JP2005263107A - Ejector abnormality detection method and system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ejector abnormality detection method and system capable of detecting abnormality of clogging of an ejector passage in a vehicle with an air ejector. <P>SOLUTION: The vehicle is equipped with the air ejector introducing a larger brake booster negative pressure than an intake manifold negative pressure into the brake booster. The system calculates a negative pressure value of an amount increased by the ejector by subtracting the intake manifold negative pressure from the brake booster negative pressure, and determines that it is abnormal when the difference subtracting a predetermined reference value (for example, the negative pressure value on the specification increased by the ejector in the normal time) from the calculated negative pressure is out of the predetermined range. Especially, when the difference is smaller than the lower limit of the predetermined range, it is determined that the ejector passage is in an abnormality of clogging. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention generally relates to a method and a system for detecting an abnormality of an air ejector in a vehicle equipped with an air ejector, and more particularly, to an ejector abnormality detection method and system capable of detecting a clogging abnormality of an ejector flow path.

  2. Description of the Related Art Conventionally, in a vehicle, there is known a vehicle brake device that includes an air ejector that introduces a brake booster negative pressure larger than an intake manifold negative pressure between an engine intake system and a brake booster (for example, a patent) Reference 1 and 2).

An air ejector (hereinafter simply referred to as “ejector”) increases the flow velocity of the passing air by allowing air to flow in from the upstream side of the throttle valve and exhausting the air downstream of the throttle valve with a venturi effect. Thus, the brake booster negative pressure is increased more than the intake manifold negative pressure on the engine side.
JP-A-60-29366 Japanese Patent Laid-Open No. Sho 62-214244

  By the way, as described above, the ejector is connected to the internal flow path connected to the upstream side of the throttle valve of the intake pipe and the downstream side of the throttle valve of the intake manifold in order to increase the negative pressure of the brake booster by the venturi effect. It has a relatively narrow channel that allows both to communicate with the internal channel. On the other hand, minute foreign matter (for example, soot and PM in exhaust gas from a diesel engine vehicle) may flow from the intake pipe to the ejector through the blow-by gas of the engine or the air cleaner.

  For this reason, in a vehicle equipped with an ejector, there is a possibility that a relatively narrow flow path of the ejector is blocked (clogged) by the foreign matter as described above. Such a clogging abnormality is disadvantageous because it can cause the ejector function to deteriorate.

  The present invention has been made to solve such problems, and it is a main object of the present invention to provide an ejector abnormality detection method and system capable of detecting an ejector flow path clogging abnormality in a vehicle equipped with an air ejector.

A first aspect of the present invention for achieving the above object is a method for detecting an ejector abnormality in a vehicle having an air ejector for introducing a brake booster negative pressure larger than an intake manifold negative pressure to the brake booster,
Subtract the intake manifold negative pressure from the brake booster negative pressure to calculate the negative pressure value increased by the ejector,
This is an ejector abnormality detection method in which an ejector abnormality is determined when a difference obtained by subtracting a predetermined reference value from the calculated negative pressure value is outside a predetermined range.

  In the first aspect, the predetermined reference value is, for example, a negative pressure value on the spec that is increased by the ejector during normal operation.

  In the first aspect, the predetermined range is a numerical range including, for example, 0, and is preferably selected in consideration of errors such as individual differences of pressure sensors.

  According to the first aspect, since it can be determined whether or not the negative pressure increased by the ejector deviates from the predetermined reference value to some extent, whether or not there is any abnormality in the ejector. Can be determined.

  More specifically, for example, when the difference is smaller than the lower limit value of the predetermined range, it is determined that the ejector flow path is clogged abnormally. Conversely, when the difference is larger than the upper limit value of the predetermined range, the ejector flow path is determined. It can be determined that the damage is abnormal.

