JPH03286168A - Trouble diagnosing device for engine - Google Patents

Abstract

PURPOSE:To judge a trouble with high precision by judging the existence of anomaly of an engine according to the magnitude reletion between a prescribed value and the exhaust temperature detected by an exhaust temperature detecting means installed in an exhaust passage on an upper stream side than an exhaust purifying device, in a prescribed operation region. CONSTITUTION:In the prescribed operation region which is judged by the revolution speed of the engine 1 and the intake manifold pressure detected by a pressure sensor 6, the temperature in misfire of the exhaust gas which passes through an exhaust passage 8 on the upper stream side than an exhaust purifying device 11 lowers below the temperature in the normal case, while in case of the excessive delayed angle, abnormal combustion is carried out in the exhaust passage, and the temperature at that point becomes higher than that in the normal case, and a prescribed value is set at the temperature between the temperature in the normal case and at least one anomaly case, and the magnitude relation between the temperature detected by an exhaust temperature detecting means 9 and the prescribed value is judged by an engine anomaly judging means 17, and at least one anomaly of the engine is judged. Accordingly, the misfire due to the trouble in an ignition system, fuel cut state due to the trouble in a fuel system can be judged with high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine failure diagnosis device for determining the presence or absence of an abnormality in an engine, such as abnormal combustion in the engine due to engine misfire 9 over-retardation of ignition timing. It is.

[Conventional technology]

Conventional engine failure diagnostic equipment installs a temperature sensor inside a catalyst that is installed in the engine exhaust passage and purifies engine exhaust gas, and detects a signal equivalent to the catalyst exhaust temperature output from this temperature sensor and a signal equivalent to a predetermined temperature. By comparing the size with the value, it was determined whether there was an abnormality in the engine based on the comparison result.

When the engine misfires, unburned fuel from the misfired cylinder flows to the exhaust purification device, ie, the catalyst, and causes a chemical reaction such as an oxidation reaction or a reduction reaction, so that the catalyst exhaust temperature increases. By detecting the catalyst exhaust temperature at this time using a temperature sensor, engine failure can be diagnosed as described above. If the engine failure diagnosis device determines that the engine is abnormal, it lights up a display lamp to indicate the abnormality to notify the driver.

[Problems to be Solved by the Invention] As described above, the conventional engine failure diagnosis device has the problem that, for example, in the high engine load range, the air-fuel ratio is on the Lynch side.
As unburned fuel is discharged as part of the exhaust gas, the fuel comes into contact with the catalyst and causes a chemical reaction, raising the catalyst exhaust temperature, making it difficult to distinguish it from a misfire. There were difficult challenges.

Additionally, if the comparison temperature is set high to improve the accuracy of failure diagnosis, by the time the temperature sensor installed on the catalyst detects a catalyst exhaust temperature that is higher than the set temperature, the catalyst has already reached a high level of unburned fuel. There was a problem with overheating, deterioration, or combustion in response to heat, making it unusable.

Furthermore, conventional engine failure diagnosis devices can determine misfires when the fuel supply system is normal and the ignition system is at fault; There is a problem in that it is not possible to determine whether a misfire occurs when fuel is not supplied to the cylinders of the engine due to a malfunction.

Further, due to an abnormality in the ignition system, the ignition timing may be too late, causing abnormal combustion of fuel in the exhaust passage of the engine, and the temperature of the exhaust gas may rise abnormally. In this case, conventional engine failure diagnosis devices have had problems such as being unable to distinguish between misfires and misfires.

This invention was made to solve the above-mentioned problems, and it detects the temperature in the exhaust passage at least upstream of the exhaust purification device and determines whether or not there is an abnormality in the engine. The purpose of this invention is to obtain an engine failure diagnosis device capable of making judgments.

[Means for resolving issues]

The engine failure diagnosis device of the present invention includes an exhaust salinity detection means installed in the exhaust passage upstream of the exhaust purification device, a means for detecting various parameters of the engine operating state, and an engine operating state that is within a predetermined operating range. and an engine abnormality determining means that determines whether or not there is an abnormality in the engine based on the magnitude relationship between the exhaust temperature detected by the exhaust temperature detecting means and a predetermined value in a predetermined operating range. It is something.

Further, the exhaust temperature detecting means is the first temperature detecting means, a second temperature detecting means is provided within the exhaust purification device or downstream thereof, and the engine abnormality determining means is detected by the second temperature detecting means. The presence or absence of each of a plurality of abnormalities in the engine is determined by also determining the magnitude relationship between the temperature and other predetermined values.

C-Function] In the engine failure diagnosis device of the present invention, in a predetermined operating range, in the case of a misfire, the temperature of the exhaust gas passing through the exhaust passage upstream of the exhaust purification device is lower than normal;
In the case of a retarded angle, abnormal combustion occurs in the exhaust passage, so the temperature of that part becomes higher than normal, and a predetermined value is set to the temperature between normal and at least one abnormality, and the exhaust salinity is detected. The engine abnormality determining means determines the magnitude relationship between the temperature detected by the means and the predetermined value, thereby determining an abnormality in at least one engine.

Furthermore, in a given operating range, if fuel is not supplied due to a failure in the fuel system, unburned fuel will not be included in the exhaust gas even if there is a misfire. If the temperature of the passing exhaust gas is lower than normal, and a malfunction in the fuel system causes excess fuel to be supplied, causing a misfire, or even if fuel is supplied, a misfire occurs due to a malfunction in the ignition system, the fuel may be removed from the exhaust purification system. The internal temperature or the temperature of the exhaust gas that has passed through it becomes higher than normal due to abnormal overheating of the exhaust purification device in response to the reaction, and setting another predetermined value to the temperature between the normal and at least one abnormal time, Second
The temperature of the exhaust gas inside or passing through the exhaust gas purification device detected by the temperature detection means of the first embodiment and another predetermined value are discriminated by the engine abnormality discrimination means, and the discrimination result when the first temperature detection means is used. In combination, it is possible to identify which abnormality is among a plurality of abnormalities.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. 1st
The figure shows the configuration of an engine section according to a first embodiment of the present invention, and in the figure, 1 is a well-known, for example, 4-cylinder spark ignition engine mounted on a moving body such as an automobile, 2 is an intake manifold of engine l, 3 is intake manifold 2
4 is an injector that injects fuel into the intake manifold 2. 5
6 is a throttle valve that adjusts the intake air amount of engine 1;
7 is a pressure sensor that detects the negative pressure downstream of the throttle valve 5 as an absolute pressure, and 7 is a coolant temperature sensor that detects the coolant temperature of the engine 1. 8 is an exhaust manifold of the engine 1, 9 is an exhaust temperature sensor that detects the temperature of exhaust gas flowing inside the exhaust manifold 8, 1o is an intake temperature sensor attached to the intake manifold 2, and 11 is a three-way catalyst that purifies the exhaust gas. The exhaust temperature sensor 9 is installed in the common exhaust passage upstream of the three-way catalyst 11. 12 is an ignition coil that supplies high voltage to a spark plug (not shown) of the engine 1 via a power distributor (not shown); 13 is connected to a unit that forms an ignition signal, and is connected to a unit that forms an ignition signal in response to the applied ignition signal; 14 is a cranking switch that is turned on when the starter starts operating, 15 is a battery, and 16 is a key switch. 17 is engine 1
A control device 30 inputs various parameters of the engine 1, performs various calculations and judgments according to these parameters, controls the fuel injection amount from the injector 4, and determines whether or not there is an abnormality in the engine 1. This is an indicator lamp that warns of abnormalities.

Next, the internal configuration of the control device 17 will be described with reference to FIGS. 2 and 3. In FIG. 2, 100 is a microcomputer, which includes a CPU 200 that executes the flowchart shown in FIG. 3, a free running counter 201. A timer 202, an A/D converter 203 that converts an analog signal into a digital signal, an input port 204 that adjusts the level of the digital signal and inputs it, a nonvolatile device that functions as a work memory and sets/resets an engine abnormality flag. ROM 206 that stores the control program such as the flowchart shown in FIG. 3, an output boat 207 for outputting the calculated fuel injection amount and engine abnormality display signal, and a common bus 208 that connects the above components. It consists of

A first input terminal 101 is connected to, for example, the collector of the final stage transistor of the igniter 13 connected to the primary winding of the ignition coil 12, and is used to input a signal for detecting, for example, the engine speed to the microcomputer 100. Face, 102 is a pressure sensor 6, a cooling water temperature sensor 7
, a second human interface circuit for inputting analog output signals from the exhaust temperature sensor 9 and the intake temperature sensor 10 to the A/D converter 203. These sensors 6°7.
9.10 outputs an analog detection signal that increases as the detected pressure or temperature increases, for example. 103
is a third human power interface circuit for inputting various signals such as on/off signals of the cranking switch 14 to the microcomputer. Reference numeral 104 denotes an output interface circuit which converts the fuel injection amount outputted from the output boat 207 into a time-width pulse and outputs it to the injector 4, and also outputs a lighting signal for lighting the indicator lamp 30 in response to an engine abnormality signal. 105 is connected to the battery 15 via the key switch 16 and supplies constant voltage power to the microcomputer 100; 106 is always connected to the battery 15 to prevent the memory contents of the RAM 205 from being erased; This is a second power supply circuit as a backup power supply.

Next, the general operation of the engine section will be explained with reference to FIGS. 1 and 2. When the key switch 16 is turned on, the control device F receives constant voltage from the first power supply circuit 105 and starts operating.

When the 111m device 17 starts operating, the engine 1 is supplied with fuel and starts, and the cranking switch 14 is turned on.

The engine 1 takes in combustion air through the air cleaner 3, intake manifold 2, and throttle valve 5111. In addition, fuel is supplied to the throttle valve 5 from the fuel system (not shown).
The fuel is injected and supplied to the engine 1 by the injector 4 located on the more upstream side under the control of the control device 17 . Furthermore, when the igniter 13 cuts off the power to the primary S wire of the ignition coil 12, the high voltage generated in the secondary winding is supplied to the spark plug (not shown) provided in the relevant cylinder to ignite the cylinder. The exhaust gas after combustion is discharged into the atmosphere through the exhaust manifold 8 and the three-way catalyst 11.

On the other hand, the pressure sensor 6 detects the intake manifold pressure (hereinafter referred to as intake manifold pressure) P in the intake manifold 2 downstream from the throttle valve 5, and outputs an analog detection signal corresponding to the intake manifold pressure P. The cooling water temperature sensor 7 detects the cooling water temperature of the engine 1, and outputs an analog detection signal corresponding to the cooling water temperature.The intake air temperature sensor 1o detects the temperature of the intake air of the engine 1, and outputs an analog detection signal corresponding to the cooling water temperature. The exhaust temperature sensor 9 detects the temperature of exhaust gas passing through the exhaust manifold 8 upstream of the three-way catalyst 11, and outputs an analog detection signal corresponding to the exhaust temperature. Control device 1
7 performs analog-to-digital (A/D) conversion on the analog detection signals of these sensors 67, 9, and 10 via the second human interface circuit 102 and the A/D converter 203 and reads them. Further, the control device 17 receives a change in the ignition pulse signal from the igniter 13 via the first human interface circuit 101 as an interrupt input signal. Then, the control device 17 calculates the basic fuel amount using a well-known method based on the period of the ignition pulse signal from the igniter 13 and the output signal of the pressure sensor 6, and corrects it based on the output signals of the other sensors 7.10. The driving time of the injector 4 is determined using the timer 202, and the valve opening time of the injector 4 is controlled from the output boat 207 via the output interface circuit 104 using the timer 202. Further, the control device 17 determines whether or not there is an abnormality in the engine 1 as described below, and when it is determined that there is an abnormality, the display lamp 30 is turned on.

As mentioned above, the control system W17 executes the flow of the main routine (not shown) at the start of operation and calculates the fuel injection amount. Then, the interrupt processing routine shown in FIG. 3 is executed. First, in step 301, the change in the signal of the igniter 13 when 111t of the ignition coil 12 is cut off is detected by the first input interface circuit 1.
01, the time from the previous ignition to the current ignition is measured by the counter 201, and based on this measurement data, rotation speed data N representing the rotation speed N of the engine 1 is generated.
! In the zero-order step 303 to calculate D, the output of the exhaust temperature sensor 9 is converted into a digital exhaust temperature (!l T t and read. Next, in step 304, the intake manifold pressure P in the intake manifold 2 is detected. The output of the pressure sensor 6 is converted into a digital intake manifold pressure value pn and read.

In step 305, the engine speed N□ and the intake manifold pressure P are determined based on the engine speed data N representing the engine speed N, and the intake manifold pressure value Pゎ representing the intake manifold pressure P.
It is determined whether or not it is within the abnormality determination zone shown in the shaded area in FIG. The predetermined operating range of the engine in this shaded area is the operating range excluding the operating range where the exhaust temperature is high due to high revolutions and high loads, and the operating range when the engine is in an idling state. Moreover, it is set in a stable predetermined region. This shaded area is
Data corresponding to the engine rotation speed N and data corresponding to the output of the pressure sensor 6 of the intake manifold pressure P are stored in advance in the ROM 206 as a map or function. Using this data, it is possible to determine whether the current operating conditions are within the engine abnormality determination zone indicated by the shaded area. If it is within the engine abnormality determination zone indicated by the hatched area, the process moves to step 306 and reads the timer value TM.The timer of this timer value TM is, for example, a soft timer, and is counted and amplified at predetermined time intervals by, for example, an interrupt processing routine or a main routine. It is something that counts up every predetermined number of steps.

If it is outside the engine abnormality determination zone other than the shaded area, the process moves to step 307 and the timer value TM is reset to zero. Therefore, this timer (iiTM) measures the duration of time during which the operating conditions of the engine 1 are within the engine abnormality determination zone shown in the shaded area in FIG.

In step 308 after the processing in step 306, the timer value TM is compared with a predetermined value T M o corresponding to the time required to stabilize the output of the exhaust temperature sensor 9, and when the timer value TM is equal to or greater than the predetermined ITM, step 309 Move to. Step 3
In step 09, the exhaust temperature value T read in step 303 is detected by the exhaust temperature sensor 9, which corresponds to the exhaust temperature between normal combustion and a misfire due to fuel supply interruption due to fuel system failure or ignition system failure, etc. It is determined whether or not the value is equal to or greater than a determination darkness value T3, which is a digital conversion value equivalent to the output of . If T is less than T1, a misfire has occurred and the temperature of the exhaust gas has become lower than the temperature equivalent to the determination dark value, so an engine abnormality flag is set in step 310. T, ≧T.

If it is removed, the temperature of the exhaust gas is higher than the temperature equivalent to the determination threshold value due to combustion, so step 311 is performed.
Reset the engine abnormality flag. Step 30
7. After the negative determination in step 308 and the processing in either step 310 or step 311, the process proceeds to the next step (not shown).

Figure 5 shows the flow from point B (750 PPM, 200 wm Hg) outside the engine abnormality determination zone shown in Figure 4 to point A (3000 RPM, 4) within the engine abnormality determination zone.
The transient characteristics of the output of the exhaust temperature sensor 9 when the temperature changes to 10 n As the exhaust temperature rises, the output of the exhaust temperature sensor 9 (temporarily Tt
) gradually increases. After the output changes to point A, it becomes stable after a period of time corresponding to the timer value T Ma has elapsed. When this stabilization is achieved, the presence or absence of an abnormality is determined in step 309, so there will be no erroneous determination.

As described above, when the control device 17 sets the engine abnormality flag, it lights up the display lamp 30 via the output boat 207 and the output interface circuit 104.

FIG. 6 shows a flowchart of the second embodiment, and shows the hardware*
* is the same as in FIG. 1 and FIG. 2, and its explanation will be omitted. In FIG. 6, the same steps as in FIG. 3 are given the same reference numerals 301.303 to 308310.311. A second embodiment will be described with reference to FIG. First, step 7, step 301, to get the rotation speed data N! After calculating 11, in the next step 302, the output of the intake temperature sensor 10 is converted into a digital intake temperature value TA and read. Step 3
03~Step 307 is processed, and then step 30
At step 8, when the timer value TM is greater than or equal to the predetermined value TMO, the engine l
It is determined whether or not the operating condition continues to be within the engine abnormality determination zone for a predetermined period of time or more, and if yes, step 40
Go to 1. In step 401, the exhaust gas temperature value T read in step 303 is calculated as a function of the intake air temperature value TA read in step 302.
) or more. If not, it is a misfire and the engine abnormality flag is set in step 310, and if it is normal, the engine abnormality flag is reset in step 311.

As shown in FIG. 7, as the intake air temperature T increases, the exhaust temperature 4a T eO increases, that is, the exhaust temperature also increases during normal times (vAc,>, when one cylinder misfires, including when fuel cannot be supplied). (Song wAcz>both rise. Therefore, in order to set the temperature conversion value of the judgment threshold r+(Ti) to fall between the two curves C, , C, it is necessary to increase it as the intake air temperature rises. As a matter of fact, the determination threshold f, (T,) is set in this manner.

FIG. 8 shows a flow chart of the third embodiment, which differs from the second embodiment in that the cooling water temperature is used instead of the intake air temperature.

The hardware configuration is the same as in FIGS. 1 and 2. First, step 3 after calculating the rotation speed data N0 in step 301.
At 02A, the output of the cooling water temperature sensor 7 is converted into a digital cooling water temperature value Tw and read. Steps 303 to 308 are performed, and if it is determined that the operating conditions of the engine 1 continue to be within the engine abnormality determination zone for a predetermined period of time, the process moves to step 402. In step 402, it is determined whether or not the exhaust gas temperature value T read in step 303 is greater than or equal to the determination threshold fl(TW) calculated as a function of the cooling water temperature value T read in step 302A. If not, it is a misfire, so an engine abnormality flag is set in step 310, and if it is, it is normal, so the flag is reset in step 311.

In Figure 9, the intake air temperature in Figure 7 is replaced with the cooling water temperature, and C1
is C1, C1 is C4, judgment threshold f, (TA) is f
t(Tw) shows the same tendency as in FIG. 7.

FIG. 10 shows a flowchart of the fourth embodiment, in which the determination threshold value is replaced with a predetermined value M'r + and the function value f+(Nzo, P
The difference is that a). The hard tank bottom is the same as in FIGS. 1 and 2. In FIG. 10, step 301. Steps 303 to 308 are performed, and if the operating conditions of engine I are within the engine abnormality determination zone for a predetermined time or longer, the process moves to step 403. In step 403, the exhaust gas temperature value Tt read in step 303 is calculated as a function of the rotational speed data NtI read in step 301 and the intake manifold pressure value P9 read in step 304. (Ni1 Po) or more is determined.

If this is not the case, there is a misfire, and an engine abnormality flag is set in step 310, and if the engine is normal, then the flag is reset in step 311.

Figure 11 shows the temperature conversion value of the judgment threshold f I (N□., P,) corresponding to the engine speed N and intake manifold pressure P, and a map obtained by converting this figure into data is used for calculations. are doing. By using this map, step 40
3, the determination threshold f + (Nt++, P o)
can be found. Judgment threshold f+(N!n, Po
) increases as the engine speed N and/or intake manifold pressure P increases.

The second to fourth embodiments have the advantage that a misfire due to a failure in the fuel system or a failure in the ignition system can be accurately determined in accordance with engine parameters.

FIG. 12 shows the configuration of the engine section according to the fifth embodiment of the present invention, and FIG. 13 shows the configuration of the control device according to the fifth embodiment.
In FIGS. 12 and 13, the same or corresponding parts as in FIGS. 1 and 2 have the same reference numerals 1 to 3.5 to
8.10-17100-106, 200-208 are attached, and the explanation thereof is omitted.

In the following, #l for the first cylinder in engine 1
, the one for the second cylinder is abbreviated as #2, the one for the third cylinder is abbreviated as #3, and the one for the fourth cylinder is abbreviated as #4, and those related to each cylinder are also given this symbol. 41 to 44 are first cylinders provided for each cylinder of the engine 1.
Injector for cylinder (#1) to 4th cylinder (#4), 9
Reference numerals 1 to 94 indicate exhaust temperature sensors #1 to #4 that are installed in exhaust passages for each cylinder of the exhaust manifold 8 and detect the temperature of exhaust gas for each cylinder. Reference numerals 31 to 34 are indicator lamps #1 to #4 that illuminate to indicate an abnormality in each cylinder of the engine 1.

One of the #1 to #4 injectors 41 to 44 is selected, the injector is driven via the output port 207 of the control device 17 and the output ink face circuit 104, and the fuel is supplied to the relevant cylinder of the engine 1. The exhaust gas temperature for each cylinder of the engine 1 is determined by #1 to #4 exhaust temperature sensor 9.
1 to 94, respectively, and the control device 1 via the second human power interface circuit 102 and the A/D converter 203.
7, the digital values are sequentially read in. Control device 17
When an abnormality is detected in a certain cylinder of the engine 1, the #1 to #4 indicator lamps 31 to 340 for the relevant cylinder are turned on via the output port 207 and the output interface circuit 104.

Other engine operations are obvious from the explanation of the first embodiment, so their explanation will be omitted.

The flowchart in Figure 14 is the first control program.
ROM 20 in the control device 17 shown in FIGS. 2 and 13
It is stored in 6. In FIG. 14, steps that are the same as those in FIG. 3 are given the same reference numerals 301304 to 308 to simplify their explanation.

First, in step 301, rotation speed data representing the engine rotation speed N is calculated.In step 303A, the outputs of the #1 to #4 exhaust temperature sensors 91 to 94 are sequentially digitalized by the A/D converter 203. #1 to #4 exhaust temperature value T. Convert to 1 to T and read sequentially, step 3
In 04, the intake manifold pressure (a
Read PD.

In step 305, the rotation speed data N! It is determined from D and the intake manifold pressure value Pa whether the operating conditions of the engine I are within the engine abnormality determination zone. If it is within the zone, the timer value TM is read in step 306, and if it is outside the zone, the timer value TM is reset to O in step 307. In step 308 after step 306, it is determined whether or not the timer ITM is equal to or greater than a predetermined value 7M corresponding to the time required to stabilize the outputs of exhaust temperature sensors #1 to #4. If TM≧TM, steps 410 and 413
, 416 and 419, the #1 to #4 exhaust temperature values T, ~T! read in step 303A are read. 4 and determination threshold T1
are sequentially compared, and it is sequentially determined whether each exhaust gas temperature value is equal to or higher than the determination threshold value T1. This determination threshold T1 is the difference between the exhaust temperature of a certain cylinder during normal combustion and the exhaust temperature when a misfire occurs due to a failure in the fuel system or ignition system in the first to fourth cylinders of the engine 1. It is a digital conversion value corresponding to the output of the exhaust temperature sensor for the cylinder of the #1 to #4 exhaust temperature sensors 91 to 94 corresponding to the exhaust temperature of the cylinder. If it is determined in each of steps 410, 413, 416, and 419 that the darkness value is less than T1, a misfire is indicated in steps 411, 414, 417, and 420. Therefore, the engine abnormality flag FC (however, G=1 to 4) is set, and if it is determined that it is equal to or higher than the determination threshold T1, steps 412, 415,
In steps 418 and 421, the engine abnormality flag FG is reset to indicate normality. Negative determination of steps 307 and 308, steps 420 and 421
After any one of these processes, the process moves to the next step (not shown).

#1 to # according to the set state of the engine abnormality flag FG.
For example, if only the engine abnormality flag F3 is set, the control device 17 lights only the #3 indicator lamp 33 because the third cylinder has misfired.

According to the fifth embodiment, it is possible to identify whether the cylinder is abnormal and to issue a warning.

FIG. 15 and FIG. 16 show a sixth embodiment of this invention,
The same or corresponding parts as the first embodiment have the same reference numerals 4.6, 7,
9.10.14-17.100201-208,301
．． 303 to 311 are attached. This sixth embodiment is the first
The difference from the embodiment is as follows. second indicator lamp 30A,
30B are provided and connected to the output interface circuit 104 of the control device 17, and the flowchart shown in FIG. 16 is stored in the ROM 206 as a control program.

In FIG. 15, if the control device 17 determines that the misfire is due to a failure in the fuel system or ignition system, the first indicator lamp 30A is activated.
If it is determined that abnormal combustion is due to over-retardation due to a failure in the ignition system, only the second indicator lamp 30B is lit, and when normal, the first and second indicator lamps 30A and 30 are lit.
Turn off B. For other engine operations, please refer to 1.
Since the operation is the same as that of the embodiment, the explanation thereof will be omitted.

In FIG. 16, the same process steps 301 and 303 to 311 as in the first embodiment are performed, and a misfire is determined by comparing the exhaust gas temperature value T and the first determination threshold value T1. If so, the engine abnormality flag A is set in step 310.
If it is determined that there is no misfire, step 31
1, the engine abnormality flag A is reset. After this set or reset, in step 430, step 30
It is determined whether or not the exhaust gas temperature value T1 read in step 3 is less than or equal to the first determination threshold T and the larger second determination threshold Tt.

This second judgment interval fat 'r t is a digital conversion value corresponding to the output of the exhaust temperature sensor 9 corresponding to the exhaust temperature between the exhaust temperature during normal combustion and the exhaust temperature during abnormal combustion due to retardation of ignition timing, etc. It is set. In the case of over-retardation, etc., the combustion flame jumps into the exhaust passage, so the exhaust temperature sensor 9 detects a higher exhaust gas temperature than in normal conditions @Tz>'
If rz is not below, it is abnormal combustion, so step 431
The engine abnormality flag B is set at , and if it is less than T, ≦T2, there is no abnormal combustion, so the engine abnormality flag B is reset. The control word W, 17 is set to the first . The second indicator lamps 30A and 30B are selectively turned on, and if both flags A and B have been reset, they are all turned off.

