EP1507965A1

EP1507965A1 - Method and device for cooling an internal combustion engine

Info

Publication number: EP1507965A1
Application number: EP03730060A
Authority: EP
Inventors: Bernd Wenderoth; Stefan Dambach
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2002-05-17
Filing date: 2003-05-16
Publication date: 2005-02-23
Also published as: KR20050010007A; US20050166870A1; MXPA04010638A; US7409927B2; DE10222102A1; AR039979A1; CA2485186C; CN1653250B; PL209335B1; CN1653250A; AU2003240665A1; BR0309995A; CA2485186A1; WO2003098015A1; JP2005530945A; ZA200410121B; PL372491A1

Abstract

The invention relates to a method and a device for cooling an internal combustion engine. An aqueous, non-ionic coolant composition is used in a cooling circuit (14) of the internal combustion engine (11). In order to also ensure long-lasting protection against corrosion for light metal components of the engine that come into contact with the coolant, e.g. components made of magnesium or magnesium alloys, the cooling circuit has at least one deionization device (28), for example, an ion exchanger, for the coolant.

Description

Method and device for cooling an internal combustion engine

description

The present invention relates to a method and a device for cooling an internal combustion engine, and an internal combustion engine with an internal combustion engine and a corresponding cooling device.

Internal combustion engines, for example internal combustion engines for motor vehicles, usually have an internal combustion engine and a cooling circuit in which a cooling liquid circulates. Different cooling circuits of such internal combustion engines are described, for example, in European patent application EP-A 0 038 556 or in German patent applications DE-A 198 03 884, DE-A 199 38 614 or DE-A 199 56 893. A coolant circulates in the cooling circuit of these internal combustion engines, which is slid through cooling jackets in the engine block / crankcase and in the cylinder head. The coolant is usually first led through the cooling jacket of the crankcase and then through the cooling jacket of the cylinder head. However, it is also possible to divide the cooling liquid into two separate sub-circuits by means of a preferably controllable valve before entering the engine housing and to conduct it separately into the cooling jackets of the crankcase and cylinder head. By means of a control device, it is then possible to regulate the two partial cooling circuits independently of one another as required, depending on parameters of the internal combustion engine.

Coolant concentrates diluted with water are used as cooling liquids that circulate in the cooling circuits, which on the one hand ensure good heat dissipation and on the other hand ensure reliable frost protection. Most of the coolants intended for cooling circuits for internal combustion engines contain alkylene glycols, especially ethylene glycol or propylene glycols, as the main component. However, alkylene glycol / water mixtures are very corrosive at the operating temperatures of internal combustion engines. Therefore, the different metals in the cooling system, such as copper, brass, iron, steel, cast iron (gray cast iron), lead, tin, chrome, zinc and aluminum and their alloys, as well as solder metals, such as solder (soft solder), must be sufficient be protected from a wide variety of types of corrosion, such as pitting, crevice corrosion, erosion or cavitation. For this reason, coolants contain tel for the cooling circuits of internal combustion engines in addition to the antifreeze agents and corrosion inhibitors.

Typical coolant formulations, as described for example in WO-A 01/32801, EP-A 0 816 467, WO-A 97/30133 or EP-A 0 557 761, therefore also contain ionic corrosion inhibitors in the form of organic carboxylic acid salts, such as Example alkali salts of 2-ethylhexanoic acid or sebaic acid and / or in the form of inorganic salts, such as nitrates, nitrites, borates or molybdates.

In the automotive industry, efforts are currently being made to reduce fuel consumption by reducing the weight of motor vehicles. In engine construction, too, efforts are being made to reduce the weight of the units, for example by using light metals or light metal alloys. In recent developments, for example, attempts are being made to design engines partially or completely from magnesium or magnesium alloys.

However, it has been shown that because of the increased chemical reactivity of magnesium, the coolants which are commercially available today and which contain ionic corrosion inhibitors offer practically no corrosion protection for components made of magnesium and its alloys.

The applicant's international patent application WO-A 02/08354 describes for the first time completely nonionic coolant concentrates and aqueous coolant compositions containing these coolant concentrates. These are coolants with anti-freeze components based on alkylene glycols and their derivatives or glycerin, which contain 0.05 to 10% by weight of one or more carboxylic acid amides and / or sulfonic acid, if necessary, in addition to other corrosion inhibitors, which means in particular with light metals such as Aluminum and magnesium or their alloys provide very good protection against corrosion.