A second aspect of the present invention for achieving the above object is a system for detecting an ejector abnormality in a vehicle having an air ejector for introducing a brake booster negative pressure larger than an intake manifold negative pressure to the brake booster,
Measuring means for measuring the brake booster negative pressure;
Estimating means for estimating intake manifold negative pressure from throttle opening and throttle air inflow amount;
A calculation means for subtracting the intake manifold negative pressure estimated value from the brake booster negative pressure measurement value to calculate a negative pressure value increased by the ejector;
An ejector abnormality detection system comprising: determination means for determining an ejector abnormality when a difference obtained by subtracting a predetermined reference value from the calculated negative pressure value is outside a predetermined range.

  In the second aspect, the predetermined reference value is, for example, a negative pressure value on the spec that is increased by the ejector during normal operation.

  In the second aspect, the predetermined range is a numerical range including, for example, 0, and is preferably selected in consideration of errors such as individual differences of pressure sensors.

  According to the second aspect, since it can be determined whether or not the negative pressure increased by the ejector deviates from the predetermined reference value to some extent, whether or not there is any abnormality in the ejector. Can be determined.

  More specifically, for example, when the difference is smaller than the lower limit value of the predetermined range, the determination unit determines that the ejector flow path is clogged, and conversely, the difference is larger than the upper limit value of the predetermined range. When it is larger, it can be determined that the ejector flow path is broken abnormally.

  ADVANTAGE OF THE INVENTION According to this invention, the ejector abnormality detection method and system which can detect the clogging abnormality of an ejector flow path in the vehicle provided with the air ejector can be provided.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings. Note that the basic concept, main hardware configuration, operating principle, basic control method, etc. of the air ejector and the vehicle brake system using the air ejector, which are the prerequisites of the present invention, are known to those skilled in the art. Detailed explanation is omitted.

  Hereinafter, an ejector abnormality detection system and method according to an embodiment of the present invention will be described with reference to FIGS.

  First, a schematic configuration of an ejector abnormality detection system 100 according to the present embodiment will be described with reference to FIG. In the present embodiment, the vehicle includes an engine 101 as a power source. The engine 101 has an intake pipe 102 that introduces air from the atmosphere into each cylinder. An air cleaner 103 that filters air taken into each cylinder of the engine 101 is provided at the inlet of the intake pipe 102. An air flow meter 104 is disposed downstream of the air cleaner 103 in the intake pipe 102. The air flow meter 104 outputs a signal corresponding to the amount of air taken into the engine 101 from the atmosphere to the engine ECU 105. Engine ECU 105 detects the amount of intake air (air flow rate) to engine 101 based on the output signal of air flow meter 104.

  A throttle valve 106 is disposed on the downstream side of the air flow meter 104 in the intake pipe 102. An electric motor (not shown) as an actuator is connected to the throttle valve 106. This electric motor is driven and controlled in accordance with a command from the engine ECU 105 and has a function of adjusting the opening degree of the throttle valve 106. The throttle valve 106 is an electronic throttle that is adjusted to an opening degree corresponding to the drive of the electric motor, and adjusts the amount of air supplied to the engine 101.

  An engine main body (E / C) 108 provided with cylinders is connected to the intake pipe 102 via intake manifolds (intake manifolds) 107 having branches corresponding to the number of cylinders of the engine 101. Intake manifold 107 is provided with a fuel injection valve (not shown) corresponding to each cylinder of engine 101. Each fuel injection valve injects and supplies an appropriate amount of fuel to the branch at an appropriate timing. The fuel injected and supplied from the fuel injection valve is mixed with the air from the intake pipe 102 and supplied to each cylinder of the engine 101.

  In the present embodiment, the vehicle includes a brake device 109. The brake device 109 has a brake pedal 110 operated by a vehicle driver. A brake booster 111 is connected to the brake pedal 110. A negative pressure generated on the downstream side of the throttle valve 106 of the engine 101 is guided to the brake booster 111 through a negative pressure introduction path 112. In addition, the brake booster 111 includes a pressure sensor 113 that measures the magnitude of the negative pressure in the negative pressure chamber (not shown) of the brake booster 111 and outputs it to the engine ECU 105. Note that a check valve (not shown) is provided in the negative pressure introduction path 112 so that the negative pressure in the negative pressure chamber of the brake booster 111 does not flow backward to the engine 101 side.

