DE102007044300B4 - Evaporator for liquefied petroleum gas and liquefied petroleum gas incinerator - Google Patents

Abstract

The LPG combustion apparatus for internal combustion engines has an evaporator which is heated by a first liquid (6). This liquid (6) is heated by a three-phase heat exchanger (8). The first phase of the three-phase heat exchanger (8) is formed by combustion exhaust gases (11) of the engine, the second phase by a liquid (13) and in particular cooling water of the engine and the third phase is said first liquid supplied to the evaporator becomes (Fig. 1).

Description

The The invention relates to an evaporation device for liquefied gas according to the preamble of Claim 1.

The EP 1 173 669 B1 (= DE 600 12 315 T2 ) describes a Flüssiggasverdampfungsvorrichtung for sea water cooled marine engines, the device having a radiator with evaporation chamber and hot chamber, which are adjacent to each other and are separated by a common wall and the hot chamber is traversed by warm sea water running from the cooling circuit of the engine.

Internal combustion engines, operated with LPG are becoming increasingly prevalent as they are more environmentally friendly are gasoline or diesel engines and compared to the latter lower fuel costs.

The LPG must ago the feed to the engine from the liquid Phase are transferred to the gas phase, what with an evaporator or generally also evaporator called. The gas should be at a temperature between 60 ° C and Be heated to 80 ° C.

The heat required for this is in the EP 1 173 669 B1 taken from heated seawater, which drains from a cooling circuit of the engine.

Problematic is doing that in the warm-up phase of the engine is not the required operating temperature the evaporator is reached. During the Warm-up phase, such engines are therefore usually also with Gasoline operated. This is particularly problematic in boat engines, the common their cooling water from the busy waters refer, so that at low water temperatures the warm-up phase takes a long time or even a liquefied gas operation at all not possible.

The DE-PS-911 922 describes that evaporators are acted upon for LPG of internal combustion engines with exhaust gases of the internal combustion engine, but considers this to be disadvantageous, since a good control of the temperatures is not readily possible and the temperatures of the exhaust gases are so high that a per se desired assembly of the evaporator the control device also required because of the risk of damage to the sensitive parts of the controller is problematic due to excessive heating. Therefore, this document also proposes, in turn, to use as the heat source, the cooling water of the internal combustion engine or in air-cooled internal combustion engines to pressurize the evaporator with a partial flow of the cooling air around the engine.

Heat exchangers charged with the exhaust gas of an internal combustion engine have been proposed for various purposes. The DE 85 03 285 U1 wants to use it to heat the water from windscreen washer systems of motor vehicles. The DE 197 13 442 C2 thus cools an exhaust gas catalyst. The DE 100 35 760 A1 also wants to cool a catalyst. The DE 600 19 231 T2 uses an exhaust gas heat exchanger to recover heat. The DE-PS 883 443 uses an exhaust gas heat exchanger to overheat the liquid gas and uses the resulting excess pressure to gain external work by relaxation.

task The present invention is to provide the evaporation apparatus of to improve the aforementioned type so that they quickly required operating temperature and this with easier Regulation keeps stable.

These The object is achieved by the features specified in claim 1 solved. Advantageous embodiments and further developments of the invention are the dependent claims refer to.

The The basic idea of the invention is a three-phase heat exchanger. use. The The first phase is formed by the combustion exhaust gases of the engine. The second phase is a liquid and in particular water and preferably cooling water from the cooling system of the motor. The third phase is also a liquid, preferably Water that is fed to the evaporator to evaporate the liquefied gas.

The evaporation device according to the invention can be used both in water-cooled and air-cooled internal combustion engines and in particular also in boat engines whose cooling water is taken from the water used by the boat. The heat exchanger used in the invention causes the combustion exhaust gases of the first phase to heat the liquid of the second phase. Thus, the combustion exhaust gases are cooled, which improves the efficiency of the engine, reduces pollutant emissions and spares a catalytic converter in the engine exhaust system downstream of the catalytic converter. If the liquid of the second phase removed from the water cooling system of the engine, it will be heated faster in the warm-up phase of the engine and the engine thereby reaches its operating temperature faster. This allows the engine to be switched from gasoline operation to gas operation earlier, which is beneficial to the environment. Also, by earlier reaching the operation Temperature of the engine reduces the wear.

The liquid the second phase is in heat exchange with the liquid the third phase of the evaporator circuit and gives their heat to this from.

The Temperature of the second phase can be relative Easily regulate, for example, by a control valve, the amount the liquid flowing through the heat exchanger the second phase temperature dependent regulates.

