JPS635574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel control device for an automobile engine.

In recent years, there has been an increasing demand for automobile exhaust purification, and fuel control devices have also tended to become more complex. However, since automobiles are products destined for mass production, it is difficult to mass produce fuel control devices using devices that are difficult to adjust.
Additionally, unless the device is easily adjustable during regular inspections (vehicle inspections, etc.), it will be difficult to maintain long-term performance. Therefore, the exhaust performance of used cars may deteriorate, and the air purification effect will be weakened.

In conventional fuel control devices, fuel control parameters are fixed or adjustable to some extent, but the adjustment work is very cumbersome, so there is a risk of variations, deterioration, and changes over time in the engine and other parts. For these reasons, the control performance deteriorates and a predetermined exhaust purification performance cannot be maintained.

SUMMARY OF THE INVENTION An object of the present invention is to provide a fuel control device that eliminates the above-mentioned drawbacks, allows easy performance maintenance, and is suitable for mass production.

In order to achieve the above object, in the present invention,
A sensor that detects the operating state of the engine, an electrically rewritable non-volatile memory, and a functional relationship that takes the signal from the sensor as input and is adapted to each operating state of the engine according to the data in the non-volatile memory. a control means for controlling fuel according to the output of the function generating means; a means for detecting that the engine continues to be in an idling state; means for detecting that the operating state (for example, full throttle) is continued, and detecting and determining the operation result of the control means when the engine is in an idling state and in the above-mentioned predetermined operating state;
means for outputting a rewriting signal for rewriting the data so as to make the operating result in the operating state appropriate, and also make the operating result in other operating states appropriate by inferring from the result; and in response to the rewriting signal. rewriting means for rewriting data in the non-volatile memory, and configured to self-correct the functional relationship of the control system in other operating states by inferring from the idling state and other predetermined operating states. are doing.

Hereinafter, a conventional fuel control device will be explained first, and then the present invention will be explained in detail.

FIG. 1 is a block diagram of an example of a conventional fuel injection control device.

In FIG. 1, an intake pressure sensor 1 generates a voltage proportional to the intake pressure. Next, the feed forward controller 2 is a circuit that calculates an appropriate fuel supply amount from the output of the intake pressure sensor 1.

Generally, an appropriate fuel supply amount is non-linear with respect to the intake pressure, and requires characteristics such as those shown in FIG. 2, for example. Therefore, as the feed forward controller 2, a function generator having characteristics as shown in FIG. 2 can be used. Note that the intake pressure sensor itself may be provided with nonlinearity.

In addition to the intake pressure sensor, a cooling water temperature sensor, an air temperature sensor, etc. may be used for correction calculations, but these are omitted in this example.

Next, the pulse generator 3 generates a pulse having a width corresponding to the output of the feed forward controller 2 in synchronization with the engine rotation. In order to detect engine rotation, a crank angle sensor 4 is used that generates one pulse every time the crankshaft rotates, for example.

The injection valve 5 is then driven by the pulse generated by the pulse generator 3, and injects fuel into the intake manifold in an amount proportional to the pulse width of the pulse.

In the conventional fuel injection control device as described above, the function generator used as the feed forward controller 2 conducts experiments in advance to determine the fuel supply characteristics, and the function is set according to the characteristics. It is extremely difficult to compensate for variations in engines and other parts, or to correct changes in characteristics due to deterioration.

Next, FIG. 3 is also a block diagram of an example of a conventional fuel injection control device.

In the conventional example shown in FIG. 3, in addition to the conventional example shown in FIG. 1, feedback control is performed using an exhaust sensor attached to an exhaust pipe or an exhaust manifold.

As the exhaust sensor, for example, an oxygen sensor that detects the oxygen concentration in exhaust gas is used.

The oxygen sensor detects excess oxygen concentration in exhaust gas, that is, incomplete combustion. As the oxygen sensor, for example, a zirconia oxygen meter having characteristics as shown in FIG. 4 is used.

Using this oxygen sensor, it is possible to determine whether the ratio of air to fuel (hereinafter referred to as air-fuel ratio) is appropriate. Therefore, by correcting the fuel supply amount based on the output signal of this oxygen sensor, it is possible to correct changes in various conditions such as deterioration of parts.

In the conventional example shown in FIG.
The output of the oxygen sensor 6 is corrected by the signal of the oxygen sensor 6.

However, the oxygen sensor only detects the state of exhaust gas after combustion, and there is a considerable time delay between when fuel is supplied and when the result is detected. Therefore, when conditions suddenly change, such as when the load suddenly changes, the control cannot follow up.
Since good control cannot be achieved with feedback control alone, a feedback controller with quick response is also required.

Furthermore, as can be seen from the characteristics shown in FIG. 4, since the operating range of the oxygen sensor is narrow, the control range of the feedback controller cannot be made very large. Therefore, if there are large variations in engine parts, etc., or if there are large changes over time, it may become impossible to perform sufficient control.

The present invention can compensate for the drawbacks of the conventional example as described above.

The present invention will be explained below.

FIG. 5 is a diagram showing an embodiment of the present invention.

In FIG. 5, 8 is a variable function generator serving as a feed forward controller, and 9 is a memory for function generation built in the variable function generator. The memory 9 is rewritable and non-volatile, and may be, for example, a core memory (magnetic memory) or a semiconductor memory. Since such memory is generally a digital element,
The generated functional form is as shown in Figure 6.
It becomes step-like.

Further, 10 is an idling switch that is turned on when the idling state continues for a certain period of time, and 11 is a full throttle switch that is turned on when the full throttle state continues for a certain period of time. Further, as the load sensor, the throttle opening sensor 13 is used instead of the intake pressure sensor, but the intake pressure sensor 1 may be used in the same manner as described above.

