JPH0343647A - Control device of internal combustion engine - Google Patents

Abstract

PURPOSE:To increase accuracy of abnormality judgment and improve starting property by lowering a standard value at the time of starting an internal combustion engine, compared with the general time, when the output value of a means for calculating control quantity of the internal combustion engine is compared with the standard value to judge abnormality. CONSTITUTION:The operating state of an internal combustion engine M1 is detected by a means M2, and the control quantity of the internal combustion engine M1 is calculated by a means M3 on the basis of this detection result, and also a determined control quantity of the internal combustion engine M1 is synthesized by a means M4. The output value of the means M3 is compared with a determined standard value, and abnormality of the means M3 is judged by a means M5. The above determined standard value is changed by a means M7 to be lower at the start of the internal combustion engine M1 than that in the general operating time. As the control output to the internal combustion engine M1, the output of the means M4 is selected by a means M6 at the time of abnormality of the means M3, and the output of the means M3 at the normal time of the means M3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a micro combinator (hereinafter referred to as "microcomputer-1").
The present invention relates to a device for controlling the fuel 1M, ignition timing, etc. of an internal combustion engine using a calculation means such as (referred to as ), and particularly relates to a device for controlling the internal combustion engine by monitoring the state of a microcomputer.

(Prior art) Conventionally, internal combustion engines have been operated using computing means such as microcomputers.
11m, the microcomputer is monitored for abnormalities, and if an abnormality is determined, the microcomputer cannot perform normal operation, so the internal combustion engine is controlled in a so-called backup mode, that is, by a fixed injection signal and a fixed ignition signal. In this way, efforts are being made to prevent abnormalities in internal combustion engines due to microcomputer abnormalities.

Conventionally, internal combustion was detected by monitoring abnormalities in the microcomputer! When controlling the ff1lII, a technique is known that uses a calculated ignition signal (for example, Japanese Patent Laid-Open No. 59-20565). It has been determined that there is an error and the system has entered backup mode.

[Problem to be solved by the invention]

However, in a specific operating state such as when the internal FF11 is started, the N applied voltage may decrease and the operating state of the microcomputer may be determined to be abnormal. In other words, as is well known, the calculated ignition signal is output near the compression top dead center of the internal combustion engine, that is, when the power supply voltage is lowest, and the reference value for abnormality determination is the operating state in which the power supply voltage decreases. Since it is always constant regardless of the power supply voltage, the microcomputer becomes unable to perform calculations due to a drop in the power supply voltage 74F+, and a predetermined number of times 3! until the power supply voltage is restored. ! Subsequently, the calculated ignition signal could not be output, and the microcomputer was judged to be abnormal even though it was normal, and went into backup mode. There is a risk.

In this case, if you switch to backup mode, even if the microcomputer abnormality determination is canceled, you will not be able to immediately return to normal control based on microcomputer calculations because you will need to check the microcomputer status for a specified period of time. The amount of fuel given to the internal combustion engine is controlled by the backup mode.
Alternatively, the ignition timing will not be optimal depending on the n-open state at that time. - Inside the shell, the backup mode is
Since the fuel pressure or ignition timing is not set during a cold start to match the normal operation, there is a problem that fuel becomes lean during such a cold start and startability deteriorates.

This effect is particularly large in start injectorless systems that do not have a start injector.

The present invention has been made in view of the above points, and the Wl value for determining an abnormality in the first stage of calculation of a microcomputer, etc. is made looser at the time of starting when the power supply voltage decreases than during normal operation. It is an object of the present invention to improve the startability of an internal combustion engine without being determined to be abnormal even though the engine is partially operating normally.

[Means to solve the problem]

FIG. 1 shows an original diagram of the device of the invention.

In the figure, the operating state detection means M2 detects the operating state of the internal combustion engine M1.

The calculating means M3 calculates and outputs a control amount for controlling the internal combustion engine according to the detection result of the operating state detecting means M2.

The predetermined filJ l2II ffi combination means M4 synthesizes and outputs a predetermined υ1611 fear 3 representing a predetermined control term for the internal combustion v1 step according to the detection result of the operating state detection means M2.

