JP2005069175A - Vehicle control device - Google Patents

Abstract

To provide a vehicle control device capable of appropriately performing air-fuel ratio control of a vehicle engine.
A vehicle control device that controls the operation of an ejector 2 that increases a negative pressure from an engine intake system 20 supplied to a brake booster 3, wherein the ejector 2 is operated until a predetermined time T1 has elapsed after the engine 4 is started. The operation of is prohibited. As a result, it is possible to prevent the intake air amount from becoming unstable immediately after the engine 4 is started, and to prevent the intake air amount from being promoted by the operation of the ejector, thereby realizing appropriate air-fuel ratio control.
[Selection] Figure 2

Description

  The present invention relates to a vehicle control apparatus that performs operation control of an ejector installed in a vehicle.

Conventionally, as an ejector for increasing the negative pressure supplied to a brake booster, as described in JP-A-2002-212385, the brake booster is connected via a control valve, and the negative pressure chamber of the brake booster is predetermined. It is known that it operates when the control valve valve opens without reaching negative pressure, and stops when the negative pressure chamber of the brake booster reaches a predetermined negative pressure and the control valve valve closes. This ejector intends to always provide a stable negative pressure to the negative pressure chamber of the brake booster by appropriately controlling the operation according to the operating state of the engine.
JP 2002-212385 A

  In the above-described ejector, there is a problem that the accuracy of the air-fuel ratio control of the engine is lowered due to its operation. That is, when the ejector is activated at the time of starting the engine, the amount of air taken into the engine fluctuates and the air-fuel ratio is disturbed. Further, the idle rotation and the air-fuel ratio become unstable due to the deviation of the idle air amount.

  Accordingly, the present invention has been made to solve such problems, and an object of the present invention is to provide a vehicle control device that can appropriately perform air-fuel ratio control of a vehicle engine.

  That is, the vehicle control device according to the present invention is a vehicle control device that controls the operation of an ejector that increases the negative pressure from an engine intake system supplied to a brake booster. The operation is prohibited.

  According to the present invention, by prohibiting the operation of the ejector until a predetermined time has elapsed after the engine is started, it is prevented that the intake air amount becomes unstable immediately after the engine is started by the ejector operation. And appropriate air-fuel ratio control can be realized.

  The vehicle control device according to the present invention is characterized in that even if the pressure in the negative pressure chamber of the brake booster is higher than a predetermined pressure, the operation of the ejector is prohibited when the intake pipe pressure of the engine intake system is equal to or lower than the predetermined pressure. To do.

  According to the present invention, since the intake pipe pressure is low even if the pressure in the negative pressure chamber of the brake booster is higher than the predetermined pressure, the pressure in the negative pressure chamber can be reduced without operating the ejector. For this reason, unnecessary operation of the ejector can be reduced, fluctuations in the intake air amount can be prevented, and appropriate air-fuel ratio control can be realized.

  Further, the vehicle control device according to the present invention is a vehicle control device installed in a vehicle in which the negative pressure from the engine intake system supplied to the brake booster can be amplified by the ejector, and is sucked into the engine based on the operating state of the ejector. The correction means which correct | amends the amount of intake air to be performed is provided.

  According to the present invention, since the amount of intake air taken into the engine when the ejector is operating can be accurately calculated, appropriate air-fuel ratio control can be realized.

ADVANTAGE OF THE INVENTION According to this invention, the vehicle control apparatus which can perform the air fuel ratio control of the engine of a vehicle appropriately can be provided.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.
(First embodiment)
FIG. 1 is a schematic configuration diagram of a vehicle control apparatus according to the present embodiment.

  As shown in FIG. 1, the vehicle control device 1 according to this embodiment is a device that controls the operation of the ejector 2, and realizes appropriate air-fuel ratio control through the operation control of the ejector 2. The vehicle control device 1 is installed in a vehicle (not shown) provided with an ejector 2. The ejector 2 amplifies the negative pressure supplied to the brake booster 3.

