SYSTEM AND METHODS FOR MECHANICAL VACUUM PUMP EXHAUST

• US 20160348614A1
• Filed: 05/27/2015
• Published: 12/01/2016
• Est. Priority Date: 05/27/2015
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Dudar, Aed M., Jentz, Robert Roy
• Granted Patent: US 9,689,350 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B60T 13/46 Vacuum systems
• CPC Class Codes: B60T 17/02 Arrangements of pumps or compressors, or control devices therefor
• CPC Class Codes: F01M 13/00 Crankcase ventilating or breathing
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02M 25/0809 Judging failure of purge control system
• CPC Class Codes: F02M 25/0836 Arrangement of valves controlling the admission of fuel vapour to an engine, e.g. valve being disposed between fuel tank or absorption canister and intake manifold
• CPC Class Codes: F02M 25/0872 Details of the fuel vapour pipes or conduits
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

A system for an engine is provided, the system comprising a vacuum pump at least partially deposed within an engine crankcase, and a fuel vapor canister coupled to an exhaust conduit of the vacuum pump via a one-way valve. By coupling the vacuum pump exhaust to the fuel vapor canister, unmetered fuel vapor flow to the engine intake may be reduced, thus decreasing engine stall events. Further, crankcase pressure may more accurately represent airflow through the crankcase via a crankcase ventilation system, thereby improving the accuracy of crankcase ventilation diagnostics.

Claims

1. A system for an engine, comprising:

a vacuum pump at least partially deposed within an engine crankcase; and

a fuel vapor canister coupled to an exhaust conduit of the vacuum pump via a one-way valve.

2. The system of claim 1, further comprising:

a fuel tank coupled to the fuel vapor canister via a vent conduit; and

a fuel tank isolation valve coupled to the vent conduit, and wherein the exhaust conduit of the vacuum pump is mechanically connected to the vent conduit between the fuel tank isolation valve and the fuel vapor canister.

3. The system of claim 2, further comprising:

a crankcase vent tube mechanically connected to the engine crankcase via an oil separator and mechanically connected to an intake passage of the engine; and

a pressure sensor deposed within the crankcase vent tube.

4. The system of claim 3, wherein the fuel vapor canister is mechanically connected to the intake passage of the engine via a purge line, the purge line mechanically connected to the intake passage upstream of the crankcase vent tube.

5. The system of claim 4, further comprising:

a canister purge valve deposed within the purge line;

a canister vent valve deposed within a vent line coupled between the fuel vapor canister and atmosphere; and

a pressure sensor deposed within the vent line.

6. The system of claim 1, further comprising an oil separator coupled between the vacuum pump and the valve and wherein the one-way valve is a check valve.

7. The system of claim 1, wherein the vacuum pump is coupled to a camshaft cover of the engine crankcase.

8. The system of claim 1, wherein the vacuum pump is configured to provide vacuum for a brake booster.

9. A method for an engine, comprising:

routing exhaust of a vacuum pump deposed within an engine crankcase to a fuel vapor canister where actuation of the vacuum pump does not alter a pressure within the engine crankcase; and

indicating degradation of a crankcase vent tube based on a crankcase vent tube pressure during a condition where an intake manifold vacuum is dynamically changing.

10. The method of claim 9, further comprising:

indicating degradation of an intake side of the crankcase vent tube based on a crankcase vent tube pressure during an engine crank event.

11. The method of claim 10, further comprising:

indicating degradation of a vacuum pump exhaust line based on a fuel vapor canister temperature and a crankcase vent tube pressure during an engine crank event; and

not indicating degradation of the intake side of the crankcase vent tube based on a crankcase vent tube pressure during an engine crank event responsive to a fuel vapor canister temperature change below a threshold.

12. The method of claim 9, further comprising:

indicating degradation of a crankcase side of the crankcase vent tube based on a crankcase vent tube pressure during a condition wherein engine intake air flow is increasing.

13. The method of claim 12, further comprising:

indicating degradation of a vacuum pump exhaust line based on a fuel vapor canister temperature and a crankcase vent tube pressure during a condition wherein engine intake air flow is increasing; and

not indicating degradation of the crankcase side of the crankcase vent tube based on a crankcase vent tube pressure during an engine crank event responsive to a fuel vapor canister temperature change below a threshold.

14. The method of claim 9, further comprising:

sealing an evaporative emissions system during a condition wherein the vacuum pump is activated; and

indicating degradation of a canister side of an evaporative emissions system based on a fuel vapor canister pressure.

15. The method of claim 9, further comprising:

adjusting engine operations responsive to an indication of degradation of a crankcase vent tube.

16. A method for an engine, comprising:

indicating degradation of an exhaust line of a vacuum pump deposed within a crankcase based on a fuel vapor canister temperature and a crankcase vent tube pressure;

not indicating degradation of a crankcase vent tube based on a crankcase pressure responsive to an indication of degradation of the exhaust line; and

adjusting engine operations responsive to an indication of degradation of the exhaust line.

17. The method of claim 16, further comprising:

during an engine crank event, indicating an crankcase side of the crankcase vent tube is intact responsive to an observed crankcase pressure change within a threshold of an expected crankcase pressure change; and

during the engine crank event, indicating degradation of the exhaust line responsive to an observed crankcase pressure change outside of a threshold of an expected crankcase pressure change and a fuel vapor canister temperature change below a threshold temperature change.

18. The method of claim 16, further comprising:

during a condition wherein engine intake air flow is increasing, indicating an intake side of a crankcase vent tube is intact responsive to an observed crankcase pressure change within a threshold of an expected crankcase pressure change; and

during the condition wherein engine intake air flow is increasing, indicating degradation of the exhaust line responsive to an observed crankcase pressure change outside of a threshold of an expected crankcase pressure change and a fuel vapor canister temperature change below a threshold temperature change.

19. The method of claim 16, further comprising:

closing a fuel tank isolation valve responsive to activation of the vacuum pump.

20. The method of claim 19, further comprising:

closing a canister vent valve responsive to activation of the vacuum pump; and

indicating degradation of a canister side of an evaporative emissions system based on a fuel vapor canister pressure.