JP3518106B2 - Control device for multi-cylinder internal combustion engine - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, such as a CPU, for controlling ignition and fuel injection of the internal combustion engine.
The present invention relates to a circuit for allocating an energization control signal output from a computing means such as the above to the ignition device of a corresponding cylinder.

[0002]

2. Description of the Related Art In order to control ignition of an internal combustion engine, for example, a CPU calculates an energization time and an ignition timing according to a state of the internal combustion engine such as a rotation speed, and a coil corresponding to an ignition cylinder based on the calculation result. An ignition control device for an internal combustion engine, which supplies an energization control signal to the engine, is widely used.

In such an apparatus, when the CPU directly outputs the energization control signal to a plurality of cylinders, the CPU requires as many output ports as the number of cylinders. However, the number of output ports that requires time accuracy such as the energization control signal is limited to one CPU, and increasing the number to the same number as the number of cylinders increases the cost of the device. In addition, the number of cylinders of the recent internal combustion engine for vehicles has been increased to 6 to 12 cylinders, and the output which requires time accuracy other than ignition control is increased, so that the output port is increased. Has reached the limit.

Therefore, the ignition control signal for the internal combustion engine is output from the CPU using only one output port, and the ignition control signal is distributed to a plurality of cylinders by the ignition distribution circuit to obtain the energization control signal. The device is US Pat.
No. 787,354. The ignition distribution method in this device will be described with reference to FIG. 6 in the case of a double distributorless ignition (D-DLI) of a 6-cylinder internal combustion engine.

In FIG. 6, an ignition control signal (IGTin) output from a specific port of the CPU includes ignition timings and energization times of consecutive cylinders based on a cylinder discrimination signal and a rotation angle signal (not shown). CP in the form
It is output as a pulse waveform created inside U. Then, this IGTin is supplied to the ignition distribution circuit by the energization control signal (IGT1i) for the second and fifth cylinders, and the third and sixth cylinders, respectively.
It is distributed as the energization control signal for the cylinder (IGT2i) and the energization control signal for the first and fourth cylinders (IGT3i).
The specific distribution method in this conventional ignition distribution circuit is that the next cylinder is detected after the last ignition end timing (falling edge of IGTin) is detected in order to maximize the energization time to the ignition coil. The ignition control signal is distributed to.

Furthermore, if noise or the like is superposed on the ignition control signal from the CPU or the ignition control signal is omitted, the normal ignition control signal cannot be output to the cylinder. The ignition control signal is distributed by the edge created by directly using the rotation angle signal from the rotation angle sensor that outputs a pulse at a fixed interval of every ° C A without passing through the CPU.

[0007]

However, the above-mentioned device is complicated because it requires a circuit for detecting the signal edge of the rotation angle sensor in addition to the ignition control signal in order to distribute the ignition control signal. If a special abnormality occurs and the ignition control signal and the rotation angle signal are mixed,
Since the edge detected first has priority, the energization timing may be incorrect.

In addition to this, in the system in which one ignition control signal is distributed, the output permission range is after the end of the energization period of the previous ignition cylinder as shown in FIG. Therefore,
As shown in FIG. 7, continuous energization control signals (IGT1
i, IGT2i, IGT3i) cannot be overlapped to perform overlap ignition between different cylinders. Therefore, in an internal combustion engine having a large number of cylinders such as 6 to 12 cylinders, the energization time to the ignition coil must be shortened, and a high-performance ignition coil that can generate high energy with a short-time energization is required, and the cost is low. This causes problems such as an increase in engine performance and a decrease in the performance of the internal combustion engine due to the limited energization time.

In view of the above problems, the present invention uses, for example, an ignition control device for an internal combustion engine to distribute the ignition control signal sent from the CPU using the rotation phase information from the angle sensor of the internal combustion engine. It is an object of the present invention to enable overlap energization even when the ignition control signals must be overlapped between the cylinders.