  As the ejector 2, for example, an ejector that amplifies negative pressure when air is supplied to the venturi portion 2 a and stops negative pressure amplification when the air supply is stopped is used. The negative pressure supplied to the brake booster 3 is supplied from the intake system of the engine 4, for example, the intake manifold 5, and the negative pressure is amplified by the operation of the ejector 2.

  The brake booster 3 multiplies the depressing force of the brake pedal 10 by negative pressure and transmits it to the master cylinder 11 to operate a brake (not shown). The brake pedal 10 is provided with a stop switch 12 that detects whether or not the brake is depressed.

  The negative pressure chamber 3 a of the brake booster 3 is connected to the intake manifold 5 via the ejector 2. A throttle valve 21 is disposed in the intake system 20 on the upstream side of the intake manifold 5. The throttle valve 21 is operated by a throttle motor 22.

  An air cleaner 23 is installed on the upstream side of the throttle valve 21. A bypass path 30 is connected to the air cleaner 23 separately from the intake system 20 in which the throttle valve 21 and the like are installed. The bypass path 30 is a flow path that communicates between the air cleaner 23 and the ejector 2.

  A vacuum switching valve 31 that distributes and shields the bypass path 30 is disposed in the bypass path 30. By opening and closing the vacuum switching valve 31, the circulation and shielding of the bypass passage 30 can be switched, and the operation of the ejector 2 can be controlled by the switching.

  That is, by opening the vacuum switching valve 31, air is supplied to the ejector 2 through the bypass passage 30, and the ejector 2 is activated by the air supply, and the negative pressure supplied to the brake booster 3 is increased. On the other hand, by closing the vacuum switching valve 31, the bypass path 30 is in a shielded state, and the supply of air to the ejector 2 is stopped. Thereby, the operation of the ejector 2 is stopped, and the amplification of the negative pressure supplied to the brake booster 3 is stopped.

  The pressure in the negative pressure chamber 3 a of the brake booster 3 is measured by the pressure sensor 25. Further, the intake pipe pressure of the intake manifold 5 is measured by the pressure sensor 26. The pressure sensor 25 and the pressure sensor 26 are each connected to an ECU (Electronic Control Unit) 40, and a detection signal is input to the ECU 40.

  The ECU 40 controls the entire apparatus and includes, for example, a CPU, a ROM, a RAM, an input signal circuit, an output signal circuit, a power supply circuit, and the like. The ECU 40 outputs a control signal to the vacuum switching valve 31 and controls the operation of the ejector 2 through the operation control of the vacuum switching valve 31.

  The ECU 40 also outputs a control signal to the throttle motor 22 to control the throttle opening of the throttle valve 21. Further, the detection signal of the stop switch 12 is input to the ECU 40.

  Next, the operation of the vehicle control device according to the present embodiment will be described.

  FIG. 2 shows a flowchart of the operation of the vehicle control device according to this embodiment. Each control process of this flowchart is executed by the ECU 40 unless otherwise specified. As shown in S10 of FIG. 2, it is first determined whether or not a predetermined time T1 has elapsed since the engine 4 was started.

  Here, the predetermined time T1 is a set time set in advance in the ECU 40, and is set to 1 second, for example. When it is determined that the predetermined time T1 has not elapsed since the start of the engine 4, the process proceeds to S18, the operation of the ejector 2 is prohibited, and the ejector 2 is in the operation stop state. That is, an operation stop control signal is output from the ECU 40 to the vacuum switching valve 31, the vacuum switching valve 31 is closed, the bypass path 30 is blocked, and the ejector 2 is inactivated.

  On the other hand, when it is determined that the predetermined time T1 has elapsed since the start of the engine 4, the routine proceeds to S12, where it is determined whether or not the pressure condition is satisfied. For example, it is determined whether or not the intake pipe pressure of the intake manifold 5 is higher than a predetermined pressure p1. The predetermined pressure p1 is a pressure value set in advance in the ECU 40. For example, a pressure (50 kPa) obtained by subtracting 50 kPa from the atmospheric pressure (100 kPa) is set.

