OIL COOLING CIRCUIT OF AN AUTOMATIC TRANSMISSION

Abstract

An oil supply system for an automatic transmission or for an automated manual transmission in a drive train. The oil supply system includes an oil sump and a heat exchanger, wherein the oil supply is provided for at least the following operating states of the automatic transmission: a converter mode; a drive mode in one of the mechanical gears; and a retarder mode.
To optimize cooling of the oil volume flows in the different operating states two heat exchangers are provided, through which an oil volume flow can be conducted depending on the operating state of the transmission.

Claims

1. An oil supply system for an automatic transmission or for an automated manual transmission in a drive train, the oil supply system comprising: an oil sump providing an oil supply; and a plurality of heat exchangers including a first heat exchanger and a second heat exchanger, at least a portion of the oil supply flowing through the heat exchangers, the oil supply being used for at least the following operating states of the transmission: a converter mode; a drive mode in one of the mechanical gears; and a retarder mode; and wherein oil volume flows through the first and second heat exchangers is conducted depending on the operating state of the transmission.

2. The oil supply system of claim 1, further comprising a measuring device measuring an oil circuit temperature of the oil volume flows in all operating states.

3. The oil supply system of claim 1, further comprising a measuring device having a sensor by which the temperature of the oil volume flows flowing into the first and/or the second heat exchanger is measured.

4. The oil supply system of claim 1, wherein the heat exchangers have different oil volume flows.

5. The oil supply system of claim 1, wherein the oil volume flow through the first heat exchanger and the oil volume flow through the second heat exchanger flow at a volume ratio of 1:2.

6. The oil supply system of claim 1, further comprising a plurality of valves controlling the oil volume flows through the first heat exchanger and through the second heat exchanger.

7. The oil supply system of claim 1, further comprising a pressure control valve for regulating of an oil volume flow through a converter, wherein the pressure control valve is provided between the converter and the first and second heat exchangers.

8. The oil supply system of claim 1, further comprising: a first switching valve; and a second switching valve, the switching valves in the braking mode of the retarder directs an oil volume flow through the second heat exchanger to dissipate the brake energy.

9. The oil supply system of claim 8, wherein the first switching valve is switched in such a way that, when the transmission is in the drive mode, with a mechanical gear of the transmission engaged, an oil volume flow is directed from the oil sump by way of a bypass line through the second heat exchanger and/or through the first heat exchanger.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The above-mentioned and other features and advantages of this invention, and the manner of attaining them, will become more apparent and the invention will be better understood by reference to the following description of an embodiment of the invention taken in conjunction with the accompanying drawings, wherein:

[0027] FIG. 1 is a functional diagram, in schematic form, of an embodiment of an oil circuit for an oil supply of the present invention; and

[0028] FIG. 2 is a perspective view of a heat exchanger console coupled to the oil circuit of FIG. 1.

[0029] Corresponding reference characters indicate corresponding parts throughout the several views. The exemplification set out herein illustrates one embodiment of the invention in one form, and such exemplification is not to be construed as limiting the scope of the invention in any manner.

DETAILED DESCRIPTION OF THE INVENTION

[0030] Exemplary embodiments provided according to the present invention are illustrated by the drawings and now referring to FIG. 1 there is illustrated a functional diagram of the inventive oil circuit for supplying oil to an automatic transmission. The schematic herein has been reduced to the details relevant to the invention which are necessary for oil cooling. A pump, which is not illustrated, conveys the oil from an oil sump 19 by way of an oil supply line 3 to all relevant components in the transmission, so that the oil supply for at least the following operating states of the automatic transmission is ensured:

[0031] a converter mode;

[0032] a drive mode in one of the mechanical gears; and

[0033] a retarder mode.

[0034] These three operating states effect an energy input into the oil which leads to a temperature increase of the oil. When the motor vehicle that contains the present invention starts, the transmission is switched into a travelling mode by operation of a valve 26. For the travelling mode, a control valve 5 is controlled in such a way that at least a partial volume of an oil volume flow 21d, which is conveyed by the pump, is directed through a converter 2.

[0035] The function of control valve 5 is to regulate the output control of converter 2, which will not be discussed in further detail herein. The heated oil, in other words an oil volume flow, is conducted by way of a line 6 and a WT (heat exchanger) feed line 7 to heat exchangers 11 and 12.

[0036] In the drive mode, in one of the mechanical gears of the automatic transmission, oil volume flow 21d is conducted from oil sump 19 by way of bypass line 4, line 6 and WT (heat exchanger) feed line 7 to heat exchangers 11 and 12.

[0037] Different switching operations are now possible here. In the illustrated switching position of first switching valve 13, oil volume flow 21d is conducted, originating from converter 2, through second heat exchanger 12 and first heat exchanger 11. Oil volume flow 21d separates into oil volume flows 21a and 21b.

[0038] It is also contemplated that only first switching valve 13 is switched into the second switching position, so that oil volume flow 21d, originating from converter 2 or bypass 4, is conducted by way of a connecting channel 25a, only through first heat exchanger 11. Oil volume flow 21d corresponds to oil volume flow 21a.

[0039] In contrast, in the retarder mode, both switching valves 13 and 14 are switched simultaneously, so that only second heat exchanger 12 is used for cooling the oil in retarder operation, in order to dissipate the braking energy. The retarder control is not discussed further in connection with this invention.

[0040] Alternatively, it could also be provided that, in a first step, switching valve 14 is switched so that the retarder is filled, and at the latest when the filling process is complete, switching valve 13 is switched, so that the entire oil volume flow 21c is pumped through retarder 9 and is conducted by way of connecting channel 25b through heat exchanger 12.

[0041] Also decisive for the invention is a measuring device 20, the position of which is shown in greater detail in the region of connecting channel 25b in FIG. 2. This is provided for measuring the temperature of oil volume flow 21b. The one sensor of measuring device 20 is arranged on connecting channel 25b. The temperature of oil volume flow 21b into second heat exchanger 12 can thus be measured for all operating states.

[0042] Since in all operating states an oil volume flow is conducted by way of connecting channel 25b, the temperature of oil volume flow 21b is measured for all operating states. Critical temperatures can thus be monitored in any operating state. The function of the transmission is thus ensured, and the oil is protected from overheating.

[0043] In the event of potential oil overheating, regulating strategies are implemented, by way of which the oil temperature is regulated to definable temperature limits. For example, the reduction in the braking power of the retarder.

[0044] The additional illustrated lines and elements of the oil circuit are not further discussed in connection with this invention since they are not relevant to the explanation of the invention. However, they are necessary for the overall functionality of the transmission.

[0045] While this invention has been described with respect to at least one embodiment, the present invention can be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the invention using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this invention pertains and which fall within the limits of the appended claims.

COMPONENT IDENTIFICATION LIST

[0046] 1 oil circuit [0047] 2 converter [0048] 3 oil feed line [0049] 4 bypass line [0050] 5 valve-converter control [0051] 6 line [0052] 7 WT (heat exchanger) feed line [0053] 8 Leakage flow line [0054] 9 retarder [0055] 10 feed line [0056] 11 heat exchanger [0057] 12 heat exchanger [0058] 13 switching valve [0059] 14 switching valve [0060] 15 return line [0061] 16 filling line [0062] 17 gap filling line [0063] 18 return line [0064] 19 oil sump [0065] 20 measuring device with sensor [0066] 21a, b, c, d oil volume flow [0067] 22 heat exchanger console [0068] 23 heat exchanger [0069] 24a,b holder [0070] 25 connecting channels [0071] 26,27 valves