JP4186706B2 - Vehicle control apparatus and control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to fuel supply and stop control for an engine, which is a drive source of a vehicle, and more particularly to control for stopping fuel supply during deceleration in order to improve fuel efficiency.
[0002]
[Prior art]
Control to stop fuel supply during deceleration to improve fuel efficiency, so-called fuel cut control, improves fuel efficiency by reducing fuel supply to the engine as much as possible without compromising driving performance and riding comfort. Control. In general, the supply of fuel is stopped when the engine speed enters a predetermined range during deceleration while the engine is idling. More specifically, the fuel supply is stopped when the throttle valve is closed while the engine is running and the engine speed is gradually reduced to a value equal to or lower than the fuel cut speed that defines the upper limit of the range. When the engine speed further decreases and reaches a return speed that defines the lower limit of the range, the fuel supply is resumed. The return rotational speed is set to a rotational speed that does not cause an engine stall and maintains a stable rotational speed of the engine. From the viewpoint of improving fuel efficiency, it is desirable that the return rotational speed from the fuel cut is set low and the fuel cut is performed for as long as possible.
[0003]
Such fuel cut control is basically executed based on the engine speed. For example, unless the driver performs a sudden braking operation or the like, the vehicle is in a coast down state, and when the running resistance is substantially constant, the engine speed is decelerated at a substantially constant rate. That is, basically, the engine speed has a tendency to decrease almost linearly to satisfy the driver's feeling of deceleration. When the engine speed is within the fuel cut region, the fuel is cut and the fuel is reduced. Various techniques have been disclosed that extend the cut time as much as possible (that is, do not lower the engine speed below the return speed from the fuel cut).
[0004]
Japanese Patent Laid-Open No. 7-166902 (Patent Document 1) discloses a fuel cut device for an engine that performs fuel cut in as wide a range as possible reflecting the driver's intention when the vehicle is decelerated. The engine fuel cut device includes a detection unit that detects when the vehicle is decelerating, a sensor that detects the engine speed, and a fuel supply unit that supplies fuel in an operating state where the engine speed is equal to or greater than a reference value NC1 when the vehicle decelerates. The fuel cut circuit for stopping the engine, the circuit for detecting that the downshift operation of the transmission is performed, and the downshift operation is performed in the driving state where the engine speed is not less than the reference value NC2 lower than the reference value NC1 when the vehicle is decelerated. And a fuel cut circuit for stopping the fuel supply of the fuel supply unit immediately after the fuel is supplied.
[0005]
According to the fuel cut device disclosed in this publication, when the downshift operation of the transmission is performed in an operating state in which the fuel cut is performed in an operating state where the engine speed is equal to or greater than the reference value NC1 when the vehicle is decelerated, Subsequently, fuel cut is continued. When the engine speed increases to a reference value NC2 or more by performing a downshift operation of the transmission in an operating state in which fuel is supplied in an operating state where the engine speed is lower than the reference value NC1 when the vehicle is decelerated. A fuel cut is performed. That is, when the downshift operation of the transmission is performed during deceleration of the vehicle, the rotational range in which the fuel cut is performed can be lowered from NC1 to NC2, so that the effectiveness of the engine brake can be enhanced and the fuel consumption can be reduced.
[0006]
Japanese Patent Application Laid-Open No. 8-11591 (Patent Document 2) discloses a control device that improves fuel consumption by performing fuel cut for as long as possible without causing an abnormality in the operation of the engine. In the control device disclosed in this publication, an automatic transmission that performs a shift based on a plurality of parameters including a parameter corresponding to a vehicle speed is connected to an engine, and the engine speed during deceleration is within a predetermined range. A fuel supply control device for a vehicle with an automatic transmission that stops supply of fuel to an engine. The control device includes an engine speed prediction circuit that predicts an engine speed when a downshift is executed in the vicinity of a return speed for restarting fuel supply, and the predicted engine speed is a return speed. And a fuel cut continuation circuit that continues to stop the supply of fuel when the rotational speed is higher.
[0007]
According to the control device disclosed in this publication, the fuel supply to the engine is stopped when the engine speed gradually falls during the deceleration and enters a predetermined range. When the engine speed further decreases and approaches the return speed that defines the lower limit of the range, the engine speed prediction circuit calculates the engine speed at the speed set by the downshift from the current speed. Predict. If the predicted engine speed is higher than the return speed at which the fuel supply is resumed, the fuel cut continuation circuit continues to stop the fuel supply. In other words, if the engine is decelerated with a decrease in engine speed and, as a result, a downshift occurs, the fuel speed may be temporarily lower than the return speed even if the engine speed temporarily falls in the process. Will continue to stop supply and improve fuel efficiency.
