JP2007062459A - Controller for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce switching frequency to a supercharging area requiring increased fuel supply, improving fuel consumption. <P>SOLUTION: This controller is provided with a continuously variable transmission, which continuously changes output rotation of an internal combustion engine for transmitting it to a drive wheel, and a supercharger using emission energy for performing supercharging. When a boost pressure is within a predetermined cooperative boost area II (step S11) and an accelerator opening change rate ΔAPO is less than a predetermined value a (step S13), control is carried out for maintaining the boost pressure within the cooperative boost area II (step A19) while controlling the gear ratio to a low-speed side (steps A16-18). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine control device including a turbocharger and an automatic transmission.

Patent Document 1 discloses a control of a vehicle including a continuously variable transmission that continuously changes output rotation of an internal combustion engine and transmits the output to driving wheels, and a turbocharger that performs supercharging using exhaust energy. An apparatus is disclosed. In this device, the speed of the continuously variable transmission is increased in order to accelerate the rise of the supercharging pressure during acceleration.
JP 2003-39989 A

  In a vehicle equipped with a turbocharger as described above, in the negative pressure region where the boost pressure is lower than atmospheric pressure (0 kPa), the air-fuel ratio is generally set to the lean side with an emphasis on fuel efficiency. On the other hand, in the supercharging region where the boost pressure exceeds the atmospheric pressure (0 kPa), the fuel injection amount is increased in order to avoid an excessive increase in exhaust temperature and knocking due to supercharging. As compared with the air-fuel ratio, the air-fuel ratio is set closer to rich. Therefore, when the vehicle is frequently switched from the negative pressure region to the supercharging region during practical running, the fuel increase is performed each time, and the fuel consumption increases. In particular, in a supercharged vehicle using a turbocharger in order to reduce the size of the internal combustion engine and reduce the displacement, supercharging is performed from a relatively low load region. Even in the driving range often used during practical driving, such as constant driving and slow acceleration, there is a tendency to frequently switch from the negative pressure range to the supercharging range. Since the effect diminishes, countermeasures have been desired.

  The present invention has been made in view of such a problem, and is a novel vehicle that can improve fuel efficiency by suppressing the frequency of switching to a supercharging region where fuel increase is performed without impairing drivability. The main purpose is to provide a control device.

  In a vehicle control device comprising: an automatic transmission that shifts the output rotation of an internal combustion engine and transmits the output rotation to drive wheels; and a supercharger that performs supercharging using exhaust energy, the boost pressure of the internal combustion engine is detected A boost detection means; a boost area determination means for determining whether the boost pressure is in a predetermined cooperative boost area; an acceleration request detection means for detecting an acceleration request; and a predetermined cooperative acceleration area based on the acceleration request. An acceleration region determining means for determining whether there is a boost control means for controlling the boost pressure, a shift control means for controlling the gear ratio of the automatic transmission, the cooperative boost region, and a cooperative acceleration region. In this case, it is characterized by having cooperative control means for cooperatively controlling the boost pressure and the gear ratio so as to maintain the boost pressure within the cooperative boost region.

  According to the present invention, by cooperatively controlling the gear ratio and the boost pressure, the boost pressure is maintained in a predetermined cooperative boost region without impairing drivability, and the boost pressure is increased in the supercharging region where fuel increase is performed. The frequency of switching can be suppressed and the fuel consumption can be effectively reduced.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a system configuration of a vehicle according to the present invention. This vehicle includes an internal combustion engine 10 that generates rotational power by burning fuel, an automatic transmission 11 that shifts the output rotation of the internal combustion engine 10 and transmits it to drive wheels 12, and excess energy using exhaust energy. And a turbocharger 13 for feeding. The internal combustion engine 10 is a spark ignition type gasoline engine having an ignition plug. However, a compression self-ignition diesel engine may be used. The automatic transmission 11 is preferably a continuously variable transmission capable of continuously changing the gear ratio steplessly or continuously like a well-known belt-type continuously variable transmission or toroidal continuously variable transmission. As is well known, the supercharger 13 includes a turbine 15 provided in the exhaust passage 14, a compressor 17 provided in the intake passage 16, and a rotating shaft 18 that couples both 15 and 17 so as to rotate together. When the turbine 15 rotates according to the exhaust amount (exhaust energy), the compressor 17 is rotationally driven via the rotary shaft 18 to supercharge the intake air amount.

  In the intake passage 16, an electronically controlled throttle valve 20 that opens and closes the intake passage 16 is provided on the upstream side of the compressor 17, and a plurality of intake branch passages 16 </ b> A connected to each cylinder of the internal combustion engine 10 are provided. An intake flow control valve 21 for controlling the tumble flow and swirl flow of the intake air flowing into the cylinder is provided. The exhaust passage 14 is provided with a bypass passage 22 that bypasses the turbine 15 and an electronically controlled waste gate valve 23 that opens and closes the bypass passage 22.

