Electric liquid heater for vehicles with plug connector including vent duct

Abstract

Described is a liquid heater having a housing, in which a flow channel runs from an inlet to an outlet, a heating resistor arranged within the housing for heating liquid flowing through the flow channel, control electronics which are arranged in an interior space of the housing, the interior space being sealed off from the flow channel, and a plug connector attached to the housing. Provided according to this disclosure, the plug connector has a vent duct which is closed by a membrane and which leads to the interior space sealed against the ingress of liquid, in which interior space the control electronics are arranged.

Claims

1. A liquid heater, comprising: a housing in which a flow channel runs from an inlet to an outlet; a heating resistor arranged within the housing and configured for heating liquid flowing through the flow channel; control electronics arranged in an interior space of the housing, the interior space being sealed off from the flow channel; and an electrical plug connector attached to the housing; wherein a vent duct extends through the electrical plug connector and wherein the vent duct is closed by a membrane and leads to the interior space and wherein the vent duct is covered at an outer end thereof by a cover.

2. The liquid heater according to claim 1, wherein the membrane is attached to an inner side of the plug connector facing the sealed interior space.

3. The liquid heater according to claim 1, wherein the cover allows air to enter the vent duct in a radial direction.

4. A liquid heater, comprising: a housing in which a flow channel runs from an inlet to an outlet; a heating resistor arranged within the housing and configured for heating liquid flowing through the flow channel; control electronics arranged in an interior space of the housing, the interior space being sealed off from the flow channel; an electrical plug connector attached to the housing; wherein a vent duct extends through the electrical plug connector and wherein the vent duct is closed by a membrane and leads to the interior space and wherein the vent duct is covered at an outer end thereof by a cover; and wherein the cover has a section protruding into the vent duct.

5. The liquid heater according to claim 1, wherein the control electronics are arranged on a circuit board having openings into which press-in contacts of the plug connector engage.

6. The liquid heater according to claim 1, wherein the heating resistor is arranged together with the control electronics in the sealed interior space.

7. The liquid heater according to claim 6, wherein the sealed interior space has two chambers connected by an air duct, wherein the control electronics are arranged in one of the two chambers and the heating resistor is arranged in the other chamber.

8. The liquid heater according to claim 1, wherein the heating resistor comprises a conducting path on a substrate plate made of sheet metal coated with a dielectric.

9. The liquid heater according to claim 8, wherein an underside of the substrate plate facing away from the heating resistor defines an interior surface of the flow channel and the opposite side of the substrate plate having the conducting path disposed thereon faces the interior space which is sealed off from the flow channel.

10. The liquid heater of claim 1, wherein the plug connector includes a housing member and the vent duct extends through the housing member of the plug connector.

11. The liquid heater of claim 4, wherein the cover is a separate component and is mounted on the electrical plug connector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The above-mentioned aspects of exemplary embodiments will become more apparent and will be better understood by reference to the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

(2) FIG. 1 is an embodiment of a liquid heater according to this disclosure;

(3) FIG. 2 is a further view of the liquid heater;

(4) FIG. 3 is a sectional view of FIG. 1 along the section line A-A;

(5) FIG. 4 is a sectional view of FIG. 2 along the section line C-C;

(6) FIG. 5 is the plug connector of the water heater;

(7) FIG. 6 is a rear view of the plug connector; and

(8) FIG. 7 is a sectional view of FIG. 5 along the section line B-B.

DESCRIPTION

(9) The embodiments described below are not intended to be exhaustive or to limit the invention to the precise forms disclosed in the following description. Rather, the embodiments are chosen and described so that others skilled in the art may appreciate and understand the principles and practices of this disclosure.

(10) FIGS. 1 to 4 show a liquid heater which can be used as a flow heater for aqueous liquids in motor vehicles. The liquid heater has a housing 1 made of metal, for example, aluminum, in which a flow channel 15 for liquid to be heated runs from an inlet 2 to an outlet 3.

(11) FIG. 3 shows a sectional view of the housing 1 along the angled section line A-A of FIG. 1, FIG. 4 a sectional view of the housing 1 along the angled section line C-C of FIG. 2. In the embodiment shown, the housing 1 has two housing parts 1a, 1b, which are connected to one another by screws 18 and enclose the flow channel 15 between them, and a housing cover 1c.

(12) One or more electrical heating resistors are arranged in the housing 1. In the embodiment shown, a plurality of heating resistors is provided as conducting paths 21 on a substrate, for example, a metal sheet covered with an insulator layer, e.g. a dielectric. Together with the substrate, these conducting paths form heating plates 4. In the exemplary embodiment shown, the heating plates 4 limit a flow channel 15 in the housing 1 for the liquid to be heated. The conducting paths 21 and thus the electrical heating resistors are arranged on a side of the substrate facing away from the flow channel 15, that is, they are located on a dry side of the heating plates 4 and thus in a chamber 14 in the housing 1, the chamber being sealed off from the flow channel 15.

(13) The energization of the heating resistor(s) is controlled by control electronics 6 also arranged in the housing 1. The control electronics 6 comprise a circuit board with circuit elements, particularly transistor switches, which are arranged in an interior space of the housing 1, the interior space being sealed off from the flow channel 15. The chamber 14, in which the heating resistors are arranged, can be part of this interior space, for example, by being connected to it by an air duct 16. In the exemplary embodiment shown, the control electronics 6 and the heating resistors are arranged in different chambers 13, 14 connected by an air duct 16, so that the control electronics 6 are thermally decoupled from the heating resistors, but pressure equalization via the air duct 16 is possible.

(14) The housing 1 bears a plug connector 14, via which the heating resistor(s) can be connected to a voltage source, particularly a high voltage source. In addition, the housing bears a plug connector 5, via which the control electronics 6 can be connected to a voltage source. The plug connector 5 is shown in FIGS. 4 to 6. FIG. 5 shows a longitudinal section of the plug connector 5 and FIG. 7 shows a sectional view along the section line B-B of FIG. 5. The plug connector 5 has contact pins 8 which are designed at one end as press-in contacts 19 which are pressed into openings 20 on the circuit board of the control electronics 6. The plug connector 5 can be fastened to the housing 1 by means of screws 13.

(15) A special feature of the plug connector 5 is that a vent duct 10 runs in a housing 9 of the plug connector 5 and is closed by an air-permeable membrane 11. The membrane 11 prevents the ingress of moisture, but enables pressure equalization between the interior space in which the control electronics 6 are arranged and the surroundings of the liquid heater via the vent duct 10. When the air temperature in this interior space of the liquid heater increases due to the heating resistors or waste heat from the control electronics 6, air can flow out of the interior space and a problematic pressure increase in this interior space can thus be avoided, which could stress the seal to the flow channel 15.

(16) As shown in FIG. 7, the membrane 11 is arranged on the inner side of the plug connector 5 and thus protected from damage. At its outer end, the vent duct is covered by a cover 12. The cover 12 allows air to enter the vent duct 10 in the radial direction. The cover 12 can be designed as a separate component which projects with a section into the vent duct 10, for example, pressed into the vent duct 10.

(17) While exemplary embodiments have been disclosed hereinabove, the present invention is not limited to the disclosed embodiments. Instead, this application is intended to cover any variations, uses, or adaptations of this disclosure using its general principles.

(18) 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.

LIST OF REFERENCE NUMERALS

(19) 1 housing

(20) 1a housing part

(21) 1b housing part

(22) 1c housing cover

(23) 2 inlet

(24) 3 outlet

(25) 4 heating plates

(26) 5 plug connector

(27) 6 control electronics

(28) 8 contact pins

(29) 9 plug connector housing

(30) 10 vent duct

(31) 11 membrane

(32) 12 cover

(33) 13 chamber

(34) 14 chamber

(35) 15 flow channel

(36) 16 air duct

(37) 18 screw