JP2015001259A - Drive system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive system which raises an oil temperature when the oil temperature is low, and suppresses the lowering of the drivability of a vehicle.SOLUTION: A drive system 1 comprising a power transmission device 3 having a plurality of friction fastening elements comprises: oil temperature detection means 13 which detects a temperature of oil for cooling a plurality of the friction fastening elements; deceleration determination means 5 which detects whether or not a vehicle is decelerated; oil temperature control means 5 which brings a specified friction fastening element in a released state out of a plurality of the friction fastening elements into a slip state when the temperature of the oil is lower than a prescribed oil temperature and the vehicle is decelerated, and raises the temperature of the oil by heat which is generated by the specified friction fastening element in the slip state; and brake control means 6 which reduces a wheel brake force on the basis of a brake force which is generated by the specified friction fastening element in the slip state.

Description

  The present invention relates to a drive system.

  Patent Document 1 discloses that when the temperature of the oil is low, the engagement force of the friction brake mechanism is increased and the temperature of the oil is increased by frictional heat generated by the friction brake mechanism.

JP 2010-48286 A

  However, in the above-described technology, there is a problem in that, by increasing the engagement force of the friction brake mechanism, a deceleration higher than the deceleration intended by the driver may occur, a shock may occur, and the drivability deteriorates. There is a point.

  Further, if the increase in the engagement force is suppressed so as not to deteriorate the drivability, the temperature rise of the oil is suppressed. Therefore, the state where the oil viscosity is high and the power loss of the power transmission device is large continues for a long time. There is a problem that the fuel consumption of the source deteriorates.

  The present invention has been invented to solve such problems, and even when the coupling force of the friction brake mechanism is increased, the drivability is prevented from deteriorating and the fuel efficiency of the power source is also deteriorated. It aims at suppressing this.

  A drive system according to an aspect of the present invention is a drive system including a power transmission device having a plurality of frictional engagement elements, and an oil temperature detection unit that detects the temperature of oil that cools the plurality of frictional engagement elements; Deceleration determining means for determining whether or not the vehicle is decelerating, and a specific frictional engagement element that is in a released state among a plurality of frictional engagement elements when the oil temperature is lower than a predetermined oil temperature and the vehicle is decelerating On the basis of the oil temperature control means for increasing the temperature of the oil by the heat generated by the specific frictional engagement element that is in the slip state, and the braking force generated by the specific frictional engagement element that is in the slip state, Braking force control means for reducing wheel braking force.

  According to this aspect, when the oil temperature is low and the vehicle is decelerating, the specific frictional engagement element in the released state is set to the slip state, and the braking force generated by the specific frictional engagement element in the slip state is reduced. By reducing the wheel braking force on the basis, it is possible to increase the temperature of the oil and improve the fuel efficiency of the engine, for example, and to suppress the deterioration of drivability.

It is a schematic block diagram of the vehicle drive system of this embodiment. It is a schematic block diagram of a hydraulic circuit. It is a skeleton figure which shows the gear train of the planetary gear transmission of an automatic transmission. It is a figure which shows the combination of the fastening and releasing state of each fastening element in an automatic transmission. It is a flowchart explaining brake force cooperation control. It is a figure which shows the relationship between target deceleration, oil temperature, and target oil pressure. It is a time chart which shows the change of the brake force in brake force cooperation control.

  A vehicle according to an embodiment of the present invention will be described with reference to the drawings.

[Vehicle configuration]
FIG. 1 is a schematic configuration diagram of a vehicle drive system according to the present embodiment.

(Drive system)
The drive system 1 includes an engine 2, which is a prime mover, an automatic transmission 3, an engine controller 4, an automatic transmission controller 5, an ABS controller 6, and various sensors 10-17.

  The automatic transmission 3 is a horizontal type for a front engine / front drive, and includes a torque converter 30, a planetary gear transmission 31 (see FIG. 3), and a final gear and a differential gear that are not shown. Torque generated in the engine 2 is input to the input shaft IN of the automatic transmission 3 through the torque converter 30. The planetary gear transmission 31 shifts the input rotation at a gear ratio corresponding to the selected shift speed, and transmits torque to the output shaft (not shown). Oil circulates in the automatic transmission 3, and lubrication and cooling of the fastening elements (friction fastening elements) and the like are performed by the oil.