  Further, as various sensors for detecting the driving state of the vehicle, a boost pressure sensor 24 for detecting a pressure in the intake passage 16 downstream of the throttle valve 20, that is, a boost pressure (boost), a driver's acceleration request / acceleration intention In addition to the accelerator opening sensor 25 that detects the opening of the corresponding accelerator pedal, an oil temperature sensor, a water temperature sensor, and the like are provided. The control unit (control unit: C / U) 30 is mainly composed of a microcomputer, and in addition to engine control processing such as fuel injection control and ignition timing control, based on detection signals from the various sensors described above. Control processing such as the opening degree of the throttle valve 20, the opening degree of the waste gate valve 23, the opening degree of the suction flow control valve 21, and the gear ratio of the continuously variable transmission 11 is stored and executed.

  FIG. 2 is a characteristic diagram showing the relationship between the engine (engine) speed and the boost pressure. In the normal control in step S14 of FIG. 3 described later, the boost pressure (intake air amount) and the gear ratio are controlled so that the fuel consumption is minimized. Specifically, in the negative pressure regions I and II where the boost pressure is lower than 0 kPa corresponding to atmospheric pressure, the air-fuel ratio is set to the lean side. However, in the supercharging region III where the boost pressure exceeds 0 kPa, the fuel is increased in order to avoid an excessive increase in exhaust temperature and knocking due to supercharging, compared to the negative pressure regions I and II. The air-fuel ratio is set closer to rich. For this reason, when the fuel pressure is frequently switched from the negative pressure regions I and II to the supercharging region III, the amount of fuel is increased each time, so that the fuel consumption increases and the fuel efficiency is impaired.

  In particular, the present embodiment is a so-called fuel-efficient supercharged vehicle that uses a turbocharger 13 in order to reduce the size of the internal combustion engine 10 and reduce the displacement, and from a relatively low load range. Since supercharging is performed, there is a tendency to frequently switch from the negative pressure regions I and II to the supercharging region III even in an operation region that is often used during practical traveling, such as constant traveling operation or slow acceleration operation. There is a specific problem that the fuel efficiency improvement effect due to the downsizing of the engine, which is the original purpose, is reduced.

  Therefore, in the present embodiment, the following control is performed in order to suppress the frequency of switching to the supercharging region III. 3 to 5 are flowcharts showing examples of the control, and this routine is repeatedly executed, for example, every predetermined short period (10 ms or a predetermined crank angle). 6 and 7 are time charts during slow acceleration according to the present embodiment.

  In step S11, it is determined whether the boost pressure is in a predetermined cooperative boost region II. This cooperative boost region II is a negative pressure region in the vicinity of 0 kPa corresponding to atmospheric pressure, that is, a region II adjacent to the supercharging region III among the negative pressure regions I and II, and has a predetermined reference boost pressure (negative pressure). ) A band having a predetermined width 2b centered on Bt.

  In step S12, based on the accelerator opening APO detected by the accelerator opening sensor 25, an accelerator opening change rate ΔAPO corresponding to the acceleration request by the driver is calculated. This ΔAPO is obtained, for example, by the difference between the accelerator opening APO one calculation before and the current accelerator opening APO.

  In step S13, it is determined whether the accelerator opening change rate ΔAPO is greater than 0 and less than a predetermined determination value a. That is, based on the accelerator opening change rate ΔAPO corresponding to the driver's acceleration request, it is determined whether or not it is a cooperative acceleration region corresponding to constant speed running and slow acceleration driving.

  When both step S11 and step S14 are affirmed, that is, only in the cooperative boost region II and the cooperative acceleration region, the process proceeds to step S15 and subsequent steps while maintaining the boost pressure in the cooperative boost region II. The boost pressure and the gear ratio are cooperatively controlled so as to obtain a predetermined target driving force. In other operating ranges, the process proceeds to step S14, and the normal control described above is performed.

  In step S15, the target driving force is calculated based on the accelerator opening APO. In step S16, the target gear ratio of the continuously variable transmission 11 is calculated so that the boost pressure is maintained in the cooperative boost region II while ensuring the target driving force. More specifically, the target gear ratio is corrected to the low speed side, that is, the lowest side where the engine speed increases so that an acceleration feeling according to the driver's acceleration request can be obtained even during slow acceleration.

  In step S17, it is determined whether or not the target gear ratio can be set. Specifically, it is determined whether or not the boost pressure can be maintained in the cooperative boost region II when the target gear ratio can be set, that is, at a higher speed side than the lowest and when the target gear ratio is set. . If the target gear ratio cannot be set, the process proceeds from step S17 to step S14, and the normal control described above is performed.

