Apparatus, for motor vehicles having a liquid-cooled engine, for heating windshield washer liquid or the like

An apparatus, for a motor vehicle having a liquid-cooled engine, for heating windshield washer liquid or the like. The apparatus includes a cylindrical heat-exchanger housing that, via hose connectors that are disposed at both ends of the housing, can be disposed directly in the coolant line between the engine and a radiator, with the interior of the housing, through which the coolant flows, containing a tube coil that is helically wound in the longitudinal direction of the housing. Liquid that is to be heated flows through the tube coil, and the ends of the latter are conveyed out of the housing in a radial direction. The housing is divided, in an axial direction, into two semicylindrical shells which have abutting longitudinal edges that can be sealingly interconnected. The tube coil is adapted to be placed between the shells, and the housing is provided on the periphery of at least one of the shells with two radially extending pass-through sleeves through which respective ones of the radially extending tube coil ends can extend. Each pass-through sleeve has an outer end that is remote from the housing and on which a sealing ring and a coupling nut is disposed to seal the tube coil end in the pass-through sleeve.

BACKGROUND OF THE INVENTION 
The present invention relates to an apparatus, for a motor vehicle having a 
liquid-cooled engine, for heating windshield washer liquid or the like. 
The apparatus includes a cylindrical heat-exchanger housing that, via hose 
connectors that are disposed at both ends of the housing, can be disposed 
directly in the coolant line between the engine and a radiator, with the 
interior of the housing, through which the coolant flows, containing a 
tube coil that is helically wound in the longitudinal direction of the 
housing. The liquid that is to be heated flows through the tube coil, and 
the ends of the latter are conveyed out of the housing in a radial 
direction. 
Various apparatus are known for motor vehicles in order to be able to 
utilize the heat that is released by the engine and is to be withdrawn by 
the cooling water of the radiator in a heat exchanger for generating warm 
windshield washer liquid. German Pat. No. 32 32 371, Gercken dated May 21, 
1987, discloses a heatable windshield washer apparatus, the heat exchanger 
of which is disposed in the cooling water hose circuit and comprises a 
tubular housing through which the cooling water flows. Disposed coaxially 
in this housing is a double-walled tube, the hollow space of which forms 
the heat-exchanger channel for the wash liquid. The two connector fittings 
that are connected to the wash-liquid line and that lead to the hollow 
space of the double-walled tube project radially from this tube and extend 
through the wall of the housing. With such a heat-exchanger configuration, 
the double-walled tube can be placed axially in the tubular housing only 
without the connector fittings, and the latter can be inserted through the 
wall of the housing only after the double-walled tube is placed in the 
housing, whereupon the connector fittings must be connected to the 
double-walled tube in the housing. This requires a complicated and 
expensive manufacturing procedure. German Offenlegungsschrift 21 12 473, 
Nitterl et al dated Oct. 5, 1972, corresponding to U.S. Pat. No. 
3,756,510, Nitterl et al, dated Sept. 4, 1973, discloses a heat exchanger 
for a heatable windshield washer apparatus, the tubular housing of which, 
through which cooling water flows, being closed off at the ends by end 
caps that are placed thereon and that contain hose connectors. A tube coil 
that is helically wound in the longitudinal direction of the housing is 
disposed in the latter as a heat-exchanger channel for the wash liquid. 
The connection ends of the tube coil for the wash liquid line project out 
through openings of the tubular housing or of the end caps; in particular, 
at one heat-exchanger end, a connection end projects out radially, and at 
the other heat-exchanger end, a connection end projects out at an inclined 
angle to the longitudinal axis of the housing. The tube coil can be 
installed in the housing only if the connection end that is inclined at an 
angle is first directed axially, so that when the tube coil is introduced 
into the tubular housing with this connection end in front, it can pass 
through the tubular housing. After the tube coil has been placed in the 
tubular housing, this connection end is then bent into the desired or 
required inclined position. Such a procedure can, of course, lead to 
damage of the material of the tube coil. This heretofore known 
heat-exchanger configuration additionally requires significant 
manufacturing effort in order to sealingly and securely connect the end 
caps to the tubular housing, for example by sealingly welding the abutting 
or overlapping edges of the sheet-metal housing and the cap all the way 
around. Significant manufacturing effort is also required in order to 
reliably seal the connection ends of the tube coil in the pass-through 
openings of the tubular housing or of the end caps to prevent cooling 
water from escaping from the heat exchanger; this can be accomplished, for 
example, by soldering a copper tube coil into the passthrough openings of 
the tubular sheet-metal housing and the caps. 
