JPH03286169A - Engine output controller - Google Patents

Abstract

PURPOSE:To suppress the reduction of the engine output to the utmost by setting the control pattern which is most desirable and available in the control of the rest output varying means on the basis of the preference order when troubles are detected in a part of the output varying means. CONSTITUTION:One surge tank 10 and the other surge tank 11 are connected through the first short communication passage 20 and the second long communication passage 21, and when the first communication passage 20 is opened (S valve 22 is opened), the dynamic effect of intake due to resonance is obtained, and when the second communication passage 21 is opened (A valve 23 is opened), the dynamic effect of the intake due to inertia is obtained. When a part of an output varying means 22 or 23 is broken, the pattern which is most desirable and available under a trouble state is set on the basis of the preference order, and the control for the rest normal output varying means is carried out, and the extreme reduction of the output can be prevented.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to an engine output control device.

(Prior Art and its Problems) Some engine output control devices are known that are capable of varying engine output under the same load, such as variable valve timing or variable intake. There is. Taking variable intake as an example, a passage switching valve is installed in the intake passage, and by opening and closing this passage switching valve depending on the operating condition of the engine, the actual length of the intake passage is changed. It is known that a high engine output can be obtained in the following manner (see Japanese Utility Model Application No. 61-152731). That is, by switching the passage switching valve, the length of the intake passage is determined according to the operating condition of the engine, thereby maximizing the engine's performance in the operating condition. Therefore, if high output is to be exerted over a wider range, a plurality of the passage switching valves described above may be provided to perform fine control.

However, in a device with multiple output variable means such as the above-mentioned passage switching valve, even if one of the output variable means fails, the original output improvement effect will not be obtained, and on the contrary, the output will decrease significantly. This may be the cause of That is, in the case where a plurality of output variable means are arranged, a control pattern that provides the maximum output among these combinations is set, and the output variable means are controlled based on this control pattern. For this reason, failure of some of the output variable means is not limited to the problem that the above control pattern cannot be realized, but in combination with the remaining normal output variable means, depending on the control of this normal output variable means, the engine This may lead to a large drop in output and cause torque shock.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an engine output control device that suppresses a drop in engine output as much as possible by utilizing the remaining normal output variable means when some of the output variable means fail. There is a particular thing.

(Means for Solving the Problems) In order to achieve this technical problem, the present invention includes a plurality of output variable means for varying the engine output generated under the same load, and a plurality of output variable means for varying the engine output generated under the same load. control pattern storage means for prioritizing and storing a plurality of control patterns obtained by combining the output variable means in descending order of the resulting engine output; and an output variable means for some of the plurality of output variable means. and a failure detection means for detecting a failure of the output variable means, and when a failure of the part of the output variable means is detected, a method that can be taken when controlling the remaining output variable means under the failure state of the part of the output variable means. The control pattern setting means sets the most desirable control pattern based on the priority order.

(Function, Effect) With the above configuration, when some of the output variable means fails, the most desirable control pattern that can be taken under this failure condition is set based on the priority, and the remaining normal output is set. Since the variable means is controlled, it is possible to achieve the maximum engine output that can be obtained while preventing an extreme decrease in output. Therefore, it is possible to suppress as much as possible the occurrence of a significant decrease in output due to failure of some of the output variable means and the occurrence of torque shock accompanying this.

(“Example”) Hereinafter, an example of the present invention will be described based on the attached drawings.

In FIG. 2, the symbol 1 is the negative bank of the V-type six-cylinder engine, and 2 is the other bank. Three cylinders 3 to 5 are arranged in series in the negative bank 1, and the other bank 2, three cylinders 6 to 8 are arranged, and the intake stroke of each cylinder 3 to 8 is the same as that of cylinders 3 to 5 and 6, which are present in each bank 1 and 2.
-8 are arranged so that they are not adjacent to each other. That is, the negative bank 1 and the other bank 2 alternately perform the intake stroke.

■ Sandwiched between bank I of - and another bank 2 like this
Two surge tanks 10 and 11 are arranged in the upper region of the bank central space 9, and these surge tanks 1
The upstream side of 0.11 is gathered into a common intake passage 12. Among the surge tanks 10 and 11, the - surge tank 10 is for the - bank 1, and the - surge tank 10 and the cylinders 3 to 5 are connected via independent intake passages 13 to 15, respectively. . In addition, other surge tanks 11 are used for other banks 2, and these other surge tanks 11 and cylinders 6 to 8 are respectively connected to independent intake passages 1.
6 to 18. The surge tank 10 and the other surge tanks 11 are connected by a short first communication passage 20 and a long second communication passage 21, and the first communication passage 20 has a first on-off valve (hereinafter referred to as , S
A second on-off valve (hereinafter referred to as A valve) 23 is provided in the second communication passage 21,
These S valve 22 and A valve 23 are controlled by a control unit (not shown). By providing the first communication passage 20 and the second communication passage 21 as described above, when the first communication passage 20 is opened (S valve 22 is opened), the dynamic effect of intake due to resonance is suppressed. When the second communication passage 21 is opened (the A valve 23 is opened), the dynamic effect of intake due to inertia is obtained. FIG. 3 shows the output characteristics obtained by various combinations of opening and closing of the S valve 22 and opening and closing of the A valve 23.