Reference numeral 12 denotes a memory rewriting device comprising an on-vehicle digital computer and a writing device.

In addition, in FIG. 5, the same reference numerals as in FIG. 1 indicate the same parts.

The operation of the embodiment shown in FIG. 5 will be explained below.

A memory rewriting device 12 modifies the memory at the address corresponding to the idling state when the idling switch 10 is on, and modifies the memory at the address corresponding to the full throttle state when the full throttle switch 11 is on.

The above correction is made as follows. The memory rewriting device 12 inputs the input and output of the feedback controller 7, that is, the fuel supply amount before and after correction by the feedback control, and detects the difference therebetween, that is, the amount of correction due to the feedback. The memory at the address corresponding to the intake pressure value at that time is rewritten according to the correction amount. In this case, instead of inputting the input and output of the feedback controller 7, the signal of the oxygen sensor 6 may be directly inputted. For example, it is determined whether the amount of fuel supplied is increased or decreased depending on the state of the oxygen sensor 6. In other words, if there is an excess of air, the amount of fuel supplied may be increased, and if there is an insufficient amount of air, the amount of fuel supplied may be decreased. Further, if necessary, the new fuel supply amount may be determined by referring to the current fuel supply amount.

Next, points other than idling and full throttle are corrected by interpolation calculations. For example, in Fig. 7, the value Yi at idling in the old function indicated by the broken line, the value Y at an arbitrary point,
Full throttle value Yf, corrected idling value Yi', corrected full throttle value Yf', point to be calculated by interpolation (point corresponding to Y above)
, the total throttle opening θ ₀ , and the throttle opening θ at the point where the correction calculation should be made, the correction value to be obtained is
Y' can be determined, for example, using the following equation.

Y′=Y+(Y′f−Yf)θ/θ ₀ +(Y′i−Yi)θ ₀ −θ
/θ ₀ By performing such calculations, it is possible to obtain a new curve function that passes through points Yi' and Y'f and is similar to the old function form shown by the broken line. In general, changes in a function due to variations or deterioration of parts are such that the curve as a whole moves up and down or changes in slope, and the shape of the function changes rapidly, that is, a concave function changes to a convex function. Since this is not the case, a new function can be created using simple interpolation calculations as shown above.

In addition, when performing the above adjustment, steady operation must be performed under various operating conditions in order to accurately match the memory rewrite address and operating condition and to stabilize the operation of sensors, etc. in that operating condition. is necessary.

However, while a car is running, it is generally rare to perform steady operation. However, both the idling state and the full throttle state are extreme states, and it often happens that a constant operating state continues. Therefore, as in the embodiment shown in FIG. 5, if the idling state and the full throttle state are detected, the memory is directly corrected for both of the above points, and the other points are corrected by interpolation calculation. Adjustments can be made even during normal driving.

When making adjustments at a factory, service station, etc., steady operation can be performed even in operating states other than the above, so it is necessary to detect that a predetermined operating state other than the above continues.
It may also be configured to perform interpolation calculations in the same manner as above using that point as a reference.

Further, the calculation section of the memory rewriting device 12 may be a digital computer or may be dedicated hardware. Furthermore, since it is expected that a digital computer will be installed in a vehicle for various control purposes in the future, it is also possible to use such a digital computer.

As explained above, according to the present invention, fuel control parameters can be easily corrected to appropriate values. Therefore, when manufacturing the fuel control device, it is possible to roughly set the fuel control parameters, and then test drive the device onboard and make fine adjustments.This also makes it possible to compensate for variations in the engine, sensors, and other parts. is easy and suitable for mass production. In addition, since the memory is directly corrected in the idling state and other predetermined driving states, and other points are corrected by interpolation calculation, it is possible to make adjustments even during normal driving. In addition, since it is possible to easily make re-corrections at any time, it has many effects, such as making it easier to maintain exhaust purification performance.

[Brief explanation of the drawing]

FIG. 1 is an example of a conventional fuel injection control device, FIG. 2 is a diagram showing the relationship between intake pressure and fuel supply amount, and FIG. 3 is an example of a conventional fuel injection control device with a feedback function. FIG. 4 is a characteristic diagram of an example of an oxygen sensor, FIG. 5 is a diagram of an embodiment of the present invention, FIG. 6 is a diagram of an example of characteristics of a variable function generator, and FIG. 7 is an explanatory diagram of an interpolation method. Explanation of symbols 1... Intake pressure sensor, 2... Feed forward controller, 3... Pulse generator, 4
...Crank angle sensor, 5...Injection valve, 6...Oxygen sensor, 7...Feedback controller, 8...Variable function generator, 9...Memory for function generation, 10...Idling switch, 11...Full throttle switch, 12...Memory Rewriting device, 13... Throttle opening sensor.

Claims (1)

[Claims] 1 A sensor that detects the operating state of the engine, an electrically rewritable non-volatile memory, and a function that takes the signal from the sensor as input and is adapted to each operating state of the engine according to the data in the non-volatile memory. a function generating means for transmitting a related output; a control means for controlling fuel according to the output of the function generating means; a means for detecting that the engine continues to be in an idling state; means for detecting that the engine continues to operate in the operating state, and detecting and determining the operation result of the control means when the engine is idling and in the above-mentioned predetermined operating state, and detecting the operation result in the operating state. means for outputting a rewriting signal for rewriting the data so as to make the data appropriate and to infer from the result that the operation results in other operating states are also appropriate; and in response to the rewriting signal, the data in the non-volatile memory A fuel control device for an engine, comprising a rewriting means for rewriting the engine, and self-corrects the functional relationship of the control system in other operating states by inferring from an idling state and other predetermined operating states. .