[0008]
In addition, Patent Documents 3 to 5 disclose techniques for improving fuel efficiency by extending the fuel cut time in the same manner.
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 7-166902
[0010]
[Patent Document 2]
Japanese Patent Laid-Open No. 8-11591
[0011]
[Patent Document 3]
JP-A-9-86227
[0012]
[Patent Document 4]
JP 10-259751 A
[0013]
[Patent Document 5]
JP 2002-161771 A
[0014]
[Problems to be solved by the invention]
By the way, the vehicle is equipped with a compressor of an air conditioner (hereinafter referred to as “air conditioner”) that is a load on the engine, which is called an auxiliary machine, and an alternator that generates electric power to charge a secondary battery. Has been. Since these auxiliary machines are engine loads, if these loads increase during the fuel cut, the return rotational speed from the fuel cut is increased to prevent the engine from stalling. If the return rotational speed from the fuel cut is increased, the time during which the fuel cut is executed is shortened, which is a problem in terms of improving fuel consumption.
[0015]
However, the techniques disclosed in any of the above-mentioned patent documents do not take into consideration the problem that the time during which the fuel cut is executed due to the fluctuation in the return rotational speed from the fuel cut by such an accessory is shortened. .
[0016]
The present invention has been made to solve the above-described problems, and its object is to increase the fuel cut time by extending the fuel cut time in consideration of the state of accessories that affect the engine mounted on the vehicle. It is providing the control apparatus and control method of a vehicle which can implement | achieve improvement of this.
[0017]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a vehicle control device that is mounted on a vehicle and a fuel cut execution means for executing fuel cut when the engine speed is within a predetermined range during deceleration of the vehicle. Detecting means for detecting the load state of the auxiliary machine driven by the vehicle, changing means for changing the range according to the load state of the auxiliary machine, and automatic transmission of the vehicle so as not to deviate from the changed range And control means for controlling.
[0018]
According to the first invention, when the fuel cut is executed during the coast down, the load state of the auxiliary machine is detected by the detecting means, and the range of the fuel cut is changed by the changing means according to the load state of the auxiliary machine. Is done. For example, when the engine load is increased by an air conditioner compressor or alternator, the engine speed is changed so that the return rotation speed from the fuel cut increases. The control means monitors such an increase in the return rotational speed, and in such a case, sets the coast down point (determined by the vehicle speed or the like at the timing of downshift during the coast down). change. That is, even if the fuel cut return rotational speed increases, the engine rotational speed is increased by lowering the engine rotational speed so that the engine rotational speed does not fall below the fuel rotational return rotational speed (by increasing the gear ratio of the automatic transmission). . However, when the coast down point is changed to the high speed side, it is preferable that the low speed side is possible as long as the engine speed exceeding the fuel cut return rotational speed can be obtained. This is to suppress the deterioration of drivability due to the occurrence of a shift shock caused by downshifting at high speed. As a result, even if the fuel cut return rotational speed is changed so as to increase, the engine cut speed does not fall below the changed fuel cut return rotational speed, so that the fuel cut is continued. As a result, it is possible to provide a vehicle control device that can improve fuel efficiency by extending the fuel cut time in consideration of the state of auxiliary equipment that affects the engine mounted on the vehicle.
[0019]
In the vehicle control device according to the second aspect of the invention, in addition to the configuration of the first aspect, the range defines the fuel cut return rotational speed that is the engine rotational speed when returning from the fuel cut. The changing means includes means for changing the range so as to increase the fuel cut return rotational speed when the load state becomes high. The control means includes means for controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed.
[0020]
According to the second invention, when the operating state of the auxiliary machine is changed and the engine load increases, the engine speed is changed so that the return rotational speed from the fuel cut increases. In such a case, the coast down point is changed to the high speed side. In other words, even if the fuel cut return speed increases, the engine speed is increased to increase the engine speed by increasing the gear ratio of the automatic transmission so that the engine speed does not fall below the return speed from the fuel cut. . Thereby, the fuel cut is continuously performed, and the fuel cut time can be extended to improve the fuel consumption.
