Crankcase ventilation system with a flow control device for on board diagnostics
Flow control devices herein have a housing defining a plurality of parallel conduits. The first conduit has a normally closed check valve defined to open under a first preselected pressure differential controlling flow through the first conduit in a first direction of flow. The second conduit has a normally neutral check valve defined to open under a second preselected pressure differential in a second direction of flow that is opposite the first direction of flow. The third conduit defines a restriction profile, i.e., has a restrictor, having a third preselected pressure differential. The flow control devices are included as part of an engine system, more specifically a crankcase ventilation breach detection system.
1. A crankcase ventilation breach detection system of an internal combustion engine comprising:
an internal combustion engine having a crankcase and an intake manifold;
a positive crankcase ventilation valve in fluid communication between the crankcase and intake manifold to regulate the flow of blow-by-gas from the crankcase to the intake manifold;
a crankcase ventilation tube in fluid communication with air from an air intake and the blow-by-gas;
a flow control device within the fluid flow path of the crankcase ventilation tube, the flow control device comprising a housing defining a plurality of parallel conduits comprising a first conduit having a normally closed check valve controlling flow through the first conduit, the normally closed check valve opening under a first preselected pressure differential in a first direction of flow from the air intake to the crankcase, and a second conduit having a normally neutral check valve that opens under a second preselected pressure differential in a second direction of flow from the crankcase to the air intake, and a third conduit defining a restriction profile that is continuously open and having a third preselected pressure differential; and
a pressure sensor positioned between the parallel conduits and the crankcase, wherein detection of no pressure differential by the pressure sensor indicates a breach in the system.
2. The system as claimed in claim 1 , wherein the internal combustion engine has a turbocharger and the crankcase ventilation tube connects upstream of the compressor of turbocharger.
3. The system as claimed in claim 2 , wherein the second preselected pressure differential is the same or lower than the first preselected pressure differential.
4. The system as claimed in claim 1 , wherein the first preselected pressure differential is greater than the third pressure differential, and the second pressure differential is the same or less than the third pressure differential.
5. The system as claimed in claim 1 , wherein the flow control device has a first port in fluid communication with all of the plurality of parallel conduits and a second port in fluid communication with all of the plurality of parallel conduits, and the second port is shaped as a cap that is permanently attachable to the air intake.
6. The system as claimed in claim 5 , wherein the cap has a radially outer flange and a radially inner flange and is adhered an opening of the air intake or welded to the opening of the air intake.
7. The system as claimed in claim 6 , wherein welded includes spin welding, vibration welding, or induction welding.
8. The system as claimed in claim 7 , wherein the flow control device includes a sensor port in the first port and a pressure sensor operatively connected to the sensor port.
9. The system as claimed in claim 8 , wherein the pressure sensor detects increased vacuum levels if the normally closed check valve does not open and indicates an error, and the pressure sensor detects a higher than normal pressure if the normally neutral check valve does not open and indicates an error.
10. The system as claimed in claim 1 , wherein the normally closed check valve comprises a hemispherical poppet check valve.
11. The system as claimed in claim 10 , wherein the hemispherical poppet check valve, in a closed position, seats a convex surface of the poppet valve against a convex surface of the first conduit.
12. The system as claimed in claim 10 , wherein the hemispherical poppet check value has a spring biasing the poppet sealing member to the closed position.
13. The system as claimed in claim 10 , wherein the normally neutral check valve comprises a sealing disc translatable between an open position and a closed position in response solely to a pressure differential in the system, and the sealing disc is flexible and is bowl-shaped in the open-position and is flat in the closed position.
14. A flow control device comprising:
a housing defining a plurality of parallel conduits comprising:
a first conduit having a normally closed check valve controlling flow through the first conduit, wherein the normally closed check valve opens under a first preselected pressure differential in a first direction of flow;
a second conduit having a normally neutral check valve that opens under a second preselected pressure differential in a second direction of flow that is opposite the first direction of flow; and
a third conduit defining a restriction profile having a third preselected pressure differential.
15. The device as claimed in claim 14 , wherein the first preselected pressure differential is greater than the third preselected pressure differential.
16. The device as claimed in claim 14 , wherein the second preselected pressure differential is the same or lower than the first preselected pressure differential.
17. The device as claimed in claim 14 , wherein the first preselected pressure differential is greater than the third pressure differential, and the second pressure differential is the same or less than the third pressure differential.
18. The device as claimed in claim 14 , wherein the flow control device has a first port in fluid communication with all of the plurality of parallel conduits and a second port in fluid communication with all of the plurality of parallel conduits, and the second port is shaped as a cap that is permanently attachable to an air intake.
19. The device as claimed in claim 14 , wherein the flow control device has a first port in fluid communication with all of the plurality of parallel conduits and defines a sensor port in the first port for connection to a pressure sensor, and a pressure sensor operatively connected to the sensor port.
20. The device as claimed in claim 14 , wherein the normally closed check valve comprises a hemispherical poppet check valve and a spring biasing the hemispherical poppet sealing member to a closed position.
21. The device as claimed in claim 20 , wherein the hemispherical poppet check valve, in the closed position, seats a convex surface of the hemispherical poppet sealing member against a convex surface of the first conduit.
22. The device as claimed in claim 14 , wherein the normally neutral check valve comprises a sealing disc translatable between an open position and a closed position in response solely to a pressure differential in the second conduit, and the sealing disc is flexible and is bowl-shaped in the open-position and is flat in the closed position.