In the case of the sixth embodiment, it is possible to distinguish between misfire and abnormal combustion due to over-retardation, etc., and issue a warning.

FIG. 17 shows a seventh embodiment of the present invention, in which the hardware configuration is the same as that in FIG. 15, but the control program is different as shown in FIG. 17. In FIG. 17, the same steps as in FIG. 6 of the second embodiment have the same reference numerals 301 to 308, 401.31.
(1,311 is attached. First, steps 301 to 3
08,401゜310.311, the same process as in Fig. 6 is performed to determine the magnitude of the exhaust temperature value T and the first judgment threshold value r+('ri) calculated as a function of the intake air temperature flTA. If it is determined that there is a misfire, an engine abnormality flag A is set in step 310, and if there is no misfire, step 311 is set.
The engine abnormality flag A is reset at .

After this cent or reset, the process moves to step 440, and the exhaust temperature value Tt read in step 303 is changed to step 30.
The second judgment darkness value f! is calculated as a function of the intake temperature value T1 read in step 2. (TA) Determine whether or not the value is less than or equal to (TA). This second determination threshold f! As shown in FIG. 18, (TA) is converted into temperature and is set between the exhaust gas temperature curve C3 during normal operation and the exhaust gas temperature curve C1 during over-retardation which is larger than CI, and the intake air temperature curve C1 on the horizontal axis. It increases with increasing temperature.

The other curves have the same tendency as explained in FIG. T t〉f! (T a), and if it is not less than or equal to T, then in step 441, an engine abnormality flag B is set to indicate abnormal combustion during over-retardation, and T,≦r.
, (T,) is less than or equal to, it is not over-retarded, so step 4
At step 42, the engine abnormality flag B is reset.

In the case of the seventh embodiment as well, the two indicator lamps are individually turned on and then turned off in accordance with the cent and reset states of the engine abnormality flags A and B.

FIG. 19 shows an eighth embodiment of the present invention, in which the node configuration is the same as that in FIG. 15, but the control program is different as shown in FIG. In FIG. 19, the same steps as in FIG. 8 of the third embodiment have the same reference numerals 301302A and 303 to 3.
0B, 402310.311 is attached. First, steps 301, 302A, 303-308, 402310
．． 311, the same process as in FIG. 8 is performed, and the exhaust temperature value T,
If a misfire is determined by comparing the magnitude with the first determination threshold fl (Tw) calculated as a function of the cooling water temperature values TI and I, an engine abnormality flag A is set in step 310. At step 311, engine abnormality flag A is reset. After this cent or reset, the process moves to step 450, where the exhaust temperature value TF read in step 303 becomes the cooling water temperature value T read in step 302A,
Second judgment darkness value fZ(TW) calculated as a function of
Determine whether it is less than or equal to. This second determination threshold ft(T
As shown in Fig. 20, w) is converted into temperature and is set between the exhaust temperature curve 1cs during normal operation and the exhaust temperature curve C6 during over-retardation, which is larger than C1, and increases the cooling water temperature. rises with The other curves are the same as the trends explained in Figure 9 - Tt > f x (Tw)
If T7≦f!, then in step 451, engine abnormality flag B is set to indicate abnormal combustion during over-retardation, and T7≦f! If (Tw) is less than or equal to the value, the engine abnormality flag B is reset in step 442 because the engine is not over-retarded.

Also in the case of this eighth embodiment, the engine abnormality flags A, H
The two display lamps are turned on and off individually depending on the reset state.

FIG. 21 shows a ninth embodiment of the present invention, in which the node configuration is the same as the 15th TgJ, and the control program is the 21st embodiment.
Different as shown. In FIG. 21, the same steps as in FIG. 10 of the fourth embodiment have the same reference numerals 301, 303 to 30.
8,403.310311 is attached. First, the same processing as in FIG. 10 in steps 301, 303 to 308, 403, 310, and 311 is performed, and the first If it is determined that there is a misfire by comparing the magnitude with the determination threshold ft (Nto, Pa), the engine abnormality flag A is set in step 310, and if it is determined that there is no misfire, the engine abnormality flag A is reset in step 311. . The temperature conversion value of this first determination threshold value f+(Nt++, Pa) is the same as that shown in FIG. After this cent or reset, proceed to step 460 and step 3
Even under the same operating conditions, the exhaust temperature value T read in 03 is the first
The rotation speed data N read in step 301 is larger than the determination threshold value f+(NiD, PD). and the intake manifold pressure value P read in step 304, the second judgment interval Jfi f z(N to.

Pゎ) or less. This second judgment threshold f
The temperature conversion value of z(Nt++, P'o) is shown in correspondence to the engine rotation speed N and the intake manifold pressure P, as shown in FIG. Like the first determination threshold value f+(Nza, PD), this FIG. 22 is also mapped and stored in advance for calculation.

If Tt > fz(Nx++, P,) and is not less than or equal to Tt, an engine abnormality flag B is set in step 461 to indicate abnormal combustion due to over-retardation, and T,≦fz(
Nip, Po), the engine abnormality flag B is reset in step 462 to indicate that there is no excessive retardation. In the case of the ninth embodiment as well, each indicator lamp is turned on depending on the state of the engine abnormality flags A and H.

In the seventh to ninth embodiments, in addition to the advantages of the second to fourth embodiments, abnormal combustion during over-retardation can be determined with high precision according to engine parameters.

23 and 24 show a tenth embodiment of the present invention, in which in addition to the hardware configuration shown in FIGS. 12 and 13, second #1 to second #4 indicator lamps 35 to 38 is provided and connected to the output interface circuit 104. The flowchart in Figure 24 is written as a control program.
It is stored in OM206. In Figure 24, the first
The same steps as in Figure 4 have the same symbols 301, 303A304.
~308, 410~421 are attached.

Steps 410 to 412 and Steps 413 to 415
Steps 410A to 412A are performed during step 41
Steps 413A to 415A are performed between steps 3 to 415 and steps 416 to 418, and steps 416 to 418 are performed.
and step 416A~ between step 419~4210
Steps 418A and 419A to 421A are newly provided after steps 419 to 421, respectively.

Step 301, Step 303A, Step 304~
308 and steps 410 to 421, that is, the first
By performing the same processing as in Figure 4, the exhaust temperature value T for each cylinder is
The engine abnormality flags F1 to F4 are set and reset for each cylinder by comparing el~T with the first determination threshold T.

This engine abnormality flag is set in the corresponding cylinder when a misfire occurs due to a failure in the fuel system or a failure in the ignition system.

Steps 410A, 413A, 416A, 419
At step A, each of #1 to #4 exhaust gas temperature values Ttl to T read in step 303A is sequentially compared with the second judgment threshold T2, and each exhaust gas temperature value is determined as the second judgment threshold. It is determined whether or not T2 or less. This second determination interval 4a T t is the same as that defined in FIG. 16 of the sixth embodiment, and is a threshold value for determining abnormal combustion due to excessive retardation. In each of steps 41OA, 413A, 416A, and 419A, the second determination threshold T! If it is determined that the
17A and 420A, an engine abnormality flag FGA (however, G = 1
~4), and if it is determined that the second determination threshold ['rz or less is equal to or less than
In step 421A, the engine abnormality flag FGA is reset because there is no over-retardation and no abnormal combustion.

The first # depends on the set state of the engine abnormality flag FG.
1 to the first #4 indicator lamps 31 to 34 are turned on, and the second #1 to second #4 indicator lamps 35 to 38 are turned on depending on the set state of the engine abnormality flag FGA. lights up. For example, if the second cylinder misfires and the engine abnormality flag F2 is set, the first
#2 indicator lamp 32 is lit, and when the engine abnormality flag F3A is set due to abnormal combustion in the third cylinder due to over-retardation, the second #3 indicator lamp 37 is lit.

In the case of the first embodiment, it is possible to individually identify and warn about misfires (including cutoff of fuel supply due to not only ignition system failures but also fuel system failures) and abnormal combustion due to over-retardation for each cylinder. .

In the first to tenth embodiments described above, the control program shown in the flowchart shown in the figure is executed as an interrupt processing routine every predetermined number of revolutions of the engine, every predetermined number of steps, or every predetermined time, or as part of the flow of the main routine. It goes without saying that it would be better to handle it as a separate section.

In the second to tenth embodiments described above, the timer value T
Although the count-up operation of the timer M has not been described, it may be a soft timer operation that counts up by 1 every predetermined time or every predetermined number of steps, as in the first embodiment, or the count-up operation of the timer M may be performed using A hardware-configured counter that counts clock pulses may also be used.

