JPH0647346B2 - Hydraulic control of automatic transmission - Google Patents

Description

Detailed Description of the Invention [Industrial applications]

TECHNICAL FIELD The present invention relates to an improvement in a hydraulic control device for an automatic transmission of a vehicle having a function capable of acting an engine exhaust brake.

[Prior art]

Conventionally, especially in large vehicles and vehicles that use a diesel engine, in order to increase the effect of engine braking, the valve provided in the middle of the exhaust pipe is closed to block the flow of exhaust gas, and the internal resistance of the engine is reduced. A vehicle that can act as an engine exhaust brake (exhaust retarder) for increasing the vehicle speed and decelerating the vehicle has been put into practical use. Generally, this engine exhaust brake has a main switch (manual switch), a throttle switch that is turned on when the accelerator pedal is fully closed in conjunction with the accelerator pedal, and a switch that is turned on when the vehicle speed is equal to or higher than a predetermined value. Are configured to operate when both are ON. On the other hand, a gear transmission mechanism and a plurality of friction engagement devices are provided,
An automatic transmission for a vehicle, which is configured to selectively switch the engagement of the friction engagement device by operating a hydraulic control device to achieve any one of a plurality of shift speeds, has been widely put into practical use. There is. The friction engagement device generally includes two sets of friction plate elements that are supported so as to be rotatable relative to each other, and a hydraulic servo device that drives the friction plate elements, and a hydraulic pressure is supplied to the hydraulic servo device. Then, the two sets of friction plate elements are strongly pressed against each other, and are coupled so that torque can be transmitted between them. Conventionally, line pressure is generally used as the hydraulic pressure for such a friction engagement device. This line pressure was adjusted by the primary regu- lator valve to automatically adjust the basic hydraulic pressure generated by the oil pump to the vehicle speed or the engine load (slottle opening). As a result, it has the minimum necessary pressure even when the throttle is fully closed so that smooth shift control can be performed, and the maximum pressure is the required pressure in the state that includes the full throttle opening and maximum throttle stall. Is controlled so that Generally, the line pressure for engaging the friction engagement device is
It is set when the engine exhaust brake is not working. This is because the engine exhaust brake acts very little over the entire running time, and the working hydraulic pressure of the friction engagement device is adjusted in accordance with the characteristics of the engine exhaust brake during this short time. This is because the setting of the hydraulic pressure becomes too high during most of the traveling, which causes inconveniences in terms of fuel consumption, shift feeling, and the like.

[Problems to be Solved by the Invention]

However, conventionally, since the action and non-action of the engine exhaust brake have not been taken into consideration in setting the line pressure as described above, when the engine exhaust brake acts by satisfying the predetermined condition. In addition, since the reverse drive torque of the engine increases (about twice) as compared with the time of non-operation, the torque to be transmitted by the friction engagement device also increases accordingly and the friction engagement device is engaged. There was a problem that the oil pressure in the tank was insufficient and the durability could be disadvantageous. By the way, as a conventional technique that considers the control of the engine exhaust brake and the control of the automatic transmission in combination, for example, there is a disclosure in Japanese Patent Publication No. 58-28414. However, this disclosure involves the detection of the downshift operation of the automatic transmission with respect to the selection of the action or non-action of the engine exhaust brake, and the hydraulic pressure applied to the friction engagement device during the action or non-action of the engine exhaust brake. There is no suggestion of changing.

[Object of the Invention]

The present invention has been made in view of such a conventional problem, and a good friction engagement device is provided even when an engine exhaust brake is applied while maintaining good fuel economy during normal traveling or gear shifting feeling. It is an object of the present invention to provide a hydraulic control device for an automatic transmission that can maintain excellent durability.

[Means for solving problems]

The present invention relates to a hydraulic control device for an automatic transmission of a vehicle having a function capable of operating an engine exhaust brake, a means for detecting whether or not the engine exhaust brake is in operation, and an engine exhaust brake in operation. In some cases, the above object is achieved by providing a means for increasing the line pressure of the hydraulic control device.