  If the target speed ratio can be set, the process proceeds from step S17 to step S18, and a command signal corresponding to the target speed ratio set in step S16 is output to the continuously variable transmission 11, and the speed ratio is set to the target speed ratio. Control toward the low speed side (low gear). In the subroutine of step S19, control is performed so that the boost pressure is maintained within the cooperative boost region II.

  FIG. 4 shows an example of the boost pressure control subroutine of step S19 in FIG. In this example, based on the detection signal of the boost pressure sensor 24, the opening degree TVO of the throttle valve 20 is fed back so as to maintain the boost pressure in the vicinity of the target value Bt (negative value) that is the reference boost pressure. Control (see FIG. 7). Specifically, in step S21, the actual boost pressure B0 is calculated based on the detection signal output from the boost pressure sensor 24. In step S22, a deviation ΔB (Bt−B0) of the actual boost pressure B0 with respect to the target value Bt is calculated. In step S23 and step S24, it is determined whether the deviation ΔB is out of the band 2b of the cooperative boost region II. If the actual boost pressure B0 is lower than the cooperative boost region II, the process proceeds from step S23 to step S25, the throttle opening TVO is increased by a predetermined value ΔTVO, and if the actual boost pressure B0 is higher than the cooperative boost region II, the process proceeds from step S24 to step S26. As a result, the throttle opening TVO is decreased by a predetermined value ΔTVO.

  FIG. 5 shows another example of the boost pressure control subroutine of step S19 of FIG. In this example, based on the detection signal of the boost pressure sensor 24, the opening WGVO of the waste gate valve 23 is set so as to maintain the boost pressure in the vicinity of the target value Bt (negative value) that is the reference boost pressure. Feedback control is performed (see FIG. 7). Specifically, in step S21, the actual boost pressure B0 is calculated based on the detection signal output from the boost pressure sensor 24. In step S22, a deviation ΔB (Bt−B0) of the actual boost pressure B0 with respect to the target value Bt is calculated. In step S23 and step S24, it is determined whether the deviation ΔB is out of the band 2b of the cooperative boost region II. If the actual boost pressure B0 is lower than the cooperative boost region II, the process proceeds from step S23 to step S25A, the opening degree WGVO is decreased by a predetermined value ΔWGVO, and if the actual boost pressure B0 is higher than the cooperative boost region II, the process proceeds from step S24 to step S26A. The opening degree WGVO is increased by a predetermined value ΔWGVO.

  According to the present embodiment as described above, the boost pressure and the gear ratio are cooperatively controlled in a cooperative acceleration region such as constant running or slow acceleration operation, thereby giving an acceleration feeling corresponding to the driver's acceleration request. However, the boost pressure can be maintained within the cooperative boost region II. Therefore, the fuel consumption performance can be improved by suppressing the frequency of switching to the supercharging region III where fuel increase is performed without impairing drivability.

  Next, the technical features and operational effects of the present invention will be described with reference to the above embodiments. However, the present invention is not limited to the configurations of the embodiments to which reference numerals are attached, and includes various modifications and changes without departing from the spirit of the present invention. For example, in the above embodiment, the cooperative boost region II is simply set as a negative pressure region having a constant width 2b in the vicinity of the atmospheric pressure. However, the present invention is not limited to this. Any low region is acceptable.

  (1) In a control apparatus for a vehicle, comprising: an automatic transmission 11 that shifts the output rotation of an internal combustion engine 10 and transmits the output rotation to drive wheels 12; and a supercharger 13 that performs supercharging using exhaust energy. Boost detection means (boost pressure sensor 24) for detecting the boost pressure of the engine 10, boost region determination means (step S11) for determining whether the boost pressure is in a predetermined cooperative boost region II, and an acceleration request are detected. Acceleration request detecting means (accelerator opening sensor 25), acceleration area determining means (step S13) for determining whether the vehicle is in a predetermined cooperative acceleration area based on the acceleration request, and boost control means for controlling the boost pressure Shift control means for controlling the gear ratio of the automatic transmission 11, and the boost in the case of the cooperative boost region II and the cooperative acceleration region. Cooperative boost to maintain in the region II, has a cooperative control means (step S15 to S19) for cooperatively controlling the said boost pressure and speed ratio.

  According to such a configuration, by supervising the gear ratio and the boost pressure, the boost pressure is maintained in the cooperative boost region II and the fuel increase is performed without impairing drivability. The frequency of switching to can be reduced, and fuel efficiency can be improved.