  The intake manifold pressure of the intake manifold 5 may be based on the detection signal of the pressure sensor 26, but is estimated based on the amount of intake air taken into the engine 4 when the installation of the pressure sensor 26 is omitted. May be.

  For example, an intake air amount detection means such as an air flow meter is installed in the intake system 20, and the intake pipe pressure PM [kPa] is calculated by the following equation (1) based on the intake air amount detected by the intake air amount detection means. Calculate.

PM = (KLSM / KLMAX) * KPA * 101.325 (1)
In equation (1), KLSM is the intake pipe load factor [%] and is calculated by (intake air amount / exhaust amount) * 100. KLMAX is the maximum intake pipe load factor [%], and is calculated from the maximum value of the intake pipe load factor for each engine rotation and valve timing. KPA is an atmospheric pressure correction value, and is calculated based on KLSM and KLTA (intake pipe load factor increase value) in a stable operation state. For example, this KPA is calculated by the following equation (2).

KPA = KLSM / KLTA (2)
In S12, the pressure condition may be whether or not the pressure in the negative pressure chamber 3a of the brake booster 3 is higher than the predetermined pressure p2. In this case, when the pressure in the negative pressure chamber 3a of the brake booster 3 is higher than the predetermined pressure p2, it is determined that the pressure condition is satisfied. In this case, the pressure value based on the detection signal of the pressure sensor 25 may be used as the pressure in the negative pressure chamber 3a. The predetermined pressure p2 is a pressure value set in advance in the ECU 40. For example, a pressure (50 kPa) obtained by subtracting 50 kPa from the atmospheric pressure (100 kPa) is set.

  In S12, when the intake pipe pressure of the intake manifold 5 is equal to or lower than the predetermined pressure p1, or the pressure in the negative pressure chamber 3a is equal to or lower than the predetermined pressure p2, it is determined that the negative pressure is large and the pressure condition is not satisfied, and S18 , The operation of the ejector 2 is prohibited, and the ejector 2 is turned off.

  On the other hand, when the intake pipe pressure of the intake manifold 5 is higher than the predetermined pressure p1 or the pressure of the negative pressure chamber 3a is higher than the predetermined pressure p2 in S12, it is determined that the negative pressure is small and the pressure condition is satisfied, and the process goes to S14. Transition.

  In S14, it is determined whether or not the vehicle speed V of the vehicle is faster than a predetermined vehicle speed V1. As the vehicle speed V, for example, a vehicle speed value read based on a detection signal of a vehicle speed sensor (not shown) installed in the vehicle is used. The predetermined vehicle speed V1 is a vehicle speed value set in advance in the ECU 40, and is set to 3 km / h, for example.

  When it is determined in S14 that the vehicle speed V of the vehicle is not higher than the predetermined vehicle speed V1, the process proceeds to S18, the operation of the ejector 2 is prohibited, and the ejector 2 is turned off. On the other hand, when it is determined that the vehicle speed V of the vehicle is faster than the predetermined vehicle speed V1, the process proceeds to S16 and the ejector 2 is turned on.

  That is, an operation control signal is output from the ECU 40 to the vacuum switching valve 31, and the vacuum switching valve 31 is opened. For this reason, the bypass path 30 is in a state where it can flow, and air is supplied to the ejector 2 through the bypass path 30. As a result, the ejector 2 is activated, and the negative pressure supplied to the negative pressure chamber 3a is amplified. Then, the control process ends.

  As described above, according to the vehicle control apparatus 1 according to the present embodiment, the intake air amount is immediately after the engine 4 is started by prohibiting the operation of the ejector 2 until the predetermined time T1 has elapsed after the engine 4 is started. Can be prevented from being promoted by the operation of the ejector 2, and appropriate air-fuel ratio control can be realized.

