JPS60101238A - Fuel control device in engine - Google Patents

Abstract

PURPOSE:To facilitate the manufacturing of an engine and as well to make it possible to maintain the performance of air-purification, by self-correcting the relationship between functions for a control system with the self-judgement of results of operation upon steady state running of the engine so that the relationship is suitably applied to several engine running conditions. CONSTITUTION:When a steady state running detector 10 detects a steady state running condition, a memory rewrite device 11 receives the amounts of fuel supply before and after compensation by a feed-back control 7, or variations in the amount of fuel in accordance with the output of an oxygen sensor 6, and rewrites the address of a memory 9 in a variable function generator 8 serving as a feed-forward controller, corresponding to the value of intake-air pressure detected by an intake-air pressure sensor 1 at that point in accordance with the compensated amount of fuel. Further, another intake-air pressure is set to carry out a similar operation, repeatedly, so that the content of the memory 9 is rewritten to establish new functions. With this arrangement, fuel control parameters may be compensated to appropriate values.

Description

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

In recent years, the demand for automobile exhaust purification has increased.
Accordingly, fuel control devices also tend to become more complex. However, since automobiles are products destined for mass production,
When producing fuel control devices, it is difficult to mass produce 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 effect of air purification 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, and this reduces the risk of variations, deterioration, and changes over time in the engine and other parts. Therefore, 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 maintenance of performance, and is suitable for mass production.

In order to achieve the above object, the present invention has the following features.

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 data so as to make the operation results appropriate in each of the operating states; The control system is equipped with a rewriting means for rewriting data, and is configured to self-determine the operation results during steady engine operation and self-correct the functional relationships of the control system to suit each operating state.

Below, a conventional fuel control device will first be explained.

Next, 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 feedforward controller 2 is a circuit that calculates an appropriate fuel supply amount from the output of the intake pressure sensor 1. Generally, the 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 feedforward 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 also be used for correction calculations.

It is omitted in this example.

Next, the pulse generator 3 generates a pulse having a width corresponding to the output of the feedforward controller 2 in synchronization with the engine rotation. In order to detect engine rotation, a rank angle sensor 4 is used, which 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 feedforward controller 2 conducts experiments in advance to determine the fuel supply characteristics and sets the function according to those characteristics. It is extremely difficult to compensate for variations in characteristics or 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 addition to the conventional example shown in FIG. 1 described above, the conventional example shown in FIG.
Feedback control is performed using an exhaust sensor attached to the exhaust pipe or 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 the nine parts.

In the conventional example shown in FIG.
The configuration is such that the correction is performed using the signal.

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, control cannot follow sudden changes in conditions such as when the load suddenly changes.

Since feedback control alone cannot provide good control, a feedforward controller with quick response is also required. Furthermore, as can be seen from the characteristics shown in FIG. 4, the operating range of the oxygen sensor is narrow, so 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 feedforward controller, and 9 is a memory for function generation built into the variable function generator. This memory 9 is
It is rewritable and non-volatile.For example, core memory (magnetic memory, semiconductor memory, etc.) is used. Since such memory is generally a digital element, the functional form generated is As an example is shown in Fig. 6, it has a two-step shape.

Further, IO 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 is composed 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, detects the difference between them, that is, the amount of correction by feedback, and 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 input directly. 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 excess air, increase the fuel supply amount.

If it is insufficient, just reduce it. Furthermore, if necessary, the new fuel supply amount may be determined by referring to the current fuel supply amount.

Next, by setting another intake pressure and performing the same operation as above, and repeating the process to rewrite all of the memory 9,
Complete the new function.

The reason why the steady-state operation detector is used as described above is to ensure that the rewritten address in the memory corresponds accurately to the operating state and to stabilize the operation of sensors, etc. in that operating state.

Also, since it is uneconomical both in terms of time and technology to create a new function by running under all conditions, the seventh
As shown in the figure, the work is very simple if you limit the points to be directly corrected to representative points and calculate the other points by interpolation or extrapolation using linear or multidimensional curves. become. The above calculations can be easily performed using a digital computer within the memory rewriting device ll. In Fig. 7, the broken line is the function form before modification.

The solid line indicates the modified function form, and the three points A, B, and C indicate directly modified points.

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. In addition, it is expected that digital computers will be installed in vehicles for various control purposes in the future.

It is also possible to use the 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 while it is mounted on the vehicle and make fine adjustments.This also makes it possible to compensate for variations in the engine, sensors, and other parts, making manufacturing easier. It is suitable for mass production. Also, 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, and FIG. 6 is a diagram of an example of characteristics of a variable function generator.
FIG. 7 is an explanatory diagram of a function modification method. Explanation of symbols 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 1
0...Steady operation detector 11...Memory rewriting device agent Junnosuke NakamuraFigure 1Figure 2To TsutsusaFigure 3Figure 4 Appropriate empty space Toto

Claims (1)

[Claims] A sensor that detects the operating state of the engine, an electrically rewritable non-volatile memory, and a signal from the sensor as input, and each operation of the engine according to the data in the non-volatile memory. A function generating means for sending out a function-related output suitable for a state, and a control means for controlling fuel according to the output of the function generating means. means for detecting that the engine is in steady operation;
means for detecting and determining the operation results of the control means when the engine is in a steady operating state, and outputting a rewriting signal for rewriting the data so as to make the operating results appropriate in each of the operating states; and a rewriting means for rewriting the data in the non-volatile memory in response to a signal, and self-judging the operation results during steady engine operation and self-correcting the functional relationship of the control system to suit each operating state. An engine fuel control device featuring: