Internal combustion engine with crankcase ventilation

Abstract

An internal combustion engine having a crankcase with a base and an oil tank, wherein a first connection between the crankcase and the oil tank is formed with a first valve, which is open in the direction from the crankcase to the oil tank and closed in the opposite direction, and a second connection between the crankcase and the oil tank is formed with a second valve, which is open in the direction from the oil tank to the crankcase and is closed in the opposite direction. The first valve is arranged on the base of the crankcase and the second valve is arranged above the first valve.

Claims

1. An internal combustion engine, comprising: a crankcase with a bottom and an oil tank; a first connection formed between the crankcase and the oil tank by way of a first valve which is open in the direction from the oil tank to the crankcase and closes in the opposite direction, wherein a pressure equalization between the crankcase and the oil tank occurs as a result of passage of a gas from the oil tank into the crankcase via the first valve, a second connection formed between the crankcase and the oil tank by way of a second valve which opens in the direction from the crankcase to the oil tank and closes in the opposite direction, wherein the second valve is arranged on the bottom of the crankcase, and the first valve is arranged above the second valve, and a suction pump for removal of oil from the oil tank and for delivery of the oil via a line to a lubricating point of the internal combustion engine.

2. The internal combustion engine according to claim 1, wherein the crankcase and the oil tank have a common dividing wall which separates the crankcase and the oil tank from one another.

3. The internal combustion engine according to claim 1, wherein the first valve is a diaphragm valve.

4. The internal combustion engine according to claim 3, wherein the second valve is a diaphragm valve.

5. The internal combustion engine according to claim 1, wherein the oil tank has a breather which is arranged at a top thereof.

6. The internal combustion engine according to claim 5, wherein the breather of the oil tank is at the same time the crankcase breather of the crankcase of the internal combustion engine.

7. The internal combustion engine according to claim 1, wherein the first valve and the second valve are at a vertical spacing from one another of at least 10 centimeters.

8. A motor vehicle comprising an internal combustion engine according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic diagram of an internal combustion engine according to an exemplary embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(2) FIG. 1 shows an internal combustion engine 1 with a combustion chamber 29 which can be enlarged and decreased by a piston 14 which can be moved up and down in a cylinder 13. The internal combustion engine 1 sucks in air via an intake line 26. Fuel can be fed to the combustion chamber via an injector 30, with the result that ignitable mixture comprising fuel and air is produced in the combustion chamber 29. After the ignitable mixture has burned in the combustion chamber 29, it is discharged via the exhaust gas line 27. The internal combustion engine 1 is preferably an internal combustion engine in a motor vehicle 12. It can also be, however, an internal combustion engine 1 in any other desired application.

(3) The internal combustion engine 1 has a crankshaft 15 which is driven via connecting rods 16 by the cylinders of the internal combustion engine. The crankshaft 15 is situated in a crankcase 2. An oil tank 3 adjoins the crankcase 2. The oil tank 3 is connected to the crankcase 2 via a first connection 4 and via a second connection 6. A first valve 5 which can be opened only in the direction from the oil tank 3 to the crankcase 2 exists in the first connection 4. A second valve 7 which can be opened only in a direction from the crankcase 2 to the oil tank 3 exists in the second connection 6. The first connection 4 and the second connection 6 with the first valve 5 and the second valve 7 are situated in a dividing wall 9 which separates the crankcase 2 from the oil tank 3. The dividing wall 9 is, in particular, a common boundary wall of the crankcase 2 and the oil tank 3. The dividing wall 9 forms a bottom 8 of the crankcase and at least one side wall 19 of the crankcase. The first connection 4 and the first valve 5 are situated in the side wall 19 of the dividing wall 9. The second connection 6 and the second valve 7 are situated in a bottom wall 8 of the dividing wall 9. The first connection 4 and the first valve 5 and the second connection 6 and the second valve 7, respectively, are at a vertical spacing 11 from one another which is, for example, 10 cm or more. Blow-by gas 17 and oil 18 can pass from the combustion chambers 29 of the internal combustion engine 1 through gaps 24 between the cylinder 13 and the piston 14. Therefore, blow-by gas 17 and oil 18 form an (undefined) mixture within the crankcase 2. The oil 18 collects in the lower region of the crankcase 2, because said oil 18 has a greater weight than the blow-by gas 17. The oil 18 can pass via the second valve 7 and the second connection 6 from the crankcase 2 into the oil tank 3. At the same time, a pressure equalization can occur by way of a gas passage through the first connection and first valve from the oil tank 3 into the crankcase 2. On its upper side, the oil tank 3 has a breather 10 which at the same time forms the (only) crankcase breather 20 of the crankcase 2. Blow-by gas 17 which is to be conveyed out of the crankcase 2 has to exit through the breather 10 or the crankcase breather 20. The blow-by gas can be fed from the crankcase breather 20 via a return line 25 to the intake line 26 of the internal combustion engine. The breather 10 and the first connection 4 and the first valve 5 are all preferably arranged above an oil level 28 which can be set as a maximum in the oil tank 3. In order to lubricate the internal combustion engine 1, oil 18 can be removed from the oil tank 3 with the aid of a suction pump 21 which can feed the oil via a line system 23 to any desired lubricating points 22 of the internal combustion engine 1, only one lubricating point 22 being indicated here by way of example.

(4) The internal combustion engine which is described here is advantageous in comparison with internal combustion engines with conventional means for the delivery of oil from the crankcase into an oil tank. The internal combustion engine becomes more reliable and less expensive by virtue of the fact that additional pumps can be dispensed with. Friction can be reduced by way of the omission of an additional pump for the delivery of oil from the crankcase into an oil tank. This increases the economic efficiency of the internal combustion engine.

LIST OF DESIGNATIONS

(5) 1 Internal combustion engine 2 Crankcase 3 Oil tank 4 First connection 5 First valve 6 Second connection 7 Second valve 8 Bottom 9 Dividing wall 10 Breather 11 Vertical spacing 12 Motor vehicle 13 Cylinder 14 Piston 15 Crankshaft 16 Connecting rod 17 Blow-by gas 18 Oil 19 Side wall 20 Crankcase breather 21 Suction pump 22 Lubricating point 23 Line system 24 Gap 25 Return line 26 Intake line 27 Exhaust gas line 28 Oil level 29 Combustion chamber 30 Injector

(6) 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.