  Further, in the vehicle control apparatus 1 according to the present embodiment, when the pressure condition of S12 is whether or not the intake pipe pressure of the engine 4 is not less than the predetermined pressure p1, the pressure in the negative pressure chamber 3a of the brake booster 3 is the predetermined pressure. Even if it is higher, the operation of the ejector 2 is prohibited when the intake pipe pressure of the engine 4 is not more than a predetermined pressure. In this case, since the intake pipe pressure is low even if the pressure in the negative pressure chamber 3a of the brake booster 3 is higher than a predetermined pressure, the pressure in the negative pressure chamber 3a can be reduced without operating the ejector 2. By performing such control processing, unnecessary operation of the ejector 2 can be reduced, and fluctuations in the intake air amount due to the operation of the ejector 2 can be prevented, and appropriate air-fuel ratio control can be realized.

Further, by prohibiting the operation of the ejector 2 when it is determined that the vehicle speed V of the vehicle is not faster than the predetermined vehicle speed V1, the operation of the ejector 2 during low-speed traveling is prohibited. Thereby, the action | operation of the ejector 2 can be reduced and appropriate air fuel ratio control is realizable.
(Second embodiment)
Next, a vehicle control device according to the second embodiment will be described.

  The vehicle control device according to the present embodiment has the same hardware configuration as the vehicle control device according to the first embodiment shown in FIG. 1, but the operation of the ejector 2 is based on the operating state of the brake stop switch 12. It differs from the vehicle control device according to the first embodiment in that control is performed.

  FIG. 3 shows a flowchart of the operation of the vehicle control device according to this embodiment. Each control process of this flowchart is executed by the ECU 40 unless otherwise specified. As shown in S20 of FIG. 3, it is determined whether or not a predetermined time T1 has elapsed since the engine 4 was started. For example, 1 second is set as the predetermined time T1.

  When it is determined that the predetermined time T1 has not elapsed since the start of the engine 4, the process proceeds to S28, in which the operation of the ejector 2 is prohibited, and the ejector 2 enters an operation stop state.

  On the other hand, when it is determined that the predetermined time T1 has elapsed since the start of the engine 4, the routine proceeds to S22, where the predetermined time T2 has elapsed since the brake stop switch 12 was turned off. It is determined whether or not. The predetermined time T2 is a set time set in advance in the ECU 40, and is set to 5 seconds, for example.

  In S22, when it is determined that it is not before the predetermined time T2 has elapsed from when the brake stop switch 12 is switched from on to off, the process proceeds to S28, in which the operation of the ejector 2 is prohibited and the ejector 2 is deactivated. It becomes a state.

  On the other hand, if it is determined that the predetermined time T2 has not elapsed since the brake stop switch 12 was turned off, the process proceeds to S24, where it is determined whether the vehicle speed V is higher than the predetermined vehicle speed V1. To be judged. The predetermined vehicle speed V1 is a vehicle speed value set in advance in the ECU 40, and is set to 3 km / h, for example.

  When it is determined in S24 that the vehicle speed V of the vehicle is not higher than the predetermined vehicle speed V1, the process proceeds to S28, the operation of the ejector 2 is prohibited, and the ejector 2 is turned off. On the other hand, when it is determined that the vehicle speed V of the vehicle is faster than the predetermined vehicle speed V1, the process proceeds to S26 and the ejector 2 is turned on. Then, the control process ends.

  In addition, the process of S20, S24, and S26 mentioned above is performed similarly to S10, S14, and S16 of 1st embodiment.

  As described above, according to the vehicle control apparatus of the present embodiment, the intake air amount is reduced immediately after the engine 4 is started by prohibiting the operation of the ejector 2 until the predetermined time T1 has elapsed after the engine 4 is started. Instability can be prevented from being promoted by the operation of the ejector 2, and appropriate air-fuel ratio control can be realized.

  Further, the consumed negative pressure can be recovered by operating the ejector 2 under a certain condition for a predetermined time T2 from when the brake stop switch 12 is turned off.