[0010]

According to the present invention, the control signal for each cylinder having the pulse length corresponding to the calculated control amount of the engine control parameter corresponding to each cylinder is used as the control timing for each cylinder. The number of output ports can be less than the number of cylinders by alternately outputting through multiple output ports that are less than the number of cylinders, and the output of overlapping control signals is possible even between cylinders in consecutive control sequences. Is possible. Therefore, a high-performance ignition coil that can generate high energy by energizing for a short time becomes unnecessary and cost can be reduced. Further, although this control signal has a period of overlapping each other, each control signal includes control information for a plurality of cylinders, and
Since the control cylinder is determined using the value of the rotation phase of the rotation angle sensor and the information of multiple cylinders is distributed to each cylinder, the timing is also compared with that of edge detection that distributes at a single timing. There is an effect that the influence of an error due to the influence of noise or the like can be suppressed and the reliability of the control device can be improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments to which the present invention is applied will be described below with reference to the drawings. FIG. 1 is a schematic block diagram showing a control system of a six-cylinder internal combustion engine for a vehicle which is a first embodiment. This 6 cylinder internal combustion engine is a V type engine,
The first cylinder # 1, the third cylinder # 3, and the fifth cylinder # 5 are arranged in one bank, and the second cylinder # 2, the fourth cylinder # 4, and the sixth cylinder # 6 are arranged in the other bank. It has a D-DLI. The ignition order is the order of the cylinder numbers, and the ignition is performed alternately for each bank.

Reference numeral 1 in the figure denotes an electronic control unit for controlling the ignition timing, fuel injection amount, etc. of the internal combustion engine. Reference numeral 2a is a cylinder discrimination sensor 2a which is attached to a cam shaft of an engine (not shown) and outputs a pulse signal (G2) every 720 ° C. Two
The rotation angle sensor 2b is attached to the crankshaft of the engine and outputs a pulse signal (NE36) every 10 ° C.
Is. Details of the cylinder discrimination sensor 2a and the rotation angle sensor 2b will be described later.

These sensors are connected to the interface of the electronic control unit 1. In addition, a plurality of analog signal lines such as idle switch, starter switch, air conditioner switch and other switch signals, air flow meter output, throttle sensor output, cooling water temperature, intake air temperature, battery voltage, etc. are interfaced to the electronic control unit 1. Connected to.

The outputs of the cylinder discrimination sensor 2a and the rotation angle sensor 2b are input to the input ports of the filter circuits 3a and 3b, respectively. The outputs of the filter circuits 3a and 3b are input to the input port of the waveform shaping circuit 4. The waveform shaping circuit 4
The waveform shaping in step 1 will be described later. The output pulse from the waveform shaping circuit 4 is input to the ignition distribution and backup circuit 5. On the other hand, the output of the waveform shaping circuit 4 is also transmitted to the bus 14. The outputs of the ignition distribution circuit and the backup circuit 5 are used to drive a power transistor (power Tr) 6 for driving the ignition coil. Here, the filter circuits 3a and 3b, the waveform shaping circuit 4, the ignition distribution circuit and the backup circuit 5, and the power Tr 6 are configured by one integrated circuit 7.

Reference numeral 8 is a CPU as a calculation means. CP
U8 is composed of a one-chip microcomputer in which a RAM 9 and a ROM 10 are integrated in one package. CPU8, R
The AM 9 and the ROM 10 are connected to the bus 14, respectively.
The output of the sensor for each of the aforementioned analog signals is connected to the input port of the multiplexer 11. The output of the multiplexer 11 is connected to the input terminal of the A / D converter 12. The output terminal of the A / D converter 12 is connected to the bus 14. The output of the sensor related to the switch input is connected to the input terminal of the input buffer 13. The output terminal of the input buffer is connected to the bus 14 described above.

The CPU 8 is provided with two dedicated output ports for outputting two ignition control signals (IGT1i, IGT2i) corresponding to each bank. The two output ports are connected to the input ports of the ignition distribution and backup circuit 5 described above. Specifically, two ignition control signals (IGT1) for each bank are output from the two output ports.
i, IGT2i), and the ignition distribution and backup circuit 5 outputs three energization control signals (IGT1o,
IGT2o, IGT3o) and output to the ignition device 18 described later.

Output ports for outputting control signals for the CPU lamps, solenoids, valves, etc. are connected to the drive circuit 16, and the outputs of the drive circuit 17 are connected to various lamps, solenoids, valves, etc. (not shown). An output port for outputting a fuel injection control signal of the CPU is connected to the drive circuit 17, and an output of the drive circuit 17 is connected to an injector (not shown).