  When the brake pedal 110 is depressed, the brake booster 111 generates an assist force having a predetermined boost ratio with respect to the brake pedal force using the negative pressure from the engine 101. The assist force generated by the brake booster 111 is supplied to a wheel cylinder (not shown) via a master cylinder (not shown), and becomes a braking force that stops the rotation of wheels (not shown).

  An ejector 114 is provided in the negative pressure introduction path 112 that communicates the brake booster 111 and the engine 101 described above. The ejector 114 has a first port 115a connected to the intake pipe 102 downstream of the air flow meter 104 and upstream of the throttle valve 106, and a second port 115b connected to the downstream side of the throttle valve 106 of the intake manifold 107. And a third port 115c connected to the negative pressure chamber of the brake booster 111.

  In the ejector 114, a decompression chamber (not shown) communicating with the third port 115c, an outlet chamber (not shown) communicating with the second port 115b, and a diffuser (not shown) communicating both chambers. ) And are provided. The diffuser includes a tapered taper portion (not shown) formed on one end side of the decompression chamber, a divergent taper portion (not shown) formed on one end side of the outlet chamber, and a relatively narrow flow path that connects both the taper portions. (Not shown). In the decompression chamber, a nozzle communicating with the first port 115a and having the nozzle hole directed to the diffuser is disposed in the vicinity of the tapered portion.

  The ejector 114 has a function of increasing the negative pressure generated in the brake booster 111 (hereinafter referred to as “brake booster negative pressure”) more than the negative pressure generated in the engine 101 (hereinafter referred to as “in-manifold negative pressure”). In other words, the ejector 114 injects air introduced from the intake pipe 102 into the first port 115a by the intake manifold negative pressure toward the diffuser to generate a high-speed jet of air, and the air is supplied from the second port 115b to the intake manifold. It discharges to 107. When such a high-speed jet of air is performed, the negative pressure in the decompression chamber increases due to the venturi effect, so that the brake booster negative pressure guided to the brake booster 111 increases more than the intake manifold negative pressure.

  Between the first port 115a of the ejector 114 and the intake pipe 102, an on / off valve 116 for switching between communication and blocking between the two is interposed. The on / off valve 116 is connected to the engine ECU 105 and is driven to open and close by the engine ECU 105. The on / off valve 116 shuts off the first port 115a and the intake pipe 102 when the signal supplied from the engine ECU 105 is in an off state, and first when the signal supplied from the engine ECU 105 is in an on state. This is a two-position valve that allows the port 115a and the intake pipe 102 to communicate with each other.

  The engine ECU 105 is supplied with various information of the engine 101 from various sensors, such as engine water temperature, engine speed, throttle opening, accelerator opening, and the like. Based on the engine information, the throttle valve 106 and the on / off valve 116 are driven and controlled.

  Based on the above configuration, the operation of the ejector abnormality detection system 100 according to the present embodiment will be described. In this embodiment, in order to detect an abnormality in the ejector, the magnitude of the negative pressure increased by the ejector during operation of the ejector is monitored.

  First, the operation of the ejector 114 will be described. The intake manifold negative pressure generated in the intake manifold 107 of the vehicle differs depending on the load of the engine 101, the rotational speed, and the like. When the engine is cold (for example, within a few minutes after the engine is started and the engine water temperature is 70 degrees Celsius or lower), the throttle valve 106 is opened widely to warm the engine catalyst, and a large amount of air is generated in the engine body 108 Flows into the side. At this time, the intake manifold negative pressure decreases due to the increase in intake, and the brake booster negative pressure also decreases accordingly. When the brake booster negative pressure is small, a sufficient differential pressure with respect to the atmospheric pressure is not generated, and the brake booster 111 can obtain a large boost ratio even if the driver depresses the brake pedal 110. Can not. This increases the driver's brake operation burden during vehicle braking.

  Therefore, the engine ECU 105 determines whether or not the engine 101 is in a cold state based on the above-described various engine information (in particular, the engine water temperature), that is, the brake booster 111 cannot obtain a predetermined boost ratio. It is determined whether or not. When it is determined that the engine 101 is in the cold state, an on signal is supplied to the on / off valve 116 to operate the ejector 114.