In the figure, a dotted line 30 indicates a torque curve when the A valve 23 is closed and the S valve 22 is opened. solid line 31
shows a torque curve when both the A valve 23 and the S valve 22 are closed.

A broken line 32 shows a torque curve when the A valve 23 is opened and the S valve 22 is closed. A virtual line 33 shows a torque curve when both the A valve 23 and the S valve 22 are opened. When looking at these torque curves, in the region up to the engine speed Nl, if the generated torque is listed in order from the largest to the smallest, the solid line 31 (valve A closed, valve S closed), the virtual line 33 (A (valve open, valve S open), broken line 32 (valve A open, valve S closed), and dotted line 30 (valve A closed, valve S open). If these are prioritized in descending order of generated torque, the result will be as shown in the first horizontal column of FIG. 1. Similarly, the region of engine rotation speed N1 to N2 and the region of N2 to N3
If the engine speed is divided into a region where the engine speed is higher than N3 and a region where the engine speed is higher than N3, and priorities are assigned in descending order of the generated torque in each region, the result will be as shown in the second horizontal column onwards in FIG.

Based on the above, when both the A valve 23 and the S valve 22 are operating normally, in each area, based on the aspect with the highest priority shown in the first vertical column in FIG. ,
The opening and closing of the A valve 23 and the S valve 22 is controlled.

Therefore, the output characteristic obtained thereby is a curve obtained by connecting the largest torque curves in each region in FIG. 3.

Next, the basic concept of fail control when the A valve 23 or the S valve 22 fails will be explained with reference to FIG. 1.

Now, assume that the A valve 23 is stuck in the closed state (case ■). In this case, in the region up to the engine speed Nl, the A valve 23 can be closed in the first and fourth priority order. Of these, if the S valve 22, which has the first priority, is closed, a larger output will be obtained than if the S valve, which has the fourth priority, is opened. Therefore, in this case, the mode with the first priority is set to prevent a large drop in output. In the next engine speed range N1-N2, the A valve 23 can be closed in the second and fourth priority order.

Among these, if the S valve 22, which has the second priority, is opened, a larger output can be obtained than if the S valve 22, which has the fourth priority, is closed. Therefore, in this case, the second priority mode should be set. Similarly, in the N2 to N3 region, the mode with the third priority is set, and in the next region where the engine speed is higher than N3, the mode with the first priority is set. be. In addition, when the A valve 23 is stuck in the open state (Case II), when the S valve 22 is stuck in the closed state (Case IIT), and when the S valve 22 is stuck in the open state (Case ■). In this case, as in case 1 above, the mode with a higher priority among the possible modes is set to prevent a large drop in output. This is shown in a list in FIG.

In FIG. 4, the parts enclosed by squares are valves that are controlled differently from the normal state.

Based on the above-mentioned premise, an example of control at the time of failure will be explained based on the flowchart shown in FIG.

First, in step S1, after confirming that the throttle valve (not shown) as an output control valve is fully open, in step S2, when the engine speed Ne reaches a predetermined value Ne1 (see Fig. 3) In step S3
It is determined whether the intake air amount Qa is smaller than a predetermined value Qal (see FIG. 3), and if YES, the process advances to step S4, where a fail judgment is made for case ① or case ②. That is, referring to FIG. 3, since there is a region where the predetermined engine rotation speed Nel is smaller than the rotation speed N1, if both the A valve 23 and the S valve 22 are normal, both the A valve 23 and the S valve 22 are closed. It should have been announced (
(See normal control in Figure 4). However, the fact that the intake air amount Qa is smaller than the predetermined value Qal means that in the torque curve shown in FIG. 3, the A valve 23, which shows the torque curve indicated by the dotted line 30, is closed and the S valve 22 is open. This means that the A valve 23 showing the torque curve indicated by the broken line 32 is open and the S valve 22 is closed. Then, A
Is the valve 23 stuck in the open state, or is the S valve 22
Either the valve is stuck in the open state. Therefore, case ■ or case ■ shown in FIG.
By opening both the S valve 3 and the S valve 22, it becomes possible to create a state with a high priority in each case (2) or (2). For this reason, in the next step s5, valve opening signals are output to the A valve 23 and the S valve 22.