The energization control signals (IGT1o, IGT2o, IGT3o) output from the electronic control unit 1 are input to the ignition device 18. Specifically, the power transistor (Tr) 6 and the ignition device 18 provided in the electronic control unit 1
The power transistor (Tr) 19 provided therein is connected. The power Tr 19 is connected to the ignition coil 20. The ignition coil 20 is connected to an ignition plug 21. Since the ignition device 18 of this embodiment is a double distributorless ignition (D-DLI), two ignition plugs 21 are provided for each ignition coil 20.
Are connected.

With the above configuration, the state of the vehicle or the internal combustion engine is detected by the sensor such as the rotation angle sensor 2b, and the CPU 8 determines the optimum ignition timing, the fuel injection amount, etc. according to the detected state.
Calculate with. Further, the ignition device 18 and the like are controlled based on the calculation result. Next, the waveform shaping process in the waveform shaping circuit 4 will be described with reference to FIG. As described above, the rotation angle sensor 2b uses 10 ° C. with 360 ° C. as one cycle.
The pulse signal (NE36) for each A is output. Specifically, the pulse signal (NE36) outputs one pulse every 10 ° C. However, the rotation angle sensor 2b determines that the top dead center (T) of a predetermined cylinder (first cylinder # 1 and fourth cylinder # 4 in this embodiment).
Before DC) It has a toothless structure in which pulses of 160 ° C and 170 ° C are not output.

The cylinder discrimination sensor 2a outputs a pulse signal (G2) having 720 ° C. A as one cycle. Specifically, the pulse signal (G2) is in the off period within a predetermined crank angle (in the present embodiment, a predetermined angle range within 120 ° C. after the tooth-missing position corresponding to the first cylinder # 1). Output pulse. The waveform shaping circuit 4 uses the above-mentioned two pulse signals (NE
36, G2), and outputs the three pulse signals (NE12, TDC, G2O) shown in FIG. 2 by the method described below.

The pulse signal (NE36) is a waveform shaping circuit 4
It is converted into an angle pulse signal (NE12) every 30 ° C. by being divided by. On the other hand, a pulse signal (NE
36), based on the tooth-missing position, the first cylinder # 1 and the fourth cylinder # 1
TDC that turns off only at the crank position of TDC of cylinder # 4
It is converted into a pulse signal. Further, in the waveform shaping circuit 4, the pulse signal (NE36) is set to 1 with the missing tooth position as the starting point.
Whether or not the pulse signal (G2) changes from OFF to ON during 20 ° C. is used to determine whether it is 360 ° C. on the first cylinder # 1 side or 360 ° A on the fourth cylinder # 4 side ( In this embodiment, there is a change from off to on in the case of the first cylinder side,
In the case of the 4th cylinder side, there is no change from off to on),
Based on this result, it is converted into a pulse signal (G2O) which is turned on at 360 ° C. on the first cylinder # 1 side and turned off at 360 ° C. on the fourth cylinder # 4 side.

Next, the configuration of the ignition distribution and backup circuit 5 will be described with reference to FIG. The ignition distribution / backup circuit 5 is roughly divided into an ignition distribution signal generation circuit 32 and a backup logic 33.
Pulse signal (NE12) created by the waveform shaping circuit 4
Is connected to the input of the missing tooth determination logic 30 for detecting the missing tooth position. The pulse signal (NE12) is also connected to the input of the crank counter 31 that counts the crank position. The output of the missing tooth determination logic 30 is also connected to the input of the crank counter 31. Crank counter 3
1 is reset at the tooth-missing position of the NE 12 and is counted up every 30 ° C. The output of the crank counter 31 is connected to the input of the ignition distribution signal generation circuit 32 and the input of the backup logic 33, respectively.

The pulse signal (G2O) from the waveform shaping circuit 4 is further connected to the input of the ignition distribution signal generation circuit 32. The output of the ignition distribution signal generation circuit 32 is CP
It is connected to the input of the ignition distribution logic 34 for distributing the ignition control signal (IGT1i, IGT2i) from U8. The ignition distribution logic 34 is composed of a combination of an AND circuit and a NOR circuit as shown in the figure. An ignition control signal (IGT1i, IGT2i) is input to the input of the ignition distribution logic.

