EP0394796B1 - Heating system, especially for vehicles with an internal combustion engine and a heating device - Google Patents

Description

The invention relates to a heating system, in particular for motor vehicles, which uses waste heat from an internal combustion engine and has a heater which can be operated with liquid fuel for generating heat independently of the operation of the internal combustion engine or in addition to engine waste heat, the heater being spatially assigned to the oil pan of the internal combustion engine, which is associated with an indentation is provided, in which the heater is mounted so as to protrude with its heat-emitting region and has a liquid space between the heat-emitting region of the heater and the indentation, through which the liquid to be heated flows. DE-A-37 12 670 describes such a heating system which corresponds to the preamble of claim 1.

Heating devices for motor vehicles which can be operated with liquid fuel and which generate heat independently of or in addition to the operation of the internal combustion engine are known. Their most important area of application is the preheating of the motor vehicle interior and / or the internal combustion engine, so that when the vehicle starts moving, the motor vehicle user already finds a warm vehicle interior with defrosted windows and a drive motor of the motor vehicle that is no longer undercooled. Cold start wear on the internal combustion engine is significantly reduced. Exhaust emissions are also reduced during the warm-up phase.

It is known (DE-A 37 12 670) to spatially assign the heater to the oil pan of the internal combustion engine such that not only water is heated for the vehicle heater by the heater, but also heat in the shortest possible way Oil pan located oil of the internal combustion engine is supplied.

The invention has for its object to integrate the heater more cheaply in such a heating system.

To achieve this object, the indentation of the oil pan with its longitudinal direction of extension is arranged essentially parallel to the crankshaft axis of the internal combustion engine and off-center. A feed line to the liquid flow space in the indentation and a discharge from this liquid flow space are integrated in the heater.

In the known heating system described, the heater is located with its main direction of extension perpendicular to the crankshaft axis and overall below the crankshaft. This results in an overall increase in the overall height of the internal combustion engine. In contrast, there is no or at most a slight increase in the overall height of the internal combustion engine in the configuration of the heating system according to the invention. This is very desirable because modern motor vehicles endeavor to arrange the bonnet as low as possible or to make it flat, and because the internal combustion engine cannot be arranged at any depth for reasons of ground clearance.

The main area of the heater is - roughly speaking - cylindrical. In an embodiment of the invention, this main area is designed with the smallest possible diameter, the length being less restrictive.

The invention also provides a heating system in which the internal combustion engine is designed with liquid cooling and an electric circulating pump for the cooling liquid, in which the heating device is designed as a liquid heating device, and in which the heating device is integrated into the cooling liquid system of the internal combustion engine is, so that the circulation pump can pump coolant through the heater when the internal combustion engine is stopped. Because of this design, the previously used liquid circulation pump of the heater is not necessary. Their function is taken over by the electric circulation pump of the internal combustion engine. An electric circulation pump for the coolant has the great advantage that it can work independently of the instantaneous speed of the internal combustion engine, in particular its delivery capacity can be adjusted to the current cooling requirement of the internal combustion engine or heat requirement for heating the vehicle interior.

The invention also provides a heating system in which the lubricating oil circuit of the internal combustion engine is equipped with an electric oil pump, so that the stationary internal combustion engine can be heated by pumped-over lubricating oil heated by the heating device. This results in a more extensive preheating of the internal combustion engine, since the lubricating oil circuit leads practically through the entire internal combustion engine. In addition, an electric oil pump has the essential advantage over an oil pump mechanically driven by the internal combustion engine that its delivery volume or delivery pressure can be selected independently of the instantaneous speed of the internal combustion engine. In particular, it is possible to increase the delivery volume or delivery pressure when idling or at low engine speeds compared to previous practice with a mechanical drive of the oil pump.

The spatial assignment of the heater to the oil pan of the internal combustion engine can also be used according to the invention to extract heat from the hot lubricating oil of the internal combustion engine, particularly when the internal combustion engine is operating at high power and / or at high outside temperatures. Due to the invention, the oil pan is integrated, so to speak, into a heat exchanger through which the coolant of the internal combustion engine can flow. When the internal combustion engine is operating at high power and / or at high outside temperatures, the coolant of the internal combustion engine is at a lower temperature than the lubricating oil, which can be at a temperature of more than 140 ° C. under the conditions described.

• Fig. 1 eine schmatisierte Stirnansicht eines Verbrennungsmotors mit in die Ölwanne integriertem Heizgerät, und zwar in Richtung der Kurbelwellenlängsachse und von der Hinterseite des Verbrennungsmotors her gesehen;
• Fig. 2 einen horizontalen Teil-Längsschnitt des Verbrennungsmotors von Fig. 1 gemäß II-II, und zwar in vergrößertem Maßstab und beschränkt auf den Anordnungsbereich des Heizgeräts;
• Fig. 3 die Gestaltung eines Kühlflüssigkeitskreislaufs eines Verbrennungsmotors mit zugeordnetem Heizgerät.

