JPH08200533A - Flow control device - Google Patents

Abstract

PURPOSE: To prevent stepping-out to enable preventing responsiveness from worsening by detecting the fluctuation of the motor torque of a synchronous motor, calculating a settling time that matches the motor torque fluctuation detected, adding the calculated settling time to a driving period, and then driving the synchronous motor. CONSTITUTION: The amount of exhaust gas recirculation, i.e., the amount of EGR is map retrieved by an EGR amount retrieval means 206 from the basic amount of fuel and engine speed, is then subjected to correction by an EGR amount correction means 211, and converted into an EGR valve opening area by an EGR valve opening calculation means 207. Further, after substitution to the number of EGR valve driving steps by an EGR valve driving step number conversion means 208, an output signal is output by a synchronous motor driving pulse output means in accordance with a predetermined excitation pattern in order to control an EGR valve 210. When the fluctuation of motor torque is recognized by a motor torque fluctuation judging means 209, a settling time is added to the output signal, which is then input to the EGR valve 210.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate control device using a flow rate control valve driven by a synchronous motor.

[0002]

2. Description of the Related Art As a fluid parameter control device for engine control, an ISC control device for controlling an auxiliary intake air amount to maintain a constant idling speed, a reduction of NOx contained in exhaust gas, or a fuel consumption improvement. Therefore, there are an EGR control device that controls the exhaust gas recirculation amount, an evaporation control device that controls the evaporated fuel amount in order to prevent the evaporated fuel from the fuel tank from being released to the atmosphere, and the like.

When the flow rate control valve in these flow rate control devices is out of step, engine malfunction occurs due to abnormal increase in idle speed, surging due to unstable combustion, abnormal air-fuel ratio (overrich or overlean), and the like.

Particularly in recent years, a large amount of EGR or a large amount of evaporative purge has been required to comply with exhaust emission regulations and fuel consumption regulations, and a step out of the flow control valve may lead to an engine stall immediately, and a driver may be stalled. Not only uncomfortable but also very dangerous.

Conventionally, it is generally known that the above-mentioned step-out prevention control is provided to prevent step-out and ensure safety during operation.

Prevention of step-out in the case of using a flow control valve driven by a synchronous motor In the prior art, consideration is given to a fail-safe function at the time of failure such as no output signal to the synchronous motor. However, the settling time is provided only when the driving direction of the synchronous motor is switched.

Further, it is known that the settling time is prevented from being deteriorated in response by using different values depending on the motor torque fluctuation state.

[0008]

The above-mentioned prior art is provided with step-out prevention control to prevent step-out and ensure safety during operation, and to keep the step-out prevention control to a necessary minimum to improve responsiveness. Although it was possible to prevent the deterioration, it did not have a fail-safe function in case of a control device failure such as no output signal to the synchronous motor being output at all.

An object of the present invention is to provide a flow rate control device capable of preventing deterioration of responsiveness by preventing step-out.

[0010]

According to the present invention, a means for exerting a unilateral stress is provided on the valve constituent portion of a flow control valve driven by a synchronous motor, and the torque fluctuation is judged by a motor torque fluctuation judging means of the synchronous motor. The settling time is set in the driving cycle according to the state, and the settling time has at least two values.

[0011]

The flow control valve can be closed even when the control device fails such that the output signal to the synchronous motor is not output at all, and EGR, auxiliary intake air, evaporation purge and the like can be avoided. In addition, the settling time is set in the drive cycle according to the motor torque fluctuation state of the synchronous motor to prevent out-of-step, and the settling time is used to prevent deterioration of responsiveness by using at least two values. Is possible.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exhaust gas recirculation system, that is, an EGR control system according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an example of an overall block diagram of an EGR control device according to the present invention.

The basic fuel amount calculation unit 202 calculates the basic fuel amount from the intake air amount measured by the intake air amount detection unit 201 and the engine speed. On the other hand, the concentration of air-fuel ratio is determined by detecting the oxygen concentration contained in the exhaust gas by the oxygen concentration sensor so as to obtain an arbitrary air-fuel ratio according to the operating conditions. The air-fuel ratio correction coefficient is obtained from the determination result and the engine load condition by the air-fuel ratio correction means 205, and the injected fuel quantity is output as Duty by the injected fuel quantity calculation means 203 from the basic fuel amount and the air-fuel ratio correction coefficient and the fuel injection means 2
Fuel is injected by 04.