[Action]

In the present invention, it is detected whether or not the engine exhaust brake is in operation, and the line pressure of the hydraulic control device is increased only when the engine exhaust brake is in operation. Occasionally, a normal line pressure with good fuel economy or gear shifting feeling is generated, and the line pressure is increased only when a strong hydraulic pressure is required to ensure the durability of the friction engagement device. it can.

【Example】

Embodiments of the present invention will be described in detail below with reference to the drawings. First, FIG. 2 shows an overall outline of an automatic transmission for a vehicle to which this embodiment is applied. This automatic transmission includes a torque converter 20 as its transmission part, an overdrive mechanism 40,
An underdrive mechanism 60 having three stages of forward movement and one stage of reverse movement is provided. The torque converter 20 includes a pump 21 and a turbine 2.
2, a stator 23, and a lockup clutch 24. The pump 21 is connected to the crankshaft 10 of the engine 1, and the turbine 22 is connected to a carrier 41 of the planetary gear unit in the overdrive mechanism 40. In the overdrive mechanism 40, the planetary pinion 42 rotatably supported by the carrier 41 meshes with the sun gear 43 and the ring gear 44. A clutch C ₀ and a one-way clutch F ₀ are provided between the sun gear 43 and the carrier 41, and a brake B ₀ is provided between the sun gear 43 and the housing Hu.
Is provided. The underdrive mechanism 60 is provided with two examples of a planetary gear device on the front side and on the gear side. This planetary gear device includes a sun gear 61, ring gears 62 and 63, planetary pinions 64 and 65, and carriers 66 and 67, which are common to each other. The ring gear 44 of the overdrive mechanism 40 is connected to the ring gear 62 via the clutch C ₁ .
A clutch C ₂ is provided between the ring gear 44 and the sun gear 61. Further, the carrier 66
Is connected to the ring gear 63, and the carrier 66 and the ring gear 63 are connected to the output shaft 70. On the other hand, between the carrier 67 and the housing Hu,
A brake B ₃ and a one-way clutch F ₂ are provided, and further, between the sun gear 61 and the housing Hu,
The brake B ₂ is provided via the clutch F ₁ in one direction, and the brake B ₁ is provided between the sun gear 61 and the housing Hu. This automatic transmission is provided with the transmission section as described above, and inputs signals from the throttle sensor 100 for detecting the throttle opening that reflects the load state of the engine 1 and the vehicle speed sensor 102 for detecting the vehicle speed. By means of the central processing unit (ECU) 104, the electromagnetic solenoid valves S _{1 to} S ₃ (for shift valves) and S _L (for rock up clutch) in the hydraulic control circuit 106 are set in accordance with a preset shift pattern. ) Is driven and controlled, and the engagement of the clutches, brakes, etc. is combined as shown in FIG. 3 to perform gear shift control. In FIG. 3, the mark ◯ indicates the engaged state, and the mark x indicates the engaged state only when the engine brake is used. In FIG. 2, reference numeral 110 is a shift position sensor for detecting the positions of N (neutral), D (drive), R (reverse), etc. operated by the driving vehicle, and 112 is a pattern select switch. Then E
(Economical traveling), P (power traveling), etc. are detected, 114 is a water temperature sensor for detecting the engine cooling water temperature, 116 is a foot brake, and 118 is a side brake operation. Brake switches are shown respectively. Next, FIG. 1 shows a main part in the hydraulic control circuit 106. In the figure, 10 is an oil pan and 12 is the oil pan 1.
An oil pump for pumping the oil in 0 to generate a basic hydraulic pressure, and 14 for adjusting the basic hydraulic pressure generated by the oil pump 12 to generate a line pressure according to the throttle opening degree or the like. It is the primary regulator valve of. 16 is a secondary regulator valve,
Reference numeral 18 is a throttle valve, 30 is a shift valve, 32 is a governor valve, 33 is a manual valve, and 34 is a friction engagement device. The primary regulator valve 14 has seven lands 14A to 14G, and is characterized in that the land 14G is added as compared with the conventional one. The line pressure of the line pressure oil passage 50 is fed back to the land 14G and applied via the port 14X. An orifice 36 and a solenoid valve 38 are provided in the feed back oil passage, and the solenoid valve 38
It is controlled by a switch 26 which is turned on when the engine exhaust brake is applied. Reference numeral 39 is a battery, and the switch 26 will be described in detail later. Further, since the functions of the valves are the same as the conventional ones, the description of the operation of each valve will be omitted here, and the increase control of the line pressure when the engine exhaust brake is operated will be described in detail. The line pressure is increased as follows. When the exhaust brake is applied, the switch 26 is turned on, the solenoid valve 38 is at the position shown in the figure, and the drain oil passage 38A
The line pressure oil passage 50 (52) from the port 14X of the primary regulator valve 14 to the land 14
Acts on G. The balance equation of the primary regulator valve 14 at this time is as follows. In the formula, A, B,
F and G are lands 14A, 14B, 14F and 1 respectively.
4G area, _{P L} is the line _pressure, Surotsutoru pressure from _{P TH} is Surotsutorubarubu 18, K is the load of the spring 14Y. P _L (B−A) = K + P _TH (F−G) + P _L × G (1) P _L = 1 / (A−B−G) · K + (F−G) / (A−B−G) _PTH (2) In the formula (1), P _L × G is a term that is increased compared to the conventional case. As a result, the line pressure becomes as shown in the above formula (2), and the pressure is adjusted higher than in the conventional case, so that the hydraulic pressure acting on the friction engagement device 34 is set higher. The higher the hydraulic pressure acting on the friction engagement device, the shorter the engagement can be completed, that is, the time during which the two friction plate elements slide on each other can be shortened, and the durability is correspondingly reduced. You will be able to improve. The switch 26 is turned on and off by a configuration as shown in FIG. FIG. 4 shows a relay computer 200 in which various signals are input to the engine exhaust brake.
It is shown that it is operated by. In addition to the switches such as the clutch switch 202, the accelerator switch 204, the neutral switch 206, etc., the relay computer 200 has a vehicle speed signal 102 for the main switch 210.
Is entered together with. This relay computer 200
When it determines that the engine exhaust brake should be actuated by these inputs, it outputs a predetermined signal to the fuel control motor 212 and the magnetic valve 214, and turns on the switch 26. In the engine exhaust brake, a negative pressure is supplied from the vacuum tank 216 to the vacuum cylinder 218 via the magnetic valve 214, and the negative pressure causes the vacuum cylinder 218 to move.
The exhaust retarder 222 provided in the middle of 0 blocks the flow of the air in the exhaust pipe 220 to be in an operating state. In the above embodiment, the line pressure itself is fed back to the primary regulator valve 14 as a means for increasing the line pressure. However, in the present invention, the means for increasing the line pressure is limited. Instead of this, for example, another modulator hydraulic pressure may be applied, or a duty control hydraulic pressure may be applied.