[0021]
According to a third aspect of the present invention, in addition to the configuration of the first aspect, the vehicle control apparatus automatically controls the control means when the engine speed is predicted to deviate from the range when the range is changed by the changing means. Determining means is further included for deciding to execute the control operation of the transmission with priority over the range changing operation by the changing means.
[0022]
According to the third aspect of the present invention, when the operating state of the accessory is changed and the engine load increases, the range in which the fuel cut is executed is changed so that, for example, the return rotational speed from the fuel cut increases. When the engine speed is predicted to deviate from the range in which the fuel cut is performed due to such a change in the range, that is, when the engine speed is predicted to be lower than the fuel cut return speed, the determination is made. The means gives priority to the control of the automatic transmission prior to such a range change. Specifically, priority is given to downshifting of an automatic transmission. After downshifting first to increase the engine speed, the return speed from the fuel cut is changed. In this way, the engine speed that has been raised in advance does not fall below the return speed from the fuel cut, so the fuel cut is continued, and the fuel cut time can be extended to improve fuel efficiency. .
[0023]
In the vehicle control apparatus according to the fourth aspect of the invention, in addition to the configuration of the third aspect of the invention, the range defines the fuel cut return rotational speed that is the engine rotational speed when returning from the fuel cut. The changing means includes means for changing the range so as to increase the fuel cut return rotational speed when the load state becomes high. The control means includes means for controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed. If the engine speed is predicted to be lower than the fuel cut return speed when the fuel cut return speed is increased by the change means, the determining means changes the automatic transmission after downshifting the automatic transmission. Means for determining to increase the fuel cut return rotational speed by the means is included.
[0024]
According to the fourth invention, when the operating state of the auxiliary machine is changed and the engine load increases, the engine speed is changed so that the return rotational speed from the fuel cut increases, but the downshift is performed prior to this change. It is. Since the downshift is performed first, the return rotational speed from the fuel cut is increased with the engine rotational speed increased. For this reason, the engine speed that has been increased by the downshift in advance does not fall even if the engine speed is changed from the fuel cut that has been changed to increase, so the fuel cut is continued and the fuel cut time The fuel consumption can be improved by extending
[0025]
In the vehicle control apparatus according to the fifth invention, in addition to the configuration of any one of the first to fourth inventions, the auxiliary machine is a compressor of an air conditioner, and the vehicle control apparatus according to the sixth invention In addition to the structure of any one of the 1st-4th invention, in addition, an auxiliary machine is generators, such as an alternator and a generator.
[0026]
According to the fifth and sixth aspects of the invention, when the fuel cut is being performed during the coast down, for example, when the compressor or alternator of the air conditioner starts to operate, the engine load increases. This will increase the return rotation speed. Therefore, it is monitored that the return rotational speed from the fuel cut is increased, and the engine rotational speed is increased by downshifting so as not to fall below the return rotational speed. In addition, after giving priority to downshifting and increasing the engine speed, the return speed from the fuel cut is increased. Thereby, the fuel cut is continuously performed, and the fuel cut time can be extended to improve the fuel consumption.
[0027]
According to a seventh aspect of the present invention, there is provided a vehicle control method, comprising: a fuel cut execution step for executing fuel cut when the engine speed is within a predetermined range during deceleration of the vehicle; A detection step for detecting the load state of the auxiliary machine, a change step for changing the range according to the load state of the auxiliary machine,
And a control step for controlling the automatic transmission of the vehicle so as not to deviate from the changed range.
[0028]
According to the seventh invention, when the fuel cut is executed during the coast down, the load state of the auxiliary machine is detected at the detecting step, and the range of the fuel cut is determined according to the load state of the auxiliary machine at the changing step. Is changed. For example, when the engine load is increased by an air conditioner compressor or alternator, the engine speed is changed so that the return rotation speed from the fuel cut increases. The control step monitors that the return rotational speed increases, and in such a case, changes the coast down point. That is, even if the fuel cut return rotational speed increases, the engine rotational speed is increased by downshifting so that the engine rotational speed does not fall below the return rotational speed from the fuel cut. As a result, even if the fuel cut return rotational speed is changed so as to increase, the engine cut speed does not fall below the changed fuel cut return rotational speed, so that the fuel cut is continued. As a result, it is possible to provide a vehicle control method that can improve fuel efficiency by extending the fuel cut time in consideration of the state of auxiliary equipment that affects the engine mounted on the vehicle.
[0029]
In the vehicle control method according to the eighth aspect of the invention, in addition to the configuration of the seventh aspect, the range defines the fuel cut return rotational speed that is the engine rotational speed when returning from the fuel cut. The changing step includes a step of changing the range so as to increase the fuel cut return rotational speed when the load state becomes high. The control step includes a step of controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed.
[0030]
According to the eighth aspect of the present invention, when the operating state of the auxiliary machine is changed and the engine load is increased, the return rotational speed from the fuel cut is increased. In such a case, the coast down point is changed to the high speed side. In other words, even if the fuel cut return speed increases, the engine speed is increased to increase the engine speed by increasing the gear ratio of the automatic transmission so that the engine speed does not fall below the return speed from the fuel cut. . Thereby, the fuel cut is continuously performed, and the fuel cut time can be extended to improve the fuel consumption.
[0031]
In addition to the configuration of the seventh invention, the vehicle control method according to the ninth invention is automatic by the control step when the engine speed is predicted to deviate from the range when the range is changed by the change step. The method further includes a determination step for determining to execute the control operation of the transmission with priority over the range change operation by the change step.
[0032]
According to the ninth aspect of the present invention, when the operating state of the accessory is changed and the engine load increases, the range in which the fuel cut is executed is changed, for example, so that the return rotational speed from the fuel cut increases. When the engine speed is predicted to deviate from the range in which the fuel cut is performed due to such a change in the range, that is, when the engine speed is predicted to be lower than the fuel cut return speed, the determination is made. In the step, the control of the automatic transmission is prioritized before such a range change. Specifically, priority is given to downshifting of an automatic transmission. After downshifting first to increase the engine speed, the return speed from the fuel cut is changed. In this way, the engine speed that has been raised in advance does not fall below the return speed from the fuel cut, so the fuel cut is continued, and the fuel cut time can be extended to improve fuel efficiency. .
[0033]
In the vehicle control method according to the tenth aspect of the invention, in addition to the configuration of the ninth aspect, the range defines the fuel cut return rotation speed that is the engine rotation speed when returning from the fuel cut. The changing step includes a step of changing the range so as to increase the fuel cut return rotational speed when the load state becomes high. The control step includes a step of controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed. If the engine speed is predicted to fall below the fuel cut return speed when the fuel cut return speed is increased by the change step, the decision step is changed after the automatic transmission is downshifted by the control step. The step of determining to increase the fuel cut return rotational speed by the step is included.
[0034]
According to the tenth aspect of the invention, when the operating state of the auxiliary machine is changed and the engine load is increased, the return rotational speed from the fuel cut is changed so as to increase, but the downshift is performed prior to this change. It is. Since the downshift is performed first, the return rotational speed from the fuel cut is increased with the engine rotational speed increased. For this reason, the engine speed that has been increased by the downshift in advance does not fall even if the engine speed is changed from the fuel cut that has been changed to increase, so the fuel cut is continued and the fuel cut time The fuel consumption can be improved by extending
[0035]
In the vehicle control method according to the eleventh invention, in addition to the configuration of any of the seventh to tenth inventions, the auxiliary machine is a compressor of an air conditioner, and the vehicle control method according to the twelfth invention. In addition to the structure of any one of the seventh to tenth inventions, the auxiliary machine is a generator such as an alternator or a generator.
[0036]
According to the eleventh and twelfth aspects of the present invention, when the fuel cut is being performed during coast down, for example, when the compressor or alternator of the air conditioner starts operating, the engine load increases. This will increase the return rotation speed. Therefore, it is monitored that the return rotational speed from the fuel cut is increased, and the engine rotational speed is increased by downshifting so as not to fall below the return rotational speed. In addition, after giving priority to downshifting and increasing the engine speed, the return speed from the fuel cut is increased. Thereby, the fuel cut is continuously performed, and the fuel cut time can be extended to improve the fuel consumption.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
[0038]
Hereinafter, a power train of a vehicle including a control device according to an embodiment of the present invention will be described. The control device according to the present embodiment is realized by an ECU (Electronic Control Unit) 1000 shown in FIG. In the present embodiment, the automatic transmission is described as an automatic transmission having a torque coupling with a fluid coupling and a planetary gear type reduction mechanism.
[0039]
The present invention is not limited to such a configuration. The fluid coupling may be a fluid coupling instead of a torque converter, and the automatic transmission may be a continuously variable transmission such as a belt type. There may be. In the case of a continuously variable transmission, the gear stage in the following description is a gear ratio.
