Method for crankcase ventilation in a boosted engine

Patent metadata

Field	Value
Publication number	US-2016369718-A1
Application number	US-201514743280-A
Country	US
Kind code	A1
Filing date	Jun 18, 2015
Priority date	Jun 18, 2015
Publication date	Dec 22, 2016
Grant date	—

Abstract

Methods and systems are provided for ventilating a crankcase in a boosted engine. An example method may include selectively enabling one of crankcase ventilation and aspirator motive flow via an electrically controlled valve, the aspirator motive flow being enabled in response to a demand for vacuum from a vacuum consumer. In this way, the crankcase of the boosted engine may be ventilated until the vacuum consumer demands vacuum.

First claim

1 . A method for a boosted engine, comprising:
selectively enabling one of crankcase ventilation flow and aspirator motive flow via an electrically controlled valve responsive to a desired engine air flow and a demand for vacuum from a vacuum consumer.

2 . The method of claim 1 , wherein crankcase ventilation flow is enabled when the desired engine air flow is higher than a threshold flow.

3 . The method of claim 2 , wherein crankcase ventilation flow includes flowing fuel vapors from a crankcase of the boosted engine through a crankcase ventilation (CV) valve and the electrically controlled valve directly into an intake manifold of the boosted engine.

4 . The method of claim 3 , wherein the aspirator motive flow is enabled via the electrically controlled valve in response to the demand for vacuum from the vacuum consumer, and wherein the aspirator motive flow generates a vacuum at an aspirator, the vacuum being supplied to the vacuum consumer.

5 . The method of claim 4 , wherein aspirator motive flow includes flowing air from an inlet of a compressor through an aspirator into the intake manifold of the boosted engine via the electrically controlled valve.

6 . The method of claim 5 , wherein aspirator motive flow does not flow through the CV valve, and wherein the crankcase ventilation flow does not flow through the aspirator.

7 . The method of claim 3 , further comprising terminating each of crankcase ventilation flow and aspirator motive flow concurrently via the electrically controlled valve responsive to the desired engine air flow being lower than the threshold flow.

8 . A method for a boosted engine, comprising:
during a first condition,
flowing crankcase ventilation flow to an intake manifold while not flowing aspirator motive flow; and
during a second condition,
enabling aspirator motive flow while not flowing crankcase ventilation flow to the intake manifold; and
during a third condition,
not flowing each of crankcase ventilation flow and aspirator motive flow.

9 . The method of claim 8 , wherein the first condition, the second condition, and the third condition are mutually exclusive of each other.

10 . The method of claim 9 , wherein the first condition includes a desired engine air flow higher than a threshold flow, and wherein the second condition includes a vacuum level lower than a threshold level in a vacuum consumption device, and wherein the third condition includes the desired engine air flow lower than the threshold flow.

11 . A method for a boosted engine, comprising:
discontinuing vapor flow from a crankcase by adjusting a valve in response to determined brake actuation.

12 . The method of claim 11 , wherein determined brake actuation further includes a reduction in vacuum level in a brake booster, the vacuum level reducing below a threshold level.

13 . The method of claim 12 , wherein adjusting the valve includes adjusting the valve to enable motive flow through an aspirator, the aspirator coupled to the brake booster, and wherein the motive flow through the aspirator generates vacuum.

14 . The method of claim 13 , further comprising adjusting the valve to enable vapor flow from the crankcase and discontinue motive flow through the aspirator in response to each of vacuum level in the brake booster higher than the threshold level and a desired engine air flow higher than a threshold flow.

15 . The method of claim 14 , further comprising adjusting the valve to discontinue each of vapor flow from the crankcase and motive flow through the aspirator in response to the desired engine air flow being lower than the threshold flow.

16 . The method of claim 11 , wherein the valve is electrically controlled, and wherein adjusting the valve includes commanding the valve via a controller.

17 . A system, comprising:
a boosted engine including a compressor; a crankcase ventilation system including a crankcase ventilation (CV) valve coupled to a crankcase of the boosted engine; an aspirator capable of generating vacuum, the aspirator coupled to a vacuum consumer; a three-way valve coupled to each of the crankcase and the aspirator; and a controller with computer-readable instructions stored in non-transitory memory for: in response to a demand for vacuum from the vacuum consumer,
adjusting the three-way valve to enable motive flow through the aspirator instead of enabling crankcase ventilation flow.

18 . The system of claim 17 , wherein the three-way valve is coupled intermediate the CV valve and an intake manifold of the engine, and wherein the three-way valve is coupled intermediate the aspirator and the intake manifold.

19 . The system of claim 18 , wherein the controller includes further instructions for adjusting the three-way valve to enable crankcase ventilation flow in response to the demand for vacuum from the vacuum consumer being met.

20 . The system of claim 18 , wherein the controller includes further instructions for modifying the three-way valve to block each of crankcase ventilation flow and motive flow through the aspirator in response to a desired engine air flow lower than a threshold flow.

Assignees

• Ford Global Tech Llc

Inventors

• Pursifull Ross Dykstra
• Crisp Nicholas Dashwood

Classifications

• F02M25/06

  adding lubricant vapours · CPC title

• F02B37/162

  by bypassing, e.g. partially, intake air from pump inlet to pump outlet · CPC title

• F01M13/00

  Crankcase ventilating or breathing · CPC title

• B60T13/46

  Vacuum systems · CPC title

• F02M35/10222

  Exhaust gas recirculation [EGR]; Positive crankcase ventilation [PCV]; Additional air admission, lubricant or fuel vapour admission · CPC title