  Then, the intake pipe 102 and the first port 115a of the ejector 114 communicate with each other by opening the on / off valve 116, and high-speed air flows from the first port 115a to the second port 115b through the diffuser. Therefore, the brake booster negative pressure higher than the intake manifold negative pressure is guided to the brake booster 111 by the action of the ejector 114.

  On the other hand, when it is determined that the engine 101 is not in the cold state, the engine ECU 105 supplies an off signal to the on / off valve 116 in order to inhibit the operation of the ejector 114. Then, when the on / off valve 116 is closed, the intake pipe 102 and the first port 115a of the ejector 114 are blocked, and air flows from the first port 115a to the second port 115b via the diffuser. Therefore, a brake booster negative pressure equivalent to the intake manifold negative pressure is introduced to the brake booster 111.

  As described above, when the intake manifold negative pressure is relatively low, the ejector 114 is operated to introduce a brake booster negative pressure larger than the intake manifold negative pressure to the brake booster 111.

  Next, the ejector abnormality detection process will be described. As described above, the ejector 114 has the first port 115a connected to the intake pipe 102 downstream of the air flow meter 104 and upstream of the throttle valve 106 in order to increase the brake booster negative pressure more than the intake manifold negative pressure due to the venturi effect. A relatively narrow flow path is provided between the internal flow path communicating with the internal passage and the internal passage communicating with the second port 115b connected to the downstream side of the throttle valve 106 of the intake manifold 107. In such a structure of the ejector 114, since there is a possibility that minute foreign matter that has passed through the blow-by gas of the engine 101 or the air cleaner 103 flows from the intake pipe 102, foreign matter accumulates in a relatively narrow flow path of the ejector 114. The flow path may be blocked by

  Therefore, in the ejector abnormality detection process according to the present embodiment, the negative pressure increasing effect by the ejector 114 is monitored, and a warning for alerting the vehicle driver when a flow path clogging or other abnormality occurs ( A warning is issued. Hereinafter, the flow of this process will be described with reference to FIG. In the present embodiment, the ejector abnormality detection process is mainly executed by the engine ECU 105 as an example.

  First, it is determined whether or not the ejector 114 is operating (S201). If the ejector 114 is not operating (“NO” in S201), the abnormality detection process is not executed and the routine is terminated.

  If the ejector 114 is operating (“YES” in S201), the engine ECU 105 then reads the output signal from the pressure sensor 113 and acquires the value of the brake booster negative pressure (S202).

  Next, the engine ECU 105 executes a calculation for estimating the intake manifold negative pressure value from the throttle opening and the throttle air inflow amount (S203).

  Next, the engine ECU 105 subtracts the estimated value of the intake manifold negative pressure from the actual measured value of the brake booster negative pressure to calculate the negative pressure increased by the ejector (hereinafter referred to as “ejector actual effect negative pressure”) ( S204).

  Next, the engine ECU 105 subtracts the known normal effect negative pressure B that is held in advance from the calculated ejector actual effect negative pressure A (S205). Here, the normal effect negative pressure represents the magnitude of the negative pressure increasing effect on the specifications obtained from the basic performance of the ejector 114 under normal conditions. Therefore, by comparing the ejector actual effect negative pressure A and the normal effect negative pressure B, it is possible to know how much performance of the ejector 114 is exhibited at that time.

  In the present embodiment, in comparing the ejector actual effect A and the normal effect B, an error such as an individual difference of the pressure sensor 113 is taken into account, even though the actual effect A is not the normal effect B. If the actual effect A−the normal effect B | ≦ constant C (that is, −C ≦ (A−B) ≦ + C), it is determined as normal. Here, the constant C is a value selected in consideration of the error.

  On the other hand, if the value of (actual effect A−normal effect B) is outside the above range (−C to + C), it is determined that some abnormality has occurred in the ejector. Specifically, in the case of (A−B) <− C, it is determined that the ejector effect that is actually exhibited at that time is significantly lower than the normal value, and the ejector flow path is clogged. It is determined that an abnormality has occurred (S206). In the case of (A−B)> + C, it is determined that the ejector effect that is actually exerted at that time is significantly higher than the normal value, and the ejector flow path is damaged. It is determined that an abnormality in the direction in which the road area increases (S207).

