JPS6329099B2 - - 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 is in a steady operating state; and when the engine is in a steady operating state; means for detecting and determining the operation results of the control means and outputting a rewriting signal for rewriting the values of the data in each operating state so that the operation results in each of the operating states are appropriate; and a rewriting means for rewriting data in the non-volatile memory, and configured to self-judge the operating results during steady engine operation and self-correct the functional relationships of the control system to suit each operating state. There is.

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, intake pressure sensor 1
generates a voltage proportional to the intake pressure. Next, the feed forward controller 2
This is a circuit that calculates the appropriate amount of fuel to be supplied from the output of the 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 a memory is generally a digital element, the generated function form is step-like, as shown in an example in FIG.

Further, 10 is a steady operation detector, and 11 is a memory rewriting device.

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

The operation of the above embodiment will be explained below.

Steady operation detector 10 sends an operation signal to memory rewriting device 11 when the vehicle to be adjusted is in a steady operation state (for example, when a constant intake pressure state continues for a certain period of time or more). This memory rewriting device 11
consists of an on-vehicle digital computer and a writing device.

This memory rewriting device 11 inputs the input and output of the feedback controller 7, that is, the fuel supply amount before and after correction by feedback control, and detects the difference therebetween, that is, how much correction amount there is due to 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. Furthermore, if necessary, the new fuel supply amount may be determined by referring to the current fuel supply amount.

Next, set another intake pressure, perform the same operation as above, and repeat the process to completely rewrite the memory 9 to complete the new function.

Note that the purpose of detecting steady operation and performing adjustment as described above is to accurately match the rewrite address in the memory with the operating state and to stabilize the operation of sensors, etc. in that operating state.

In addition, since it is uneconomical both in terms of time and technology to create a new function by operating under all conditions, only representative points are directly modified, as shown in Figure 7. The work becomes very simple if the other points are calculated using interpolation or extrapolation using linear or multidimensional curves. The above calculation is performed by memory rewriting device 1
This can be easily done using a digital computer. In Fig. 7, the broken line shows the function form before correction, the solid line shows the function form after correction, and A, B,
The three points in C indicate points that were directly corrected.

As described above, in the embodiment shown in FIG. 5, adjustment during automobile production or periodic inspection is very easy, so that exhaust purification performance can be easily maintained and it is also suitable for mass production.

Further, adjustments can be easily made even in locations where no special measurement adjustment device is available. Furthermore, it is possible to compensate for the poor response and narrow control range in the conventional example shown in FIG.

Note that the calculation section of the memory rewriting device 11 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 it is configured to detect and judge the operation results during steady operation,
Judgments can be made accurately. 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 a function correction 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...Function generation memory, 10...Steady operation detector, 11...Memory rewriting device.

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 sending out 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 is in a steady operating state; and a means for detecting when the engine is in a steady operating state. ,
means for detecting and determining the operation result of the control means and outputting a rewriting signal for rewriting the value of the data in each operating state so as to make the operating result in each operating state appropriate; and rewriting means for rewriting the data in the non-volatile memory, and self-judging the operational results during steady engine operation and self-correcting the functional relationships of the control system to suit each operating state. engine fuel control device.