Fresh gas supply device for an internal combustion engine and method of operating same

Abstract

A fresh gas supply device for an internal combustion engine having an exhaust gas turbocharger includes a charge air inlet for taking in a compressed charge air flow from the exhaust gas turbocharger; an outlet which is connected to the charge air inlet via a valve section, said valve section being closed in a closed position by at least one flap valve which can be pivoted, preferably, about a flap rotational axis; an adjusting device which is coupled to the at least one flap valve for adjusting the same in the closing direction; and a compressed air inlet for taking in compressed air into the outlet. The compressed air inlet is arranged such that the compressed air is directed into a compressed air flow in the direction of the valve section to the at least one flap valve. A corresponding method for operating the fresh gas supply device is provided.

Claims

1. A fresh gas supply device for an internal combustion engine having an exhaust gas turbocharger, the fresh gas supply device comprising: a charge air inlet for inlet of compressed charge air flow from the exhaust gas turbocharger; an outlet connected to the charge air inlet; a valve portion arranged between the charge air inlet and the outlet, the valve portion being closeable by at least one valve in a closing position that blocks the compressed charge air flow from the exhaust gas turbocharger to the outlet; an adjusting device coupled to the at least one valve for adjusting the at least one valve into the closing position; and a compressed air inlet for inlet of compressed air into the outlet, the compressed air inlet being operatively arranged to direct the compressed air from the compressed air inlet in a direction toward the at least one valve such that the compressed air from the compressed air inlet impinges against an outlet side of the at least one valve in a manner that assists movement of the at least one valve to the closing position.

2. The fresh gas supply device according to claim 1, wherein the at least one valve is a flap valve pivotable about a flap access of rotation.

3. The fresh gas supply device according to claim 2, wherein the flap valve is coupled eccentrically to the flap axis of rotation.

4. The fresh gas supply device according to claim 2, wherein the flap valve has a first onflow portion cooperating with the charge air flow and a second onflow portion cooperating with the compressed air flow.

5. The fresh gas supply device according to claim 2, wherein the flap valve is a spring non-return flap valve, and wherein the adjusting device is a restoring spring.

6. The fresh gas supply device according to claim 5, wherein the flap valve is coupled eccentrically to the flap axis of rotation.

7. The fresh gas supply device according to claim 3, wherein the flap valve has a first onflow portion cooperating with the charge air flow and a second onflow portion cooperating with the compressed air flow.

8. The fresh gas supply device according to claim 6, wherein the flap valve has a first onflow portion cooperating with the charge air flow and a second onflow portion cooperating with the compressed air flow.

9. The fresh gas supply device according to claim 4, wherein the compressed air flow is oriented onto the second onflow portion of the flap valve for adjusting the flap valve into the closing position.

10. The fresh gas supply device according to claim 8, wherein the compressed air flow is oriented onto the second onflow portion of the flap valve for adjusting the flap valve into the closing position.

11. The fresh gas supply device according to claim 9, wherein the compressed air inlet includes an injection port operatively configured for guiding the compressed air flow onto the second onflow portion of the flap valve.

12. The fresh gas supply device according to claim 10, wherein the compressed air inlet includes an injection port operatively configured for guiding the compressed air flow onto the second onflow portion of the flap valve.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a diagrammatic sectional illustration of an internal combustion engine with an exhaust gas turbocharger and with a fresh gas supply device according to the prior art;

(2) FIG. 2 is a diagrammatic sectional illustration of a conventional fresh gas supply device according to the prior art in a position for compressed air;

(3) FIG. 3 is a diagrammatic sectional illustration of the conventional fresh gas supply device according to FIG. 2 in a position for charge air;

(4) FIG. 4 is a diagrammatic sectional illustration of an exemplary embodiment of a fresh gas supply device according to the invention in a position for charge air; and

(5) FIG. 5 is a diagrammatic sectional illustration of the fresh gas supply device according to the invention, as shown in FIG. 4, in the position for additional air.

DETAILED DESCRIPTION OF THE DRAWINGS

(6) Identical structural elements or functional units having the same function are identified in the figures by identical reference symbols.

(7) FIGS. 1 to 3 have already been described above and are not explained any further unless necessary.

(8) FIG. 4 illustrates a diagrammatic sectional illustration of an exemplary embodiment of a fresh gas supply device 20 according to the invention in a position for charge air.

(9) The fresh gas supply device 20 has an essentially cylindrical housing body 21 with a charge air inlet 9 (see also FIG. 1) arranged on the right in FIG. 4 and with an outlet 10 arranged on the left. The charge air inlet 9 has adjoining it an inlet portion 16 which merges via a valve portion 17 having a flap valve 23 into an outlet portion 18.

(10) The compressor 3 of the exhaust gas turbocharger 2 is connected to the charge air inlet 9 via the charge air cooler 5 (see FIG. 1). The compressor 3 delivers a charge air stream 28 which flows through the fresh gas supply device 20 in the longitudinal direction of the latter through the charge air inlet 9 in the direction of the outlet 10 and leaves the outlet 10 in the same direction as an intake flow 29.

(11) A compressed air inlet 11 with an injection port 19, as the exit of a compressed air line 12 into the outlet portion 18, is arranged near to the outlet 10. The compressed air line 12 and the compressed air inlet 11 are arranged with respect to the fresh gas supply device 20 such that a compressed air flow 30 (see FIG. 4) is directed, opposite to the charge air flow 28, toward the valve portion 17. In other words, the compressed air line 12 is attached to the fresh gas supply device 20 such that the compressed air line 12 is directed, opposite to the direction of the intake flow 29 of the intake line 13 (see FIG. 1), toward the valve portion 17 at an angle to the longitudinal direction of the fresh gas supply device 20.

(12) The flap valve 23 is arranged so as to be pivotable about a flap axis of rotation 24 and, in this example, is coupled to an adjusting device 22. The adjusting device 22 is formed with a restoring spring (not illustrated). The restoring spring forces the flap valve 23 clockwise into the closing position, shown in FIG. 5, or the position, for the compressed air against a stop portion 25 of the housing body 21. The flap valve 23 then, with its peripheral margin designed for this purpose, seals off the valve portion 17, with the result that the valve portion 17 is closed. This position is shown in FIG. 5.

(13) When the internal combustion engine 1 is in operation, the intake flow 29 generates in the outlet portion 18 a vacuum which, together with the charge air flow 28, pivots the flap valve 23 counterclockwise, the valve portion 17 being opened in the fully opened position of the flap valve 23 (flap valve 23 parallel to the longitudinal direction of the fresh gas supply device 20), said position being shown in FIG. 4. For this purpose, the flap valve 23 is fastened eccentrically to the flap axis of rotation 24 and has on its longer portion, that is to say from the flap axis of rotation 24 beyond the center of the flap valve 23 as far as its margin, a first onflow portion 26 and a second onflow portion 27 opposite to the first onflow portion 26. The first onflow portion 26 cooperates with the charge air flow 28 in such a way that the charge air flow 28 generates by way of the first onflow portion 26 a moment which pivots the flap valve 23 counterclockwise counter to the force of the restoring spring of the adjusting device 22. Of course, the flap valve 23 can enlarge or reduce the valve portion 17, depending on the current pressure and flow conditions.

(14) In the case of a torque requirement with a high air demand, the turbocharger 2 cannot immediately deliver this air. In this case, in addition, compressed air is injected, for example via a valve, not shown, in the compressed air line 12, in a compressed air flow 30 through the compressed air line 12 and the injection port 19 into the outlet portion 18 in the direction toward the valve portion 17 such that the flap valve 23 closes the valve portion 17 with the assistance of the compressed air flow 30 in addition to the restoring force of the spring of the adjusting device. The compressed air flow 30 is directed against the second onflow portion 27 and gives rise via its flow force (dynamic pressure) to a moment at the flap valve 23 clockwise about the flap axis of rotation 24 for the purpose of closing the flap valve 23. Since the system pressure in compressed air installations in vehicles usually amounts to at least 8 bar and, when the internal combustion engine 1 is under low load, and only in this operating range is external charging by the compressed air flow 30 employed, the charge pressure of the charge air flow 28 is markedly less than 1 bar, the closing time of the flap valve 23 is considerably shortened. Owing to this high dynamic pressure of the compressed air flow 30 in the outlet portion 18, the flap valve 23 remains closed in a stable manner while this additional air is being injected.

(15) Since the flap valve 23 is closed, the charge air pressure of the turbocharger 2, which, owing to the compressed air supplied, acquires a corresponding exhaust gas stream and accelerates more quickly, is also increased more quickly. When the charge air pressure has reached a specific value, the quantity regulating device or the valve (not shown) in the compressed air line 12 is closed (in a manner not described in any greater detail here) and the dynamic pressure of the compressed air flow 30 in the outlet region 18 decreases, while the flap valve 23, assisted by the charge air flow 28 acting on the first onflow portion 26, can open again (FIG. 4).

(16) A method for operating the fresh gas supply device 20 has a first method step in which a torque requirement of the internal combustion engine is determined. In this case, further operating parameters of the internal combustion engine 1, such as, for example, the pressure of the charge air flow 28 and/or the rotational speed of the internal combustion engine, may be monitored and may also be involved in the decision. If a torque requirement is correspondingly present, the charge air flow 28 generating only low or no pressure, in a second method step compressed air is injected into the fresh gas supply device 20 opposite to the direction of the charge air flow 28. In this case, the flap valve 23 is closed. When the charge pressure rises or the charge air flow 28 increases on account of a higher rotational speed of the internal combustion engine 1 and therefore also of the turbocharger 2, the injection of compressed air is discontinued.

(17) It is contemplated, for example, that more than one restoring spring is provided as an adjusting device 22.

(18) For example, the compressed air line 12 may branch into two or more ducts and issue at least partially on the circumference of the fresh gas supply device 20 with two or more injection ports into the outlet portion 18.

(19) More flap valves 23 than one may also be provided.

(20) The housing body 21 may also have other shapes, for example an elliptic cross section. The housing body 21 may also have an angled or arcuate form in its longitudinal direction.

(21) It is contemplated that the flap valve 23 is a non-return valve in which at least one side edge runs in a straight line and is provided with the flap axis of rotation 24, the flap valve 23 being pivotable about this side edge.

(22) The injection port 19 may be shaped favorably in terms of flow such that it steers the compressed air stream onto the second onflow portion 27 of the flap valve 23 in a directed manner.

LIST OF REFERENCE SYMBOLS

(23) 1 Internal combustion engine 2 Exhaust gas turbocharger 3 Compressor 4 Exhaust gas turbine 5 Charge air cooler 6 Compressed air reservoir 7 Air compressor 8 Fresh gas inlet 9 Charge air inlet 10 Outlet 11 Compressed air inlet 12 Compressed air line 13 Intake line 14 Exhaust gas line 15 Exhaust gas outlet 16 Inlet portion 17 Valve portion 18 Outlet portion 19 Injection port 20 Fresh gas supply device 21 Housing body 22 Adjusting device 23 Flap valve 24 Flap axis of rotation 25 Stop portion 26 First onflow portion 27 Second onflow portion 28 Charge air flow 29 Intake flow 30 Compressed air flow

(24) The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.