  When the ejector abnormality is detected (S206 or S207), a warning is issued to the vehicle driver (S208). As this warning, one type of warning indicating an ejector abnormality may be issued, or different types of warnings may be issued in the case of clogging abnormality (S206) and other abnormality (S207). In any case, this warning may be performed, for example, by turning on a warning lamp or the like provided on the instrument panel, or by displaying character information or the like on the display for the HUD or the navigation system. It may be performed, or may be transmitted by sound from a speaker, or may be performed visually and / or audibly by arbitrarily combining two or more of these.

  As described above, according to this embodiment, in a vehicle equipped with an ejector, during the ejector operation, the measured value of the brake booster negative pressure and the estimated value of the intake manifold negative pressure are used. This type of abnormality can be easily detected.

  In the above-described embodiment, as an example, the ejector abnormality detection process according to the present invention is executed by the engine ECU 105. However, the present invention is not limited to this, and the brake ECU or a newly dedicated process is provided. It may be executed by another ECU such as an ECU.

  In the above embodiment, as an example, the normal effect B of the ejector is treated as a constant value. However, the present invention is not limited to this, and the normal effect B of the ejector is changed when the temperature changes with temperature. You may make it correct | amend the value of the ejector normal time effect B used in a calculation process using information, such as external temperature.

  The present invention can be used for a vehicle equipped with an ejector. The appearance, weight, size, running performance, etc. of the vehicle to be mounted are not limited.

It is the schematic which shows the system configuration | structure of the ejector abnormality detection method and system which concern on one Example of this invention. It is a flowchart which shows the flow of the ejector abnormality detection process which concerns on one Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Ejector abnormality detection system 101 Engine 102 Intake pipe 103 Air cleaner 104 Air flow meter 105 Engine ECU
106 Throttle valve 107 Intake manifold 108 Engine body (E / C)
109 Brake device 110 Brake pedal 111 Brake booster 112 Negative pressure introduction path 113 Pressure sensor 114 Air ejector 115a First ejector port 115b Second ejector port 115c Third ejector port 116 On / off valve

Claims (6)

A method of detecting an ejector abnormality in a vehicle equipped with an air ejector for introducing a brake booster negative pressure larger than the intake manifold negative pressure to the brake booster,
Subtract the intake manifold negative pressure from the brake booster negative pressure to calculate the negative pressure value increased by the ejector,
An ejector abnormality detection method comprising: determining an ejector abnormality when a difference obtained by subtracting a predetermined reference value from the calculated negative pressure value is outside a predetermined range. The ejector abnormality detection method according to claim 1,
An ejector abnormality detection method comprising: determining that the ejector flow path is clogged abnormally when the difference is smaller than a lower limit value of the predetermined range. The ejector abnormality detection method according to claim 1 or 2,
An ejector abnormality detection method, wherein when the difference is larger than an upper limit value of the predetermined range, it is determined that the ejector passage is broken. A system for detecting an ejector abnormality in a vehicle having an air ejector for introducing a brake booster negative pressure larger than the intake manifold negative pressure to the brake booster,
Measuring means for measuring the brake booster negative pressure;
Estimating means for estimating intake manifold negative pressure from throttle opening and throttle air inflow amount;
A calculation means for subtracting the intake manifold negative pressure estimated value from the brake booster negative pressure measurement value to calculate a negative pressure value increased by the ejector;
An ejector abnormality detection system comprising: a determination unit that determines an ejector abnormality when a difference obtained by subtracting a predetermined reference value from the calculated negative pressure value is outside a predetermined range. The ejector abnormality detection system according to claim 4,
The ejector abnormality detection system, wherein the determination means determines that the ejector flow path is clogged abnormally when the difference is smaller than a lower limit value of the predetermined range. The ejector abnormality detection system according to claim 4 or 5,
The ejector abnormality detection system according to claim 1, wherein the determination unit determines that the ejector flow path is abnormal when the difference is larger than an upper limit value of the predetermined range.

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