  The various sensors 10 to 17 are the engine rotational speed sensor 10 that detects the engine rotational speed, the throttle opening sensor 11 that detects the throttle opening, the position of the range selected by the driver's operation of the select lever 7 or the selected position. Range position sensor 12 for detecting a gear position, oil temperature sensor 13 for detecting oil temperature, vehicle speed sensor 14 for detecting vehicle speed, brake fluid pressure sensor 15 for detecting brake fluid pressure, vehicle acceleration or deceleration detected G sensor 16 and wheel rotation sensor 17.

(Engine controller)
The engine controller 4 receives detection signals from the engine rotation sensor 10 and the throttle opening sensor 11 and outputs a control signal to the engine 2 to control the engine rotation speed and the like. Further, an engine rotation signal and a throttle opening signal are output to the automatic transmission controller 5.

(Automatic transmission controller)
The automatic transmission controller 5 performs shift control. That is, first, based on the vehicle speed signal and the throttle opening signal, the target shift stage is determined with reference to the shift schedule stored in advance in the automatic transmission controller 5. Secondly, the automatic transmission controller 5 outputs a shift command signal to the automatic transmission 3 and controls the engagement / release of the engagement element via the hydraulic circuit 32 to execute the shift. Achieve the stage.

(Hydraulic circuit)
FIG. 2 shows a hydraulic circuit 32 for the automatic transmission controller 5 to control the fastening / release of the fastening element. The hydraulic circuit 32 is provided with a plurality of hydraulic control valves 40 to 44 corresponding to a plurality of fastening elements. The automatic transmission controller 5 controls the hydraulic pressure supplied to each fastening element by outputting signals to these hydraulic control valves 40 to 44 and controlling the opening and closing thereof.

  Each engagement element, that is, low clutch L / C, high clutch H / C, 2-6 brake 2-6 / B, 3-5 reverse clutch 3-5R / C, low & reverse brake L & R / B is engaged respectively. The piston chambers 20 to 24 are fastened by being supplied with a D range pressure or an R range pressure as a fastening pressure, and released by releasing the fastening pressure.

  The line pressure PL is supplied to the manual valve 46 via the line pressure oil passage 60. The D range pressure and the R range pressure are line pressures PL through the manual valve 46, and are generated only when the D range and the R range are selected, respectively. The line pressure PL is supplied to the pilot valve 45, and the pilot valve 45 regulates the line pressure PL to generate a pilot pressure.

  The fastening pressure supplied to each said fastening piston chamber 20-24 is controlled by the 1st-5th hydraulic control valves 40-44 provided one each corresponding to each fastening element. The D range pressure from the manual valve 46 is supplied to the first to third hydraulic control valves 40 to 42 via the D range pressure oil passage 62. The fourth hydraulic control valve 43 is directly supplied with the line pressure PL, and the R range pressure from the manual valve 46 can also be supplied through the R range pressure oil passage 63. The fifth hydraulic control valve 44 is directly supplied with the line pressure PL. The pilot pressure is supplied to the hydraulic control valves 40 to 44 through the pilot pressure oil passage 61.

  The first hydraulic control valve 40 includes a duty solenoid 40a and a pressure regulating valve 40b. Similarly, the second to fifth hydraulic control valves 41 to 44 have duty solenoids 41a to 44a and pressure regulating valves 41b to 44b. Duty solenoids 40a to 44a generate a shift control pressure by a solenoid force using pilot pressure as a source pressure.

  The pressure regulating valves 40b to 42b of the first to third hydraulic control valves 40 to 42 are fastened to the fastening piston chambers 20 to 22 using the D range pressure as a source pressure and the shift control pressure and the feedback pressure as an operation signal pressure. Regulate each pressure.

  When the D range is selected, the pressure regulating valve 43b of the fourth hydraulic control valve 43 regulates the fastening pressure of the fastening piston chamber 23 using the line pressure PL as the original pressure and the transmission control pressure and the feedback pressure as the operation signal pressure. On the other hand, when the R range is selected, the line pressure PL, which is the R range pressure, is supplied as it is to the 3-5 reverse clutch 3-5R / C using the R range pressure as the operation signal pressure.

  The pressure regulating valve 44b of the fifth hydraulic control valve 44 regulates the fastening pressure of the fastening piston chamber 24 using the line pressure PL as the original pressure and the shift control pressure and the feedback pressure as the operation signal pressure.