FIG. 7 shows the exhaust gas recirculation amount, that is, the EGR amount.
From the basic fuel amount and engine speed as shown in E
After the GR amount searching means 206 searches the map, the EGR amount correcting means 211 corrects the EGR amount from the information of the engine load condition such as the idle determination switch, the throttle opening sensor, and the cooling water temperature sensor, and the EGR valve is corrected. The opening area calculation means 207 converts the opening area into an EGR valve opening area. Further, the converted EGR valve opening area is replaced by the EGR valve driving step number converting means 208 by the EGR valve driving step number as shown in FIG. 8, and then the EGR valve 2 driven by the synchronous motor.
In order to control 10, the output signal is output by the synchronous motor drive pulse output means along a predetermined excitation pattern.

Here, the motor torque fluctuation determining means 209
When the fluctuation of the motor torque is confirmed by, the settling time is added to the output signal and is input to the EGR valve 210.

FIG. 2 is an example of an overall block diagram relating to the idle speed control device of the present invention, that is, the ISC control device, but since the control contents are the same as those in FIG.

FIG. 3 is an example of an entire block diagram relating to the evaporated fuel control device of the present invention, that is, the evaporation control device, but since the control contents are the same as those in FIG. 1, the description thereof is omitted.

FIG. 4 shows an example of the system configuration of an internal combustion engine including the EGR control device of the present invention. The air passes through the air cleaner 161 and is guided to the intake air amount detecting means, that is, the air flow meter 1. A hot wire air flow sensor is used for the air flow meter 1. This air is connected to duct 16
0, a throttle body 159 having a throttle valve for controlling the intake air amount, and a flow control valve in an idle rotation control device provided so as to bypass the throttle body,
That is, it enters the collector 158 through the ISC valve 54.
Here, the air is the intake pipe 16 of each cylinder directly connected to the engine.
4 and is sucked into the cylinder. Further, instead of the air flow meter 1, the pressure sensor 14 may be used to measure the intake pipe pressure and detect the engine load.

The fuel is sucked and pressurized from the fuel tank 155 by the fuel pump 52, passes through the fuel damper 153 and the fuel filter 152, and the pressure regulator 154 regulates the differential pressure between the collector 158 and the upstream of the injector 51 to a constant pressure, and the intake pipe. It is injected into the intake pipe from an injector provided.

The air flow meter 1 outputs a signal corresponding to the intake air amount. Further, the crank angle sensor 2 built in the distributor 157 outputs a pulse for each predetermined crank angle, and these outputs are input to the control unit 151 to calculate the crank angle and the engine speed.

A throttle sensor 4 for detecting the opening of the throttle valve is attached to the throttle body 159,
This sensor signal is input to the control unit 151 to detect the fully closed position of the throttle valve and the acceleration.

A water temperature sensor 6 for detecting the cooling water temperature is attached to the engine main body 162, and the sensor signal is input to the control unit 151 to detect the warmed-up state of the engine 162 and increase the fuel injection amount or ignition. The timing is corrected, the radiator fan 56 is turned on / off, and the target rotation speed during idling is set.

The mixture of fuel and air burned in the cylinder becomes exhaust gas and is discharged from the exhaust pipe 190. A part of the exhaust gas discharged is controlled by the exhaust gas recirculation amount control means, that is, the EGR valve 210 provided in the middle of the exhaust gas recirculation passage 211 that connects the exhaust pipe 190 and the intake pipe 164, according to the operating state of the engine 162. The pressure is adjusted to the exhaust gas recirculation amount and is recirculated to the intake pipe 164.

The air-fuel ratio sensor 5 is an engine exhaust pipe 190.
It is mounted on the vehicle and outputs a signal according to the oxygen concentration of the exhaust gas.

The evaporated fuel generated from the fuel tank 155 is adsorbed on the activated carbon in the canister 20 to prevent the evaporated fuel from being released into the atmosphere. The evaporated fuel adsorbed in the canister 20 is sucked into the air sucked from the one-way valve located upstream of the drain cut valve 21 due to the pressure difference between the fuel tank 155 and the intake pipe 164, flows into the collector 158, and flows into the collector 158. Preventing overflow.
Further, the purge control valve 2 which is a flow rate control valve in the evaporated fuel control device located downstream of the canister 20.
2 controls the amount of air containing evaporated fuel to a constant amount with respect to the amount of intake air.

