JPS62170761A - Exhaust gas recirculating device for engine - Google Patents

Abstract

PURPOSE:To prevent the trouble including the deterioration of EGR system, in the predeterminated engine operating condition, by providing the cause-effect relationship between a operating condition of EGR and an exhaust gas concentra tion, that is, between an EGR control degree and an exhaust sensor signal. CONSTITUTION:In an EGR signal generating means 1 of an arithmetic device 5, an EGR valve 2 is energized with a signal corresponding to EGR quantity determined by the relationship between an engine speed and load ratio in an engine 100, thus the EGR quantity to the engine 100 is set. And, the concentra tion of exhaust gas from the engine 100 is detected by an exhaust sensor 3 and the detected signal T is input a time comparition means 4 so as to be compared with the signal (t) from the EGR signal generating means 1, and if the predetermined relationship comes into non-existence, the subject matter is displayed in a warming means 6. Thus, the EGR mechanism is monitored by effectively utilizing the existent mechanism, thereby it is possible to prevent the trouble including the deterioration of the EGR system.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine exhaust gas recirculation device (hereinafter referred to as an EGR device), and in particular to monitoring the quality of the operational function of the EGR device to prevent exhaust pollution. The present invention relates to an engine EGR device suitable for ensuring safety.

[Conventional technology]

The EC)R device, as shown in Japanese Unexamined Patent Publication No. 52-125979, is a comprehensive control device that combines fuel 9 ignition timing control based on engine operating information such as intake air amount and engine rotation speed. Accurate exhaust gas purification function has been achieved. Of course, there are some systems that are equipped with an independent EGR device, but it has long been known from various documents and publications that these EGR functions are highly effective in reducing NO. However, this effect is only possible if the EGR device is functioning properly; for example, if the EGR pulp, pulp control means, communication pipe, or other functional system fails, the exhaust gas purification performance will be affected. This results in a significant decrease in air pollution, which in turn has a negative impact on air pollution.

[Problems to be Solved by the Invention] However, conventionally known methods monitor the operating state of the EGR pulp using a separate position detection (for example, a lift sensor, a position switch), or a pressure sensor is installed in the communication pipe. All of these require new additional equipment and are expensive, and all of these additional equipment have disadvantages in terms of reliability under high temperatures unique to automobiles. It contained. Furthermore, these systems do not take into account the interconnected monitoring of the functional operation of the EGR device, and there is a problem that can only be detected through processes such as periodic mandatory vehicle inspections.

In view of the above-mentioned problems, an object of the present invention is to effectively utilize existing functions without using new devices to improve EG.
By linking and monitoring functions! 2.An object of the present invention is to provide an engine EGR device that can prevent malfunctions in functional operation including deterioration of the EGR system.

[Means for solving problems]

For the above purpose, since the air-fuel ratio (A/F) becomes leaner as the EGR amount increases, in a predetermined engine operating state, the operating state of the EGR amount and the exhaust gas concentration, that is,
This is achieved by creating a causal relationship between the EGR control amount and the exhaust sensor (for example, 02 sec/s) signal.

[Effect]

In a predetermined state of the engine (for example, slightly richer than the A/F ternary point), when the EGR amount is increased for a desired time, the exhaust gas concentration moves to the lean side for the desired time. As a result, the change time of exhaust gas concentration is E
The GR amount is reflected appropriately in accordance with the energization time.

〔Example〕

An embodiment of the present invention will be described below.

FIG. 2 shows a block diagram of the present invention, in which 1 indicates the EG determined from the relationship between engine speed and load factor.
An EGR signal generating means 2 which performs energization commensurate with the amount of R receives the signal t from the EGR signal generating means 1 and activates the engine 100.
an EGR valve that sets the EGR amount for the GC; 3 an exhaust sensor that detects the concentration of exhaust gas from the engine 100;
4 is a time comparing means for comparing the signal t of the EGR signal generating means 1 and the change signal 'l of the exhaust sensor 3;
It is an arithmetic device incorporating GR signal generation means 1, time comparison means 4, and means for processing information such as the rotational speed of the engine 100 described above. Further, 6 is a warning means, which compares the time of the signal t of the EGR signal generation means 1 and the signal T of the exhaust sensor 3 by the time comparison means 4, and as a result, a predetermined relationship is not established. is configured to display its contents.

Next, the functional operation of the apparatus of the present invention shown in FIG. 2 will be explained with reference to FIGS. 1 and 3. The operation time chart in FIG. 1 shows the BGR operation and the signal states of the exhaust sensors when the engine is in a predetermined operating state. First, the air-fuel ratio of the fuel supplied to the engine is determined at the ternary point (A/F: 14
．． 7), and in this state turn EGR from OFF to ON for a predetermined time t.
, while energizing. That is, when EGRt is operated from low to high, the exhaust gas becomes lean, and the signal from the exhaust sensor moves from rich to light during the T period. Similarly, EGR operation time is 1b
,,1. When the exhaust sensor signal is energized for a period of time, the signal form of the exhaust sensor signal changes to the EGR, T concentration, and Tc corresponding to the energization time, as shown in the figure.

It has been confirmed through experiments that the relationship shown in FIG. 3 can be established between the EGR activation time t and the transition time T of the exhaust sensor signal.

Therefore, the operating function of the EGR system can be understood as a change in the air-fuel ratio of the fuel in the engine, that is, a change in the signal form of the exhaust sensor, and the quality of the EGR function can be confirmed.

FIG. 4 shows an example in which the EGR control device of this system is incorporated into an electronic engine control device. In this Figure 4, 10
0 is an engine, 104 is an intake air amount sensor, and 201 is a distributor that supplies ignition energy to each cylinder of the engine, and is equipped with a rotation angle sensor that detects the rotational speed of the reed engine.

The intake air amount sensor 10 is provided on the upstream side of the engine 100.
4. A throttle valve 105 having an opening sensor 107 and an intake pipe 101 are arranged as shown in the figure, while an air distribution pipe 102 and a muffler 202 are arranged on the downstream side. Furthermore, a fuel injection valve 200 for supplying fuel is installed near the intake pipe 101 of the engine 100.

Furthermore, part of the exhaust gas is transferred to the exhaust pipe 102 through the intake pipe 10.
Exhaust passage 103A for recirculating to 1.

103B is disposed, and an EGR pulp 2 for controlling the amount of recirculation (EGR amount) of exhaust gas is disposed inside this exhaust passage. Further, an exhaust sensor 3 for detecting the combustion state of the engine is attached to a part of the exhaust pipe. Reference numeral 5 denotes an arithmetic unit of the electronic engine control device, which also includes other engine operating state detectors 107 such as the engine rotational speed, intake air amount, throttle valve opening, and temperature.
The fuel amount and ignition timing are calculated and controlled based on input signals from the
GR, quantity and exhaust sensor 3 signal processing are performed and EGR4'
The system is configured so that the operation of the a function is checked and the result is displayed on the warning means 6 (for example, a lamp, etc.).

In the above-described embodiment, the intake air amount is detected as a parameter of the engine operating information, but the pressure of the intake pipe 101 may be used instead.

FIG. 5 is an example of a flowchart of the embodiment shown in FIGS. 1 and 2. Further, this flowchart is shown as an example from among the control flowcharts of the electronic engine control device shown in FIG.

When the engine is started, the arithmetic unit 5 described above is configured to repeatedly execute arithmetic processing at a predetermined cycle according to a predetermined control program, and to control the energization of each device based on the results. (not shown). During this arithmetic processing, when the EG'RJ check mode (for example, at the idle position or during desired steady operation) is reached, the interrupt processing routine of step 200 is entered. Step 20
If the exhaust sensor is not in the active region at 0, step 5
00 and waits for the next interrupt request. On the other hand, when the exhaust sensor is in the active region, the process moves from step 200 to step 201. In step 201, it is determined whether A/F (Q) (air-fuel ratio) feedback is in progress and the EGR control region is in progress. If both are in the EGR control region, the process moves to step 500 and the original control requested by the engine is executed. wait for an interrupt request. If one of the pre-control conditions is not satisfied, the process moves to step 202, increments the EGf'L check counter, moves to step 203, stops the A/lli' feedback control, and moves to step 204. In step 204, the A/F is adjusted by a predetermined value α from the three-dimensional point l(,
It is fixed to the i ch side and the process moves to step 205. Step 2
In step 05, it is determined whether the counter in step 202 has reached the desired value N times or not, and if it is less than N times, the process moves to step 208.

The EGR pulp is operated for a predetermined time t1 and the amount of EGR is “
Move to the “large” side and proceed to step 209. Step 20
In step 9, the result of moving the EGFL amount to 1" side in the previous step 208 is measured by the signal change time Tm of the exhaust sensor, and the process moves to step 300, and it is determined whether the relationship Tm = β・t is established. (Here, β is a coefficient with a range greater than or equal to 0.) As a result, if T = β・t, EX) El maneuver is 1 normal operation and step The process moves to step 308, where the A/F feedback control is restarted, and the process moves through step 309 to step 500, where it waits for the next interrupt. On the other hand, in step 300, TA=β·t.

If the relationship is not established, the process moves to step 301 and the BGR valve is set to 1. and then move to step 302.
The operations shown in steps 209 to 300 are performed in step 30.
Execute between 2 and 306.

In other words, the EGR pulp energization time t (tbyte')
The relationship between the temperature change time T (rTm, δTc) and the exhaust sensor aging time T (rTm, δTc) is sequentially determined.

Next, if the above relationship is not established in step 306, the process proceeds to step 307.The EGR "NG" counter is incremented, and the process proceeds to step 309.Step 309
Then, it is determined whether the EGR "NG" counter has reached the predetermined value Ny times or not. As a result, when the EGR "NG" counter has reached the predetermined value Ny times, proceed to step 400. Set the EGR "FAIL" flag and proceed to step 400, indicating that the EGR function is NG. A warning will be issued.

Then, when the determination result in step 205 is N times, the EGR check counter and the EGR"'NG" counter are cleared in steps 206 and 207, and then the operation steps from step 208 are executed.

In the flowchart of the above embodiment, the EGR pulp energization time t is changed into three stages, and when all three stages fail, EGR, function N, and all functions are processed. Step 307 from row
Alternatively, the process may be performed after moving to the .

Further, step 308 and step 309 shown in FIG.
may be replaced.

The point is that when the amount of EGR is increased, the relationship between the exhaust sensor signal and the exhaust sensor signal becomes dilute (:l,ean), that is, EGR.

This configuration determines and confirms the quality of the EGR function based on the amount and changes in exhaust gas concentration.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to check whether the EGR operating function is being performed normally without providing a new device. Therefore, compared to the method of adding new devices, this method has the effect of preventing cost increases due to improved functionality and improving reliability.

Another advantage is that a self-check of the functions can be performed while the engine is still installed and without the driver's awareness.

In addition, since the EGR function is checked throughout the engine control system, if there is an increase in NO due to EGR or system failure, it is possible to quickly notify the occurrence of a failure and have emergency measures taken, thereby preventing air pollution. It has effects such as being advantageous in terms of exhaust gas countermeasures.

4. Brief explanation of the drawings.

Fig. 1 is a time chart diagram of an embodiment of the present invention, Fig. 2 is a block diagram showing an embodiment of the invention, Fig. 3 is a relationship diagram of the embodiment of Fig. 2 and Fig. 1; Fig. 4 is a configuration diagram of an electronic engine control device incorporating one embodiment shown in Figs. 1 to 3, and Fig. 5 is a control flowchart of one embodiment shown in Figs. 1 to 3. .

DESCRIPTION OF SYMBOLS 1... EGR signal generation means, 2... EGR, pulp, 3... Exhaust sensor, 4... Time comparison means, 5...
- Arithmetic device, 6... Warning means.

Claims (5)

[Claims] 1. an exhaust passage for recirculating exhaust gas to an intake manifold of the engine; a valve disposed in the exhaust passage for controlling the amount of exhaust gas passing through the exhaust passage; and means for energizing operation of the valve. An exhaust gas recirculation system for an engine, comprising: a sensor for detecting exhaust gas concentration; a means for opening the valve for a predetermined period of time to detect operation of the valve; and a change in the exhaust gas concentration depending on the time during which the valve is opened. An exhaust gas recirculation device for an engine, characterized by comprising means for comparing times. 2. In the exhaust gas recirculation device according to claim 1, the opening time of the valve is changed so that the change time of the exhaust gas recirculation amount and the change time of the exhaust gas concentration are linked. An exhaust gas recirculation device characterized by comprising: 3. In the exhaust gas recirculation device according to claim 2, when the operating state of the engine is in a preset exhaust gas recirculation operation range and in a feedback control range, the amount of recirculation of exhaust gas and the concentration of exhaust gas are controlled. An exhaust gas recirculation device characterized in that a means for comparing a change over time is stopped. 4. The exhaust gas recirculation device according to claim 2 above is configured to issue an alarm when there is a deviation greater than a desired value between the change time of the exhaust gas recirculation amount and the change time of the exhaust gas concentration. . 5. In the exhaust gas recirculation device according to claim 1, the feedback control is stopped, the air-fuel ratio is moved by a desired value from the ternary point, and the air-fuel ratio is clamped, thereby controlling the temporal change in the amount of exhaust gas recirculation and the exhaust gas. An exhaust gas recirculation device designed to compare changes in concentration over time.