(Gear train)
FIG. 3 is a skeleton diagram showing the gear train of the planetary gear transmission 31 of the automatic transmission 3.

  The planetary gear transmission 31 has a simple planetary gear set G1 and a Ravigneaux type planetary gear set G2. The planetary gear set G1 has a first sun gear S1, a first carrier C1, and a first ring gear R1, and inputs reduced rotation to the planetary gear set G2. The planetary gear set G2 includes a large-diameter second sun gear S2, a small-diameter third sun gear S3, a second carrier C2, and a second ring gear R2. The second carrier C2 supports a pair of pinions composed of a short pinion P1 and a long pinion P2. The short pinion P1 meshes with the third sun gear S3, and the long pinion P2 meshes with the second sun gear S2.

  The input shaft IN to which engine torque is input via the torque converter 30 is directly connected to the first ring gear R1 via the first member M1. The input shaft IN is coupled to the second carrier C2 via the second member M2 and the high clutch H / C.

  The first carrier C1 is coupled to the third sun gear S3 via the third member M3, the low clutch L / C, and the fifth member M5. The first carrier C1 is also coupled to the second sun gear S2 via the third member M3, the 3-5 reverse clutch 3-5R / C, and the sixth member M6.

  The first sun gear S1 is fixed to the transmission case TC via the fourth member M4. The sixth member M6 can be fixed to and released from the transmission case TC via the 2-6 brake 2-6 / B.

  The second carrier C2 is rotatably supported with respect to the transmission case TC via the seventh member M7 and the low & reverse brake L & R / B, and the rotation can be fixed and released. . The second carrier C2 is also supported so as to be rotatable in one direction with respect to the transmission case TC via the seventh member M7 and the low one-way clutch L / OWC, and the rotation direction thereof can be restricted. Yes. The low & reverse brake L & R / B and the low one-way clutch L / OWC are arranged in parallel so that one of the operations can be selected.

  The second ring gear R2 is connected to the output gear OUT via the eighth member M8.

(Combination of fastening elements)
The automatic transmission 3 configured as described above realizes six forward speeds (1st to 6th) and first reverse speed (Rev) by combining the fastening elements shown in FIG. In FIG. 4, ◯ indicates fastening, no marking indicates release, ○ indicates crossing, but it operates when the engine is braked, and ● indicates that it is mechanically engaged (rotation restriction) only when the engine is driven.

(ABS controller)
The ABS controller 6 receives input of output signals from signals from the wheel rotation sensor 17, the brake hydraulic pressure sensor 15, and the transmission controller 5, outputs a hydraulic signal to the ABS actuator 8, and provides hydraulic pressure for operating the wheel brake 9. Control and control wheel braking force.

[Brake force coordination control]
When the oil temperature is low, the automatic transmission controller 5 and the ABS controller 6 set the engagement element (specific friction engagement element) released at the time of braking to the slip state, and the engagement element (hereinafter referred to as slip) The engagement element to be brought into a state is referred to as a friction brake element). The slip state refers to a state in which the fastening element is not completely fastened but semi-fastened and a rotational speed difference is generated in the fastening element.

  The brake force cooperative control will be described using the flowchart shown in FIG.

  In step S100, the automatic transmission controller 5 determines whether or not the oil temperature detected based on the signal from the oil temperature sensor 13 is lower than a predetermined oil temperature. The predetermined oil temperature is a preset temperature that is slightly lower than the oil temperature at normal temperature. For example, when the temperature at normal temperature is 80 ° C., the predetermined temperature is 70 ° C. The process proceeds to step S101 when the oil temperature is lower than the predetermined oil temperature, and proceeds to step S111 when the oil temperature is equal to or higher than the predetermined oil temperature.

  In step S101, the automatic transmission controller 5 determines whether a shift is being performed. The process proceeds to step S102 when the shift is not being performed, and proceeds to step S111 when the shift is being performed.