The control unit 151 includes a CPU 170, a ROM 173, a RAM 171, and a backup RAM 17, as shown in FIG.
2, an interrupt controller 174, a timer 175, an input processing circuit 178, and an output processing circuit 176, which are connected by a bus 177. Based on various information processed by the input processing circuit 178, the CPU 170 performs processing based on a program stored in the ROM 173, using the RAM 171 and the backup RAM 172 capable of holding the stored contents even when the ignition switch 9 is turned off. At this time, the timer 175
Also, an interrupt instruction is issued from the interrupt controller 174 on the basis of information from the input processing circuit 178, and interrupt processing is also performed at a suitable time.

Further, the external load detection of the engine using the electric load switch 12 for detecting the electric load 168 ON and the power steering switch 13 for detecting the load of the power steering 165, the fuel pump 52, the air conditioner 55, and the radiator fan 56. The ON / OFF control of is also performed by the control unit 151.

FIGS. 8 to 13 are charts showing the control amount of the exhaust gas control means, that is, the number of steps of the EGR valve and the behavior of the motor torque fluctuation parameter when the present invention is used.

FIG. 8 shows an example of the relationship between the excitation state and the settling time when the number of steps of the EGR valve changes from large → small → large.

Exhaust gas recirculation means control amount, that is, output that is output along a predetermined excitation pattern by the synchronous motor drive pulse output means for controlling the EGR valve in accordance with the target step number target value When the step number monitor value calculated based on the signal is not synchronized, it is driven by two-phase excitation, and when the step number target value is synchronized with the step number monitor value, it is for the purpose of suppressing the heat generation amount of the motor part. One phase is excited.

Here, when switching from two-phase to one-phase excitation, the settling time is set to synchronize at the timing of overshoot of the motor rotor and the timing of transition of the excitation pattern due to switching from two-phase to one-phase excitation. The magnetic field magnetized in the motor rotor and the magnetic field generated by the excitation of the stator repel each other, and the motor torque does not decrease significantly, and the actual EGR valve It is possible to prevent deviation of the valve position, that is, step out.

FIG. 9 shows an example of the relationship between the excitation state and the settling time when the number of steps of the EGR valve changes from small → large → small.

The one-sided stress applied to the EGR valve valve component increases the overshoot of the motor rotor when the number of steps changes from large → small → large, but the number of steps changes from small → large → small. Sometimes, the overshoot is attenuated, so that even if the settling time is shortened when the number of steps changes from large → small → large to small → large → small, step out does not occur.

FIGS. 10 and 11 show an example of the relationship between the motor rotation direction and the settling time when the number of steps of the EGR valve changes, but the mechanism for preventing step-out is shown in FIGS.
The explanation is omitted because it is the same as the content of.

12 and 13 show an example of the relationship between the drive control cycle and the settling time when the number of steps of the EGR valve changes, but the mechanism for preventing step-out is the same as the contents of FIGS. Omit.

14 to 17 show an example of a flow chart of a method for setting the settling time according to the motor torque fluctuation.

FIG. 14 shows an example of the entire flow chart for calculating the exhaust gas recirculation amount from the engine load and engine speed and setting the settling time.

In step 301, the map is searched for the EGR amount from the engine load and the engine speed, and in step 302 E
The EGR valve opening area is obtained by multiplying the GR amount by an EGR amount correction value obtained from information of an engine load condition such as an idle determination switch, a throttle opening sensor, and a cooling water temperature sensor. Further, in step 303, the EGR valve opening area is converted into the number of EGR drive steps, and in step 304, a predetermined excitation pattern is obtained by the synchronous motor drive pulse output means for controlling the EGR valve driven by the synchronous motor. An output signal is output along.

Here, in step 305, the motor torque fluctuation is judged, and when the motor torque fluctuation occurs, the settling time according to the motor torque fluctuation state is added to the output signal and input to the EGR valve.

FIG. 15 shows an example of a flow chart of a settling time setting method in the case where the motor torque fluctuation is judged by reversing the motor rotation direction.

In step 311, it is judged whether or not the driving direction of the output signal output along the predetermined excitation pattern by the synchronous motor drive pulse output means is reversed, and when it is reversed, the routine proceeds to step 312. In step 312, it is judged whether or not the driving direction of the output signal is reversed from the valve opening direction to the valve closing direction. When it is reversed from the valve opening direction to the valve closing direction, the settling time is short, and the valve direction is reversed from the valve closing direction to the valve opening direction. In this case, the settling time is set long and added to the drive control cycle (steps 313 and 314).