The invention and refinements of the invention are explained in more detail below with reference to exemplary embodiments illustrated in the drawings. It shows:

• Figure 1 is a schematized front view of an internal combustion engine with a heater integrated in the oil pan, namely in the direction of the longitudinal axis of the crankshaft and seen from the rear of the internal combustion engine.
• FIG. 2 shows a horizontal partial longitudinal section of the internal combustion engine from FIG. 1 according to II-II, to be precise on an enlarged scale and limited to the arrangement area of the heater;
• Fig. 3 shows the design of a coolant circuit of an internal combustion engine with an associated heater.

1 shows an internal combustion engine 2 with cylinder block 4, cylinder head 6, valve cover 8, air intake system 10, air filter 12, start of exhaust system 14, schematically indicated crankshaft 16 with crankshaft axis 18, and with an oil pan 20. The oil pan 20 is without enlargement their vertical dimensions are used laterally in order to create a receiving space for a heater 22 off-center from the crankshaft axis 18.

2 shows in more detail how the heat exchange area of the heater 22, which spatially makes up the main part of the heater 22, is integrated into the oil pan 20. In the region of the bulge 24 of the oil pan 20 there is a - roughly speaking - cylindrical indentation or pocket 26 in the oil pan 20. The indentation 26 is open to the front or rear end of the internal combustion engine 2, otherwise closed everywhere, and in one piece with the rest of the oil pan 20 educated. The oil pan 20 together with the indentation 26 is preferably made of metal, in particular die-cast aluminum. Si can also consist of plastic, for example. The indentation 26 can on its outside or the inside of the oil pan 20 Side with ribs 28 to improve the heat transfer. The axial direction of extension of the indentation 26 is parallel to the crankshaft axis 18. The length of the indentation 26 in the axial direction depends on the desired or required thermal output of the heater 22. The length can take up almost the entire length of the oil pan 20. The indentation 26 can, however, also be shorter axially, for example in order to leave space axially in front for an oil pump or an intake system for the oil circuit of the internal combustion engine 2 (not shown).

The heater 22 itself, which is shown in part schematically in FIG. 2, essentially consists of a heater base part 30, an essentially cylindrical flame tube 32 that axially supports it, and a jacket 34 made of metal surrounding the flame tube 32. The base part 30 essentially comprises a combustion air blower, a fuel pump which may also be arranged separately, a combustion chamber at the transition to the flame tube 32, an electrical ignition device in the combustion chamber and a temperature sensor (overheating switch), these elements not being shown separately. The flame tube 32 is open at the front end removed from the base part 30. The essentially cylindrical jacket 34 is closed at its end 34 adjacent to the open end of the flame tube 32. The hot combustion gases flow axially forward in the flame tube 32 and then axially back in the annular space between the flame tube 32 and the jacket 34. They leave the heater 22 through an exhaust gas line 36. Between the overall deep cup-shaped jacket 34 and the overall deep cup-shaped indentation 26 there is a space 38 through which the coolant of the internal combustion engine 2 flows, a supply line 40 and a discharge line 42 being indicated schematically are. In order to achieve a targeted flow through this space 38, it can be divided, for example, in FIG. 2 below the plane of the drawing and in FIG. 2 above the plane of the drawing by an axially extending partition wall 44, which ends axially at the front where the jacket 34 ends. In this way, the coolant flows in the in FIG. 1 left half of the space 38, comes axially forward from the left half into the right half and flows axially back on the right side in FIG. 1. Analogously, one could also provide a forward flow in the upper half of the space 38 and a reverse flow in the lower half of the space 38. There are further possibilities for a suitable flow control, for example a forward flow in space 38 as a whole and a backflow through a separate line. The combustion gases of the heater 22 give off most of their heat through the jacket 34 to the coolant flowing through the space 38, and the coolant gives off at least some of their heat through the wall of the indentation 26 to the lubricating oil in the oil pan 20.

The base part 30 and the jacket 34 have flanges which are fastened to a corresponding outer flange 48 of the oil pan 20 by means of a common clamping ring 46. The jacket 34 is provided on the inside and / or outside with elevations 50 or ribs, which can, for example, run in a spiral to the liquid or. To make gas flow through the corresponding room more turbulent, thereby increasing the heat transfer.

The solution drawn has the advantage that the oil pan has no potential leak.

3 shows a preferred example of how the heater 22 can be integrated into the coolant circuit of the internal combustion engine 2. It is an embodiment in which the heater 22 does not have its own liquid pump and in which an electrically driven circulation pump 52 is provided for the coolant of the internal combustion engine 2.

A first part of the total coolant circuit of the internal combustion engine 2 essentially consists of the circulation pump 52, which is connected on the output side via a line 76 to coolant flow-through spaces in the internal combustion engine 2, a line 54 which is arranged from the other end of these coolant flow-through spaces to one in the bow of the vehicle , the cooler 56 exposed to the wind, a further line 58 which leads from the cooler 56 back to the circulating pump 52, and a bypass line 60 which leads past the cooler 56 and which leads from the line 54 to the line 58. At the beginning of the bypass line 60, a thermostatic valve 62 is installed, which conducts the cooling liquid through the bypass line 60 when the internal combustion engine 2 is cold and through the cooler 56 when the internal combustion engine 2 is hot.

A second part of the coolant system essentially contains a first line 64, one assigned to the vehicle interior Heat exchanger 66 and a second line 68. The first line 64 is connected to the previously described line 54 near the internal combustion engine 2 with a T-piece. The second line 68 is also connected downstream of the line 54 with a T-piece. When a heating valve 70 arranged in the second line 68 is opened, a partial flow of the cooling liquid flows through the heat exchanger 66, as a result of which the interior of the motor vehicle is heated. A check valve 72 determines the flow direction of line 68.

A third part of the coolant system leads from an adjustable valve 74, which is provided in line 76, to the heater 22 and from there with a T-piece into the described first line 64.

If the adjusting valve 74 is set in the direction of the bent arrow 78 and the heater 22 is not switched on, the coolant circuit operates like a conventional coolant circuit without an additional heater. If the adjusting valve 74 is set in the direction of the straight arrow 80, all of the coolant downstream of the pump 52 first flows through the heater 22, where it is heated when the heater 22 is switched on. If the heating valve 70 is open, the heated coolant first flows through the heat exchanger 66, so that part of the heat is released to the vehicle interior. Then the coolant flows through the bypass line 60, provided that the thermostatic valve 62 has the appropriate position, and from there back to the pump 52. This is otherwise the valve position in which the heat generated in the heater 22 on the one hand for preheating the lubricating oil in the oil pan 20 and on the other hand is used to heat the vehicle interior via the heat exchanger 66, specifically, if one wishes, when the internal combustion engine 2 is stopped. When the heating valve 70 is closed, the coolant flows through the first line 64 to line 54. When the adjusting valve 74 is set to an intermediate position , the coolant flow coming from the pump 52 is divided into two partial flows, namely a first partial flow through the supply internal combustion engine 2 and a second partial flow through the heat exchanger 66, provided the heating valve 70 is open. As a result, the heat generated by the heater 22 not only benefits the heating of the vehicle interior but also the heating of the internal combustion engine 2 via the coolant. This position of the adjusting valve 74 is therefore suitable for heating the internal combustion engine 2 in addition to the vehicle interior not only via the content of the oil pan 20 but also via the coolant. this position is also suitable for operating situations in which the internal combustion engine 2 does not generate enough heat, for example short-distance traffic in winter, so that the heater 22 works as an additional heater. Such additional heating tasks are viewed by the applicant as increasingly important, especially for applications in which the internal combustion engine of a motor vehicle does not produce sufficient heat in numerous operating phases. In particular, it deals with the cases of small-volume drive motors, drive motors with high efficiency and therefore low waste heat production, as well as diesel engines.

It is understood that the coolant circuit described with reference to FIG. 3 is only one - albeit preferred - exemplary embodiment. There are a number of other ways in which the coolant circuit can be designed. If one uses a heater 22 with its own circulation pump for the heat transfer fluid and a conventionally mechanically driven circulation pump 52 for the coolant of the internal combustion engine, one can interconnect the heater 22 with the heat exchanger 66, for example, in such a way that the heat transfer fluid heated in the heater 22 flows to the heat exchanger 66 and from there directly back to the heater 22. Or you can switch the heater 22 in the bypass to the circulation pump 52, so that heated heat transfer fluid flows through the internal combustion engine 2 to heat it and also - when switched on - flows through the heat exchanger 66.

The main part of the heater 22 protruding into the oil pan 20 and the indentation can alternatively also be slightly conical with a forward decrease. diameter.

Claims (3)

1. Heating system, in particular for motor vehicles, which utilizes the waste heat of an internal combustion engine and has a heating device, which may be operated with liquid fuel, for the generation of heat independently of the operation of the internal combustion engine or in addition to the waste heat of the engine, the heating device being spatially associated with the oil sump of the internal combustion engine, which oil sump is provided with an inturned region into which the heating device is mounted to project by means of its heat-emitting region and has a liquid flow chamber (38) between the heat-emitting region of the heating device and the inturned region, which liquid flow chamber (38) is flowed through by the liquid to be heated, characterized in that the inturned region (26) of the oil sump (20) is arranged eccentrically and with its direction of longitudinal extent substantially parallel to the crankshaft axis of the internal combustion engine (2), and in that an incoming line (40) to the liquid flow chamber (38) in the inturned region (26) and an outgoing line (42) from this liquid flow chamber (38) are integrated in the heating device (22).
2. Heating system according to Claim 1, characterized in that the internal combustion engine (2) is constructed with a liquid cooling system and an electrical circulation pump for the cooling liquid, and in that the heating device (22) is integrated in the cooling liquid system of the internal combustion engine (2) so that the circulation pump can pump cooling liquid through the heating device (22) when the internal combustion engine (2) is stationary.
3. Heating system according to Claim 1 or 2, characterized in that the lubricating oil circuit of the internal combustion engine (2) is equipped with an electrical oil pump, so that the stationary internal combustion engine (2) may be heated by way of lubricating oil which is pumped around and is heated by means of the heating device (22).

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