The abnormality determination means M5 compares the calculation output of the calculation means M3 with a predetermined reference value to determine whether or not there is an abnormality in the calculation means M3.

The reference value changing means M7 makes the reference value of the abnormality determining means M5 at the time of starting the internal combustion 1III3iT looser than during normal operation.

The output selection means M6 selects the output of the predetermined control encountering means M4 as the I11 control output to the internal combustion engine when the abnormality detection means determines that there is an abnormality in the calculation means M5, and determines that there is no abnormality. If it is determined, the output of operator stage M3 is selected.

[Effect]

In the present invention, the reference value changing means M8 changes the reference value of the abnormality determining means M5 to the electric iI! It is made looser at startup when the voltage drops compared to during normal operation. For this reason, even if the calculation output of the operator stage M4 does not reach the early standard value during normal operation at the beginning of VJ when the power supply voltage drops while the calculation means M4 is partially operating normally, it is determined to be abnormal. , it is possible to utilize the calculation output from the partially normal operation of the calculation means M4, thereby making it possible to improve the startability of the internal combustion engine.

〔Example〕

FIG. 2 shows a configuration diagram of an embodiment of a gasoline engine to which the device of the present invention is applied.

fi1 In the diagram, 1 is the Ganrin engine body, 2 is the piston, 3 is the spark plug, 4 is the exhaust manifold, 5 is the intake manifold, 6 is the surge tank that absorbs the pulsation of intake air, and 7 is the intake air amount. The throttle valve 8 is an air flow meter that measures the amount of intake air.

The exhaust manifold 4 is provided with an oxygen sensor 9 that detects the concentration of residual M in the exhaust gas, and the intake manifold 5 is provided with a fuel injection valve 10 that injects fuel into the intake air of the gasoline engine body 1. . Intake temperature sensor 11
detects the temperature of intake air, the throttle sensor 12 detects the opening degree of the throttle valve 7, and the water temperature sensor 13 detects the temperature of gasoline engine cooling water.

Further, the igniter 16 generates the high voltage necessary for ignition and supplies it to the distributor 17, and the distributor 17 distributes the high voltage to the spark plugs of each cylinder in conjunction with the rotation of the crankshaft (not shown). supply The rotation angle sensor 18 outputs a rotation angle signal SNE of 24 pulses per one revolution of the distributor 17, that is, 12 revolutions of the crankshaft, and the cylinder discrimination sensor 19 outputs a rotation angle signal SNE of 24 pulses per one revolution of the distributor 17, that is, 12 revolutions of the crankshaft.
A rotation detection signal G of one pulse is output for each rotation of the motor.

20 is an electronic dollar circuit, 21 is a key switch, 22 is a starter motor, and a vehicle speed sensor 23 generates pulses with a repetition frequency depending on the vehicle speed.

The electronic tillti1 circuit 20 has the configuration shown in FIG. T! A device (CPU) 30, a read-only memory (ROM) 31 that stores processing programs, and a random access memory (RAM) used as a work area.
) 32, a backup RAM 33 that retains data even after power is stopped, an A/D converter 34 with a multiplexer function, and an I10 interface 3 with a buffer function.
5 and a backup circuit 36 for performing backup tillllll, and these are interconnected by a pass line 37.

The A/D converter 34 supplies the air flow signal from the air flow meter 8, the intake air temperature signal 8 from the intake air temperature sensor 11, the water temperature signal from the water temperature sensor 13, and the heavy speed signal from the vehicle speed sensor 23. and digitizes each signal, and these digital signals are read by the CPU 30. Also, the I10 interface 35 has an aX sensor 9. Throttle sensor 121 rotation angle sensor 18. Cylinder discrimination sensor 19. Signals from each key switch 21 come in, and each signal is read by the CPU 30.

The CPU 30 calculates each of the two fuel injection times and ignition timing based on the detection data of each sensor by the process shown in FIG. 4(A), and calculates the calculated Inn times signal AU.

Obtain the calculated ignition signal IGT. Further, the CPU 30 generates a watchdog timer signal WDC having a constant time cycle in seconds by the process shown in FIG. 4(B).

Figure 4 (A) shows CPtJ3 for each predetermined rotation angle of the crankshaft.
12 shows a flowchart of ignition timing and injection crushing processing that is interrupted and executed at 0. First, in step 81, detection data from various sensors is read. Next step 8
2, the ignition timing j+ and injection time t2 are determined from this data.
is highlighted.

For example, as in the known technology! The ignition timing, in fact, the advance angle value θ from top dead center (TDC) is calculated from the rotational speed of the lI valve, the operating state of the throttle valve 71, and the like. Further, other correction calculations are performed to obtain the actual ignition advance angle θP, and the ignition timing t1 is determined. Next, in step 83, the crushing ignition signal (Fi No. IG) at a timing representing the ignition timing t1 and the calculated ignition signal A (J representing the injection time t2 in terms of pulse width) are set to the backup circuit 3.
6 is output. In this way, -1 processing is completed, and the next υ1
Repeat the same process at different angles.

Next, FIG. 4(B) is a flowchart of the watchdog timer signal WDC output to the backup circuit 36 at the start-up 84, which is executed by the CPLJ30 at predetermined time intervals. Ru. In this way, the process ends once and is repeated after a predetermined time period. This watchdog timer signal WDC may be replaced with various other signals outputted from the CPU 30 in a predetermined manner. The calculated injection signal NTA Ll, 10 calculated ignition signals, and watchdog timer signal WDC are the rotation angle signal QNE, rotation detection signal gG, and throttle sensor 12.
The idle signal MIDL from the main switch 21 and the starter signal STA from the key switch 21 are supplied to the backup circuit 36 via the 110 interface 71-35, and the backup circuit 36 outputs! ! ! III signal and ignition signal are the fuel Fl15 injection valve 10. It is supplied to each igniter 16.

FIG. 5 shows a block diagram of the backup circuit 36. In the figure, a rotation detection signal QG and a rotation angle signal 3NE are input to terminals 40 and 41, respectively, and are supplied to a predetermined ignition signal generation circuit 42. The predetermined ignition signal generation circuit 42 generates the above-mentioned signal G,
An ignition timing signal synchronized with the rotation of the engine synthesized from the NE, that is, a predetermined ignition signal is generated and supplied to the ignition monitor 43 and the a terminal of the switch 44.

The ignition monitor 43 is supplied with a calculated ignition signal 1G and a starter signal STA from terminals 45 and 46, respectively, and is the II4 signal shown in FIG. In the figure, the predetermined ignition signal and the calculated ignition signal IGT from terminals 50 and 51 are supplied to an abnormal/normal signal generation circuit 52, where one of the predetermined ignition signals
If only one pulse of the calculated ignition signal IGT enters within the cycle, one pulse of the normal signal is output, and if the calculated ignition signal IGT does not come within one pulse of the predetermined ignition signal or if two pulses abnormally arrive, an abnormal signal is output. One pulse is output.

This abnormal signal m@Gi is supplied to the trigger input terminal T of the T-type flip 70 tube 53, inverted by the inverter 58, and supplied to the clock input terminal of the flip 70 tube 53, and the normal signal is supplied to each of the T-type flip 70 tubes 753 to 57. It is commonly supplied to the reset terminal R of both. flip flop 5
3 to 57, the outputs of the Ql terminal and the σ terminal in the previous stage are respectively supplied to the clock input terminal and the trigger input terminal r, and constitute a counter that counts the abnormal signal after being reset with a normal signal.

AND circuit 59 has 7 lips, 7 O tubes, 53.54 Q
When the terminal output is supplied and three pulses of the abnormal signal are output, an H level abnormality determination (1 is generated and supplied to the AND circuit 60.
4,55,56 Qg outputs are supplied, and when 15 pulses of the abnormal signal are output, a low level abnormality determination signal is generated and supplied to the AND circuit 62. The starter signal 8 from the terminal 63 (H level when the starter is on) is supplied to the AND circuit 62, inverted by the inverter 64, and supplied to the AND circuit 60. The AND circuit 62 takes out the abnormality determination signal g from the AND circuit 61 at the time of startup, and these abnormality determination signals 8 are sent from the terminal 66 via the OR circuit 65 to the backup determination shown in FIG. Supplied to circuit 70.

Further, the reset circuit 67 generates a reset signal and supplies it to the backup determination circuit 70 from a terminal 68 when three pulses of the normal signal are received after the abnormality determination signal output from the OR circuit 65 falls.

Returning to FIG. 5, the calculated ignition signal j31 GT from the terminal 45 is supplied to the BS terminal of the switch 44 together with the ignition monitor 43. Also, the calculation injection signal 5! from the terminal 71! T A tJ is supplied to the b terminal of switch 72 .

The watchdog timer signal WDC from the terminal 73 is supplied to the watchdog timer 74, and the watchdog timer 74 outputs an abnormality determination signal after a predetermined time has elapsed after the signal WDC is no longer input until the signal WOC is input. It is generated and supplied to the backup determination circuit 70.

The backup determination circuit 70 has a watchdog timer 74.
While the abnormality determination signal is received, it is determined that the mode is in backup mode and a switching signal of H level is generated. It determines that the mode is backup mode and generates an H-level switching signal.For other periods, it determines that it is CPU mode and generates an L-level switching signal, and supplies this determination signal to the control terminal of the switch 72 and also outputs the OR circuit. 75 to the control terminal of switch 44.

The starter signal STA from the terminal 46 is the ignition monitor 4.
3 and the II of the switch 44 through the OR circuit 75.
10 ra7- and backup injection signal generation circuit 76
The idle signal IDL from the terminal 77 is supplied to the backup injection signal generation circuit 76. The backup injection signal generating circuit 76 generates a pulse-shaped backup injection signal with a small pulse width when idling when the starter (No. ii STA is at the high level and the idle signal IDL is at the H level), The signal IDL generates a backup injection signal with a 1. level and a medium pulse width, the starter signal STA generates a backup l1fil)I signal with a low level and a large pulse width, and this backup injection signal is sent to the switch 72.
is supplied to the a terminal of the

Switch 44 is disabled during startup or backup mode.
When the H level is supplied to the ia terminal, a predetermined ignition signal of the a @ child is taken out, and the level is supplied to the control terminal during CPU mode other than starting, and the calculated ignition signal IG' of the b terminal is output.
Switching is performed to take out the T, and the taken out ignition signal is supplied to the igniter 16 from the terminal 78.

When the switch 72 is in the backup mode, the H level is supplied to the IIIall terminal to take out the backup injection signal, and in the CPU mode, the switch 72 is switched to take out the calculated injection signal TAU, and the taken out injection signal is sent to the terminal 79.
The fuel is supplied to the fuel injection valve 16.

Here, as shown in Fig. 7, if a phenomenon occurs in which the battery voltage abnormally decreases during the compression stroke of the internal combustion engine and recovers to a normal value during the explosion stroke, such as during cold start, the output from CPIJ30. The calculated ignition signal IGT and the watchdog timer signal WDC are no longer output in the abnormal area. Then, the watchdog timer 74 measures the disappearance time (m) of the watchdog timer signal WOC after it disappears, and if it continues to disappear for a predetermined period of time, it immediately detects an H level abnormality after the predetermined time (m) has elapsed. Outputs a discrimination signal.

On the other hand, the i-style ignition signal IGT has an abnormal output timing (compression stroke)! :Because it is correct, clan-
The starter signal STA disappears completely during the
level, a predetermined ignition signal is taken out from the switch 44 and supplied to the igniter 16.

Furthermore, when the starter signal is at H level, the ignition monitor 43 does not perform abnormality determination until the calculated ignition signal IGT disappears.
is determined to be the CPU mode, and a calculated injection signal is taken out from the switch 72 and supplied to the fuel injection valve. In addition, C.P.
Even if tJ30 becomes abnormal due to a decrease in battery voltage during the compression stroke, it operates normally during the other explosion, exhaust, and intake strokes, and generates and outputs the calculated injection value 3 during the normal operation.

In this way, at the time of starting, the number of ignition monitors, that is, the number of abnormal signal counts, which is the reference value for outputting the abnormality determination signal fffi, is increased from the usual 3 times to 15 times.
The fuel injection amount at the beginning 11llvf is set to the optimum value based on the calculated injection signal, thereby improving startability. By the way, although the backup injection signal when the start signal STA is at H level has a large pulse width, this is combined at the time of starting after l1ltl, so it is insufficient for the fuel injection amount during normal starting. . The reason why the number of ignition monitors is set to 15 is that during this time, normal starting is completed and the battery voltage becomes normal and stable. Depending on the case, the number of ignition monitors may be set to about 30 times.