Of the Three-phase heat exchanger Depending on the design of the engine directly on the motor housing or flanged to the cylinder head of the engine. Depending on the design can he also on the exhaust manifold be attached to the engine.

at Boat engines, the cooling water from the busy waters use, it is common practice that Cooling water escaping from the engine to lead into the exhaust pipes. The exhaust manifold is in these cases double-walled tube forming an annular space in which the cooling water is derived. The three-phase heat exchanger used in the invention can then be very simple, as below will be described in more detail.

in the The following is the invention with reference to an embodiment in connection with the drawing in more detail explained. It shows:

1 a schematic diagram of the evaporation apparatus for liquefied gas for a boat directly cooled with seawater boat engine;

2 a schematic diagram similar 1 for a boat engine cooled indirectly with seawater;

3 a schematic diagram similar 1 for an air-cooled engine;

4 a schematic diagram similar 1 for a boat engine water cooled with a closed cooling circuit; and

5 a sectional view of a three-phase heat exchanger used in the invention.

6 A section of the three-phase heat exchanger along the line AA the 5 ,

7 A schematic diagram of the evaporation device for liquid similar to 1 , in which seawater forms the second and the third phase.

1 schematically shows an internal combustion engine 1 which in the following is called only engine. The motor 1 gets out of a tank with liquefied gas 2 operated. The liquefied gas is in an evaporator 3 vaporized and transferred to the gaseous phase and from there via a fuel line 4 the engine 1 fed. The evaporator 3 is in principle a heat exchanger, via a pump 5 a heated liquid 6 which is fed from the tank 2 also supplied liquefied gas evaporates and thus converted into the gaseous state. This liquid 6 flows in a closed circuit 7 who is the pump 5 , the evaporator 6 , a three-phase heat exchanger 8th and a pipe connecting these components 9 contains.

The three-phase heat exchanger 8th is on an exhaust pipe 10 of the motor 1 connected, usually at the so-called exhaust manifold of the engine, and leads hot combustion exhaust gases 11 as the first phase of the three-phase heat exchanger 8th to.

Next is the three-phase heat exchanger 8th a cooling water pipe 12 connected, the cooling water 13 from a cooling system 14 the engine of the three-phase heat exchanger 8th as the second phase. The third phase of the three-phase heat exchanger 8th is the mentioned liquid 6 ,

The three-phase heat exchanger has a fluid-tight passageway for each of the three phases, which is related to 5 and 6 will be described in more detail, wherein the three passageways are separated from each other and are in heat exchange with each other.

In the embodiment of 1 is the cooling system 14 directly supplied with seawater via a pump 15 taken from the water used by the boat, through the cooling system 14 the engine and the three-phase heat exchanger 8th passed through and then returned to the water. The term "seawater" here refers to any of the boat used by the water, which may therefore be a sea, an inland lake, a river, etc. The exhaust pipe 10 and the cooling water pipe 12 Here are at least partially executed together as a double-walled tube, wherein the exhaust pipe 10 the inside pipe is and the cooling water pipe 12 surrounds this outside, so that the cooling water 13 with an annulus the exhaust pipe 10 surrounds and thus the exhaust pipe 10 and thus the combustion gases 11 cools and warms itself. Such double-walled exhaust and cooling water pipes are in many boat engines in use and can be tapped in some embodiments directly on the engine housing, the cylinder head or the exhaust manifold.

The three-phase heat exchanger 8th has at its output appropriate piping 10a and 12a about which the combustion gases 11 and the cooling water 13 be dissipated.

In three-phase heat exchanger 8th thus stand the combustion gases 11 the first phase and the cooling water 13 the second phase in heat exchange. At the same time the combustion exhaust gases become 11 cooled and the cooling water 13 heated. Next are this first and second phase and primarily the second phase of. Cooling water 13 in heat exchange with the liquid 6 the third phase. Essentially, the second phase in turn gives off heat to the third phase. The second phase is thus cooled again and can later in the passage through the pipe section 12a the in the pipe section 10a continue to cool the flowing combustion exhaust gases.

The liquid 6 the third phase flows in the said cycle 7 and transports the required heat to the evaporator 3 ,

In the cooling system 14 can be a control valve 16 be arranged, which is either a conventional thermostatic valve or an electrically controlled valve, which via a regulator 17 and a temperature sensor 18 is controlled, wherein the temperature sensor 18 at the three-phase heat exchanger 8th is connected and there optionally measures the temperature of the second or third phase.

2 shows a variant of the invention with a motor 1 , its cooling system 14 forms a closed circuit, which is an additional heat exchanger 19 contains and a water pump 20 , wherein the seawater in the heat exchanger 19 in heat exchange with cooling water of the engine 1 stands. That from the additional heat exchanger 19 outgoing, heated seawater 13 then the three-phase heat exchanger 8th fed. At the inlet side of the three-phase heat exchanger 8th can the exhaust pipe 10 and the cooling water pipe 12 again, as in the embodiment of 1 be formed double-walled, as in 2 shown. But it is also possible to arrange the inlets lying side by side. In a corresponding manner may also be provided on the outlet side, that the seawater 13 separated from the pipe section 10a of the exhaust pipe 10 to be led. Also it is possible the seawater 13 directly inside the pipe section 10a remove the exhaust pipe. In the 2 illustrated variant is suitable for marine engines for polluted water or sea water, where you do not water directly through the sometimes narrow cooling channels of the engine 1 wants to lead.