FIG. 16 shows an example of a flow chart of a settling time setting method when the motor torque fluctuation is judged by switching the drive control cycle. The setting method of the settling time is the same as in FIG. If it has changed, the process proceeds to step 316, and if the cycle has changed for a long time, the process proceeds to step 317.
When the cycle has changed shortly, the process proceeds to step 318.

FIG. 17 shows an example of a flow chart of a settling time setting method when the motor torque fluctuation is judged by switching the motor excitation method. The setting method of the settling time is the same as in FIG. 15, steps 319, 320, 321.
The process of 322 is performed.

18, 19 and 20 show an example of the structure of the EGR valve.

FIG. 18 shows E in the case where the stress of the spring is used as a means for applying a one-sided stress to the valve of the EGR valve.
An example of the structure of a GR valve is shown. One end of the spring 401 is fixed to the body 402, and the other end is in contact with the valve 403. The stress of the spring 401 acts only in the valve 403 closing direction, and has a valve 403 valve closing function in a fail-safe mode or the like. are doing.

FIG. 19 shows an example of the structure of the EGR valve in the case where the stress of the diaphragm is used as the means for exerting the one-sided stress on the valve of the EGR valve. Diaphragm
The outer circumference of 404 is fixed to the body 402 and the inner circumference of the valve 404.
03 is fixed to the diaphragm 40 to reduce the intake pipe negative pressure.
4 and the body 402, the stress of the diaphragm 404 is applied to the negative pressure chamber 405.
It has a structure that operates only in the valve closing direction and has a valve 403 valve closing function in a fail-safe mode or the like.

FIG. 20 shows an example of the relationship between the valve lift amount of the EGR valve and the intake pipe negative pressure acting on the valve. Figure 2
When the valve lift amount is small like 0, the valve 40
3 A large differential pressure across the intake pipe negative pressure acts only in the valve 403 opening direction. On the other hand, as shown in FIG. 21, when the valve lift amount of the EGR valve is large, there is no differential pressure across the valve 403 and the intake pipe negative pressure does not act on the valve 403.

[0049]

According to the present invention, the flow rate control valve can be closed even when the control device fails, and it is possible to avoid excessive application of EGR, auxiliary intake air, evaporation purge, and the like.
In addition, the settling time is set in the drive cycle according to the motor torque fluctuation state of the synchronous motor to prevent out-of-step, and the settling time is used to prevent deterioration of responsiveness by using at least two values. Therefore, it is possible to provide an internal combustion engine that has extremely good drivability, exhaust performance, and fuel efficiency, and that can prevent drastic deterioration of drivability such as engine stall even when the flow rate control device fails. You can

[Brief description of drawings]

FIG. 1 is an example of an entire block diagram of an EGR control device of the present invention.

FIG. 2 is an example of an overall block diagram of an ISC control device according to the present invention.

FIG. 3 is an example of an overall block diagram relating to the evaporation control device of the present invention.

FIG. 4 is an example of a system configuration of an internal combustion engine including an EGR control device of the present invention.

FIG. 5 shows an example of a control unit configuration.

FIG. 6 shows an example of EGR amount search means.

FIG. 7 is a diagram showing a relationship between an EGR valve opening area and an EGR valve target step number.

FIG. 8 is a diagram showing the relationship between the excitation state and the settling time when the number of steps of the EGR valve changes from large → small → large.

FIG. 9 is a diagram showing the relationship between the excitation state and the settling time when the number of steps of the EGR valve changes from small → large → small.

FIG. 10 is a diagram showing the relationship between the motor rotation direction and the settling time when the number of steps of the EGR valve changes.

FIG. 11 is a diagram showing a relationship between a motor rotation direction and settling time when the number of steps of an EGR valve changes.

FIG. 12 is a diagram showing a relationship between a drive control cycle and settling time when the number of steps of an EGR valve changes.

FIG. 13 is a diagram showing the relationship between the drive control cycle and the settling time when the number of steps of the EGR valve changes.

FIG. 14 is an overall flow chart until the exhaust gas recirculation amount is calculated and the settling time is set.

FIG. 15 is a flowchart of a method for setting a settling time when a motor torque fluctuation is determined by reversing the motor rotation direction.

FIG. 16 is a flowchart of a settling time setting method for determining a motor torque fluctuation by switching a drive control cycle.

FIG. 17 is a flowchart of a method for setting a settling time when a motor torque fluctuation is determined by switching a motor excitation method.

FIG. 18 is a structural diagram of an EGR valve when the stress of a spring is used as a means for applying a one-sided stress to the valve of the EGR valve.