Further, in the second to tenth embodiments, the engine abnormality determination zone in step 305 was not described in detail, but it may be the shaded zone shown in FIG. 4 of the first embodiment. In addition, in the first embodiment to the first O embodiment, the engine abnormality determination zone was defined by the engine speed N□ and the intake manifold pressure P, but instead of the intake manifold pressure P, the intake air amount It may be specified by the filling efficiency divided by the cylinder volume, the output frequency of the Kalman air flow sensor, the opening degree of the throttle valve, etc.
In this case, the intake air amount sensor requires a throttle opening sensor or the like instead of a pressure sensor. In addition, the above engine parameters may be used alone or in other suitable combinations.In addition, the condition that the cooling water temperature is above a predetermined value or after a predetermined time after starting the engine may be added as the engine abnormality determination zone. It's okay. In the latter case, it may be determined whether a predetermined time has elapsed since the cranking switch 14 was closed.

Further, in the second embodiment or the seventh embodiment, the intake air temperature is detected and used, but instead of this, the outside air temperature may be detected and used by a temperature sensor.

Furthermore, in the first to tenth embodiments, the exhaust temperature value T
, or T, ~ T, 4 was obtained for each detection, but it is the value obtained by adding the values detected one or more times consecutively up to the previous time to the currently detected exhaust temperature value and averaging the total. You may also use

Furthermore, in the first to tenth embodiments, the indicator lamp may be turned on immediately after the engine abnormality flag is set, or the indicator lamp may be turned on after the engine abnormality flag continues for a predetermined period of time or for a predetermined number of engine strokes. The display lamp may be turned on immediately after determining that it is set.

FIG. 25 shows the configuration of an engine section according to an eleventh embodiment of the present invention. In the figure, the engine 1, intake manifold 2, air cleaner 3, injector 4, throttle valve 5, pressure sensor 6, cooling water temperature sensor 7, exhaust manifold 8, exhaust temperature sensor 9, intake temperature sensor lO1 three-way catalyst 11, ignition coil 12, igniter 13, cranking switch 14, battery 15, key switch 16
The hardware configuration of the control device 17 is the same as or corresponds to that described in FIG. 1 of the first embodiment, and the explanation thereof will be omitted.

18 is installed in the exhaust passage in the three-way catalyst 11, detects the catalyst exhaust temperature, which is the temperature of the exhaust gas flowing through the catalyst 11, and outputs, for example, an analog detection signal of a magnitude proportional to the catalyst exhaust temperature. Catalyst exhaust temperature sensor, 30A, 3
0B is the first. This is the second indicator lamp.

FIG. 26 shows the internal configuration of the control device 17, etc. in the eleventh embodiment, and in FIG.
A microcomputer 1OO consisting of a U200, a counter 201, a timer 202, an A/D converter 203, an input port 204, a RAM 205, a ROM 206 storing a control program based on the flowchart shown in FIG. 27, and an output port 207; 1 to 3rd person interface circuits 101 to 103 and output interface circuit 1
04 and 1st. The second power supply circuit 105106 has the same hardware configuration as that in FIG. 2 of the first embodiment. However, the first and second indicator lamps 3OA, 30
B is connected to the output interface circuit 104, and the catalyst exhaust temperature sensor 18 is connected to the second human power interface circuit 102.

Next, we will discuss the operation of the engine section that is different from the first embodiment.
This will be explained with reference to FIG. 5 and FIG. 26.

The control device 17 includes a pressure sensor 6 , a cooling water temperature sensor 7 , an exhaust temperature sensor 9 , an intake temperature sensor 10 , and a catalyst exhaust temperature sensor 1
8 analog detection signal to the second human power interface circuit 1
02 and the A/D converter 203 and sequentially read the engine rotation speed data N from changes in the output signal of the igniter 13. Calculate. The control device 17 selectively uses the parameters read as described above to determine whether the operating conditions continue for a predetermined period of time within an engine abnormality determination zone in which a carrot abnormality can be determined. . If the first operating condition is met, the presence or absence of an abnormality in the engine 1 is determined based on the output of the exhaust gas temperature sensor 9, as in the first embodiment, and if the second operating condition is met, the catalyst exhaust temperature sensor 18 is determined. The presence or absence of an abnormality in the engine 1 is determined based on the output of the first. The second indicator lamps 30A and 30B are turned on and off, and the combination of re-judgment results indicates a misfire condition due to a failure in the ignition system of engine 1, an excessive fuel condition due to a failure in the fuel system of engine 1, and a failure in the fuel system of engine 1. It warns you so that you can identify the fuel shortage or cut state, and the normal state of the engine.

Next, detailed operation of the control device 17 will be explained with reference to FIG. 27. Control bag? 1!17 normally executes the main routine flow and calculates the fuel injection amount. Then, each time an interrupt is generated, for example, every A rotation of the engine 1, execution of the flow of the main routine is interrupted, and the interrupt processing routine shown in FIG. 27 is executed. first,
In step 301, rotation speed data N! represents engine rotation speed N0! Calculate D. In step 303B, each analog detection signal of the exhaust temperature sensor 9 and the catalyst exhaust temperature sensor 18 is converted into a digital exhaust temperature value TEAI representing the exhaust temperature via the second manual ink face circuit 102 and the A/D converter 203. It is sequentially converted and read into digitalized catalyst exhaust temperature information T- representing temperature. Step 304
Now, read the intake manifold pressure value Pゎ representing the intake manifold pressure P.

In step 305, it is determined from the rotational speed data N4° and the intake manifold pressure value P2 whether or not the engine is within the first engine abnormality determination zone Z shown in the shaded area shown in FIG. This first abnormality determination zone ZA is set in the same region as the shaded area in FIG. 4, where the exhaust gas temperature rises sufficiently to some extent and becomes stable. This first engine abnormality determination zone ZA is stored in advance in the ROM 206 as combined data of engine speed and intake manifold pressure. If it is determined that the engine is within the first engine abnormality determination zone Z, step 306
The first timer value TMA is read in step 307, and if it is determined that the zone is outside the zone zA, the first timer value TMA is reset to O in step 307. Step 306 then step 30
8, it is determined whether the first timer value TMA has exceeded a first predetermined value TMAo corresponding to the time required for the output of the first exhaust gas temperature sensor 9 to stabilize. TMA≧T
If it is M A O or above, the operating condition has been within the first engine abnormality determination zone ZA for a time equal to or longer than the first predetermined value TMA, so the process moves to step 309 and the exhaust gas read in step 303B is Temperature value T! It is determined whether A is greater than or equal to the first determination threshold+IT (defined in the description of the first embodiment for misfire determination).

When Tta≧TI, that is, when the first exhaust gas temperature value TEA is greater than or equal to the first determination threshold T1, the process advances to step 311, and RA
Reset the engine abnormality flag A in M205 and set the TE
When A<71, the process advances to step 310, and an engine abnormality flag A is set.

As will be described later, the first indicator lamp 30A is turned on via the output port 207 and the output interface circuit 104 in response to the sent flag A.

Now, for example, if a misfire occurs in a specific cylinder of engine 1 due to a failure of the spark plug, or if fuel is insufficient or cut due to failure of injector 4, the exhaust gas temperature when combusted in the combustion chamber of engine 1 Since the temperature of the unburned exhaust gas is lower than that of the engine, it is possible to detect this and indicate an abnormality.

Step 307, Step 7 Step 308 negative judgment TMA<
TMAo, step 310. Step 312 After processing any of the sytubs 311, proceed to step 312.
Then, the rotation speed data N1o representing the engine rotation speed N,
(see step 301) and the intake manifold pressure value Po representing the intake manifold pressure P (see step 3049), the engine 1
It is determined whether the operating conditions are within the second engine abnormality determination zone Z8 shown in the shaded area shown in FIG. This engine abnormality determination zone Z is a region where the catalyst exhaust temperature, which is the temperature of the exhaust gas flowing through the three-way catalyst 11, has risen sufficiently to a certain extent and is stable, and is a region where the engine abnormality determination zone It is set to, for example, an area where the air-fuel ratio is operated near the stoichiometric air-fuel ratio, excluding the operating area, and is stored in the ROM 206 in advance. When it is determined that the operating conditions are within the second engine abnormality determination zone Z shown in FIG.
3, the second timer flTMB is read.

When it is determined that the engine is outside the second engine abnormality determination zone Z, the process moves to step 314 and the second timer value TMB is reset to O. Therefore, the second timer value TMB indicates that the operating condition of the engine 1 is in the second engine abnormality determination zone Z.

The duration of time spent inside is measured. In step 315 following step 313, it is determined whether or not the second timer value TMB is greater than or equal to a second predetermined value TMB o corresponding to the time required for stabilizing the output of the catalyst exhaust temperature sensor 18. When the timer 2 (iTMB is equal to or greater than the second predetermined value TMB), the process proceeds to step 316.

In step 316, the catalyst exhaust temperature value Ttm (step 316) is performed.