The input of the switching logic 35 is the output of the backup logic 33 and the ignition distribution logic 3
4 outputs are connected. The output of the switching logic 35 is connected to the power Tr6 as described above. Next, the operations of the backup logic 33 and the switching logic 35 will be described. In the backup logic 33, the CPU
If a signal (not shown) indicating the state of No. 8 is input and an abnormal state is detected, the output DEF switches the switching logic 35 to the energization control signal from the backup logic 33 and the ignition device 1
Switch to output to 8. The energization control signal from the backup logic 33 is a fixed signal output from the outputs G ', H', and I '.

When the CPU 8 is normal, the ignition control signal (IGT1i, IGT2i) from the CPU 8 is distributed by the ignition distribution logic 34 to the energization control signal (IGT1).
o, IGT2o, IGT3o) are output to the ignition device 18. Next, the operations of the crank counter 31, the ignition distribution signal generation circuit 32, and the ignition distribution logic 34 at the normal time will be described with reference to FIG.

The crank counter outputs a pulse signal (NE1
By 2), the count is incremented by 1 every 30 ° C. and 0 to 11 counts (360 ° A) are repeated. Here, the ignition distribution signals (IGD11, IGD12, IGD21,
IGD22, IGD31, IGD32) will be described.

The ignition distribution signal IGD11 will be described as an example. The ignition distribution signal IGD11 is a signal that defines a period during which the output of the ignition control signal to the fifth cylinder # 5 is permitted. The permit period is 210 ° C before the top dead center (TDC) of the fifth cylinder.
240 ° C. from A to 30 ° C. after top dead center (TDC). The energization permission period of # 5 is between 10 and 5 counts. However, if you look at this count value only from the count value of the crank counter, 360 ° C A
Since the count value of the second cylinder # 2, which is out of phase, is the same, the combination of the crank counter and the pulse signal (G2O) is used to distinguish the second cylinder from the fifth cylinder.
The energization permission period of is set. In this example, specifically, when the crank counter for each 30 ° C. is 10 counts, it is determined whether the cylinder corresponds to the second cylinder or the fifth cylinder according to the state of the pulse signal (G2O), and the ignition distribution signal IGD11 is determined. Is output. Similar processing is performed for other ignition distribution signals (IGD12, IGD21, IGD).
22, IGD31, IGD32).

Incidentally, IGD12, IGD21, IGD2
2, IGD31, IGD32 are # 2, # 3,
The permission periods of # 6, # 1, and # 4 are shown. Next, the processing executed by the ignition distribution logic 34 will be described. The ignition distribution logic 34 includes an ignition control signal (IGT1i, IGT2i) from the CPU 8 and an ignition distribution signal (IGD11, IGT11, IGT2i) from the ignition distribution signal generation circuit 32.
IGD12, IGD21, IGD22, IGD31, I
GD32), and outputs the energization control signal (IGT1o, IGT2o, IGT3o) for each ignition coil.

Incidentally, this energization control signal is finally inverted and energized to the coil.
The period in which the waveforms of o, IGT2o, and IGT3o are Low is the actual energization period. Ignition distribution logic 3
The logical operation executed in 4 is as shown in the following equation.

Energization control signals (IGT1o) corresponding to the second cylinder and the fifth cylinder, IGT1o = NOT (IGD11 × IGT1i + IGD
12 × IGT2i) energization control signal (IGT2) corresponding to the third cylinder and the sixth cylinder
o), IGT2o = NOT (IGD21 × IGT1i + IGD
22 × IGT2i) energization control signal (IGT3) corresponding to the first cylinder and the fourth cylinder
o), IGT3o = NOT (IGD31 × IGT1i + IGD
32 × IGT2i) That is, in the above example, the CPU 8 first calculates two ignition control signals that are alternately output corresponding to the ignition order of each cylinder so that the optimum energization period and time are obtained for each cylinder. Output in ignition order (in this example, those corresponding to the 1st, 3rd and 5th cylinders are designated as IGT1i, those corresponding to the 2nd, 4th and 6th cylinders are designated as IGT2i, and they are alternately ignited from the CPU 8 in accordance with the ignition order. An ignition distribution signal for setting a permission period during which overlapping ignition is possible even for cylinders that have been output to the distribution circuit 5) and have an ignition order of before and after is set in advance for each cylinder. Therefore, from the logical product of the ignition distribution signal and the ignition control signal, energization is possible up to 30 ° C. after the top dead center of the cylinder of this time. Since the energization permission period in this example extends over the ignition period of the preceding cylinder, it is possible to secure a large energizable range.