At the operating temperatures of internal combustion engines, however, ionic decomposition products which have a corrosive action can also arise in such nonionic coolant compositions. In addition, the cooling circuit of an internal combustion engine is usually not a hermetically sealed system, so that, for example when filling cooling water, corrosive contaminants can also be introduced. In the international patent application WO-A 00/17951 a cooling system for fuel cells is described in which a pure ethylene glycol / water mixture without corrosion inhibitors is used as the coolant. In order to ensure both the purity of the coolant over a longer period and a low specific conductivity, an ion exchange unit is arranged in the cooling circuit of the fuel cell. However, WO-A 00/17951 neither mentions internal combustion engines with their specific material problems, for example with regard to the use of components made of leiσhmetall alloys, nor does this document deal with the problem of cooling liquids which contain corrosion inhibitors.

The present invention is therefore based on the technical problem of providing a method for cooling internal combustion engines which offers very good and long-lasting corrosion protection, in particular for light metals and light metal alloys at the operating temperatures prevailing in an internal combustion engine. The invention is also based on the technical problem of providing a device suitable for carrying out the method according to the invention.

This technical problem is solved by the method according to the present claim 1. Advantageous further developments of the method according to the invention are the subject of the dependent claims. The invention proposes to use at least one deionization device in the cooling circuit of an internal combustion engine. In conventional coolant compositions containing ionic corrosion inhibitors, the use of a deionizer would prevent effective corrosion protection. Therefore, the invention also proposes to use the ionization device in conjunction with a nonionic coolant composition.

The invention accordingly relates to a method for cooling internal combustion engines, in which a cooling liquid comprising non-ionic corrosion inhibitors is circulated in a cooling circuit which is in thermal contact with the internal combustion engine, and the cooling liquid is at least intermittently deionized. Surprisingly, it was found that the intermittent or continuous deionization of the cooling liquid in the cooling circuit can remove the ionic impurities that arise during operation from the cooling liquid and thus ensure long-lasting corrosion protection. By using niσhtionisσhen corrosion inhibitors, the inventive method is particularly suitable for cooling internal combustion engines, the light metal components, especially grain components made of aluminum or magnesium or their alloys.

All aqueous coolant compositions with nonionic corrosion inhibitors, in particular those as described, for example, in WO-A 02/08354 by the applicant, are particularly suitable for use as a cooling liquid in the process according to the invention.

Cooler protective formulations based on water or based on water in combination with liquid alcohol freezing point depressants can be used. Suitable liquid-alcohol freezing point depressants are alkylene glycols and their derivatives, and also glycerol, in particular propylene glycol and especially ethylene glycol. In addition, however, higher glycols and glycol ethers are also suitable, for example ethylene glycol, dipropylene glycol and monoethers of glycols, such as methyl, ethyl, propyl and butyl ethers of ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol. Mixtures of the glycols and glycol ethers mentioned, and mixtures of these glycols with glycerol and, if appropriate, the glycol ethers mentioned can also be used.

The anti-freeze and anti-corrosion agent usually present as a concentrate before mixing with water preferably contains 0.05 to 10% by weight, based on the total amount of the concentrate, of one or more carboxylic acid amides and / or sulfonic acid amides, particularly preferably one or more aliphatic, σycloali - Phatic, aromatic or heteroaromatic carboxylic acid amides and / or sulfonic acid amides each having 2 to 16 carbon atoms, in particular each having 3 to 12 carbon atoms. The araids can optionally be alkyl-substituted on the nitrogen atom of the amide group, for example by a C 1 -C ₄ -alkyl group. Aromatic or heteroaromatic backbones of the molecule can of course also carry alkyl groups. One or more, preferably one or two, amide groups can be present in the molecule. The amides can additionally carry functional groups, preferably C 1 -C 4 -alkoxy amino, chlorine, fluorine, hydroxyl and / or acetyl, in particular such functional groups can be found as substituents on aromatic or heteroaromatic rings present. Particularly preferred aromatic carboxamides, heteroaromatic carboxamides, aliphatic carboxamides, σy-cloaliphatic carboxamides with the amide group as part of the ring and aromatic sulfonamides are described in detail in WO-A 02/08354. Furthermore, the concentrate may contain aliphatic, σycloaliphatic or aromatic amines with 2 to 15 C atoms, mono- or dinuclear saturated or partially unsaturated heterocycles with 4 to 10 C atoms and / or tetra (C 1 -C 6 alkoxy) silanes. Examples of the additional components mentioned are also described more specifically in WO-A 02/08354.