[0040]
With reference to FIG. 1, the power train of the vehicle including the control device according to the present embodiment will be described. More specifically, the control device according to the present embodiment is realized by ECT (Electronic Controlled Automatic Transmission) _ECU 1020 shown in FIG. The control device according to the present embodiment may be realized by engine ECU 1010 or another ECU other than these.
[0041]
As shown in FIG. 1, the power train of this vehicle includes an engine 100, a torque converter 200, an automatic transmission 300, and an ECU 1000.
[0042]
The output shaft of engine 100 is connected to the input shaft of torque converter 200. Engine 100 and torque converter 200 are connected by a rotating shaft. Therefore, output shaft speed NE (engine speed NE) of engine 100 detected by engine speed sensor 400 and input shaft speed (pump speed) of torque converter 200 are the same.
[0043]
The torque converter 200 includes a lock-up clutch 210 that directly connects the input shaft and the output shaft, a pump impeller 220 on the input shaft side, a turbine impeller 230 on the output shaft side, and a one-way clutch 250. It is comprised from the stator 240 which expresses an amplification function. Torque converter 200 and automatic transmission 300 are connected by a rotating shaft. The output shaft rotational speed NT (turbine rotational speed NT) of the torque converter 200 is detected by a turbine rotational speed sensor 410. The output shaft rotational speed NO of the automatic transmission 300 is detected by the output shaft rotational speed sensor 420.
[0044]
FIG. 2 shows an operation table of the automatic transmission 300. According to the operation table shown in FIG. 2, the clutch elements (C1 to C4 in the figure), the brake elements (B1 to B4), and the one-way clutch elements (F0 to F3) that are friction elements are in any gear. Shows what is combined and released. At the first speed used when the vehicle starts, the clutch element (C1) and the one-way clutch elements (F0, F3) are engaged. Among these clutch elements, the clutch element C1 is particularly referred to as an input clutch 310. The input clutch 310 is also referred to as a forward clutch or a forward clutch, and as shown in the operation table of FIG. 2, the vehicle moves forward except for the parking (P) position, the reverse traveling (R) position, and the neutral (N) position. Therefore, it is always used in the engaged state when the shift stage is configured.
[0045]
The ECU 1000 that controls these power trains includes an engine ECU 1010 that controls the engine 100, an ECT_ECU 1020 that controls the automatic transmission 300, a Vehicle Stability Control (VSC) _ECU 1030, and an auxiliary ECU 1040 that controls the compressor and alternator of the air conditioner. Including. These compressors and alternators are examples of auxiliary machines, and the auxiliary machines may be other devices. The compressor of the air conditioner may be either a variable displacement compressor or a fixed displacement compressor.
[0046]
The ECT_ECU 1020 receives a signal representing the turbine rotational speed NT from the turbine rotational speed sensor 410 and a signal representing the output shaft rotational speed NOUT from the output shaft rotational speed sensor 420. The ECT_ECU 1020 also sends a signal representing the engine speed NE detected by the engine speed sensor 400, a signal representing the throttle opening detected by the throttle position sensor, and the cooling water for the engine 100 from the engine ECU 1010. And a signal representing the engine coolant temperature detected by the temperature sensor for detecting.
[0047]
These rotation speed sensors are provided to face the teeth of the rotation detection gear attached to the input shaft of torque converter 200, the output shaft of torque converter 200, and the output shaft of automatic transmission 300. These rotational speed sensors are sensors that can detect slight rotations of the input shaft of the torque converter 200, the output shaft of the torque converter 200, and the output shaft of the automatic transmission 300. This is a sensor using a magnetoresistive element.
[0048]
From the ECT_ECU 1020 to the automatic transmission 300, a control signal to the linear solenoid (SLT) for controlling the line pressure, a control signal to the linear solenoid (SLU) for slip control of the lockup clutch 210, FIG. A control signal is output to the transmission solenoid in order to shift to the gear stage shown in FIG. Based on the solenoid control signal, the line pressure is adjusted, the slip control of the lock-up clutch 210 is performed, and the clutch, brake or one-way clutch of the automatic transmission 300 is engaged or released to reduce the planetary gear type deceleration. Form the desired gear stage in the mechanism.