In addition, in this embodiment, the OR condition of the two signals, the calculated ignition signal @IGT and the watchdog timer signal WDC, is used to detect an abnormality in the microcomputer. The abnormality of the microcomputer can be quickly determined based on the watchdog timer signal WDC without having to rotate the internal combustion engine enough to obtain the required number of ignitions.

In addition, in order to prevent the microcomputer from determining an abnormality due to the decrease in battery N pressure at startup and from switching to backup, the calculated ignition signal is not monitored at startup as described in special request @63-295867, and only the watchdog timer is used. There are devices that detect abnormalities in the microcontroller.

However, if the microcontroller goes out of control and, for example, operates in external bus mode when it should be operating in single-chip mode, there is a risk that the clock signal may be output from the microcontroller's output terminal that outputs the watchdrag timer signal. be. In this case, the watchdog timer that detects an abnormality in the microcomputer is supplied with the 0 (ffi) signal, and the watchdog timer assumes that the microcomputer has started normally. If it goes out of control, the calculated ignition signal and calculated injection signal will be affected.
Since the injection signal is not output from the engine and the internal combustion engine does not shift to the backup mode, the predetermined injection signal is also not output, resulting in a problem that the internal combustion engine is not started.

In contrast, according to the above embodiment, even if the microcomputer goes out of control during startup and the calculated ignition signal is not output, and a clock signal is output instead of the watchdog timer signal, the ignition monitor 43 When the calculated ignition signal is not output a predetermined number of times, the backup mode is entered, and the 9!3 operation is performed although the startability is somewhat deteriorated due to the predetermined ignition signal and the predetermined 1lf3 error signal 3.

〔Effect of the invention〕

As described above, according to the internal combustion engine testing device of the present invention, even though the calculation means such as a microcomputer is partially operating normally at the time of startup, it is not determined to be abnormal, and the calculations at the time of startup are not determined to be abnormal. Optimal fuel injection tJ4II by means! This is extremely useful in practice, as it improves starting performance and allows starting even if the microcomputer goes out of control.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of the device of the present invention, Fig. 2 is a configuration diagram of an embodiment of a gasoline engine to which the device of the present invention is applied, Fig. 3 is a 10-step diagram of an electronic t11wJ circuit, and Fig. 4 is a C
FIG. 5 is a block diagram of a backup circuit, FIG. 6 is a block diagram of the O path of the ignition monitor, and FIG. 7 is a diagram for explaining the operation of the device of the present invention. Ml...Internal combustion 11yJ, M2...Operating state detection means, M3--Calculation means, M4...Operation black synthesis means, M
5... Abnormality identification means, M6... Selection means, M7...
・Reference value changing means, 1...gasoline engine, 3...
- Spark plug, 10...Fuel injection valve, 16-...Igniter, 30...CPU, 36...Backup circuit, 42...-Predetermined ignition signal output circuit, 43...Ignition monitor, 70... Backup determination circuit, 74...
Watchdog timer, 76...Backup injection signal generation circuit.

Claims (1)

[Scope of Claims] Operating state detection means for detecting the operating state of the internal combustion engine; calculation means for calculating and outputting a control amount for controlling the internal combustion engine according to the detection result of the operating state detection means; a predetermined control amount synthesis means for synthesizing and outputting a predetermined control amount signal representing a predetermined control amount of the internal combustion engine according to the detection result of the state detection means; and a calculation means for comparing the calculation output of the calculation means with a predetermined reference value. abnormality determining means for determining the presence or absence of an abnormality in the internal combustion engine; reference value changing means for loosening the reference value of the abnormality determining means at the time of starting the internal combustion engine by comparing it with the reference value during normal operation; Output selection for selecting the output of the predetermined control amount synthesis means as a control output to the internal combustion engine when it is determined that there is an abnormality in the means, and selecting the output of the calculation means when it is determined that there is no abnormality. A control device for an internal combustion engine, comprising: means.