The embodiment of 3 shows the evaporation apparatus according to the invention in connection with an air-cooled engine 1 coming from a cooling fan 21 with cooling air 22 is cooled. The motor 1 has for this purpose in a known manner cooling fins 23 , Downstream of these cooling fins in the exhaust air flow of the heated cooling air 22 is a heat exchanger 24 arranged by the heated cooling air 22 is flowed through. In this heat exchanger 24 is a medium, such. As water, which is heated as the second phase of the three-phase heat exchanger 8th is fed and in a closed circle 25 via a pump 26 and a surge tank 26 is encouraged. Again, as in the previous embodiments, be provided that at least a portion of the tubes of this circle 25 coaxial with the exhaust pipe 10 and / or its section 10a runs. Again, in the circle 25 a thermostatic valve 16 be arranged.

4 shows the evaporation device according to the invention in connection with a water-cooled engine 1 whose cooling water circuit 14 through a standard cooler 27 by airstream and / or a cooling fan 21 is cooled. The cooling water 13 is here as the second phase of the three-phase heat exchanger 8th fed. Out 4 one recognizes further that the three-phase heat exchanger 8th also directly to the engine 1 can be flanged. Next is the evaporator 3 shown as a countercurrent heat exchanger. Otherwise, the matches with the embodiments of the 1 - 3 readily recognizable.

5 shows an embodiment of the three-phase heat exchanger used in the invention 8th , In this embodiment, it consists of a cuboid metal block, which has a plurality of holes and openings. In the sectional plan view of 5 is a first opening 28 to recognize the one passage for the combustion gases 11 forms and to the exhaust pipe 10 is connected. Next are here three slot-like openings 29 . 30 and 31 can be seen, which also go completely through the block-shaped metal block and passages for the cooling water 13 or form the second phase. These openings 29 . 30 and 31 are opposite the opening 28 through a wall 32 separated, being over this wall 32 a heat exchange between the through the first opening 28 flowing first phase and through the openings 29 . 30 and 31 flowing second phase takes place.

Next is a channel 32 with three holes perpendicular to each other 33 . 34 and 35 present, through which the liquid 6 the third phase flows. The flow directions of the three phases are indicated by arrows 36 . 37 and 38 indicated.

The holes 33 . 34 and 35 are opposite the openings 28 . 29 . 30 and 31 offset to the outside. The holes 33 and 35 lie parallel to each other and have at their ends in each case a thread 39 , respectively. 40 for screwing on the pipe sections 12 and 12a , where the pipe sections 12 and 12a of course also flexible hoses can be.

The hole 34 has at its one end also an outwardly projecting opening with a thread 41 in which either an unillustrated blind plug or the temperature sensor 18 can be screwed. In the illustrated embodiment, the holes 33 . 34 and 35 each made from the outside of the cuboid metal block with a drill, so that at the ends of the channels 33 . 34 and 35 the drill tip corresponding recesses 42 form, which are conditioned solely by the production.

The openings 28 . 29 . 30 and 31 are also prepared in this embodiment by clamping machining, in particular milled.

Next are two holes 43 and 44 to recognize, which are provided for the passage of fastening screws.

The block-shaped metal block of the three-phase heat exchanger 8th consists of good heat-conducting metal, such as. As aluminum, copper, brass, to name just a few examples.

Out 5 one recognizes that from "inside" to the outside a temperature gradient is present. The highest temperature prevails in the opening 28 due to the hot combustion gases 11 that over the wall 32 in heat exchange with the openings 29 . 30 and 31 through which the colder second phase flows, which is thereby heated. This second phase is about wall sections 45 again in heat exchange with the holes 33 . 34 and 35 in connection, through which the third phase flows and is heated.

In the illustrated embodiment of the 5 stands the opening 28 over a wall section 46 also in direct connection with the bore 34 , so that also takes place between the first and the third phase, an immediate heat exchange.

Of course it takes place over the entire of the channels 33 . 34 and 35 coated material portion of the cuboid metal block heat exchange between all three phases instead.

Out 6 making the section along the line AA of 5 represents, you can see the flow paths of the three phases and the flow direction of the arrows 36 . 37 and 38 ,

The effectiveness of the three-phase heat exchanger 8th to achieve the necessary for the evaporation of the liquefied gas temperature depends on the particular motor to be operated and can be adjusted by appropriate dimensioning of the dimensions of the cuboid metal block.