[0049]
The ECT_ECU 1020 receives a signal representing the load state of the auxiliary machine from the auxiliary machine ECU 1040. Based on this auxiliary machine load state signal, ECT_ECU 1020 (or another ECU including engine ECU 1010, which is ECT_ECU 1020 in the present embodiment) changes the return rotational speed from the fuel cut.
[0050]
With reference to FIG. 3, a map showing the fuel cut area stored in the memory of ECT_ECU 1020 will be described. This map defines the fuel cut region by a function of the rotation speed of the engine 100 with respect to the engine coolant temperature. In this map, the start speed and the return speed of the fuel cut are stored. When the fuel cut is started as the vehicle decelerates, as shown in FIG. 3, the engine is within a range defined by the start speed of the fuel cut (including a range equal to or higher than the start speed) and the return speed. When there is a rotational speed, the fuel cut is executed when other conditions are satisfied. It should be noted that the fuel-cut starting rotational speed is determined so long as the engine speed is equal to or higher than the starting rotational speed (in the range equal to or higher than the starting rotational speed in FIG. 3), the fuel-cut starting rotational speed is satisfied. Means you can start.
[0051]
For example, when the engine 100 is in an idle state and the fuel cut is being executed when the vehicle is decelerated, is the current engine speed 100 higher than the fuel cut return speed shown in FIG. If it is greater than the fuel cut return rotational speed, the fuel cut at the time of deceleration is continued, and if it is less than the fuel cut return rotational speed, the fuel injection from the fuel cut execution state at the time of deceleration is performed. Return to the execution state (return from fuel cut).
[0052]
When this fuel cut is being performed, the lockup clutch 210 of the torque converter 200 is slip-controlled (including the deceleration flex lockup control) on state), so that the rotational speed of the engine 100 is not suddenly reduced. As a result, the time during which the fuel cut is being performed can be kept long, and at the same time, an appropriate engine brake can be secured.
[0053]
In such a map, when the load state of the auxiliary machine fluctuates so that the load of the engine 100 increases (for example, the compressor of the air conditioner is activated), the compressor 100 is driven by the engine 100. In order to prevent engine stall, control is performed to increase the return rotational speed from the fuel cut. If the return speed of the fuel cut is increased, it will be easier to return from the fuel cut, and the fuel efficiency will deteriorate. Even in such a case, the ECT_ECU 1020 that is the control device according to the present embodiment can extend the fuel cut execution time as much as possible to improve fuel efficiency.
[0054]
A control structure of a program executed by ECT_ECU 1020 shown in FIG. 1 will be described with reference to FIG.
[0055]
In step (hereinafter step is abbreviated as S) 100, ECT_ECU 1020 determines whether or not a fuel cut is currently in progress. If the fuel is currently being cut (YES in S100), the process proceeds to S200. If not (NO in S100), the process proceeds to S600.
[0056]
In S200, ECT_ECU 1020 calculates a predicted value of the fuel cut return rotational speed. In this process, the fuel cut return rotational speed (increase) is predicted according to the degree of increase in the load on the auxiliary machine depending on the operating state of the compressor or alternator of the air conditioner that is the auxiliary machine input to the ECT_ECU 1020 from the auxiliary machine ECU 1040. Is done. The range of increase in the return rotational speed from the fuel cut is set in advance in accordance with the degree of fluctuation in the load of the auxiliary machine input from the auxiliary machine ECU 1040.
[0057]
In S300, ECT_ECU 1020 determines whether or not engine speed NE is equal to or less than (fuel cut return speed predicted value + α). Here, α is a positive value. The engine speed is detected based on an engine speed signal input to ECT_ECU 1020 via engine ECU 1010. If engine speed NE is equal to or smaller than (fuel cut return rotational speed predicted value + α) (YES in S300), the process proceeds to S400. If not (NO in S300), the process proceeds to S500.
[0058]
At S400, ECT_ECU 1020 resets the fuel cut rotation speed changeable flag. When the fuel cut return rotational speed changeable flag is in the reset state, it is determined that the fuel cut return rotational speed cannot be changed. Thereafter, the process proceeds to S700.
[0059]
In S500, ECT_ECU 1020 calculates a coast-down point based on the fuel cut return rotational speed. At this time, the coast down point to be downshifted is calculated based on the current vehicle speed, the gear stage, and the predicted value of the fuel cut return rotational speed calculated in S200.