FIG. 19 is an EG in the case where the stress of the diaphragm is used as a means for applying a one-sided stress to the valve of the EGR valve.
Structural drawing of the R valve.

FIG. 20 is a diagram showing an example of the relationship between the valve lift amount of the EGR valve and the intake pipe negative pressure acting on the valve.

FIG. 21 is a diagram showing an example of the relationship between the valve lift amount of the EGR valve and the intake pipe negative pressure acting on the valve.

[Explanation of Codes] 1 ... Air flow meter, 6 ... Cooling water temperature sensor, 14 ... Pressure sensor, 20 ... Canister, 22 ... Purge control valve, 51 ... Injector, 54 ... ISC valve, 151
... control unit, 157 ... distributor, 159 ... throttle body, 162 ... engine, 1
64 ... Intake pipe, 190 ... Exhaust pipe, 210 ... EGR valve, 401 ... Spring, 402 ... Body, 403 ... Valve,
404 ... diaphragm, 405 ... negative pressure chamber.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02M 25/08 301 H // F02M 25/07 550 Q 580 F (72) Inventor Masahiro Sato Ibaraki Prefecture Hitachinaka City Oita Takaba 2477 Kashima Yatsu 3 Hitachi Automotive Engineering Co., Ltd. (72) Inventor Seiji Asano Hitachinaka City Otaka 2520 Hitachi Ltd. Automotive Equipment Division

Claims (11)

[Claims] 1. A flow rate control device having a gas flow rate control means provided in the middle of a gas flow rate, wherein the gas flow rate control means applies a one-sided stress to the valve, a synchronous motor for driving the valve, and the valve. And a means for obtaining a settling time in accordance with the motor torque variation detected by the variation detecting means, and a means for determining the motor torque variation of the synchronous motor. And a means for driving the synchronous motor by adding a settling time to a driving cycle. 2. The flow rate control device according to claim 1, wherein the settling time has two values in accordance with variations in motor torque. 3. An exhaust gas recirculation amount control device comprising exhaust gas recirculation amount control means provided midway in an exhaust gas recirculation passage communicating between an exhaust pipe and an intake pipe, wherein the exhaust gas recirculation amount control means is of a synchronous type. It is driven by a motor and is equipped with means for exerting one-sided stress on the valve component of the exhaust gas recirculation amount control means, and further has motor torque fluctuation determination means for a synchronous motor. The exhaust gas recirculation amount control device, wherein the settling time has at least two values according to the motor torque fluctuation state. 4. The exhaust gas recirculation amount control device according to claim 3, wherein the stress of a spring is used as a means for exerting a one-sided stress on the valve constituting portion of the flow rate control means. 5. The exhaust gas recirculation amount control device according to claim 3, wherein the stress of the diaphragm is utilized as a means for exerting a one-sided stress on the valve constituent portion of the flow rate control means. 6. The exhaust gas recirculation amount control device according to claim 3, wherein an intake pipe negative pressure is used as a means for exerting a one-sided stress on the valve forming portion of the flow rate control means. 7. The exhaust gas recirculation amount control device according to claim 1, wherein the fluctuation judging means judges the motor torque fluctuation of the synchronous motor by switching the excitation method. 8. The exhaust gas recirculation amount control device according to claim 1, wherein the fluctuation judging means judges the motor torque fluctuation of the synchronous motor by reversing the rotation direction. 9. The exhaust gas recirculation amount control device according to claim 1, wherein the fluctuation determining means determines a motor torque fluctuation of the synchronous motor by switching a drive control cycle. 10. An idle speed control device having a bypass passage through which air measured by an air flow meter can be supplied to an engine without passing through a throttle, and having a flow control valve in the middle of the bypass passage. The flow rate control valve is driven by a synchronous motor and is equipped with means for applying one-sided stress to the valve component of the flow rate control valve.Furthermore, it has motor torque fluctuation determination means for the synchronous motor and settles to the drive cycle when the motor torque fluctuates. The idle rotation control device is characterized in that the settling time has at least two values according to a motor torque fluctuation state by adding time. 11. An evaporative fuel amount control device having a flow rate control valve set midway in a ventilation path communicating a fuel tank and an intake pipe, wherein the flow rate control valve is driven by a synchronous motor and the flow rate control valve is also provided. Is provided with a means for exerting one-sided stress on the valve component, and further has a motor torque fluctuation determining means for a synchronous motor, and when motor torque changes, settling time is added to the drive cycle, and the settling time depends on the motor torque fluctuation state. An evaporated fuel amount control device having at least two values.