Other corrosion inhibitors and other auxiliaries, such as defoamers, dyes and bitter substances for reasons of hygiene and safety in the event of ingestion, may also be present in the usual small amounts, provided that these are nonionic components.

The coolant comprises 10 to 90% by weight of water and 90 to 10% by weight of the coolant concentrate as a ready-to-use aqueous coolant, in particular for protecting the coolant of cooling circuits for internal combustion engines.

The cooling liquid is preferably deionized chemically with the aid of ion exchangers and / or liquid deionizing agents and / or by electrochemical means.

The present invention also relates to a device for cooling an internal combustion engine, in particular for carrying out the method according to the invention, the device comprising a cooling circuit which is at least partially in thermal contact with the internal combustion engine. The device according to the invention is characterized in that at least one deionization device for cooling liquid is arranged in the cooling circuit. Ion exchangers and / or liquid deionizers and / or agents for continuous electrochemical deionization are preferably used as the deionization device.

The deionization device can be arranged at any suitable point in the cooling circuit of the internal combustion engine, for example in the main cooling circuit, so that the deionization device comes into direct contact with the cooling liquid flow, or in a bypass flow through which only a partial quantity of the cooling liquid is pumped per unit of time. or also in an expansion vessel usually provided in the cooling circuit, or in its outlet to the cooling circuit. If an ion exchanger is used as the deionization device, it is preferably contained in a filter cartridge which can be easily replaced and replaced if necessary, for example when the ion exchanger is exhausted.

Suitable ion exchangers for deionizing liquids are known per se. Organic ion exchangers are preferably used in the process according to the invention, in particular mixture products from anion exchange resins of the strongly alkaline hydroxyl type and / or cation exchange resins based on sulfonic acid groups. A corresponding commercially available combination product is, for example, the mixed-bed resin ion exchanger AMBERJET ^® UP 6040 RESIN from Rohm & Haas.

Furthermore, activated carbons or inorganic adsorbents such as aluminum oxides, silica gels, zeolites or clay minerals such as the so-called solid acids (H-clays), for example MONTMORRILONIT ^{®, can also be used} as ion exchangers for this application. A commercially available product is, for example, MONTMORRILONIT ^® KSF from Fluka.

Liquids known per se which are able to bind ions can be used as the liquid deionizing agent. The binding can take place by complexation, as is the case, for example, with known complexing agents. Examples of such compounds are sugar acids, citric acids, tartaric acid, nitrilotriacetic acid (NTA), methylglycinediacetic acid (MGDA), ethylenediaminetetraacetic acid (EDTA) and other polyaminopolycarboxylic acids, such as polyaminopolyphosphonic acids. If the complexing compounds are solids per se, the liquid deionizing agent is a solution of these compounds in a liquid which can be measured or not measured with the cooling medium. The ions can also be bound by ionic interaction. This can be the case, for example, when using amines, quaternized amines or polyamines, such as polyethyleneimine or polyvinylamine. Mixtures of a complexing agent with a compound which acts via ionic interactions are also possible, such as solutions of complexing agents in such compounds.

The liquid deionizing agent can be mixed with the cooling medium so that an intimate contact of both media is guaranteed. The deionizing agent is then separated from the cooling medium again, for example by phase separation using a phase separator or by a membrane cell. If a liquid deionizing agent is used that does not mix with the circulating coolant, one can according to a second variant, bring it into contact with the cooling liquid either directly or via a membrane, in particular an ion-permeable membrane. If the deionizing agent is essentially immiscible with the cooling liquid, the contacting can take place in a container which contains the deionizing agent and through which the cooling medium forming a second phase flows. The applicant's German patent application DE-A 102 01 276 describes the use of liquid deionizing agents in a cooling system for fuel cells in more detail.

