Injection Device and Electric Heating Device for Corresponding Injection Device

Abstract

A fuel injection nozzle is connected to a pump for injecting the fuel and to a fresh air supply for the internal combustion engine. In order to provide an injection device which allows temperature control of the injected media with a simple structure and arrangement in the motor vehicle, the injection device has an electric heating device for heating the fresh air supplied. The heating device is fluidically connected via a first hose section to the inlet side of the fresh air supply and via a second hose section to the internal combustion engine. The heating device has a layered heating block comprising at least one heat-emitting layer and at least one heat-generating layer coupled thereto in a heat-conducting manner The heat-generating layer includes at least one PTC element and conductor elements abutting opposed sides of the PTC element.

Claims

1. An injection device for an internal combustion engine, comprising: an injection nozzle that is configured to inject fuel, the injection device being configured for connection to a fuel pump and to a fresh air supply for the internal combustion engine; and an electric heating device for heating the supplied fresh air, wherein the electric heating device is configured to be fluidically connected to an inlet side of the fresh air supply via a first hose section and to the internal combustion engine via a second hose section, and wherein the electric heating device has a layered heating block comprising at least one heat-emitting layer and at least one heat-generating layer coupled thereto in a heat-conducting manner, wherein the heat-generating layer comprises at least one PTC element and conductor elements abutting opposed sides of the PTC element.

2. The injection device according to claim 1, wherein the PTC heating device comprises a two-part housing, wherein each of the housing parts forms, as a structural unit, a hose connection piece for a respective hose section and a frame segment, which at least partially surrounds the heating block.

3. The injection device according to claim 2, wherein the housing parts are formed of plastic and are interlocked with each other with the heating block enclosed.

4. The injection device according to claim 2, wherein the frame segments circumferentially surround the heating block, and wherein at least one support web is provided between a frame segment and a hose connection piece and supports the heating block in a direction of passage of the air.

5. The injection device according to claim 4, wherein the heat-generating layer is provided between opposing support webs extending parallel to the heat-generating layer.

6. The injection device according to claim 2, wherein conductor elements assigned to different polarity are formed by contact sheets which extend laterally beyond the heating block and which have contact tongues formed integrally thereon.

7. The injection device according to claim 6, wherein the contact tongues are provided in a connector housing formed by one of the housing parts.

8. The injection device according to claim 7, wherein the contact tongues and the connector housing provide a plug contact extending substantially parallel to the hose connection pieces.

9. An electric heating device, for heating fresh air supplied to an internal engine fueled by an injection device, comprising: a layered heating block; and a two-part housing, wherein each of the housing parts forms, as a structural unit, a hose connection piece and a frame segment which at least partially surrounds the layered heating block, wherein the layered heating block has at least one heat-emitting layer and at least one heat-generating layer coupled thereto in a heat-conducting manner, and wherein the heat-generating layer has at least one PTC element and conductor elements abutting on opposed sides of the PTC element.

10. In combination: an internal combustion engine; a fuel pump; a fresh air supply; an injection nozzle that is connected to the fuel pump and that is configured to inject fuel into the fresh air supply; and an electric heating device for heating the supplied fresh air, wherein the electric heating device is be fluidically connected to an inlet side of the fresh air supply via a first hose section and to the internal combustion engine via a second hose section, and wherein the electric heating device has a layered heating block comprising at least one heat-emitting layer and at least one heat-generating layer coupled thereto in a heat-conducting manner, wherein the heat generating layer comprises at least one PTC element and conductor elements abutting opposed sides of the PTC element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Further details and advantages of the present invention will be apparent from the following description of an embodiment in conjunction with the drawing. Therein:

[0017] FIG. 1 shows a schematic view of essential components of an injection device according to the present invention;

[0018] FIG. 2 shows a perspective exploded view of the electric heating device of the injection device according to FIG. 1;

[0019] FIG. 3 shows a perspective side view of the electric heating device according to FIG. 2;

[0020] FIG. 4 shows a longitudinal sectional view of the electric heating device according to FIGS. 2 and 3, and

[0021] FIG. 5 shows a top view of the electric heating device according to FIGS. 2 to 4.

DETAILED DESCRIPTION

[0022] FIG. 1 shows a schematic view of essential components of an injection device with an internal combustion engine 2, to which the air inlet side is shown on the left of the internal combustion engine 2 and the exhaust gas side on the right, which will not be discussed in detail.

[0023] A fresh air supply system characterized by reference sign 4 comprises a hose 6 which is divided into two at least adjacent to the internal combustion engine 2 and has a first hose section 10 associated with an inlet side 8 and a second hose section 12 connected to the engine. An electric heating device 14 is located between these two hose sections 10, 12.

[0024] Downstream of the electric heating device 14, an injection nozzle is characterized by reference sign 16, which is connected in terms of flow to a pressure side of a pump 18, wherein the pump 18 communicates on the inlet side with a tank 20 for fuel 22.