Further, in order to effectively utilize the D-DLI, energization signals corresponding to two cylinders using the same coil are combined by an OR circuit and then output as an energization control signal. The ignition distribution signal is originally generated from a signal of a normal rotation angle sensor that outputs a pulse for each predetermined crank angle, and can be realized with an extremely simple configuration without using a new sensor or the like. And only two output ports of the CPU for the ignition control signal are required.

Next, a second embodiment will be described with reference to FIG. The second embodiment uses a single distributorless ignition (S-DLI) type ignition device.
This is a system used for a cylinder in-line type internal combustion engine. This second
The ignition order of the embodiment is also in the order of the cylinder numbers. In the second embodiment, the CPU outputs three ignition control signals, specifically, the ignition control signals (IGT1) corresponding to the second and fifth cylinders.
i), the ignition control signal (IGT2) corresponding to the third and sixth cylinders
i), the ignition control signal (IGT3 corresponding to the first and fourth cylinders)
i) three are required. The three ignition control signals are distributed to each cylinder, that is, six cylinders by the ignition distribution circuit.

Ignition distribution signals (IGD1 to IGD1)
6) is similar to the first embodiment, the predetermined crank angle is determined from the crank counter, and the pulse signal (G2O)
It is created by the ignition distribution circuit by determining which cylinder the cylinder corresponds to (for example, the first cylinder or the second cylinder). The period of the distribution signal is Hi, that is, the energization permission period for each cylinder. The starting time of is TDC two cylinders ago,
It is widely spread. Further, the end timing of the energization permission period is permitted until the timing which is retarded by 30 ° C. from the top dead center of the ignition cylinder, as in the first embodiment. Then, in the ignition division logic, the ignition control signals (IGT1i to 3i) as in the first embodiment.
And an ignition distribution signal (IGD1 to 6), the energization control signal (IGT1o) output to the ignition device of each cylinder.
~ 6o) is distributed.

The logic for specific distribution is as follows. An energization control signal (IGT1 corresponding to the fifth cylinder
o) is IGT1o = NOT (IGT1i × IGD1) The energization control signal (IGT2o) corresponding to the sixth cylinder is IGT2o = NOT (IGT2i × IGD2) The energization control signal (IGT3o) corresponding to the first cylinder is IGT3o = NOT (IGT3i × IGD3) The energization control signal (IGT4o) corresponding to the second cylinder is IGT4o = NOT (IGT1i × IGD4) The energization control signal (IGT5o) corresponding to the third cylinder is IGT5o = NOT (IGT2i × IGD5) The energization control signal (IGT6o) corresponding to the fourth cylinder is: IGT6o = NOT (IGT3i × IGD6) According to the above-described embodiment, for example, the end time of the maximum energizable range of # 5 is set to # 4 as in the first embodiment. Can be delayed up to 30 ° C. after TDC of # 5 and after TDC of # 5.

In the above embodiment, the application of the present invention has been described with respect to a 6-cylinder internal combustion engine. However, in the case of 8 cylinders, among the ignition control signals calculated by the CPU 8, the ones corresponding to the 1st and 5th cylinders are IGT1i. , IGT2i corresponding to the 2nd and 6th cylinders, and IG for the 3rd and 7th cylinders
The ignition control signals can be distributed to the eight cylinders only by outputting the ones corresponding to the T3i and the fourth and eighth cylinders as the IGT4i from the four ports of the CPU 8 to the ignition distribution circuit 5. Particularly, when the number of cylinders is large, the present invention relating to overlap ignition is effective.

In the above embodiment, the energizable range is always set as a constant range, but the permission period may be changed depending on the operating condition. Further, the present invention can be applied not only to the control circuit ignition control circuit of the present invention but also to the drive circuit of the fuel injection valve for each cylinder.

[Brief description of drawings]

FIG. 1 is a schematic block diagram showing an embodiment of the present invention.

FIG. 2 is a timing chart showing processing in the waveform shaping circuit in the embodiment of the present invention.

FIG. 3 is a configuration diagram of an ignition distribution and backup circuit according to the first embodiment.

FIG. 4 is a timing chart illustrating the operation of the first embodiment.

FIG. 5 is a timing chart explaining the operation of the second embodiment.

FIG. 6 is a timing chart for explaining the operation of the conventional device.

FIG. 7 is an explanatory diagram showing how the energization signals overlap.

[Explanation of symbols]

1 Electronic control unit 2a cylinder discrimination sensor 2b Rotation angle sensor Ignition distribution signal 7 integrated circuits 17 Drive circuit 18 Ignition device 34 Ignition distribution logic 35 Switching logic IGT1i to IGT3i Ignition control signal IGT1o to IGT6o energization control signal IGD11 to IGD32 IGD1 to IGD6 Ignition distribution signals

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takayoshi Honda, 1-1, Showa-cho, Kariya city, Aichi Prefecture, Nihon Denso Co., Ltd. (56) Reference JP-A-3-85372 (JP, A) JP-A-62 -291469 (JP, A) JP 62-135669 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) F02P 3/04 F02P 15/00 F02D 41/00

Claims (5)

(57) [Claims] 1. A rotation angle sensor for detecting a rotation phase of a 6- cylinder internal combustion engine having a cycle of 720 ° with respect to a predetermined reference angle, and an engine corresponding to each cylinder according to an operating state of the internal combustion engine. In addition to calculating the control amount of the control parameter, a control signal for each cylinder having a pulse length corresponding to this control amount is output alternately at a control timing for each cylinder via a plurality of output ports smaller than the number of cylinders. A control signal for distributing the control signal for each cylinder from the calculation means to the signal line of the cylinder corresponding to each control signal based on the rotation phase detected by the rotation angle sensor and outputting the control signal. and a sorting unit, the control signal distribution unit, detection by said rotation angle sensor
The control signal for each cylinder corresponding to the rotational phase signal issued
Signal generation means for defining the output permission section of
And the output for each cylinder specified by the distribution signal generating means.
The power permission period ends when the start time is the upper start point of two cylinders before.
A control device for a multi-cylinder internal combustion engine, characterized in that the timing is retarded by 30 ° CA. To 2. A output enable interval for each cylinder defined by the determination signal generating means, there are overlapping section in which the overlap between the at least two cylinders, within the scope of this overlap interval, different The control device for a multi-cylinder internal combustion engine according to claim 1, wherein duplication of the control signals between the cylinders is permitted. 3. The distribution signal generation means includes a plurality of permission section pulse signal generation means for generating pulse signals for defining the output permission section of the control signal for each cylinder in parallel at the timing of the control cylinder. For each cylinder, there is provided logic means capable of calculating a pulse representing an AND section of the output permission section pulse signal from the permission section pulse signal generating means and the pulse signal of the control signal for each cylinder. The control device for a multi-cylinder internal combustion engine according to claim 2, wherein the signals from these logic means are distributed to each cylinder and output to the signal lines of the cylinders. 4. A cylinder discriminating sensor for discriminating a specific cylinder, and a waveform shaping circuit for shaping the signals of the cylinder discriminating sensor and the rotation angle sensor into a predetermined pulse signal. , The angle pulse signal of the rotation angle sensor formed by the waveform shaping circuit is counted in synchronization with the signal from the cylinder discrimination sensor, and the cylinder at the control timing is discriminated according to the counter value to discriminate the control signal. 4. The control device for a multi-cylinder internal combustion engine according to claim 1, wherein the control unit is assigned to each cylinder. 5. The control apparatus for a multi-cylinder internal combustion engine according to claim 4, wherein the waveform shaping circuit and the control signal distribution unit are configured as the same integrated circuit.