1303B) is equal to or less than a preset third determination threshold T. This third judgment threshold T
3 is the catalyst exhaust temperature of the exhaust gas flowing through the three-way catalyst 11, which becomes relatively high due to a misfire in the ignition system when fuel is supplied, and the comparatively high temperature when fuel is supplied in excess of the required amount. The catalyst exhaust temperature corresponding to the temperature between the catalyst exhaust temperature of the exhaust gas flowing through the three-way catalyst 11 which increases and the catalyst exhaust temperature of the exhaust gas flowing through the three-way catalyst 11 which is relatively low under normal conditions. It is set to a digitized value equivalent to the output of the temperature sensor 18. When T,≦T, that is, when the catalyst exhaust temperature (I!TtIl is less than or equal to the third determination threshold T), the process proceeds to step 318, where the engine abnormality flag B in the RAM 205 is reset, and T!, >T, in the opposite case, the process advances to step 317, and engine abnormality flag B is set.

As will be described later, the set flag B lights up the second display lamp 30B via the output port 207' and the output interface circuit 104.

Now, for example, unburned fuel may be present in a particular cylinder of the engine 1 due to a misfire due to a failure of the spark plug, or a case where fuel is being supplied in excess of the required amount due to a failure of the injector 4, for example. If it flows into the three-way catalyst 11 and causes a chemical reaction, causing the catalyst to overheat,
Since the catalyst exhaust temperature is higher than when the engine 1 is operating normally, this can be detected and an abnormality can be displayed.

Negative determination in steps 314 and 315 (TMB<
TMB, ), Step 317, or Step 318, in the next step 319, it is determined whether the engine abnormality flag B is set due to catalyst overheating, and if it is set, the process proceeds to Step 323. ,
Intrusion of unburned fuel into the catalyst is indicated by lighting of the second indicator lamp 30B.

If the engine abnormality flag B is not set, the process proceeds to step 320, and if, for example, there is too little fuel supplied due to a failure in the injector 4, or if no fuel is supplied, the engine abnormality flag A is set. Therefore, it is determined whether or not engine abnormality flag A is set, and if it is set, step 321 is performed.
If the first indicator lamp 30A is turned on at
The second indicator lamps 30A and 30B are turned off. After processing any one of steps 321 to 323, the process proceeds to the next step.

FIG. 30 shows the configuration of an engine section according to a twelfth embodiment of the present invention, and FIG. 31 shows the internal configuration of the control device 17 etc. in FIG. 30. In Figures 30 and 31, the fifth
The same or equivalent parts as in FIG. 12 and FIG.
~1731~34, 100~106200~208 are attached, and the explanation thereof will be omitted. A catalyst exhaust temperature sensor 18 is installed in the exhaust passage in the three-way catalyst 11 to detect the catalyst exhaust temperature, and is connected to the second human-powered ink face circuit 102. 35 to 38 are second #1 to second #4 indicator lamps provided in addition to the first #1 to first #4 indicator lamps 31 to 34;
The four indicator lamps 39 are common indicator lamps, and these indicator lamps 35 to 39 are connected to the output interface circuit 104 so as to be individually controllable. The general engine operation shown in FIGS. 30 and 31 is as follows. Since this is obvious from the eleventh embodiment, its explanation will be omitted.

FIG. 32 is a flowchart showing the operation of the control device 17, which is stored in the ROM 206 as a control program. In FIG. 32, at step 301, rotation speed data N representing the engine rotation speed N. In the next step 303C after calculating the
94 outputs are sequentially A/D converted to obtain the first to fourth exhaust temperature values T! Al~T! A4 is read, and the output of the catalyst exhaust temperature sensor 18 that detects the catalyst exhaust temperature, which is the temperature of the exhaust gas flowing through the three-way catalyst 11, is A/D converted to obtain the catalyst exhaust temperature value T. Load. subsequent steps 304-308;
In steps 410 to 421, the same processing as in FIG. 14 is performed to set engine abnormality flags A1 to A4 for each cylinder.
Reset. However, in FIG. 32, the timer + [TM in FIG. 14 is set to the first timer value TMA, and the first predetermined value TM
O to TMAo, the first to fourth exhaust temperature values Tel~
T, T for 4! AT~T! Although the engine abnormality flags F1 to F4 are changed to A1 to A4 in A4, the contents are the same.

In step 307 and step 1308, it is determined that the first timer value TMA is less than the first predetermined value (fi T M A o , and after processing either step 420 or step 421, the process proceeds to step 312. Step 312 - The processing in step 318 is as described with reference to FIG.
B. Determine whether it has continued for a considerable predetermined time or longer, and if it has continued, compare the catalyst exhaust temperature value Tc++ and the third determination threshold T3 (for determining abnormal catalyst overheating, defined in the 11th embodiment) If T, , > T, an engine abnormality flag B is set in step 317, and T, ≦
If T3, the engine abnormality flag B is set in step 318.
Reset.

After resetting the second timer value TMB in step 314, TMB<TMB in step 315.

After determining that, the process proceeds to the next step 500 in either case after the processing in step 317 or 318.

In step 500, it is determined whether or not the engine abnormality flag B is set. If it is set, the process moves to step 501 and the common display lamp 39 is turned on. If it is reset, the process moves to step 502 and the common display lamp 39 is turned off. . After processing in step 501 or 502, the process advances to step 510.

In steps 5GO to 5G4 (G takes an integer value of 1 to 4 in order), the following processing is repeated. In steer 15GO, it is determined whether or not the engine abnormality flag AC is set, and if it is not set and reset, the process proceeds to step 5G1, and the first #G display lamp 3G and the second #G display lamp are turned on. 3G+4 is turned off to indicate that the G-th cylinder of engine 1 is normal, and if it is set, the process advances to step 5G2. In step 5G2, it is determined whether engine abnormality flag B is set. If it is a reset, proceed to Step 15G3 and the first #G
The display lamp 3G is turned on, and if it is a cent, the second #G display lamp 3G+4 is turned on.

As described above, steps 510 to 514 when G=1, steps 520 to 524 when G=2, and G
Steps 530 to 534 in the case of C=3 and steps 540 to 544 in the case of C=4 are completed in order, and the first #l to first #4 display lamps 31 to 34, the second #1 ~
Controls lighting/extinguishing of the second #4 indicator lamps 35 to 38.

When the first #G indicator lamp 3G is lit, it indicates that the amount of fuel supplied to the G cylinder of the engine 1 is insufficient or not supplied due to a failure of the injector 4G or the like.

If the second #G indicator lamp 3G+4 is lit, unburned fuel flows into the three-way catalyst 11 due to a failure of the injector 4G in the G cylinder of the engine 1 or a failure of the ignition system, resulting in catalyst overheating. Show what you are doing.

If the common display lamp 39 lights up, the injector 41
This indicates that the three-way catalyst 11 is overheating due to a chemical reaction occurring due to a failure in any of the items 44 to 44 or a failure in the ignition system.

When all the indicator lamps 31 to 39 are off, it indicates that the engine is operating normally.

FIG. 33 shows the configuration of the engine section according to the 13th embodiment of the present invention, FIG. 34 shows the internal configuration of the control word W17 etc. in FIG. 33, and FIGS. 25 and 26 of the 11th embodiment The difference from 1. There are four indicator lamps 30A, 30BL, 3 instead of the second indicator lamps 30A, 30B.
0 A++, 30 B□ and ROM20
The control program stored in 6 has been changed as shown in FIG. The general operation of the engine section shown in FIGS. 33 and 34 is self-evident from the 11th embodiment, so the explanation thereof will be omitted.