It is an object of the present invention to provide an apparatus of the 
aforementioned general type that can be assembled in an easier, quicker, 
and more economical manner, of prefabricated individual components, than 
was possible with the aforementioned known types of heat exchangers, and 
that, especially at those locations where the connection ends of the tube 
coil are conveyed out of the heat-exchanger housing, and even at possible 
increased pressures in the cooling liquid circuit, assures a seal that 
reliably precludes loss of cooling water, which would, of course, be 
dangerous for the engine.

SUMMARY OF THE INVENTION 
The apparatus of the present invention is characterized primarily in that 
the housing is divided, in an axial direction, into two semicylindrical 
shells which have abutting longitudinal edges that can be sealingly 
interconnected; the tube coil is adapted to be placed between these 
shells, and the housing is provided on its periphery with two radially 
extending pass-through sleeves through which respective ones of the 
radially extending ends of the tube coil can extend; each pass-through 
sleeve has an outer end that is remote from the housing and on which a 
sealing ring and a coupling nut is disposed to seal the tube coil end in 
the pass-through sleeve. The two pass-through sleeves either can be 
disposed on the periphery of one of the shells and can be directed in the 
same radial direction as shown in FIG. 5, or they can be disposed on the 
peripheries of both shells and can be directed in opposite radial 
directions as shown in FIG. 1. 
Further specific features of the present invention will be described in 
detail subsequently. 
DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring now to the drawings in detail, the cylindrical heat-exchanger 
housing 1 of the illustrated apparatus is provided at both ends of the 
housing with hose connectors 2 in order to be able to place the apparatus 
directly in the coolant line between a liquid-cooled engine and a 
radiator, especially of motor vehicle, so that the coolant can flow 
directly through the apparatus. The two ends of the housing 1 are 
advantageously provided with stepped connectors 2, 3 in order to be able 
to use the coolant hoses that have different diameters and that are 
customary in the motor vehicle industry, with these hoses then being 
clamped in position via hose clamps. Disposed in the housing 1 is a tube 
coil 4 that is helically wound in the longitudinal direction of the 
housing. The winding of the coil 4 are spaced from one another, so that 
the coolant can intensively flow all around the windings of the coil 4, 
and these coils can intensively absorb heat from the coolant in order to 
be able to heat up a liquid, such as the wash water for the windshield 
washer unit of a motor vehicle, that flows through the tube coil 4. The 
inventive apparatus can also be very advantageously used in order, without 
additional consumption of energy, to be able to use the already constantly 
available heat of the engine cooling-water to continuously preheat the 
diesel fuel for a diesel engine to such an extent that the diesel fuel, 
especially during the cold times of the year, remains optimally able to 
flow and atomize, and in so doing can be burned in the diesel engine in an 
economical fuel-saving manner with few environmentally polluting 
particulates. 
In the axial direction, the housing 1 is divided into two semicylindrical 
shells 5 that can be tightly and sealingly connected to one another along 
their abutting longitudinal edges. The housing 1 is also provided with two 
radially extending pass-through sleeves 7 through which can be guided the 
radially directed connection ends 8 of the tube coil 4. In the illustrated 
embodiments, the two pass-through sleeves 7, just like the ends 8 of the 
tube coil 4, are directed in oppositely directed radial directions, with 
the pass-through sleeves 7 being disposed on the peripheries of the two 
housing shells 5. The ends 8 of the tube coil 4 could also be directed in 
the same radial direction, in which case the two pass-through sleeves 7, 
of course, also would be directed in the same radial direction and would 
be disposed on the periphery of only one of the shells 5. O-ring seals 9, 
and thereafter coupling nuts 10, are placed on the tube coil ends 8 that 
extend through the pass-through sleeves 7. The coupling nuts 10 can be 
screwed onto the outer ends of the sleeves 7, and together with the 
O-rings 9 seal the tube coil ends 8 in the pass-through sleeves 7 so that 
coolant does not leak out. By axially splitting the housing 1 into the two 
semicylindrical shells 5, and by forming the housing pass-throughs for the 
tube coil from the pass-through sleeves 7, the tube coil 4 can during 
assembly of the apparatus easily be placed between the two housing shells 
and in so doing the radial connection ends 8 of the tube coil 4 can easily 
be inserted through the pass-through sleeves 7 and can then be 
satisfactorily and reliably sealed therein, via the O-rings 9 and the 
coupling nuts 10, in a simple and rapid assembly step. 