[0060]
In S600, ECT_ECU 1020 determines whether or not output shaft rotation speed NOUT is equal to or less than the coast down point. The output shaft rotation speed NOUT is detected by the output shaft rotation speed sensor 420 and detected based on the output shaft rotation speed signal input to the ECT_ECU 1020. If output shaft rotation speed NOUT is equal to or less than the coast down point (YES in S600), the process proceeds to S700. If not (NO in S600), the process proceeds to S800.
[0061]
In S700, ECT_ECU 1020 transmits a control signal to the transmission solenoid of automatic transmission 300 to cause a downshift.
[0062]
In S800, ECT_ECU 1020 sets the fuel cut return rotation speed changeable flag to the set state. When the fuel cut return rotation speed changeable flag is set, the fuel cut return rotation speed can be changed.
[0063]
In S900, ECT_ECU 1020 changes the return rotation speed from the fuel cut. At this time, the fuel cut return rotational speed is changed to the fuel cut return rotational speed predicted value calculated in S200, and the fuel cut return rotational speed is increased.
[0064]
The operation of the vehicle equipped with the control device according to the present embodiment based on the structure and flowchart as described above will be described.
[0065]
During the fuel cut (YES in S100), the load of the compressor and alternator of the air conditioner increases, and the fuel cut return rotational speed prediction value is calculated (S200). When current engine speed NE is detected and engine speed NE is equal to or less than (fuel cut return speed predicted value + α) (YES in S300), the fuel cut return speed changeable flag is reset (S400). ), A downshift is executed before the fuel cut return rotational speed is changed (S700). Thereafter, the fuel cut return rotation speed changeable flag is set (S800), and the fuel cut return rotation speed is changed (S900).
[0066]
As shown in FIG. 5, when the fuel cut return rotational speed predicted value is calculated during the fuel cut, and the engine speed NE becomes equal to or less than (fuel cut return rotational speed predicted value + α), the gear stage is reduced from the fourth speed to the third speed. The engine speed NE is increased as a result of the shift. At this time, the engine speed decreases to the vicinity of the region A, but the engine speed NE increases because the gear ratio increases due to the downshift. After downshifting, the fuel cut return rotational speed changeable flag is set, and the fuel cut return rotational speed is increased by an amount corresponding to the load increase.
[0067]
At this time, since the speed change operation from the 4th speed to the 3rd speed has already been completed, the engine speed NE is still higher than the fuel cut return speed that has increased due to the load change. Therefore, fuel cut is continuously performed.
[0068]
If engine speed NE is larger than (fuel cut return speed predicted value + α) (YES in S300), a coast down point is calculated based on the fuel cut return speed (S500). At this time, even if the fuel cut return rotational speed is so increased based on the predicted value that the fuel cut return rotational speed increases as the load increases, the engine rotational speed NE increases as fuel cut continues. As such, a coast down point is calculated.
[0069]
As shown in FIG. 5, the coast down point is calculated so that the vehicle speed becomes the coast down point after the change from the coast down point before the change. When output shaft rotation speed NOUT is equal to or less than the coast down point (YES in S600), a downshift is executed (S700).
[0070]
As described above, according to the control device according to the present embodiment, when the engine load is increased by the compressor or alternator of the air conditioner, the fuel cut return rotation speed is increased by increasing the return rotation speed from the currently set fuel cut. A predicted value is calculated. When it is detected that the fuel cut return rotational speed is predicted, the coast down point is changed to the high speed side in such a case. That is, the coast down point is changed so that the engine speed is shifted down so that the engine speed does not fall below the return speed from the fuel cut (predicted increase value) even if the fuel cut return speed increases. Thereby, the engine speed can be increased so that the engine speed does not fall below the fuel cut return speed.
[0071]
As long as the engine speed that exceeds the fuel cut return speed is obtained, the coast down point is changed as low as possible to avoid downshifting at high speed as much as possible, and high-speed downshifting is possible. It is also possible to suppress the deterioration of drivability due to the occurrence of a shift shock due to.
[0072]
In addition, when the operating condition of the compressor or alternator of the air conditioner is changed and the engine load increases, a predicted fuel cut return speed is calculated so that the return speed from the fuel cut increases. A downshift is performed prior to changing to a predicted number. Since the engine is first downshifted, the return rotational speed from the fuel cut is changed to the predicted fuel cut return rotational speed with the engine speed increased. For this reason, even if the engine speed that has already been increased by the downshift is the return speed from the fuel cut that has been changed to increase (the predicted value of the fuel cut return speed), it will not fall below that. Fuel cut is continuously performed, and the fuel cut time can be extended to improve fuel efficiency.