  In step S102, the automatic transmission controller 5 selects a friction brake element based on the current shift speed. The friction brake element is a fastening element that is released at the current shift stage. The automatic transmission controller 5 selects, as a friction brake element, a fastening element that is fastened on the high speed (High) side among the gears. For example, when the current shift speed is 6th speed, the 3-5 reverse clutch 3-5R / C that is engaged when realizing the 5th speed shift speed is selected as the friction brake element. When the current shift speed is the fifth speed, the 2-6 brake 2-6 / B that is engaged when realizing the sixth speed is selected as the friction brake element. In this way, by selecting the fastening element that is fastened when realizing the gear stage that is likely to be changed thereafter as the friction brake element, it is possible to smoothly shift when the gear stage is changed. Further, by selecting the fastening element that is fastened on the high speed side as the friction brake element, it is possible to suppress the occurrence of shock when the friction brake element is in the slip state. In addition, when the vehicle decelerates, the gear stage is a high speed stage such as 6th speed, 5th speed, etc., and during this time, frictional heat is generated by the friction brake element that is originally released, Oil temperature can be raised quickly.

  In step S103, the automatic transmission controller 5 determines whether the vehicle is decelerating. Specifically, the automatic transmission controller 5 determines whether or not the brake pedal depression amount is larger than a predetermined depression amount based on a signal from the brake fluid pressure sensor 15, and the brake pedal depression amount is larger than the predetermined depression amount. Is larger, it is determined that the vehicle is decelerating, and when the depression amount of the brake pedal is equal to or smaller than the predetermined depression amount, it is determined that the vehicle is not decelerating. The process proceeds to step S104 if the vehicle is decelerating, and proceeds to step S111 if the vehicle is not decelerating.

  In step S104, the automatic transmission controller 5 calculates the target deceleration based on the brake pedal depression amount. The target deceleration increases as the brake pedal depression amount increases.

  In step S105, the automatic transmission controller 5 calculates the target hydraulic pressure of the friction brake element based on the target deceleration and the map shown in FIG. 6 based on the oil temperature. The target hydraulic pressure increases as the target deceleration increases and the oil temperature decreases. The map shown in FIG. 6 is set for each gear position.

  In step S106, the automatic transmission controller 5 supplies hydraulic pressure to the friction brake element based on the target hydraulic pressure, puts the friction brake element into a slip state, and generates friction heat in the friction brake element. The oil is warmed by this frictional heat, and the oil temperature rises.

  In step S107, the automatic transmission controller 5 determines whether the deceleration is higher than the target deceleration based on the output signal of the G sensor 16. The process proceeds to step S108 when the deceleration is higher than the target deceleration, and proceeds to step S109 when the deceleration is equal to or less than the target deceleration.

  In step S108, the ABS controller 6 controls the hydraulic pressure of the wheel brake 9 via the ABS actuator 8 to reduce the wheel brake force. Specifically, the ABS controller 6 reduces the current wheel braking force by a predetermined value. The predetermined value is a preset value.

  In step S109, the automatic transmission controller 5 determines whether the deceleration is lower than the target deceleration. The process proceeds to step S110 when the deceleration is lower than the target deceleration, and ends the current process when the deceleration is the target deceleration.

  In step S110, the ABS controller 6 controls the oil pressure of the wheel brake 9 via the ABS actuator 8 to increase the wheel brake force. Specifically, the ABS controller 6 increases the current wheel braking force by a predetermined value.

  In step S111, the automatic transmission controller 5 puts the friction brake element in a released state. For example, when performing a shift, the current shift speed is 6th speed, the shift speed after the shift is 5th speed, and the 3-5 reverse clutch 3-5R / C is selected as the friction brake element. Alternatively, the 3-5 reverse clutch 3-5R / C may be engaged without bringing the friction brake element into the released state.

  In the present embodiment, the ABS controller 6 increases or decreases the wheel brake force by a predetermined value. However, the present invention is not limited to this, and it is only necessary to be able to control the wheel brake force so that the deceleration becomes the target deceleration.

  As described above, in the present embodiment, when the oil temperature is low and the vehicle is decelerating, the oil temperature is increased by the frictional heat generated by the friction brake element, and the wheel is further driven based on the braking force generated by the friction brake element. The brake force is controlled to generate a desired brake force according to the amount of depression of the brake pedal.

  The relationship between the brake pedal depression amount when the oil temperature is lower than the predetermined temperature and the vehicle is not decelerating and decelerating, the braking force in the friction brake element, and the wheel braking force is shown in the time chart of FIG. explain.