Of course, it is also possible to use other forms of heat exchangers, for example, those in which the individual phases separating walls are formed by sheets, which may also have heat transfer ribs. Other shapes with spiraling flow paths of the three phases are possible. That in connection with the 5 and 6 described embodiment is therefore to be understood only as a possible embodiment, which can be produced in simple workshops.

7 shows a variant of the evaporation device for a boat directly cooled with seawater boat engine. This variant differs from the embodiment of 1 in that the seawater containing the cooling system 14 flows through, not only the exhaust pipe 10 surrounding cooling water pipe 12 and thus as a second liquid 13 the three-phase heat exchanger 8th is fed, but additionally at a branch point 48 at the engine 1 or its cylinder head removed and via the control valve 16 and the pipeline 9 as the third phase of the three-phase heat exchanger 8th is supplied. From there it passes through the pump 5 to the evaporator 3 and is over a pipe section 9a headed back into the water.

Thus, there is the engine 1 preheated cooling water of the third phase in the three-phase heat exchanger 8th further heated by the second phase, which in turn was heated by the engine exhaust gases of the first phase.

As in 7 hinted, that can be the evaporator 3 leaving pipe section 9 also with the pipe section 12a be connected, resulting in a pipe section 9b what is shown as an alternative to the pipe section 9a can be provided. So that would be the heat exchanger 3 leaving water of the third phase in the pipe section 12a drain and thus continue to cool the engine exhaust, as the overflowing water in the evaporator 3 was cooled.

Conveniently, the control valve 16 in this embodiment, in the pipe section for the third phase provided between the engine and the inlet for the third phase of the three-phase heat exchanger 8th lies.

Claims (10)

Liquid-gas evaporation apparatus for internal combustion engines with an evaporator heated by a heated first liquid, characterized by a three-phase heat exchanger ( 8th ), whose first phase is combustion exhaust gases ( 11 ) of the motor ( 1 ) whose second phase is a second liquid ( 13 ) and whose third phase is the evaporator ( 3 ) supplied first liquid ( 6 ). Evaporation apparatus according to claim 1, characterized in that the second liquid ( 13 ) Water is. Evaporation apparatus according to claim 2, characterized in that the second liquid ( 13 ) Cooling water of the engine ( 1 ). LPG combustion system with an internal combustion engine ( 1 ), which is an exhaust pipe ( 10 ) for combustion gases ( 11 ) and a fuel line ( 4 ) for a supply of combustible gas, with a tank ( 2 ) for liquefied petroleum gas and a heated by a first liquid ( 6 ) heatable evaporator ( 3 ) between the tank ( 2 ) and the internal combustion engine ( 1 ), characterized by a three-phase heat exchanger ( 8th ) having at least three fluid-tightly-isolated passageways ( 28 . 29 . 30 . 31 . 33 . 34 . 35 ), wherein the first passageway ( 28 ) with the exhaust pipe ( 10 ), the second passageway ( 29 . 30 . 31 ) with a liquid circle ( 14 . 12 . 25 ) and wherein the third passageway ( 33 . 34 . 35 ) with a heating circuit ( 7 ), which is the first liquid ( 6 ) the evaporator ( 3 ) feeds. LPG combustion plant according to claim 4, characterized in that the liquid circuit connected to the second passageway is a cooling water circuit ( 14 ) of the internal combustion engine ( 1 ). LPG combustion plant according to claim 5, characterized in that the exhaust pipe ( 10 ) is double-walled, wherein the outer wall ( 12 . 12a ) forms an annular space, which the liquid ( 13 ) of the second passageway ( 29 . 30 . 31 ) leads. LPG combustion system according to one of claims 4 to 6, characterized in that, in a boat engine, the second fluid ( 13 ) Water of the navigated water, which after passing through the cooling water circuit ( 14 ) of the motor ( 1 ) is returned to the water. Liquefied petroleum gas combustion plant according to one of claims 4 to 6, characterized in that the second liquid ( 13 ) circulates in a circle, a second heat exchanger ( 24 ), which in an air-cooled internal combustion engine with heated by the engine cooling air ( 22 ) is flowed through. LPG combustion system according to one or more of claims 4, 5, 6 or 7, characterized in that the second passageway ( 29 . 30 . 31 ) and the third passageway ( 33 . 34 . 35 ) with the cooling water circuit ( 14 ) of the internal combustion engine ( 1 ) are connected. LPG combustion plant according to claim 9, characterized in that the first liquid ( 6 ) after passing through the evaporator ( 3 ) and the second liquid ( 12 ) after passing through the three-phase heat exchanger ( 8th ) in a common pipe section ( 12a ) be derived.