In the embodiment illustrated in FIGS. 1 and 2, the housing is made of cast 
or injection molded material, such as plastic. The housing is preferably 
made of an aluminum casting, such as could, for example, also be used for 
the cylinder heads. Such a housing has the advantage that the two 
semicylindrical shells thereof have a high stability and strength even at 
high temperatures, and that the longitudinal edges of the shells can be 
clamped or pressed together in a satisfactorily sealed manner. For this 
purpose, the two housing shells 5 are provided along their longitudinal 
edges with outwardly projecting flanges 11 via which the shells 5, along 
with an interposed seal insert between their longitudinal edges, can be 
tightly clamped together by means of clamping bolts 12. By making the 
housing of injection moldable or castable material, especially an aluminum 
casting, it is possible to simultaneously cast the pass-through sleeves 7 
into the walls of the shells in a sealed, nonrotatable, and longitudinally 
fixed manner during the manufacture of the shells 5 themselves. So that 
the pass-through sleeves 7, for example when the coupling nuts 10 are 
screwed thereon, do not turn or shift longitudinally in the shell wall, 
and hence lose their seal in the shell wall, those ends of the sleeves 7 
that are cast into the shell wall can be provided, for example, with a 
peripheral knurling 13 that prevents rotation, and with an 
annular-groove-like reduced-diameter section 14 that prevents longitudinal 
shifting. 
In the embodiment illustrated in FIGS. 3 and 4, the two semicylindrical 
housing shells 5 are made of sheet metal. The longitudinal edges 15 of one 
of the housing shells 5 are offset in the radial direction (in the 
illustrated embodiment in an outer radial direction) and overlap the 
longitudinal edges 16 of the other shell 5. Where the longitudinal edges 
15, 16 overlap, the two housing shells 5 are tightly and securely 
interconnected after the tube coil 4 has been easily installed in the 
manner described in connection with the embodiment of FIGS. 1 and 2. This 
interconnection can be effected by means of an adhesive or via a soldering 
material, with both of these methods being well known in the 
metal-connecting industry. The overlapping longitudinal edges 15, 16 of 
the housing shells 5 can be fitted into one another to such an extent that 
the longitudinal edges 16 abut against the bends of the radially offset 
longitudinal edges 15, as a result of which the overlap gap between the 
longitudinal edges 15 and 16 is adequately closed off in the direction 
toward the interior of the housing so that liquid solder material cannot 
flow through into the interior of the housing. The pass-through sleeves 7, 
preferably from the interior side of the housing, are passed through holes 
in the sheet-metal wall of the housing shells 5, and flange-like securing 
shoulders 17 that are formed on the pass-through sleeves 7 rest against 
the inner side of the sheet-metal wall. Securement of the pass-through 
sleeves 7 can be effected by a lock nut that is screwed on and rests 
against the outer side of the sheet-metal wall. To seal a given 
pass-through sleeve 7 in the hole in the sheet-metal wall, a washer or 
other sealing member can be provided between the securing shoulder 17 and 
the sheet-metal wall. The sealed securement of a pass-through sleeve 7 
against the sheet-metal wall of the housing shell 5 can advantageously be 
effected in a mechanical manufacturing by providing the securing shoulder 
17 with a bead 18 that extends around the pass-through sleeve 7 in an 
annular manner, and via which the securing shoulder 17 contacts the 
sheet-metal wall. It is then at the location of this bead 18 that the 
securing shoulder 17 is sealingly and tightly connected to the sheet-metal 
wall via an induction weld. 
The present invention is, of course, in no way restricted to the specific 
disclosure of the specification and drawings, but also encompasses any 
modifications within the scope of the appended claims.