagram for explaining the operation of individual control, taking the case of a four-cylinder engine as an example, and FIG. 4 is a diagram showing signal waveforms of each part in FIG. 3. The arithmetic processing unit 2 is composed of a microcomputer with a central processing unit (CPU), a storage device, etc., and input/output devices such as an A/D converter, a counter, an input/output buffer, and an interrupt signal processing circuit. Various input information such as an intake air amount signal 11, an engine coolant temperature signal 12, a cylinder discrimination signal 13, an engine rotation angle signal 14, and other information signals 15 to 17 indicating the engine operating state are received as input, and the engine operating state is determined. a time-series data signal 3 corresponding to the amount of fuel to be injected into each cylinder accordingly;
Next, output distribution signals 30 to 33 indicating that the cylinder is in the intake stroke are calculated and output. Specifically, the pulse generator 4 has an internal configuration as shown in FIG. A time-series pulse signal 5 synchronized with the rotation angle signal 14 is generated. The output distribution devices 61 to 64 installed corresponding to each cylinder are each
It is composed of a two-input AND gate circuit or an analog switch, and converts the time-series pulse signal 5 into an output distribution signal 30 from the arithmetic processing unit 2.
~33 to pass according to the output pulse 70~7
Output as 3. These output pulses 70-7
3 controls the opening of fuel injection valves (not shown) to supply fuel to each cylinder of the engine according to the opening time of each valve. In this case, the output pulse 70
corresponds to the injection valve of #2 cylinder, 71 corresponds to the injection valve of #1 cylinder, 72 corresponds to the injection valve of #3 cylinder, and 73 corresponds to the injection valve of #4 cylinder.

The cylinder discrimination signal 13 is a signal synchronized with the rotation of the rotating shaft of the power distributor of the ignition system, and is a signal that is synchronized with the rotation of the rotating shaft of the power distributor of the ignition system, and is a signal that
Obtained by detecting the following current with a current detection probe etc.
Alternatively, it is obtained by detecting the passage of a protrusion provided on the rotating shaft of the power distributor using an electromagnetic pickup, and is a signal indicating that a predetermined cylinder is in the explosion stroke, for example. The engine rotation angle signal 14 is one of the ignition coils.
A signal that is triggered each time the next winding is turned on or off, or a signal that is obtained by detecting the passage of protrusions equal to the number of cylinders on the rotating shaft of the power distribution device using an electromagnetic pickup. , which is a signal indicating that one of the cylinders of the engine is in the explosion stroke, for example. In the example of a four-cylinder engine, the cylinder discrimination signal 13 is based on the crankshaft rotation.
Every 720 degrees, the engine rotation angle signal 14 is generated every 720/4=180 degrees. These signals 13, 14
is input to the arithmetic processing unit 2 and is used to determine the engine rotational speed from the signal period, and is also used as an interrupt signal for the execution of the control program described in FIG. The pulse signal 5 is a pulse having a width corresponding to the fuel injection amount, and the arithmetic processing unit 2 corresponds to the required fuel injection amount for each cylinder based on the intake air amount signal 11, the cooling water temperature signal 12, the engine rotation speed, etc. The data is calculated and the cylinder discrimination signal 13 and engine rotation angle signal 1 are obtained.
4 determines which cylinder of the engine will undergo the next intake stroke, and outputs it to the pulse generator 4 as a data signal 3 at a timing corresponding to that timing, and the pulse generator 4 generates a pulse according to the data. It is obtained by converting it into a width pulse. The output distribution signals 30 to 33 are controlled by the cylinder discrimination signal 13 and the engine rotation angle signal 14, and among the cylinders of the engine, only the output distribution signal corresponding to the cylinder that will undergo the intake stroke next is determined by the crankshaft rotation 180. It becomes a high level "1" every time. Output pulse 70~7
Reference numeral 3 is an output of the logical product (AND) of the pulse signal 5 and the output distribution signals 30 to 33, and this output controls the opening time of the fuel injection valve provided for each cylinder.

FIG. 5 is a flowchart of a control program for the case of individual control shown in FIG. First, when the power is turned on, each part of the microcomputer is initialized in block 20, and then block 2
1, input data such as an intake air amount signal and an engine rotation angle signal are input, and basic pulse data is calculated or calculated by table lookup. In the next block 22, the basic pulse data is corrected by reading the cooling water temperature signal and other signals indicating, for example, starter operation and throttle opening. Furthermore, in block 23, number data (abbreviated as CN) identifying which cylinder is currently in the intake stroke is read, and it is determined which cylinder's fuel corresponds to the pulse data obtained in blocks 21 and 22. Then, pulse data for each cylinder is calculated, and the process moves to block 24, where it is stored as pulse data for each cylinder in a storage device constituted by, for example, RAM (random access memory). Thereafter, the operations of blocks 21 to 24 are repeated. Note that various input data are converted into necessary data by an A/D converter, a pulse width measuring device, etc., and are stored at a predetermined address in the storage device.
These input reading programs are not shown. Note that in block 23, data may be corrected for each cylinder. This is due to the layout of the intake system and the pulsation of the air.
This is because the balance of intake air amount may differ for each cylinder depending on the operating state.

Next, the cylinder discrimination signal 1 is sent to the microcomputer.
When 3 is entered, the microcomputer moves to block 2.
From the state in which steps 1 to 24 are being repeated, the program in block 40 is executed by an interrupt. Here, it is determined that each cylinder of the engine has completed one complete stroke, the number data CN is returned to zero, and the program returns to blocks 21 to 24 again.

Next, when the engine rotation angle signal 14 is input to the microcomputer, it is determined that the engine's intake stroke has moved to the next cylinder, and the process moves to block 50 where the number data CN is incremented by one. Next, in decision blocks 51, 53, and 55, the value of CN is checked to determine which cylinder the fuel should be injected into, and in blocks 52, 54, 56, and 57, the output distribution signal (Fig. 3) corresponding to that cylinder is determined. (any one of 31 to 34) is set to level "1", other output distribution signals are set to level "0", and pulse data corresponding to that cylinder is read from the storage device and output to the pulse generator 4. . Note that the engine rotation angle signal is generated for each angle obtained by dividing 720 degrees by the number of cylinders, but it can also be generated for each angle obtained by dividing by an integral multiple of the number of cylinders by using a frequency division circuit or frequency division program. The same operation as described above can be performed.

Next, regarding the common control operation when the switching determination unit 8 in FIG. 8 determines that it is common control, the sixth
This will be explained using FIG. FIG. 6 shows that the time width of the data signal 3 corresponding to the amount of fuel to be injected into each cylinder output from the arithmetic processing unit 2, that is, the pulse width of the pulse signal 5 generated from the pulse generator 4 is A configuration that applies output pulses to two cylinders at a time when the period becomes longer than every 180 degrees of rotation and it is no longer possible to apply output pulses to each cylinder independently, that is, when the output pulses for each cylinder overlap. 7 is a flowchart of a control program in the case where this is the case, and FIG. 7 is a diagram showing signal waveforms at various parts of the block diagram of FIG. 3 when there is an overlap. In the flowcharts, the same block numbers are used for blocks that perform the same process. The difference between the flowchart in FIG. 6 and the flowchart in FIG. 5 is that blocks 80 and 90 are added to determine whether or not there is an overlap, and when it is determined that there is no overlap, each cylinder operates independently. Moving on to the process shown in the flowchart of FIG. 5, when it is determined that there is an overlap, the process moves to common control in which data to be used for injection to a plurality of cylinders is shared. FIG. 6 will be explained in further detail. First, when the power is turned on, blocks 20 to 23 are executed in the same way as in FIG. If it is determined that this is the case, the process moves to block 81 and the average value pulse data of the two cylinders is stored in the storage device. Thereafter, the operations of blocks 21 to 24 are repeated. Cylinder discrimination signal 1
The processing at the time of interrupt by 3 is exactly the same as in the case of FIG. When there is an interrupt by the engine rotation angle signal 14, the process moves to block 50 and the number data CN
Increase by one. The process then proceeds to block 90 where it is determined whether there is an overlap. If there is no overlap, the process proceeds to the same process as in the case of FIG. 5, and individual control is performed for each cylinder through the processes of blocks 51 to 57. When it is determined that there is an overlap, the process proceeds to decision blocks 91 and 93 to check the CN value, determine which two cylinders overlapped, and set the output distribution signal corresponding to those two cylinders to level "1" in blocks 92 and 94. , sets the other two output distribution signals to level "0", reads out the overlapped two cylinder average pulse data from the storage device, and outputs it to the pulse generator 4. In the waveform diagram of FIG. 7, cylinder #1 and cylinder #3 overlap, and cylinder #4 and cylinder #2 overlap.

If the pulse widths of two cylinders overlap further, all four cylinders may be operated at once, and the program processing can be easily inferred from the processing flowcharts of FIGS. 5 and 6. In the case of a 6-cylinder engine or an 8-cylinder engine, the power distribution signal and power distribution device can be similarly applied by increasing the number of power distribution signals and power distribution devices equal to the number of cylinders. The process may be such that the cylinders are commonly controlled.

In addition, in the explanation up to now, it has been explained that one pulse generator 4 is provided in common for all cylinders, but two pulse generators 4 are used to alternately generate output signals and an output distribution device. By managing the cylinders to be output, each cylinder can be controlled independently over a wide range, and there is an advantage that the number of installed pulse generators is not as large as the number of cylinders. Similarly, two or three pulse generators for a six-cylinder engine and two or four pulse generators for an eight-cylinder engine provide similar advantages. The presence or absence of overlap is determined by comparing the period of the engine rotation angle signal and the pulse width of the pulse signal, but in order to prevent frequent switching of the comparison results, hysteresis is used in the comparison. It would be better to have a configuration that provides leeway for the switching operation.
The cycle of the engine rotation angle signal used as a comparison standard may not be fixed to the cycle of 180 degrees of engine rotation, but may be determined using a slightly shorter reference value.

The control mechanism of the present invention can also be applied to ignition control of multiple cylinders, in which case the device of the present invention turns on and off the ignition device (for example, ignition coil and spark plug) provided for each cylinder. It can be controlled using output pulses.

As explained above, according to the present invention, a smaller number of pulse generators than the number of cylinders are provided, and output distribution devices with a simple configuration such as gate circuits are provided for the number of cylinders, and these output distribution devices Since the passage of the signal from the engine is controlled by the output distribution signal and the injection signal is given to each cylinder independently, there is no need to use a complicated output device that was required in the conventional system, and the system is inexpensive. In addition, since the device is simple, the occurrence of failures is reduced, and even if a failure should occur, it can be easily repaired. Since the configuration is configured to switch between individual control and common control depending on the determination result, each cylinder can be controlled completely independently for low to medium engine speeds, and for high speed engine rotations. Even when a large amount of fuel is required, the effect can be achieved by automatically switching over.

[Brief explanation of the drawing]

FIG. 1 is a block configuration diagram of a conventional device, FIG. 2 is a detailed diagram of the output device in FIG. 1, FIG. 3 is a control block configuration diagram of an example of individual control in the present invention, and FIG. FIG. 5 is a control program processing flowchart corresponding to FIG. 3, FIG. 6 is a control program processing flowchart when controlling by switching between individual control and common control in the present invention, and FIG.
This figure is a waveform diagram of the signals of each part in FIG. 3 when the flowchart in FIG. 6 is adopted, and FIG. 8 is a block diagram showing a configuration corresponding to the present invention. Explanation of symbols, 1, 2... Arithmetic processing unit, 3...
Data signal, 4...Pulse generator, 5...Pulse signal, 8...Switching determination section, 11...Intake air amount signal, 12...Cooling water temperature signal, 13...Cylinder discrimination signal, 14... Engine rotation angle signal, 30~3
3... Output distribution signal, 61-64... Output distribution device, 70-73... Output pulse.

Claims (1)

[Scope of Claims] 1. In a multi-cylinder engine control device that controls the operation of each cylinder of an engine having a plurality of cylinders using pulse signals, an engine load signal, a cylinder discrimination signal synchronized with engine rotation, and a cylinder discrimination signal of this cylinder discrimination signal are provided. Data corresponding to the amount of fuel to be injected into each cylinder according to the engine operating state and the cylinder to be next in the intake stroke after receiving at least input information of an engine rotation angle signal having a period obtained by dividing the period by the number of cylinders. an arithmetic processing device that calculates and outputs an output distribution signal indicating the engine rotation angle signal; a common pulse generating means that generates a pulse having a pulse width corresponding to the data and synchronized with the engine rotation angle signal; a first control means for outputting a signal logically ANDed with the output signal as an output pulse for each cylinder; and a second control means for outputting the generated pulse as a common output pulse for a plurality of cylinders. 1. A multi-cylinder engine control device comprising: an output distribution means having a plurality of cylinders; and a switching determination means for switching from the first control means to the second control means based on the time width of the data. 2. The multi-cylinder engine control device according to claim 1, wherein the arithmetic processing device is a microcomputer configured with a semiconductor integrated circuit. 3. The cylinder discrimination signal is a cylinder discrimination signal that is generated every two rotations of the engine, and the engine rotation angle signal is an engine rotation angle signal that is generated every angle obtained by dividing two rotation angles (=720 degrees) by the number of cylinders. A multi-cylinder engine control device according to claim 1, characterized in that: 4. The multi-cylinder engine control device according to claim 1, wherein the switching discrimination means is a switching discrimination means having a hysteresis characteristic in its comparison discrimination characteristic.