  When the brake pedal is depressed at time t0 and the friction brake element slips at time t1, the wheel brake force is reduced according to the brake force generated in the friction brake element. In FIG. 7, the wheel brake force when the brake force is generated only by the wheel brake 51 without making the friction brake element in the slip state is indicated by a broken line. In the present embodiment, the wheel brake force is reduced according to the brake force generated by the friction brake element, and the sum of the wheel brake force and the brake force generated by the friction brake element is generated only by the wheel brake 51. The braking force is almost equal to the case where it is applied.

[Effect of the embodiment]
The effect of the embodiment of the present invention will be described.

  When the oil temperature is low and the vehicle is decelerating, the friction brake element is put into a slip state, the oil is warmed by the frictional heat generated by the slipped friction brake element, and the brake force generated by the friction brake element is increased. Based on the wheel brake force is reduced. By increasing the oil temperature, it is possible to reduce power loss (loss due to oil agitation resistance or the like) in the fastening element, improve fuel efficiency of the engine 1, and reduce carbon dioxide emission. Moreover, it can suppress that the braking force more than the braking force which a driver | operator desires generate | occur | produces, and it can suppress that drivability deteriorates. In addition, when the oil temperature is low, the oil temperature can be increased without using a heating device (ATF former) that warms the oil, and the cost can be reduced. Further, when the oil temperature is low, control for limiting the drivability of the vehicle, for example, control for limiting the use of the high speed stage, control for limiting lock-up of the torque converter 30, and the like may be performed. It is possible to suppress the execution of simple control (effect corresponding to claim 1).

  By selecting a fastening element that is fastened on the high speed side as the friction brake element, it is possible to suppress the occurrence of a shock when the friction brake element is brought into a slip state. In addition, when the vehicle decelerates, the speed of the gear shift stage is relatively long, and by selecting the fastening element that is originally released at this time as the friction brake element, friction heat is generated by the friction brake element. The time which generate | occur | produces can be lengthened and oil temperature can be raised rapidly (effect corresponding to Claim 2).

  By controlling the target hydraulic pressure of the friction brake element based on the target deceleration and the oil temperature, it is possible to promote an increase in the oil temperature according to the state of the vehicle and to suppress a decrease in drivability. For example, if the target deceleration of the friction brake element is too high when the target deceleration is small, a shock may occur when the friction brake element is brought into a slip state. In the present embodiment, the oil temperature can be quickly raised while suppressing the occurrence of such a shock (effect corresponding to claim 3).

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  In the above embodiment, the target hydraulic pressure of the friction brake element is calculated based on the target deceleration. However, the target hydraulic pressure of the friction brake element may be calculated based on the brake pedal depression amount.

  In the above embodiment, the description is given using a vehicle equipped with a stepped transmission. However, a vehicle using a continuously variable transmission may be used, and in this case, a frictional engagement element such as a forward / reverse switching mechanism or a subtransmission mechanism is used. By setting it as a slip state, it can suppress that drivability deteriorates, raising oil temperature similarly to the said embodiment.

3 Automatic transmission (power transmission device)
5 Automatic transmission controller (deceleration judgment means, oil temperature control means, deceleration calculation means)
6 ABS controller (brake force control means)
13 Oil temperature sensor (oil temperature detection means)

Claims (3)

A drive system comprising a power transmission device having a plurality of frictional engagement elements,
Oil temperature detecting means for detecting the temperature of oil for cooling the plurality of frictional engagement elements;
Deceleration determination means for determining whether the vehicle is decelerating;
When the temperature of the oil is lower than a predetermined oil temperature and the vehicle is decelerating, a specific frictional engagement element in a released state among the plurality of frictional engagement elements is slipped and the slip state is achieved. Oil temperature control means for increasing the temperature of the oil by heat generated by the specific frictional engagement element;
A drive system comprising: brake force control means for reducing wheel brake force based on a brake force generated by the specific frictional engagement element in the slip state. The drive system according to claim 1,
The drive system according to claim 1, wherein the specific frictional engagement element is the frictional engagement element constituting a high gear. The drive system according to claim 1 or 2,
Provided with a deceleration calculation means for calculating a target deceleration based on the depression amount of the brake pedal;
The said oil temperature control means controls the hydraulic pressure supplied to the said specific friction fastening element made into the said slip state based on the said target deceleration and the temperature of the said oil.

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