In FIG. 35, the same process as in FIG. 27, step 3
01. Step 303B and steps 304 to 309 are performed to determine whether or not the operating conditions of the engine 1 continue to be within the first engine abnormality determination zone ZA for a period of time equivalent to the first predetermined value TMAO. If so, step 30
9, the exhaust temperature value T obtained from the exhaust temperature sensor 9 in step 303B! A is the first judgment threshold T1 for misfire judgment
Determine whether or not the value is greater than or equal to the value. If TEA<T, and less than that, there is a misfire, so the indicator lamp 30A is turned on in step 601, and if TEA≧TI, there is no misfire, so the indicator lamp 30AL is turned off in step 602. In the next step 603, the exhaust gas temperature value TEA is determined during the second determination period [T
It is determined whether or not the value is less than or equal to z (used for determining over-retard angle and has already been defined in the explanation of FIG. 16 of the sixth embodiment). TEa>Tz, and if it is not less than that, it is abnormal combustion due to over-retardation, so step 60
In step 4, the indicator lamp 30AH is turned on, and if TEA≦T, there is no abnormal combustion, so the indicator lamp 30A8 is turned off in step 605. Next, the same process as in FIG. 27, steps 312 to 315, are performed to determine whether the operating conditions have continued within the engine abnormality determination zone Za for a time equal to or longer than the second predetermined value TMB0, and whether or not the operating conditions have continued within the engine abnormality determination zone Za. If so, in step 610, the catalyst exhaust temperature value Trs obtained from the output of the catalyst exhaust temperature sensor 18 in step 303B becomes the fourth
It is determined whether the determination threshold is lower than 4 or more. This fourth determination threshold T is a temperature between a relatively low catalyst exhaust temperature when fuel is not supplied to the engine 1 due to a fuel system failure and a relatively high catalyst exhaust temperature under normal conditions. It is set to a value obtained by digitizing the output equivalent of the corresponding catalyst exhaust temperature sensor 18. T
If Il≧T4, the display lamp 30BL is turned off in step 612. In the next step 613, it is determined whether the catalyst exhaust gas temperature value T read in step 303B is equal to or less than a fifth determination threshold T, which is greater than the fourth determination threshold T4. This fifth judgment threshold T is calculated based on a relatively low catalyst exhaust temperature under normal conditions, abnormal combustion due to excessive retardation, excessive supply of fuel due to fuel system abnormality, and ignition system when the fuel system is normal. It is set to a value obtained by digitizing the output of the catalyst exhaust temperature sensor 18 corresponding to a temperature between the comparatively high catalyst exhaust temperature when the three-way catalyst 11 is abnormally overheated due to a misfire due to a failure, etc.

T! If lI>T, that is, the catalyst exhaust temperature (J T If the determination threshold T is below,
In step 615, the display lamp 30B is turned off.

In steps 314 and 315, TMB<TMB,
If it is determined that this is the case, the process proceeds to the next step (not shown) after processing either step 614 or step 615.

As described above, the four indicator lamps 30AL30BL,
30AM and 308M are turned on and off to identify and display the status of the engine l. This display state is shown in the table below.

Table 1 FIG. 36 shows the configuration of the engine section according to the fourteenth embodiment of the present invention, FIG. 37 shows the internal configuration of the control device 17 etc. in FIG. 36, and FIG. 30 of the twelfth embodiment, The difference from FIG. 31 is that instead of four indicator lamps, there are first #1 indicator lamps 30A and L to first #4 indicator lamps 3 for each cylinder.
0AI4L and second #1 indicator lamp 30A for each cylinder
IIM~second #4 indicator lamp 30A#a□ and indicator lamp 30B130BM, a total of 10 indicator lamps, are connected to the output ink face circuit 104 of the control device 17 so that they can be controlled individually; The point is that the flowchart shown in FIG. 38 is made into a control program and stored in the ROM 206. In addition, the same or equivalent parts as in FIGS.
．． 10 to 17, 100 to 106, and 200 to 208, and their explanations will be omitted. The general engine operation shown in FIGS. 36 and 37 is as follows. 11th. Since this is obvious from the twelfth embodiment, its explanation will be omitted.

In FIG. 38, first, in step 301, rotation speed data N and Il representing the engine rotation speed N4 are calculated. In step 303C, #1 to #4 exhaust temperature sensor 91
- 94 are sequentially A/D converted to read the first to fourth exhaust temperature values TEAl-TEA4 sequentially, and the output of the catalyst exhaust temperature sensor 18 is further A/D converted to obtain the catalyst exhaust temperature value T. ,
Load. In step 304, the intake manifold pressure value P is read from the pressure sensor 6. In steps 305 to 308, rotation speed data N is obtained. Based on the and intake manifold pressure value PD, it is determined whether the operating condition of the engine 1 continues to be within the first engine abnormality determination zone ZA for a time equal to or longer than TMA according to the timer value, and if it continues, step At step 710, if the process is not continued, the process jumps to step 312, which will be described later.

In steps 7GO to 7G5 (G takes integer values from 1 to 4 in order), the following processing is performed.

In step 7GO, it is determined whether the G-th exhaust temperature value T WAG obtained from the #G exhaust temperature sensor 9G in step 303C is equal to or greater than the first determination threshold T1 for misfire determination. If not, the G cylinder misfires, so the first #G indicator lamp 3OA#ct is turned on in step 7G1, and if it is the above, the G cylinder does not misfire, so the first #G indicator lamp is turned on in step 7G2. Turn off 30A#GL. In the next step 7G3, it is determined whether the G-th exhaust gas temperature value T WAC is less than or equal to the second determination threshold T8 for determining excessive retardation.

If it is not below, the G cylinder is over-retarded, so step 7G4
2nd #G indicator lamp 30A signal. If it is below, it means that the G cylinder is not overly retarded, and the second #G indicator lamp 30As+,o is turned off in step 7G5.

As described above, steps 710 to 715 when G=1, steps 720 to 725 when G=2, and G
Steps 730 to 735 in the case of G=3 and steps 740 to 745 in the case of G=4 are completed in order. As a result, the first #1 to first #4 indicator lamps 30A
a1L ~ 30 A, 14L, 2nd #1 ~ 2nd #4
Indicator lamp 30A cloudy 1M ~ 30A Iwa, 8 lights up individually,
The light goes off.

After resetting the first timer value TMA in step 307, TMA < TMA in step 308.

After determining that, the process advances to step 312 either after the process of step 744 or after the process of step 745. In step 312, the rotation speed data Nl and the intake manifold pressure MP
Based on ゎ, it is determined whether or not the engine is within the second engine abnormality determination zone Z.

If it is outside zone Z8, the second timer value TMB is reset to 0 in step 314, and the second timer value TMB is reset to 0.

If it is within the range, the second timer value TMB is read in step 313. In the next step knob 315, the second timer value T
It is determined whether MB is greater than or equal to a second predetermined value TMB0. If the above is the case, the process proceeds to step 610, and the catalyst exhaust temperature value T obtained in step 303C! It is determined whether Il is equal to or less than a fourth determination threshold value T4 for determining the presence or absence of fuel supply. If it is below, there is no fuel supply, so in step 611 the display lamp 30
BL is turned on, and if it is not less than that, fuel is being supplied, so in step 7 612, the indicator lamp 30BL is turned off.

In the next step 613, the catalyst exhaust temperature value T! It is determined whether II is equal to or less than a fifth determination threshold T for determining abnormal catalyst overheating. If it is not below, the catalyst is abnormally overheated, so step 6
In step 14, the indicator lamp 30BM is turned on, and if it is less than that, the catalyst is not abnormally overheated, so in step 615, the indicator lamp 30BN is turned off. Step 314, Step 31
After the negative determination in step 5 and either step 614 or step 615 are processed, the process moves to the next step.

In the case of this 14th embodiment as well, the engine condition for each cylinder can be identified from Table 1 above.

In addition, in the above-mentioned 11th to 14th embodiments, if a plurality of catalysts are provided for each bank or cylinder group, if a catalyst exhaust temperature sensor is also installed for each of the catalysts, more accurate judgment can be achieved. becomes possible.

Further, in the eleventh to fourteenth embodiments, the count-up operation of the first timer value TMA and the second timer value TMB was not described, but for example, the count-up operation of the first timer value TMA and the second timer value TMB is performed every predetermined time or every predetermined number of processes. A soft timer operation may be used to count and amplify the clock pulses, or a hardware counter may be used to count clock pulses obtained by dividing the clock pulses in the microcomputer. It goes without saying that the flowchart shown in the figure may be processed as an interrupt processing routine every predetermined number of revolutions of the engine, every predetermined number of steps, or every predetermined time, or as a part of the flow of the main routine.

In the above twelfth to fourteenth embodiments, the first and second
The engine abnormality determination zones ZA and Zl+ may be the same as those shown in Figs. 28 and 29, and
In the embodiments to the fourteenth embodiment, in order to simplify the processing, the first. The second engine abnormality determination zones Zs and Z* may be in the same region.

Furthermore, in order to simplify the process, the I-th and second timer values T
MA, TMB and 1st. The first and second predetermined values TMAo and TMBo for the second timer may be set to the same value.

Furthermore, in the 11th to 14th embodiments, the engine abnormality determination zone was defined by the engine speed and the intake manifold pressure P, but instead of the intake manifold pressure P, the intake air amount and the intake air amount were determined by the cylinder volume. Filling efficiency divided by,
It may be specified by the output frequency of the Karman air flow sensor, the opening degree of the throttle valve, etc. In this case, an intake air amount sensor, a throttle opening degree sensor, etc. are required instead of the pressure sensor. Also, one of these engine parameters may be used alone or in other combinations. In addition, as the engine abnormality determination zone, a condition may be added that the coolant temperature is at least a predetermined value or after a predetermined time after the engine is started.

