Control appliance for using in the engine compartment or in the transmission of a motor vehicle and cooling system for such a control appliance

A control unit for use in the engine compartment or in the transmission of a motor vehicle. The control unit has a line section for an engine or transmission fluid, a circuit carrier, and a base plate. The base body is mounted on the base plate. The circuit carrier is arranged between the base body and the base plate. The base body has a plurality of parallel channels each having a respective outlet. At least one of the plurality of parallel channels forms a portion of the line section. A separate cover is mounted on the base body, the cover having a single inlet coupled to the plurality of parallel channels. The cover is, other than only the inlet, connected to the base body in a fluid-tight manner, and the inlet is the only fluid passage through the cover.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a control device for use in the engine compartment or in the transmission of a motor vehicle. Furthermore, the invention relates to a cooling arrangement for such a control device.

2. Description of the Related Art

In automobile engineering control devices, in particular engine control devices or transmission control devices, are mounted on-site at the engine or in the transmission in order to save place. Thus, the requirements to the control devices are very high, when it comes to their tightness, mechanical robustness and temperature endurance. With known engines transmission oil achieves temperatures up to for example 155° C.

SUMMARY OF THE INVENTION

An aspect of the present invention cools electronic components in control devices, which are exposed to such temperatures, such that a pre-determined temperature limit for the electronic components is not exceeded.

According to aspects of the invention it was recognized that engine or transmission fluid, in particular oil, which is present in an engine or transmission fluid reservoir of a motor vehicle engine, has a temperature, which lies clearly below the temperature limit for typical electronic components. Such engine or transmission fluid can be guided via the line section for the engine or transmission fluid. Due to the thermal coupling to the housing section for the control unit comprising the electronic components tempering of the control unit is ensured, which keeps the temperature of the control unit below its temperature limit. A failure of the control unit caused by higher temperatures is thus safely prevented. The expenditure for a passive cooling of the control device can be reduced or totally avoided. A cooling of the engine or transmission fluid for ensuring that this fluid in the line section has a sufficient low temperature, can be achieved by a corresponding guidance of the fluid over a sufficient long fluid path, in which the fluid has sufficient occasion to release heat. Such a fluid path can be designed in particular in spiral form.

At least one embodiment of the invention enables a compact housing arrangement with the line section.

A design of the line section according at least one aspect of the invention allows for a cost-efficient embodiment of it and for a simple assembly. The base body of the line section can simultaneously represent the base plate, what again increases the compactness of the structure of the housing of the control device.

Materials for the base body and/or the cover according to one or more embodiments of the invention turned out to be particularly suitable for the guidance of engine or transmission fluid with a typical temperature of 120° C.

The advantages of a cooling arrangement according to one or more aspects of the invention correspond to those, which were already explained above while referring to the control device. The engine or transmission fluid pump ensures a safe and in particular steady flow of engine or transmission fluid through the line section of the housing of the control device.

A fluid cooling device according to one or more embodiments of the invention ensures a further cooling effect by the engine or transmission fluid, so that the fluid can enter the line section of the housing of the control device with again lower temperature.

As a cooling engine or transmission fluid preferably the oil usually present in the engine compartment or in the transmission can be used.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1shows schematically an oil circulation1of a motor vehicle. A part of the oil circulation1serves as a cooling arrangement for a control device2, which is used in an engine compartment of the motor vehicle. The control device2is in particular a transmission control device. However, the control device2can also be used as an engine control device.

The cooling arrangement has a transmission fluid reservoir in form of an oil sump3. A transmission fluid pump4serves for recycling transmission fluid5through a transmission fluid circulation schematically shown by arrows inFIG. 1. A transmission fluid supply6schematically shown by an arrow inFIG. 1is connected with an inlet7of a line section8of a housing9of the control device2. A housing section10for a control unit of the control device2, i.e. in particular for a control electronics, is thermally coupled to the line section8.

Details for the structure of the line section8are shown inFIGS. 2 and 3. Part of the housing9is a base plate11, at which the control unit in the housing section10is mounted. The line section8is formed section-wise by the base plate11. Alternatively, the line section8can also be placed as a separate part on the base plate11. The line section8is formed in two pieces with a base body12and a cover13. The base plate11is a component of the base body12and is integrally molded to the latter. A circuit carrier20is arranged between base body12and base plate11. The circuit carrier20carries or holds a circuit for performing the control functions of control device2described herein. The cover13is fluid-tight mounted on the base body12, however, a leakage rate being admissible up to a pre-determined tolerance limit. The cover13fluid-tight connected to the base body12in particular by welding, caulking or screwing. The base body12and the cover13can be made of aluminum, casting or plastic material.

The inlet7is formed in the cover13and is fluid connected to a fluid channel portion14in the base body12. At a side of the cover13located opposite to the inlet7the base body12comprises an outlet15, which is likewise fluid-connected to the channel portion14.

The fluid channel portion14includes a plurality of parallel channels14A,14B, each of which has a respective outlet15. At least one of the plurality of parallel channels14A,14B included in fluid channel portion14forms a portion of the line section8. The cover13is connected to the base body12in a fluid-tight manner with the exception of the opening formed by inlet7. In other words, the inlet7is the only fluid passage through the cover13.

A transmission fluid discharge16outlined inFIG. 1by a further arrow is fluid-connected to the outlet15of the line section8. The transmission fluid discharge16in turn is fluid-connected to the oil sump3. Between the transmission fluid pump4and the inlet7a fluid cooling device17is arranged.

The shown example of embodiment is a transmission fluid5, i.e. oil, in particular transmission oil.

The control device2is mounted to a transmission18schematically represented inFIG. 1. Also the transmission18is supplied with the transmission fluid5. On this occasion; temperatures up to 155° C. appear in the transmission, to which also the control device2is exposed. With the transmission fluid5furthermore a coupling19equally schematically outlined inFIG. 1is provided.

Cooling of the control device2is performed as follows: From the oil sump3with the aid of the transmission fluid pump4the transmission fluid5is transported through the fluid cooling device17to the coupling19. A part of the transported transmission fluid5is pumped via the transmission fluid supply6into the inlet7of the line section8. The transmission fluid5flows through the line section8at the housing section10of the housing9of the control device2and flows out from the channel portion14through the outlet15. In order to promote the transmission fluid flow between the inlet and the outlet15, a chimney effect can be used in the channel portion14. The leaking transmission fluid5returns via the transmission fluid discharge16into the oil sump3. In the oil sump3the transmission fluid5has a maximum temperature of approx. 120° C., which is not exceeded. This oil, which is cooler compared to the transmission temperatures, thus entails a cooling of the control unit in the housing section10of the control device2. This means that an active transmission fluid cooling, in particular an active oil cooling, is realized.