[0025] Upstream of the electric heating device 14, an intake manifold pressure sensor 24 is located in the fresh air supply 4, as well as an outlet to an exhaust gas recirculation valve 25 provided adjacent thereto and a throttle device 26 for throttling the fresh air introduced. Downstream of the throttle device 26, a mass air flow sensor with temperature sensor 28 is provided. Reference sign 30 characterizes an electronic control unit which is connected to the various components of the injection device in terms of data and controls them or receives their signals and processes them for control purposes. In this electronic control unit 30, a control system for the electric heating device 14 may also be provided. This arrangement is illustrated by a cable 31 which supplies a 12-volt power current to the electric heating device 14 under control of the electronic control unit 30.

[0026] Details of the electric heating device 14 can be seen in FIGS. 2 to 5.

[0027] As illustrated in particular by FIG. 2, the electric heating device 14 has two housing parts, a first housing part of which is characterized by reference sign 32 and a second housing part by reference sign 34. Both housing parts 32, 34 have respective hose connection pieces 36 and frame segments. The frame segment of the first housing part 32 is characterized by reference sign 38; the frame segment of the other housing part 34 by reference sign 40. The first housing part 32 further has a connector housing characterized by reference sign 42. The various functional areas of the respective housing parts 32 and 34 are each uniformly realized. The housing parts 32, 34 are each injection molded parts made of plastic.

[0028] The frame segments 38, 40 each have longitudinal beams 44 and cross beams 46, each of which delimits a rectangular accommodation space 48. The longitudinal beams 44 are each provided with double walls with a slot in between, which is interrupted by webs. This not only mechanically stiffens the longitudinal beams 44. Rather, latching receptacles 50 are formed by the second housing part 34 in any case, into which latching tongues of the first housing part 32, characterized by reference sign 52, can lock in order to connect the two housing parts 32, 34 to one another in a form-fitting manner

[0029] As particularly illustrated in FIGS. 3 and 4, the hose connection pieces 36 are flush when the housing parts 32, 34 are joined and provide a common longitudinal axis L that passes centrally through each of the hose connection pieces 36.

[0030] In FIG. 2, a heating block characterized by reference sign 54 is shown between the two housing parts 32, 34, which in this case comprises two heat-emitting layers 56 and a heat-generating layer 58 provided therebetween. This heat-generating layer 58 has a PTC element 60 and conductor elements 62 contacting this PTC element 60 on both sides, presently in the form of contact sheets formed by punching and bending. Reference sign 63 characterizes a spring which extends over the entire length of the heat-emitting layer 56 or the heat-generating layer 58. This spring 63 is supported internally against the longitudinal beams 44 and is mounted in the accommodation space 48, as is the entire heating block 54. As FIG. 4 in particular illustrates, the accommodation for the heating block 54 is created in each case in halves by the accommodation spaces 48. Each of the accommodation spaces 48 is bounded between the heating block 54 and the hose connection piece 36 of the respective housing part 32/34 by support webs 64, 66 extending perpendicularly. The support web characterized by reference sign 64 extends parallel to the heat-generating layer 58. This heat-generating layer 58 is received between the support webs 64 of the two housing parts 32, 34. The other support web 66 extends perpendicularly to the previously discussed support web 64 and penetrates centrally through the accommodation for the heating block 54, so that the two support webs 64, 66 intersect at the level of the longitudinal axis L; cf. FIG. 5.

[0031] The heating block 54 includes a plurality of contact sheets. In addition to the two conductor elements 62 mentioned above, which abut directly against the PTC element 60, the heating block 54 as a whole is bounded by further sheets, of which the front sheet characterized in FIG. 2 forms a conductor element 68 which, like the conductor element 62 provided for this purpose on the other side of the PTC element 60, forms a contact tongue 70. The two contact tongues 70 extend parallel to the longitudinal axis L and are surrounded by the connector housing 42. Thus, a plug contacting parallel to the longitudinal axis L for contacting the cable 31 with the electric heating device 14 is predetermined by the contact tongues 70 and the connector housing 42 open on one side.

[0032] It is evident that the connector housing 42 is shorter than the hose connection piece 36 of the first housing part 32. The two hose connection pieces 36 have a bead at the end over which the respective hose pieces 10, 12 are pulled. The corresponding bead prevents the hose piece 10, 12 or a hose clamp from slipping off the respective hose connection piece 36.

[0033] FIGS. 2 and 4 illustrate further contact surfaces for the heating block 54, characterized by reference sign 72. These contact surfaces are formed by the cross beams 46 and support the heating block 54 at its opposite ends. The cross beam 46 of the two housing parts 32, 34, which is provided adjacent to the connector housing 42, has longitudinal slots 74 which accommodate the two conductor elements 62, 68 forming contact tongues 70 therein and transfer them into the connector housing 42. The corresponding connector housing is closed on the underside.