In FIG. 5, a fail determination is performed in the region of engine rotational speed Nl - N2 shown in FIG. 3 by going through steps s6 and s7. That is, in step s7, the intake air amount. It is determined whether a is smaller than a predetermined value Qa2 (see FIG. 3), and if YES, step s
Proceeding to step 8, a fail judgment is made for case ■ or case ■. That is, in this region of rotational speed Nl to N2, if both the A valve 23 and the S valve 22 are normal, the A valve 23
should be open, and the S valve 22 should be closed (see normal control in FIG. 4). However, the fact that the intake air amount Qa is smaller than the predetermined value Qal means that in the torque curve shown in FIG. This means that both the A valve 23 and the S valve 22, which show the torque curve of the virtual line 33, are in an open state. If so, either the A valve 23 is stuck in the closed state, or the S valve 22 is stuck in the open state. Therefore, as shown in FIG. 4, if the A valve 23 is closed and the S valve 22 is opened, as has already been decided based on the priority order in case I or case II, ■
It becomes possible to form a state with a high priority.

Therefore, in the next step S9, a valve close signal is output to the A valve 23, and a valve open signal is output to the S valve 22.

Similarly, in FIG. 5, by going through the steps after step SIO, a fail determination is performed in the range of engine rotational speeds N2 to N3 shown in FIG. 3. Here, in step S12, a fail judgment is made between case ■ and case ■ based on the same idea as described above, but in this case, the high priority state in case ■ A valve 23 is closed, S valve 22 is
Open, the A valve 23 open, and the S valve 22 closed, which are high priority states in case (2), are controlled in the opposite way, so fail control is not performed. In other words, normal control 1 (both the A valve 23 and the S valve 22 are open) is set. Furthermore, even if the normal control is left as is, if the A valve 23 is stuck in the closed state, the result will be that the A valve 23 is closed and the S valve 22 is opened. , the output characteristic of the point 1130 shown in FIG.

On the other hand, if the S valve 22 is stuck in the closed state, as a result, the A valve 23 will be open and the S valve 22 will be closed.
The output characteristic is indicated by a broken line 32 shown in FIG. Therefore, in either case, a large drop in output does not appear as in the output characteristics shown by the solid line 31 in FIG.
It can be said that there are no practical inconveniences.

The drawings after FIG. 6 show a second embodiment of the present invention. In this embodiment, in addition to the variable intake (opening/closing control of the S valve 22 and A valve 23) in the first embodiment, variable valve timing is attached to the engine, and the valve timing for low speeds is changed in the low speed range. (Below, if necessary,
In the high-speed range, high-speed valve timing (hereinafter referred to as "H" as necessary) is used. Since the mechanical structure of such a variable valve timing is conventionally known, the explanation thereof will be omitted, and only the features of this embodiment will be explained below.

FIG. 7 shows output characteristics obtained by various combinations of opening/closing of the S valve 22, opening/closing of the A valve 23, and switching of the variable valve timing between [i'HJI and 0'L]. Based on this figure, as in the case of the first embodiment,
If priority is assigned in each region from the largest to the smallest generated torque, the result will be as shown in FIG. 6. After determining the failure of the A valve 23, the failure of the S valve 22, and the failure of the variable valve timing, the control content similar to that shown in FIG. 4 in the first embodiment is applied to each failure mode, taking into account the above priorities. The settings shown in FIGS. 8 to 10 are as follows.

Therefore, if fail control is performed based on the control details shown in FIGS. 8 to 10, it is possible to reduce the drop in engine generated torque.

[Brief explanation of drawings]

Figures 1 to 5 show the first embodiment, Figure 1 is a diagram showing the priority order in fail control of variable intake, Figure 2 is an overall configuration diagram of variable intake, and Figure 3 is A valve. , a diagram showing the engine generated torque obtained by the combination of opening and closing of the S valve, Figure 4 is a diagram that categorizes failure modes and shows the control details in each case, and Figure 5 is an example of fail control that takes the above priorities into consideration. It is a flowchart which shows. Figures 6 to 10 show the second embodiment. Figure 6 is a diagram showing the priority order in fail control between variable intake and variable valve timing, and Figure 7 is a diagram showing the priority order of variable intake and variable valve timing in fail control. FIGS. 8 to 10 are diagrams showing the engine generated torque obtained by the combination. FIG. 11: Other bank use 20: Short communication path 21: Long communication path 22: S valve (opening/closing valve) 23: A valve (opening/closing valve) Tank 1: - Bank 2 in ■ type engine: Others in ■ type engine Surge tank for bank 10 knee bank Fig. 1 Fig. 2

Claims (1)

[Claims] (1) A plurality of output variable means that vary the engine output generated under the same load, and a plurality of control patterns obtained by the combination of the plurality of output variable means, in descending order of the engine output obtained thereby. control pattern storage means for prioritizing and storing; failure detection means for detecting a failure of some of the output variable means among the plurality of output variable means; failure of some of the output variable means has been detected; In some cases, the apparatus further comprises control pattern setting means for setting the most desirable control pattern that can be taken when controlling the remaining output variable means under a failure state of some of the output variable means, based on the priority order. An engine output control device characterized by: