JPH0532574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electronically controlled fuel injection device.

<<Background of the Invention>> In this type of device, the fuel injection amount is determined based on the intake air amount of the internal combustion engine, but if the detector that detects the intake air amount fails, the internal combustion engine This may cause the inconvenience that the system may malfunction or become inoperable.

Therefore, in the past, diagnosis has been performed on a detector that detects the intake air amount of an internal combustion engine, and when diagnosing an abnormality, the fuel injection amount for the internal combustion engine is determined based on an amount in place of the intake air amount of the internal combustion engine. It was getting worse.

Regarding this device, Japanese Patent Application Laid-Open No. 148925 has been proposed. In this proposal, the intake air amount is estimated from the detected amount of internal combustion engine operating state other than the intake air amount, and based on the estimated intake air amount, fuel is supplied to the internal combustion engine. The amount of injection is required.

However, in this conventional device, the amount of air actually taken into the internal combustion engine and the estimated amount of intake air do not exactly match, so when the intake air amount detector is operating normally, Similarly, there was the inconvenience that the internal combustion engine could not be operated.

[Object of the Invention] The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to enable an internal combustion engine to operate even when the intake air amount detection system is operating abnormally in the same way as when it is operating normally. An object of the present invention is to provide an electronically controlled fuel injection device.

<<Summary of the Invention>> In order to achieve the above object, the present invention learns in advance the correspondence between the detected intake air amount and other internal combustion engine operating state detected amounts during normal operation of the intake air amount detection system, and calculates the intake air amount. A feature of the present invention is that when the detection system malfunctions, the fuel injection amount for the internal combustion engine is determined based on the intake air amount estimated using the learned data.

For this reason, the device according to the present invention is configured as shown in the diagram corresponding to the claims shown in FIG.
a group of internal combustion engine operating state quantity detectors c including; a diagnostic means d for diagnosing an abnormality of the intake air amount detector a; and an engine rotational speed other than the intake air amount when the intake air amount detector a is in normal operation; The intake air amount is estimated from a detected state quantity including a predetermined calculated characteristic, and the calculated characteristic is corrected by comparing the intake air amount detected by the intake air detector a with the estimated intake air amount. Calculation characteristics correction means e; an intake air amount detector for estimating the intake air amount from detected state quantities excluding the intake air amount and including the engine speed, using the corrected calculation characteristics when the intake air amount detector a operates abnormally; Air amount estimating means f; When the intake air amount detector a is in normal operation, the amount of fuel to be injected into the internal combustion engine is calculated based on the amount of intake air detected by the intake air detecting means, while when the intake air amount detector a is in abnormal operation, the amount of fuel to be injected into the internal combustion engine is calculated. The fuel injection amount calculation means g calculates the fuel injection amount for the internal combustion engine based on the estimated intake air amount estimated by the means f;

<<Embodiments of the Invention>> Preferred embodiments of the apparatus according to the present invention will be described below based on the drawings.

In FIG. 2, gasoline from a fuel tank 10 is sucked by a pump 12, and the pulsations of the pumped gasoline are suppressed by a damper 14 and supplied to an injector 18 via a filter 16.

Note that the pressure of gasoline supplied to the injector 18 is kept constant by a regulator 20.

As described above, gasoline at a constant pressure is applied to the injector 18, and by controlling the opening period, the injector 18 can inject gasoline in an amount corresponding to the opening period into the cylinders of the engine 22.

As shown in FIG. 3, air is taken into each cylinder of this engine 22 via an intake manifold 24.

An air flow meter 28 is provided downstream of the air filter 26, and this air flow meter 28 detects the intake air amount of the engine 22.

Although a flap type air flow meter is used as the air flow meter 28, a hot wire type or Karman vortex type can also be used.

Further, the suction pressure of the intake manifold 24 is detected by a pressure sensor 30, and this is displayed by a meter 32.

The air-fuel mixture obtained by the air intake system shown in FIG. 3 and the fuel supply system shown in FIG. 2 is ignited in the cylinder of the engine 22 by the ignition timing control device shown in FIG.

In FIG. 4, the operating state quantities (engine speed, intake air amount, throttle switch signal) related to the engine 22 detected by the engine rotation detector 34, air flow meter 28, throttle switch 36 are detected by the ignition controller 38. is supplied to.

This ignition controller 38 includes a CPU 40, a RAM 42,
ROM 44 and input/output interface 46
The operating state detection amount is taken in via the input/output interface 46.

And using them, engine 2 with CPU40
The ignition timing of 2 is also determined, and a drive signal is given from the input/output interface 46 to the transistor 48 in accordance with this.

By driving this transistor 48, an ignition voltage is generated in an ignition coil 50, and the voltage is distributed from a distributor 52 to a spark plug 54.

The air-fuel ratio of the air-fuel mixture in the cylinder of the engine 22, which is ignited by the ignition timing control device described above, is controlled by the electronically controlled electronic fuel injection device shown in FIG.

In this device, the operating state quantity of the engine 22 is detected by a group of operating state quantity detectors, and in FIG. It includes a switch 36, a water temperature detector 56, an exhaust sensor 58, a starter motor switch 60, and a battery voltage detector 62.

These detected state quantities are given to the injection amount controller 66.

This injection amount controller 66 is connected to the input interface 6
8, a CPU 70, a RAM 72, a ROM 74, and an output interface 76, and each detected state quantity is taken into the injection amount controller 66 from an input interface 68.

The injection amount controller 66 determines the basic injection amount (injection time) of gasoline to the engine 22 from the intake air amount of the engine 22 detected by the air flow meter 28, and corrects the injection amount using other detected operating state amounts. It is possible to obtain the final injection amount (injection time) by doing so.

A control command corresponding to this injection amount is supplied to an injector driver 78, and the injector 18 is controlled to open only for a period corresponding to the control command.

Here, the injection amount controller 66 is the air flow meter 28.
By monitoring the detected intake air amount, it is possible to diagnose an abnormality in the intake air amount detection system of the engine 22 including the air flow meter 28.
At the time of abnormality diagnosis, the abnormality display 80 displays the fact.

The injection amount controller 66 also controls the intake air amount detected during normal operation of the intake air amount detection system, the engine rotation speed detected by the engine rotation detector 34, and other detected state quantities such as the throttle switch 36 and the water temperature detector 56. You can learn the correspondence relationship between

Further, the injection amount controller 66 can estimate the intake air amount of the engine 22 from the learning result using the detected state quantity from which the detected intake air amount is removed when the intake air amount detection system malfunctions.

The injection amount controller 66 can select the estimated intake air amount according to the abnormality diagnosis result, and can determine the basic fuel injection amount for the engine 22 based on the estimated intake air amount.

Note that when the intake air amount detection system is repaired and the starter motor switch 60 or reset switch 82 is activated, the abnormality diagnosis state is canceled.

Next, the operation of the electronically controlled fuel injection system shown in FIG. 5 will be explained according to the flowchart.

FIG. 6 shows an outline of the operation. First, abnormality diagnosis processing for the intake air amount detection system is performed (step 200).

FIG. 7 shows the above abnormality diagnosis process,
First, the operation of the starter motor switch 60 and reset switch 82 is confirmed (step 102,
104).

If these operations are confirmed at that time, an abnormality flag indicating an abnormality in the intake air amount detection system is reset (step 106), but if they are not operating, the intake air amount detected by the air flow meter 28 is within a predetermined range. It is determined whether it is within the range (steps 108, 110).

When this determination processing section (steps 108, 110) diagnoses the system as normal, an abnormality flag reset process (step 106) is performed, but when the system is diagnosed as abnormal, the abnormality flag is set and This fact is displayed by the abnormality indicator 80 shown in FIG. 5 (step 112).

As described above, when the intake air amount detection system is diagnosed as normal, the abnormality flag is reset, and when it is diagnosed as abnormal, the abnormality flag is set and a message to that effect is displayed. .

It should be noted that possible reasons why the intake air amount detected by the air flow meter 28 exceeds the set range and an abnormality diagnosis is performed include a failure of the air flow meter 28 and the input interface 68, and a disconnection or short circuit of the signal path between them.

After the above abnormality diagnosis process (step 200) is performed, it is determined whether the intake air amount detection system is normal or abnormal by referring to the abnormality flag in FIG. 6 (step 300).

At this time, if it is determined that the intake air amount detection system is normal, the learning process (step
400) is started.

In this learning process in FIG. 8, the detected state quantities (engine speed, water temperature, throttle switch) from which the detected intake air amount is removed by the air flow meter 28 are first taken in, and from these, the engine 22
The amount of intake air is estimated using predetermined calculation characteristics (Steps 302, 304).

Then, the intake air amount detected by the air flow meter 28 is taken in (step 306), and from now on the engine 22
The actual intake air amount is calculated (step 308).

Furthermore, by comparing the estimated intake air amount and the calculated actual intake air amount, the calculated characteristics for estimating the intake air amount are corrected (step 310), and the corrected calculated characteristics are used as the previously calculated characteristics. Instead, a new one is set (step 312).

In this embodiment, the calculated characteristics are registered on a table in the form of a map.

As described above, the learning process (step 400) is performed when the intake air amount detection system is normally diagnosed, but when the system is abnormally diagnosed, the intake air amount estimation process (step 500) is performed as shown in FIG.

The contents of the process are shown in FIG. 9. First, the detected operating state quantities excluding the intake air amount detected by the air flow meter 28 are taken in (step 502).

Then, the learned calculation characteristic for estimating the intake air amount is set (step 504), and the intake air amount of the engine 22 with this calculation characteristic is estimated using the various detected driving state quantities that have been taken in at the end (step 504).
506).

This intake air amount estimation process (step 500) or the learning process (step 400)
Once the intake air amount of 2 is determined, the basic fuel injection amount (that is, the basic injection time) is determined using the intake air amount as shown in FIG. 6 (step 600).

FIG. 10 shows the contents of this process (step 600). First, by referring to the abnormality flag, it is determined whether the intake air amount detection system of the engine 22 is normal or abnormal (step 602).

At this time, when it is determined that the intake air amount detection system is operating normally, the actual intake air amount calculated in step 308 is set (step
604), and when it is determined that there is an abnormality, the intake air amount estimated in step 506 is set (step 606).

Next, the engine speed is set by the engine speed detector 34 in FIG. 5 (step 608), and the basic fuel injection amount (basic fuel injection time) is determined from the set actual intake air amount or designated intake air amount and this engine speed. ) is calculated (step 610).

In this manner, the detected intake air amount or the estimated intake air amount is selected according to the diagnosis result of the intake air amount detection system to determine the basic fuel injection amount.

Once this basic fuel injection amount is determined, the actual fuel injection amount is determined from the basic fuel injection amount in FIG. 6 (step 700).

The processing content of this process (step 700) is the 11th
As shown in the figure, first, a water temperature increase correction value T _W is determined based on the cooling water temperature detected by the water temperature detector 56 (step 702).

Then, based on the cooling water temperature and the switch signal of the starter motor switch 60, etc., a starting fuel increase correction value K _AS is determined (step 704), and an acceleration fuel increase correction value K is determined based on the cooling water temperature and the switch signal of the throttle switch 36, etc. _AI is required fuel loss value
K _FC is determined (step 708).

Furthermore _, the value obtained by adding the above values T _W , K _AS , K _{AI .} (Step 712), and a battery voltage correction value T _S is determined (Step 714). Note that the correction factor α is based on the amount of oxygen in the exhaust gas detected by the exhaust sensor 58, and the value T _S is based on the battery voltage detector 62.
It is determined based on the battery voltage detected at .

Next, the fuel injection time T _E is determined using the values α, C _0EF and the basic fuel injection time Tp determined in step 610 (step 716).

Finally, the value T _S of step 714 is added to the fuel injection time T _E to determine the fuel injection time Ti during which the injector 18 is actually opened and controlled (step 714).
718).

As explained above, according to this embodiment, when the intake air amount detection system is operating normally, its calculated characteristics are learned, and when it is abnormally operating, the calculated characteristics obtained by the learning are used to estimate the actual fuel injection time. Therefore, even if an abnormality occurs in the intake air amount detection system, the engine 2 will be operated in almost the same condition as when it is operating normally.
2 operation becomes possible.

Therefore, it is possible to easily drive the vehicle to a repair shop with the engine operating feeling similar to that under normal operation.

<<Effects of the Invention>> As explained above, according to the present invention, the estimated intake air amount calculation characteristics are learned during normal operation of the internal combustion engine, and during abnormal operation, the intake air amount is estimated according to the characteristics, and the estimated intake air amount is Since the fuel injection amount between the internal combustion engines is determined based on the air amount, it is possible to determine the estimated intake air amount that exactly matches the fuel injection amount required by the internal combustion engine, and therefore, the intake air amount can be detected in the event of abnormal operation. It becomes possible to operate the internal combustion engine in the same way as when the system is operating normally.

[Brief explanation of the drawing]

Figure 1 is a complaint response diagram, Figure 2 is an explanatory diagram of the configuration of the fuel supply system, Figure 3 is an explanatory diagram of the configuration of the air intake system, Figure 4 is an explanatory diagram of the configuration of the ignition timing control device, and Figure 5 is an explanatory diagram of the configuration of the electronic Explanatory diagram of the configuration of the controlled fuel injection device, Fig. 6, Fig. 7, Fig. 8, Fig. 9, Fig. 10, Fig. 1
FIG. 1 is a flowchart illustrating the operation of the injection amount controller 66. 18...Injector, 22...Engine, 2
8...Air flow meter, 56...Water temperature detector, 5
8...Exhaust sensor, 60...Starter motor switch, 62...Battery voltage detector, 78...Injector driver.

Claims (1)

[Scope of Claims] 1. A group of internal combustion engine operating state quantity detectors including an intake air amount detector and an engine rotation speed detector; A diagnostic means for diagnosing an abnormality of the intake air amount detector; The intake air amount detection During normal operation of the device, the intake air amount is estimated from the detected state quantities including the engine speed excluding the intake air amount from predetermined calculation characteristics, and
calculated characteristic correction means for correcting the calculated characteristic by comparing the intake air amount detected by the intake air amount detector with the estimated intake air amount; intake air amount estimating means for estimating the intake air amount from detected state quantities including the engine rotational speed excluding the intake air amount using calculated characteristics; The fuel injection amount to the internal combustion engine is calculated based on the intake air amount that is calculated, and the fuel injection amount to the internal combustion engine is calculated based on the estimated intake air amount estimated by the intake air amount estimating means in the case of abnormal operation. An electronically controlled fuel injection device comprising: fuel injection amount calculation means;