  (2) Preferably, the cooperative control means controls the boost pressure to be maintained in the cooperative boost region II while controlling the speed ratio to the low speed side (steps S15 to S18). Thus, by controlling the gear ratio to the low speed side, it is possible to appropriately give an acceleration feeling according to the driver's acceleration request.

  (3) Typically, the cooperative boost region II is a negative pressure region near atmospheric pressure. That is, the cooperative boost region II corresponds to a band in the vicinity of the supercharging region III where fuel increase is performed in the negative pressure regions I and II.

  (4) In particular, when the cooperative acceleration region corresponds to constant speed driving operation and slow acceleration operation that frequently appear during practical driving, as in the fuel-efficient vehicle of the above embodiment, the above cooperative control is performed. The fuel efficiency improvement effect by is very effective.

  (5) When the electronically controlled throttle valve 20 that opens and closes the intake passage 16 is provided, the boost pressure can be controlled by controlling the opening TVO of the throttle valve 20.

  (6) Alternatively, when an electrically controlled waste gate valve 23 that opens and closes the bypass passage 22 that bypasses the turbine 15 of the supercharger 13 is provided, the boost pressure can be increased by controlling the opening WGVO of the waste gate valve 23. Can be controlled.

  (7) Preferably, the opening degree of the throttle valve or the waste gate valve is feedback-controlled based on the detection signal (B0) of the boost detection means. By performing feedback control in this way, the boost pressure can be maintained in the cooperative boost region II with high accuracy.

  (8) The automatic transmission is preferably a continuously variable transmission 11 that continuously changes the output rotation of the internal combustion engine 10. In this case, since the gear ratio can be controlled steplessly, the above-described cooperative control can be performed with higher accuracy. However, the present invention can also be applied to a vehicle equipped with a known stepped transmission.

1 is a system configuration diagram of a vehicle to which an embodiment of the present invention is applied. The characteristic view which shows the area | region according to an engine speed and boost pressure. The flowchart which shows the flow of control of a present Example. FIG. 4 is a flowchart showing an example of a boost control subroutine of FIG. 3. FIG. 4 is a flowchart showing another example of the boost control subroutine of FIG. 3. FIG. The time chart at the time of slow acceleration which concerns on a present Example. Similarly, a time chart during slow acceleration.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine 11 ... Continuously variable transmission (automatic transmission)
DESCRIPTION OF SYMBOLS 12 ... Drive wheel 13 ... Supercharger 14 ... Exhaust passage 15 ... Turbine 16 ... Intake passage 20 ... Throttle valve (boost control means)
22 ... Bypass passage 23 ... Waste gate valve (boost control means)
24 ... Boost pressure sensor (boost detection means)
25. Accelerator opening sensor (acceleration request detecting means)
30 ... Control unit

Claims (8)

In a vehicle control device comprising: an automatic transmission that shifts the output rotation of an internal combustion engine and transmits the output rotation to driving wheels; and a supercharger that performs supercharging using exhaust energy.
Boost detecting means for detecting the boost pressure of the internal combustion engine;
Boost region determination means for determining whether the boost pressure is in a predetermined cooperative boost region;
An acceleration request detecting means for detecting an acceleration request;
Acceleration region determination means for determining whether the vehicle is in a predetermined cooperative acceleration region based on the acceleration request;
Boost control means for controlling the boost pressure;
Shift control means for controlling the gear ratio of the automatic transmission;
A cooperative control means for cooperatively controlling the boost pressure and the gear ratio so as to maintain the boost pressure in the cooperative boost region in the cooperative boost region and the cooperative acceleration region;
A control apparatus for an internal combustion engine, comprising:   2. The internal combustion engine according to claim 1, wherein the cooperative control unit controls the boost pressure within a cooperative boost region while controlling a speed ratio to a low speed side in response to an acceleration request. Control device.   The control device for an internal combustion engine according to claim 1 or 2, wherein the cooperative boost region is a negative pressure region near atmospheric pressure.   The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the cooperative acceleration region is a region corresponding to constant speed running and slow acceleration operation. The boost pressure control means includes an electrically controlled throttle valve that opens and closes the intake passage,
The control apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the cooperative control means controls the boost pressure by controlling the opening of the throttle valve. The boost pressure control means comprises an electrically controlled wastegate valve that opens and closes a bypass passage that bypasses the turbocharger turbine;
The control apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the cooperative control means controls the boost pressure by controlling the opening degree of the waste gate valve.   7. The control apparatus for an internal combustion engine according to claim 5, wherein the cooperative control means feedback-controls the opening degree of the throttle valve or waste gate valve based on a detection signal of the boost detection means. 8. The control device for an internal combustion engine according to claim 1, wherein the automatic transmission is a continuously variable transmission that continuously changes the output rotation of the internal combustion engine.

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