Further, by prohibiting the operation of the ejector 2 when it is determined that the vehicle speed V of the vehicle is not higher than the predetermined vehicle speed V1, unnecessary operation of the ejector 2 can be reduced, and appropriate air-fuel ratio control can be realized.
(Third embodiment)
Next, a vehicle control device according to the third embodiment will be described.

  The vehicle control device according to the present embodiment has the same hardware configuration as the vehicle control device according to the first embodiment shown in FIG. 1, but the correction control is performed on the intake air amount when the ejector 2 is operated. Thus, the vehicle control device according to the first embodiment and the second embodiment is different.

  In FIG. 4, the flowchart about operation | movement of the vehicle control apparatus which concerns on this embodiment is shown. FIG. 5 shows a calculation map of the correction amount used in the intake air amount correction process in S32 of FIG. Each control process in the flowchart in FIG. 4 is executed by the ECU 40.

  As shown in S30 of FIG. 4, it is determined whether or not the ejector 2 is in the on state. That is, an operation control signal is output from the ECU 40 to the vacuum switching valve 31, and it is determined whether the vacuum switching valve 31 is opened and the ejector 2 is in an operating state.

  When it is determined in S30 that the ejector 2 is not in the on state, the control process is terminated. On the other hand, when it is determined that the ejector 2 is in the ON state, the process proceeds to S32, and a correction process of the intake air amount to the engine 4 is performed.

  This correction process is a process for calculating the corrected intake air amount by subtracting the correction amount from the normal intake air amount detected by the intake air amount detecting means such as an air flow meter. By this correction processing, it is possible to appropriately correct an increase in the amount of air sucked through the bypass passage 30 by the operation of the ejector 2.

  At this time, the correction amount is set based on the intake pipe pressure, and is calculated by using, for example, a map as shown in FIG. As the intake pipe pressure, a pressure value measured by a pressure sensor may be used, or a pressure value estimated by calculation may be used. Note that the intake pipe pressure in FIG. 5 is a relative pressure value with respect to a predetermined reference pressure.

  As described above, according to the vehicle control apparatus of the present embodiment, the intake air amount taken into the engine 4 when the ejector 2 is operated can be corrected and accurately calculated. Therefore, appropriate air-fuel ratio control can be realized based on the corrected intake air amount.

  In addition, by applying the vehicle when the vehicle is idling, the amount of idle air is appropriately adjusted according to the operation of the ejector 2, and appropriate air-fuel ratio control can be realized. As a result, it is possible to prevent the idling rotational speed from being shifted during idling.

1 is a schematic configuration diagram of a vehicle control device according to a first embodiment of the present invention. It is a flowchart about operation | movement of the vehicle control apparatus of FIG. It is a flowchart about operation | movement of the vehicle control apparatus which concerns on 2nd embodiment. It is a flowchart about operation | movement of the vehicle control apparatus which concerns on 3rd embodiment. It is the figure which showed the calculation map used for the intake air amount correction process in the vehicle control apparatus of FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle control apparatus, 2 ... Ejector, 3 ... Brake booster, 3a ... Negative pressure chamber, 4 ... Engine, 5 ... Intake manifold, 20 ... Intake system, 30 ... Bypass path, 31 ... Vacuum switching valve, 40 ... ECU.

Claims (3)

In a vehicle control device that controls the operation of an ejector that increases a negative pressure from an engine intake system supplied to a brake booster,
Prohibiting the operation of the ejector until a predetermined time has elapsed since the start of the engine;
A vehicle control device.   2. The operation of the ejector according to claim 1, wherein even if the pressure in the negative pressure chamber of the brake booster is higher than a predetermined pressure, the operation of the ejector is prohibited when the intake pipe pressure of the engine intake system is equal to or lower than the predetermined pressure. Vehicle control device. In a vehicle control device installed in a vehicle that can amplify a negative pressure from an engine intake system supplied to a brake booster by an ejector,
Comprising correction means for correcting the amount of intake air taken into the engine based on the operating state of the ejector;
A vehicle control device.

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