[0073]
The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
[Brief description of the drawings]
FIG. 1 is a control block diagram of a vehicle according to an embodiment of the present invention.
FIG. 2 is an operation table of the automatic transmission shown in FIG.
FIG. 3 is a diagram showing a fuel cut area stored in an ECU.
FIG. 4 is a diagram showing a control structure of a program executed by an ECU.
FIG. 5 is a timing chart showing the operation of the vehicle equipped with the automatic transmission according to the embodiment of the present invention.
[Explanation of symbols]
100 engine, 200 torque converter, 210 lock-up clutch, 220 pump impeller, 230 turbine impeller, 240 stator, 250 one-way clutch, 300 automatic transmission, 310 input clutch, 400 engine speed sensor, 410 turbine speed sensor, 420 Output shaft speed sensor, 1000 ECU, 1010 Engine ECU, 1020 ECT_ECU, 1030 VSC_ECU, 1040 Auxiliary ECU.

Claims (12)

A fuel cut executing means for executing fuel cut when the engine speed is within a predetermined range during deceleration of the vehicle;
Detecting means for detecting an operating state of an auxiliary machine mounted on the vehicle and driven by an engine;
Changing means for changing the range according to the operating state of the auxiliary machine;
Control means for controlling the automatic transmission of the vehicle so as not to deviate from the changed range. The range defines a fuel cut return rotational speed that is an engine speed when returning from the fuel cut.
The changing means includes means for changing the range so as to increase the fuel cut return rotational speed when the load of the engine increases due to a change in the operating state of the auxiliary machine .
The vehicle control device according to claim 1, wherein the control means includes means for controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed.   When the engine speed is predicted to deviate from the range when the range is changed by the changing means, the vehicle control device changes the control operation of the automatic transmission by the control means. The vehicle control device according to claim 1, further comprising a determination unit configured to determine to execute the range change operation with priority over the unit. The range defines a fuel cut return rotational speed that is an engine speed when returning from the fuel cut.
The changing means includes means for changing the range so as to increase the fuel cut return rotational speed when the load of the engine increases due to a change in the operating state of the auxiliary machine .
The control means includes means for controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed,
If the engine speed is predicted to be lower than the fuel cut return speed when the change means increases the fuel cut return speed, the determining means lowers the automatic transmission by the control means. The vehicle control device according to claim 3, further comprising means for determining that the fuel cut return rotational speed is increased by the changing means after the shift.   The vehicle control device according to claim 1, wherein the auxiliary machine is a compressor of an air conditioner.   The vehicle control device according to claim 1, wherein the auxiliary machine is a generator. A fuel cut execution step for executing fuel cut when the engine speed is within a predetermined range during deceleration of the vehicle;
A detection step of detecting an operating state of an auxiliary machine mounted on the vehicle and driven by an engine;
A change step of changing the range according to the operating state of the auxiliary machine;
And a control step of controlling the automatic transmission of the vehicle so as not to deviate from the changed range. The range defines a fuel cut return rotational speed that is an engine speed when returning from the fuel cut.
The changing step includes a step of changing the range so as to increase the fuel cut return rotational speed when the load of the engine increases due to a change in the operating state of the auxiliary machine ,
The vehicle control method according to claim 7, wherein the control step includes a step of controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed.   In the vehicle control method, when the engine speed is predicted to deviate from the range when the range is changed by the change step, the control operation of the automatic transmission by the control step is changed. The vehicle control method according to claim 7, further comprising a determination step of determining to perform the operation with priority over the range changing operation by the step. The range defines a fuel cut return rotational speed that is an engine speed when returning from the fuel cut.
The changing step includes a step of changing the range so as to increase the fuel cut return rotational speed when the load of the engine increases due to a change in the operating state of the auxiliary machine ,
The control step includes a step of controlling the automatic transmission to downshift so as not to fall below the fuel cut return rotational speed,
In the determining step, if the engine speed is predicted to be lower than the fuel cut return rotational speed when the fuel cut return rotational speed is increased by the changing step, the automatic transmission is lowered by the control step. The vehicle control method according to claim 9, comprising a step of determining to increase the fuel-cut return rotational speed by the changing step after shifting.   The vehicle control method according to claim 7, wherein the auxiliary machine is an air conditioner compressor.   The vehicle control method according to claim 7, wherein the auxiliary machine is a generator.

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