Furthermore, in the eleventh to fourteenth embodiments described above, the exhaust gas temperature value TEA or TEAL~T! A catalyst exhaust temperature value T! I
is obtained for each detection, but the exhaust temperature is calculated by adding the currently detected exhaust temperature value or catalyst exhaust temperature value to the value detected one or more consecutive times before this time, and averaging the total. It may be used as a value or a catalyst exhaust temperature value.

Furthermore, in the eleventh to fourteenth embodiments, the indicator lamp may be turned on when the same engine abnormality determination continues for a predetermined period of time or a predetermined number of steps and is determined to be abnormal.

In the first to fourteenth embodiments described above, if it is determined that the engine is abnormal, the fuel supply may be cut, and if each cylinder can be identified, the fuel supply to the cylinder in which the abnormality has been detected may be cut. In this case, the operation can be continued. In addition, the driver can take measures by observing the lighting status of the indicator lamp. For example, if the catalyst is abnormally overheated due to a reaction between the fuel and the catalyst, stop the engine and prevent further damage to the catalyst. Can prevent chemical reactions.

Furthermore, in the 11th to 14th embodiments, the catalyst exhaust temperature sensor was installed in the catalyst, but it was installed in the exhaust passage downstream of the catalyst to detect the temperature of the exhaust gas that passed through the catalyst. It's okay.

In addition, in the eleventh to fourteenth embodiments, the first. Second judgment threshold T
,,'rx are not fixed values, but are respectively set to the intake air temperature value T or the cooling water temperature value T1. The first . Second determination threshold f I (TA), r
, (TA) or f , (T, ), f z (Tw) (or, in the first to fourteenth embodiments, any of the engine load, intake air amount, rotation speed, etc.) Select the engine parameters and set the function, for example, f I (T A + T I + l + N to, P
ゎ) It is good to decide a threshold value such as f z (Ta, Tw, Nzn, P,).

The above function may be used for the third to fifth determination thresholds.

Further, in the eleventh to fourteenth embodiments, the catalyst exhaust temperature sensor detects the temperature of the exhaust gas passing through the catalyst, but instead of this, the catalyst exhaust temperature sensor detects the temperature of the catalyst itself. It goes without saying that the temperature value TEN may be obtained and processed in the same manner as in the above embodiment.

Further, in the above embodiment, the engine rotation speed is calculated using the change in the signal from the igniter, but the engine rotation speed may be calculated using the signal from the crank angle sensor.

Further, in each of the embodiments described above, an exhaust gas temperature sensor and/or a catalyst exhaust temperature sensor may be arranged for each cylinder group to detect abnormalities in the engine for each cylinder group.

〔Effect of the invention〕

As described above, according to the present invention, in a predetermined operating range of the engine, the presence or absence of an abnormality in the engine is determined based on the magnitude relationship between the temperature of the exhaust passage upstream of the exhaust purification device and a predetermined value, or the magnitude relationship In addition to (1), the presence or absence of a plurality of abnormalities in the engine is determined based on the magnitude relationship between the temperature of the exhaust gas inside or passing through the exhaust gas purification device and other predetermined values, so according to the former It is possible to accurately measure the temperature of exhaust gas regardless of the chemical reaction with unburned fuel caused by the exhaust purification device, and it is possible to accurately determine failures such as misfires due to ignition system failures and fuel cant conditions due to fuel system failures. Furthermore, since the response of failure determination is quick, countermeasures can be taken before the exhaust purification device becomes unusable due to a chemical reaction with unburned fuel, and the exhaust purification device can be protected from damage. According to the latter, at least two of the following are possible: misfire due to fuel supply cut due to fuel system failure, misfire due to excessive fuel supply due to ignition system failure or fuel supply system failure, and delayed ignition due to ignition system failure. Failure can be determined in a way that can be identified separately and accurately. Furthermore, since abnormalities can be identified, countermeasures can be taken before the exhaust gas purification device becomes unusable, and the exhaust gas purification device can be protected from damage.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of an engine section according to a first embodiment of the present invention, FIG. 2 is a diagram showing the internal configuration of a control device etc. in FIG. 1, and FIG. 3 is a diagram showing a control device according to the first embodiment. FIG. 4 is a flow diagram showing the operation of the engine abnormality determination zone according to the first embodiment. FIG. 5 is a diagram showing temporal changes in the temperature conversion value of the exhaust temperature sensor output according to the first embodiment. 6 is a flow diagram showing the operation of the control device according to the second embodiment, and FIG.
The figure is a diagram showing the relationship between intake air temperature and detected temperature according to the second embodiment, FIG. 8 is a flow diagram showing the operation of the control device according to the third embodiment, and FIG. 9 is a diagram showing the cooling water temperature and detection according to the third embodiment. FIG. 10 is a flowchart showing the operation of the control device according to the fourth embodiment. FIG. 11 is a diagram showing the temperature conversion value of the determination threshold for engine speed and intake manifold pressure according to the fourth embodiment. 12 is a diagram showing the configuration of the engine section according to the fifth embodiment, and FIG. 13 is a diagram showing the configuration of the engine section according to the fifth embodiment.
FIG. 14 is a flowchart showing the operation of the control device according to the fifth embodiment; FIG. 15 is a diagram showing the configuration of the control device according to the sixth embodiment; FIG. 16 , 1st
Figure 7 is the 6th. Flowcharts showing each operation of the control device according to the seventh embodiment, FIG. 18 is a diagram showing the relationship between intake air temperature and detected temperature according to the seventh embodiment, and FIG. 19 is the operation of the control device according to the eighth embodiment. FIG. 20 is a flow diagram showing the relationship between the cooling water temperature and detected temperature according to the eighth embodiment, and FIG. 21 is a flow diagram showing the relationship between the cooling water temperature and the detected temperature according to the ninth embodiment. Diagram showing the operation of the I device, No. 22
The figure shows the temperature conversion value of the determination threshold corresponding to the engine speed and intake manifold pressure according to the ninth embodiment, and FIG. 23 shows the control I! according to the tenth embodiment. ii; FIG. 24 is a diagram showing the operation of the control device according to the 10th embodiment; FIGS. 25 to 27 are diagrams showing the structure of the engine section, the control device, etc. according to the 11th embodiment; , FIG. 28 and FIG. 29 are diagrams showing the operation of the first embodiment according to the eleventh embodiment.
゜ Diagram showing each of the second engine abnormality determination zones, No. 30
Figures 32 to 32 are diagrams each showing the configuration of the engine section, the configuration of the control device, etc., and their operations according to the 12th embodiment, and Figure 33
Figures 35 to 35 are diagrams showing the configuration of the engine section, the configuration of the control device, etc., and their operations according to the 13th embodiment, respectively.
38 are diagrams showing the configuration of the engine section, the configuration of the control device, etc., and their operations according to the fourteenth embodiment. In the figure, 1...engine, 23...intake manifold, 4...injector, 41-44...#1
~#4 Injector, 5... Throttle valve, 6...
Pressure sensor, 7... Cooling water temperature sensor, 8... Exhaust manifold, 9... Exhaust temperature sensor, 91-9
4...#1 to #4 exhaust temperature sensor, work 0...intake temperature sensor, ]l...three-way catalyst, 12...ignition coil, 1
3...Ignita, 15...Bakhteri, 17...
Control device, 18... Catalyst exhaust temperature sensor, 100...
microcomputer. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (2)

[Claims] (1) Exhaust temperature detection means installed in the exhaust passage upstream of the exhaust purification device that purifies engine exhaust gas and detects the temperature of exhaust gas, and various parameter detection means for detecting the operating state of the engine. , an abnormality detection region determining means for determining that the engine operating state is in a predetermined operating region within the engine operating region in which the exhaust gas temperature should rise to a certain predetermined value, and in the predetermined operating region, An engine failure diagnosis device comprising engine abnormality determining means for determining whether or not there is an abnormality in the engine based on the magnitude relationship between the exhaust temperature detected by the exhaust temperature detecting means and a predetermined value. (2) A first temperature detection means installed in the exhaust passage upstream of the exhaust purification device that purifies engine exhaust gas and detects the temperature of the exhaust gas; a second temperature detection means installed in the exhaust passage to detect the temperature of the exhaust gas that has passed through or within the exhaust purification device; a detection means for various parameters for detecting the operating state of the engine; an abnormality detection region determining means for determining that the engine operating state is in a predetermined operating region of the engine operating region in which the temperature and the temperature of the exhaust purification device should have risen to a predetermined value; and the predetermined operating region. , the magnitude relationship between the exhaust gas temperature detected by the first temperature detection means and the predetermined value, and the temperature of the exhaust gas purification device detected by the second temperature detection means or the exhaust gas that has passed through the exhaust gas purification device. An engine failure diagnosis device comprising engine abnormality determining means for determining the presence or absence of each of a plurality of abnormalities in the engine based on the magnitude relationship between the gas temperature and the above predetermined value and another predetermined value.