According to a further variant, the cooling liquid is electrochemically deionized, preferably by electrodialysis. To carry out the electrodialysis, voltage is applied to the electrodes of an electrochemical cell arranged in the cooling circuit, which removes some of the ions from the cooling circuit. Electrodialysis cells, which can be operated with or without ion exchangers, are preferably used. If ion exchangers are used, the corresponding cells are also referred to as electrode ionization cells. By using ion exchangers, a significantly lower residual conductivity of the cooling medium can be achieved than with a pure electrodialysis. Electrode ionization cells are therefore used as the preferred deionization device. The cooling medium is conducted as a diluate flow through the cell. Electrode ionization cells are known from siσh and are used, for example, for the desalination of sea water. Such a cell can consist of a bed of anion and cation exchange resins. According to another variant, anion and cation exchanger resins are arranged in two separate chambers. The diluate stream flows through the ion exchange packets and is separated from the concentrate stream by ion-selective membranes. A detailed description of a method and a device for the electrochemical deionization of the cooling liquid of a fuel cell can be found in the applicant's German patent application DE-A 101 04 771.

Finally, the present invention also relates to a liquid-cooled internal combustion engine with at least one internal combustion engine and at least one cooling circuit for the internal combustion engine, the internal combustion engine being characterized in that at least one deionization device is provided in the cooling circuit. The invention is explained in more detail below with reference to an embodiment shown in the accompanying drawings.

5 The drawings show:

FIG. 1 shows a schematic representation of the internal combustion engine according to the invention with a deionization device arranged in a cooling circuit; 10

FIG. 2 shows a variant of the arrangement of the deionization device in the cooling circuit of FIG. 1.

1 shows an internal combustion engine 10 according to the invention.

15 shown mathematically. The internal combustion engine 10 comprises an internal combustion engine 11 which has a cylinder head 12 and an engine block or a crankcase 13, and a cooling circuit 14 in which an aqueous, nonionic coolant composition is circulated by means of a cooling water circulation 15. In the illustrated

20 Example, the cooling liquid runs from the cooling water pump 15 through a distributor 16, which divides it into two cooling channels 17, 18, the distribution ratio in the distributor 16 being controllable. The control signal is supplied via a line 19 from a control unit 20, which via (not shown)

25 sensors measures the temperature of the cylinder head 12 and the crankcase 13 or the coolant emerging from the lines 17 or 18 from the internal combustion engine 11 and adjusts the distribution ratio so that none of these temperatures exceeds a predetermined maximum. After leaving the cy-

30 linderkopf 12 or the crankcase 13, the cooling lines 17, 18 are combined to a Rüσklaufleitung 21, which leads the hot cooling liquid to a heat exchanger 22, which is referred to in the motor vehicle as a cooler. Before the unification of the two passions 17, 18, the usually higher durσh-

35 set and a higher outlet temperature having cooling line 17 of the crankcase through a heating heat exchanger 23, where heat can be extracted from the coolant for heating the passenger compartment of a motor vehicle. Before the hot coolant can reach the heat exchanger / cooler 22

40 they are divided by a mixer 25 controlled by a thermostat 24 into a first partial flow leading to the cooler 22 via a line 26 and a second partial flow which bridges the cooler via a bypass line 27. Both partial flows are combined again after the first partial flow the cooler

45 22 has passed, and return to the cooling water pump 16. In the example shown, in the return line 21, a deionization device 28 provided according to the invention is arranged, for example a replaceable filter cartridge with an ion exchange resin. In the variant of FIG. 1, when an ion exchanger is used, the cooling liquid circulating in the cooling circuit 14 is continuously deionized. After exhausting the ion exchanger, the filter cartridge can be replaced. The deionization device 28 can also be designed as an electrochemical deionization cell or as a contact cell for a liquid deionization agent.

In the variant shown in FIG. 2, the deionization device 28 is arranged in a bypass 29, with a valve 30 controlling when and which portion of the coolant flow in the bypass branch 29 is deionized. The valve 30 can be controlled, for example, via a signal line 31 as a function of the values supplied by a conductivity measuring cell arranged in the cooling circuit 14 (not shown) by means of the control device 20. In this case, the cooling liquid is deionized only if an increase in the concentration of the ionic components of the cooling liquid is registered via the conductivity measuring cell. The other components of the variant of FIG. 2, which correspond to those of the variant of FIG. 1, are identified by the same reference numerals as in FIG. 1.

It goes without saying that the deionization device provided according to the invention can be arranged at any suitable point in the cooling circuit 14, for example in a line section 32 after running through the cooler 22 or in the bypass line 27.

Vergleiσhsbeispiele

For comparative tests for the regular corrosion test according to ASTM D 1384-94, an ASTM D 1384 test apparatus was supplemented in such a way that with the help of a commercial car cooling water pump (Bosch company, type PAA 12V 0 392 020 057, 12V DC voltage, maximum pump capacity 260 liters per hour ) The cooling liquid was circulated through a glass filter funnel with a frit, containing 75 g of the ion exchanger AMBERJET ^® UP 6040 RESIN (Rohm & Haas). The experiments were carried out three times with or without ion exchangers.

A mixture of 30% by weight of distilled water, 60% by weight of monoethylene glycol, 1% by weight of p-toluenesulfonamide and 0.5% by weight of triethanolamine was used as the non-ionic coolant formulation and 0.5% by weight of tolutriazole used (Example 15 from WO-A 02/08354)

Comparative example 1:

For a first comparison test, a standard metal set in accordance with ASTM D 1384 was used in both tests and, in addition to the aluminum coupon, a magnesium coupon of the alloy Mg AZ91HP was used.

The mean values from three experiments each with or without ion exchangers in the cooling circuit are shown in Table 1 below:

Table 1:

without with

Ion exchangers

Specimen Weight Change Weight Change

[mg / σm2] [mg / σm2] copper - 0.23 0.00

Weiσhlot - 3.13 + 0.01

Brass - 0.24 0.00

Steel 0.00-0.03

Gray cast iron + 0.01 - 0.09

Cast aluminum + 0.01 + 0.06 magnesium AZ91HP - 6.70 - 1.59

Trial 2:

In experiment 2, corresponding comparison tests were carried out with the ASTM standard metal set without an additional magnesium coupon. The mean values from three experiments each with or without ion exchanger in the cooling circuit are shown in the following Table 2. Table 2;

without with

Ion exchangers

Test specimen change in weight Change in weight

[mg / σm2] [mg / σm2]

Copper - 0.16 - 0.03

Soft solder - 2.51 - 1.11

Brass - 0.17 - 0.05

Steel + 0.02 - 0.01

Gray cast iron + 0.04 - 0.02 cast aluminum + 0.03 - 0.00

It can be seen that the corrosion protection of non-ionic coolant formulations can further improve the use of an ion exchanger in the cooling circuit. A particularly pronounced improvement in corrosion protection can be found in the components made of magnesium and its alloys, in particular in combination with non-ferrous metals such as copper or brass or white solder.

Claims

claims

1. A method for cooling an internal combustion engine, wherein a cooling liquid which comprises nonionic corrosion inhibitors is circulated in a cooling circuit which is in thermal contact with the internal combustion engine, and the cooling liquid is at least intermittently deionized.

2. The method according to claim 2, characterized in that an aqueous coolant composition is used as the cooling liquid, which comprises 10 to 90% by weight of a coolant concentrate based on alkylene glycols or their derivatives or glycerin, the coolant concentrate, if appropriate, among others contains niσhtionisσhen components, 0.05 to 10 wt .-% based on the total amount of the concentrate, one or more carboxamides and / or sulfonamides.

3. The method according to one of claims 1 or 2, characterized in that the cooling liquid is deionized by means of at least one ion exchanger.

4. The method according to one of claims 1 to 3, characterized in that the cooling liquid is deionized by means of a liquid deionizing agent.

5. The method according to one of claims 1 to 4, characterized in that the cooling liquid is deionized electrochemically.

6. Device for cooling an internal combustion engine, with a cooling circuit (14) which is in thermal contact with the internal combustion engine (11) at least in a partial section, so that at least one deionizing device (28) for cooling liquid is arranged in the cooling circuit is.

7. Device according to claim 6, characterized in that the deionization device (28) comprises at least one ion exchanger, preferably a mixed-bed resin ion exchanger.

8. Device according to one of claims 6 or 7, dadurσh gekennzeiσhnet that deionization device (28) is designed as a contact cell in which a liquid deionizing agent can act on the cooling liquid

5

9. Device according to one of claims 6 to 8, characterized in that the deionization device (28) comprises at least one electrodialysis cell.

10 10. Device according to claim 9, characterized in that the electrodialysis cell comprises an ion exchanger.

11. Liquid-cooled internal combustion engine with at least one internal combustion engine (11) and at least one cooling circuit 15 (14) for the internal combustion engine, characterized in that in the cooling circuit (14) at least one deionization device (28) is provided.

20

25

30

35

40

45