【The invention's effect】

As described above, according to the present invention, the hydraulic pressure applied to the friction engagement device can be increased only when the engine exhaust brake is operating, and the fuel consumption during normal traveling,
Alternatively, it is possible to obtain an excellent effect that it is possible to prevent the durability of the friction engagement device from being deteriorated while maintaining the gear shifting feeling excellent.

[Brief description of drawings]

FIG. 1 is a main part hydraulic circuit diagram showing an embodiment of a hydraulic control device for an automatic transmission according to the present invention, and FIG. 2 is an overall schematic skeleton diagram of an automatic transmission to which the above embodiment is applied. FIG. 4 is a diagram showing an engaged / combined state of each friction engagement device in the automatic transmission, and FIG. 4 is a diagram showing a configuration for operating an engine exhaust brake. 14 ... Primary regulator valve, 18 ... Slot valve, 26 ... (for detecting engine exhaust brake operation) switch, 50, 52 ... Line pressure oil passage, 200 ... (for engine exhaust brake operation) relay Computer.

Claims (1)

[Claims] 1. A hydraulic control device for an automatic transmission of a vehicle having a function capable of operating an engine exhaust brake, wherein a means for detecting whether or not the engine exhaust brake is in operation, and an engine exhaust brake in operation And a means for increasing the line pressure of the hydraulic control device at the time of, and a hydraulic control device for an automatic transmission, comprising: