Mixing device for producing a fuel/water mixture for an internal combustion engine, internal combustion engine having a mixing device, and motor vehicle

Abstract

A mixing apparatus for producing a fuel/water mixture for an internal combustion engine includes a fuel line, where via the fuel line a combustion chamber of the internal combustion engine is suppliable with fuel, a connecting region, a water line which opens into the fuel line in the connecting region where via the water line water is introducible via the connecting region into the fuel line and is mixable with the fuel, and a valve arrangement which is disposed on the water line. The valve arrangement prevents an entry of the fuel from the fuel line into the water line when a pressure of the fuel in fuel line is higher than a pressure of the water in the water line.

Claims

1. A mixing apparatus for producing a fuel/water mixture for an internal combustion engine, comprising: a fuel line wherein via the fuel line a combustion chamber of the internal combustion engine is suppliable with fuel; a connecting region; a water line which opens into the fuel line in the connecting region wherein via the water line water is introducible via the connecting region into the fuel line and is mixable with the fuel; a valve arrangement which is disposed on the water line, wherein the valve arrangement prevents an entry of the fuel from the fuel line into the water line when a pressure of the fuel in fuel line is higher than a pressure of the water in the water line; and a connecting element configured as a T-piece which connects the fuel line in the connecting region in a fluid-conducting manner to the water line and wherein the valve arrangement is integrated into the connecting element; wherein the valve arrangement comprises a check valve and a metering valve; wherein the entry of the fuel from the fuel line into the water line is prevented by the check valve and/or by the metering valve in a non-energized state of the valve arrangement.

2. The mixing apparatus according to claim 1, wherein the check valve is disposed on the water line between the fuel line and the metering valve.

3. The mixing apparatus according to claim 1 further comprising a control unit, wherein the control unit electrically actuates the valve arrangement and wherein the control unit is configured to deactivate a low side circuit and a high side circuit of the valve arrangement independently of one another.

4. The mixing apparatus according to claim 3, wherein the control unit is configured to deactivate the low side circuit and/or the high side circuit of the valve arrangement dependent on a pressure difference between the pressure of the fuel and the pressure of the water.

5. The mixing apparatus according to claim 3, wherein the low side circuit and/or the high side circuit is deactivatable by energization of an external relay.

6. The mixing apparatus according to claim 1, wherein the water line is disposed at a geodetically lower level than the fuel line at the connecting region.

7. An internal combustion engine, comprising: the mixing apparatus according to claim 1.

8. A motor vehicle, comprising: the mixing apparatus according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a diagrammatic illustration of a mixing apparatus for producing a fuel/water mixture, and

(2) FIG. 2 shows a diagrammatic illustration of one variant of the mixing apparatus.

DETAILED DESCRIPTION OF THE DRAWINGS

(3) FIG. 1 and FIG. 2 in each case show a diagrammatic illustration of a motor vehicle 22 which comprises an internal combustion engine 12. The internal combustion engine 12 comprises a plurality of combustion chambers which are not shown in further detail here, it being possible for each combustion chamber to be supplied with fuel 1 or with a fuel/water mixture 11 via at least in each case one injector which is configured for direct injection and is likewise not shown in further detail here. The fuel 1 or the fuel/water mixture 11 is converted (burned) at least partially in the respective combustion chambers, in order to move respective pistons which are assigned to the respective combustion chambers and are not shown in further detail here, and therefore to drive a crankshaft (likewise not shown in further detail) of the internal combustion engine 12.

(4) The mixing apparatus 10 serves to produce the fuel/water mixture 11 for the internal combustion engine 12. The mixing apparatus 10 comprises at least one fuel line 13, via which the respective combustion chambers of the internal combustion engine 12 can be supplied with the pressurized fuel 1. The pressurizing of the fuel 1 can take place by means of a fuel pump (not shown).

(5) Furthermore, the mixing apparatus 10 comprises at least one water line 14 which opens in at least one connecting region 15 of the mixing apparatus 10 into the fuel line 13, and via which pressurized water 2 can be introduced via the at least one connecting region 15 into the at least one fuel line 13 and can be mixed with the fuel 1 as a result. Via the mixing apparatus 10, the pure fuel 1 or, as an alternative, the fuel/water mixture 11 can therefore be fed to the respective combustion chambers. The pressurizing of the water 2 can take place by means of a water pump (not shown).

(6) The mixing apparatus 10 comprises a valve arrangement 9 which is arranged on the at least one water line 14 and which prevents an entry of fuel 1 from the at least one fuel line 13 into the at least one water line 14 due to the fluid pressure if a fuel pressure p_K which prevails in the at least one fuel line 13 has a higher pressure value than a water pressure p_W which prevails in the at least one water line 14.

(7) The at least one water line 14 is arranged at a geodetically lower level in the at least one connecting region 15 than the at least one fuel line 13.

(8) The valve arrangement 9 comprises a check valve 3 and a metering valve 4. In the present case, the check valve 3 is arranged between the at least one fuel line 13 and the metering valve on the at least one water line.

(9) In addition, the mixing apparatus 10 comprises at least one connecting element 16 which is configured as a T-piece in the present case and which connects the at least one fuel line 13 in the at least one connecting region 15 to the at least one water line 14 in a fluid-conducting manner. The valve arrangement 9 can generally be integrated into the at least one connecting element 16, although this is not shown in further detail in FIG. 1 and FIG. 2.

(10) In the present case, the check valve 3 is configured as a purely mechanically actuated check valve, whereas the metering valve 4 of the valve arrangement 9 can be actuated by means of a control unit 17 of the mixing apparatus 10. In the present case, the control unit 17 therefore serves for the electric actuation of the valve arrangement 9, the control unit 17 being set up to deactivate a low side circuit 8 and a high side circuit 7 of the valve arrangement 9 in each case independently of one another.

(11) The low side circuit 8 is connected via a low side line 6 to the metering valve 4. The high side circuit 7 is connected via a high side line 5 to the metering valve 4.

(12) In the present case, the control unit 17 is set up to deactivate the low side circuit 8 and the high side circuit 7 of the valve arrangement 9 in a manner which is dependent on a pressure difference between the fuel pressure p_K and the water pressure p_W.

(13) The high side circuit 7 and the low side circuit 8 form respective, switchable outputs of the control unit 17 which can also be called an electronic control unit. Via the high side circuit 7 and the low side circuit 8, the high side line 5 and the low side line 6, respectively, to the metering valve 4 can be switched off in each case individually, with the result that, for example, a short circuit in the low side line 6 does not lead to a permanent actuation of the metering valve 4.

(14) Although this is not shown in FIG. 1 and FIG. 2, the check valve 3 can thus also be configured as an electrically operated check valve instead of as a mechanical check valve. In this case, an actuation of the check valve 3 can likewise take place via a high side circuit (not shown in further detail here) or a low side circuit.

(15) In general, the entry of fuel 1 from the at least one fuel line 13 into the at least one water line 14 is prevented by way of the at least one check valve 3 and by way of the at least one metering valve 4 in the non-energized state of the valve arrangement 9.

(16) In contrast to FIG. 1, FIG. 2 shows one variant of the mixing apparatus 10, it being possible in the present case for the high side circuit 8 of the metering valve 4 to be deactivated by way of energization of an external relay 18 of the mixing apparatus 10. The term “external” is to be understood to mean that the relay 18 is not integrated into the control unit 17.

(17) In order to produce the fuel/water mixture 11, the fuel 1 which flows through the fuel line 13 in a flowing direction 19 which is illustrated by way of an arrow is mixed in the connecting region 15 with the water 2 which flows through the water line 14 and through the check valve 3 and the metering valve 4 in a flowing direction 20 which is illustrated by way of a further arrow, to form the fuel/water mixture 11. The fuel/water mixture 11 then flows in a flowing direction 21 which is illustrated by way of a further arrow to the respective injectors (not shown).

(18) The mixing apparatus 10 can ensure a supply of the internal combustion engine 12 or its respective combustion chambers with the fuel/water mixture 11 which can also be called an emulsion of fuel 1 and water 2. Furthermore, the mixing apparatus 10 can ensure that no discharge of fuel 1 to the surrounding area, that is to say no entry of fuel 1 from the at least one fuel line 13 into the at least one water line 14, occurs in the case of mechanical or electric component faults of the mixing apparatus 10. One example for a mechanical component fault is, for example, jamming of the check valve 3 or of a valve body of the check valve 3 in an open position. One example for an electric component fault is, for example, a short circuit in the low side line 6 and, in addition or as an alternative, in the high side line 5.

(19) In the case of the present mixing apparatus 10, the at least one fuel line 13 and the at least one water line 14 are connected to one another by means of the check valve 3 and the metering valve 4 in the at least one water line 14. The check valve 3 and the metering valve 4 are therefore closed in series and, as a result, ensure that an entry of fuel 1 from the at least one fuel line 13 into the at least one water line 14 does not occur if the water pressure p_W has a lower pressure value than the fuel pressure p_K, or if the water pressure should collapse. The water 2 can be loaded with the water pressure p_W which can lie, for example, 2 bar above the fuel pressure p_K, from a water storage container of a water pressure system (water circuit) which is not shown in further detail here, and can be introduced in accordance with the flowing direction 20 into the at least one water line 14 or can flow into the water line 14.

(20) As has already been mentioned, the check valve 3 can be of mechanical or electromechanical configuration. In the present case, the metering valve 4 for regulating a water mass of the water 2 is of electromechanical configuration and, in addition, is of self-closing configuration. The check valve 3 and the metering valve 4 therefore form a redundant solution.

LIST OF REFERENCE CHARACTERS

(21) 1 Fuel 2 Water 3 Check valve 4 Metering valve 5 High side line 6 Low side line 7 High side circuit 8 Low side circuit 9 Valve arrangement 10 Mixing apparatus 11 Fuel/water mixture 12 Internal combustion engine 13 Fuel line 14 Water line 15 Connecting region 16 Connecting element 17 Control unit 18 External relay 19 Flowing direction 20 Flowing direction 21 Flowing direction 22 Motor vehicle p_K Fuel pressure p_W Water pressure