Method and system for vacuum generation

Patent metadata

Field	Value
Publication number	US-9435300-B2
Application number	US-201313950196-A
Country	US
Kind code	B2
Filing date	Jul 24, 2013
Priority date	Dec 13, 2012
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

Methods and systems are provided for controlling motive flow through an ejector using a pneumatically controlled valve. A valve coupled upstream of an intake ejector may be adjusted based on boost pressure to control motive flow into the ejector from upstream of a compressor. This allows motive flow through the ejector to be controlled based on vacuum needs at low component cost without loss of boost pressure.

First claim

The invention claimed is:

1. A method, comprising:
determining boost pressure in at least one of an intake passage and an intake manifold; determining a vacuum level in a vacuum reservoir adjusting a valve coupled upstream of an intake ejector based on the boost pressure, the valve adjusted to control motive flow into the ejector from upstream of a compressor; wherein adjusting the valve comprises adjusting the valve based on the vacuum level in the vacuum reservoir and closing the valve in response to the boost pressure being higher than a threshold, the threshold comprising compressor inlet pressure; and
adjusting a compressor bypass valve coupled across the compressor to control the boost pressure.

2. The method of claim 1 , further comprising, drawing vacuum at the ejector and storing the drawn vacuum at the vacuum reservoir.

3. The method of claim 2 , wherein adjusting the valve based on the vacuum level comprises opening the valve responsive to the vacuum level at the vacuum reservoir being lower than a threshold, and wherein drawing vacuum includes drawing vacuum at the ejector until the vacuum level at the vacuum reservoir is above the threshold.

4. The method of claim 3 , further comprising, after the vacuum level at the vacuum reservoir is above the threshold, closing the valve.

5. The method of claim 3 , further comprising, while opening the valve, adjusting an opening of an intake throttle to maintain intake air flow rate.

6. The method of claim 1 , wherein the valve is a vacuum-actuated valve coupled to a vacuum reservoir and to an intake passage downstream of the compressor.

7. A method for an engine, comprising:
determining boost pressure in at least one of an intake passage and an intake manifold; determining a vacuum level in a vacuum reservoir; when the vacuum level of the vacuum reservoir is lower than a threshold level and the boost pressure is less than or equal to a threshold pressure, opening a valve coupled upstream of an ejector to draw motive flow into the ejector from upstream of a compressor, the motive flow discharged from the ejector into an intake manifold, downstream of an intake throttle; and
in response to one of the vacuum level of the vacuum reservoir being higher than the threshold level and the boost pressure being higher than the threshold pressure, closing the valve.

8. The method of claim 7 , wherein the threshold pressure is barometric pressure.

9. The method of claim 7 , wherein a neck of the ejector is coupled to the vacuum reservoir along a first passage, an outlet of the ejector is coupled to the vacuum reservoir along a second passage, and wherein the valve is a vacuum-actuated valve coupled to the vacuum reservoir along a third passage, the first, second, and third passages merging downstream of an outlet of the vacuum reservoir, each of the first and second passages including a check valve.

10. The method of claim 9 , wherein the second passage further couples the vacuum reservoir to an engine intake manifold downstream of a juncture with the ejector outlet and wherein the vacuum-actuated valve is coupled directly to the vacuum reservoir along the third passage.

11. The method of claim 9 , wherein the vacuum-actuated valve is further coupled to an engine intake passage, downstream of the compressor.

12. The method of claim 7 , wherein the vacuum reservoir is coupled to one or more engine vacuum consumption devices.

13. The method of claim 7 , wherein the vacuum reservoir is coupled to one or more of a brake booster, a purge canister, and a charge motion control valve.

14. A system, comprising:
an engine including an intake manifold, the intake manifold coupled to a vacuum reservoir along a first passage; a pressure sensor coupled to the vacuum reservoir to provide an estimate of the vacuum level at the vacuum reservoir; a manifold air pressure sensor that detects a boost pressure in the intake manifold
a compressor positioned in an intake passage upstream of the intake manifold;
an intake throttle upstream of the intake manifold and downstream of the compressor;
an ejector positioned in a bypass passage across the compressor and intake throttle, a neck of the ejector coupled to the vacuum reservoir along a second passage, an outlet of the ejector coupled to the vacuum reservoir and the intake manifold along the first passage;
a motive flow control valve coupled in the bypass passage upstream of an inlet of the ejector;
a vacuum actuator coupled to the motive flow control valve, the vacuum actuator coupled to the vacuum reservoir and to an outlet of the compressor; and
a controller with non-transitory computer-readable instructions for:
operating the engine system in a first mode with the motive flow control valve open to increase motive flow through the ejector; and
operating the engine system in a second mode with the motive flow control valve closed to decrease the motive flow; and wherein the engine system is operated in the first mode when the vacuum level in the vacuum reservoir is below a threshold level and the boost pressure is less than a threshold pressure, and wherein the engine system is operated in the second mode when the boost pressure is greater than the threshold pressure.

15. The system of claim 14 , wherein the engine system is operated in the first mode when the vacuum level in the vacuum reservoir is below a threshold level and the boost pressure is less than a threshold pressure, and wherein the engine system is operated in the second mode when the vacuum level is above the threshold.

16. The system of claim 15 , wherein operating in the first mode is continued until the vacuum level is higher than the threshold, and wherein the controller includes further instructions for transitioning engine system operation from the first mode to the second mode after the vacuum level is higher than the threshold.

17. The system of claim 14 , wherein the vacuum reservoir is coupled to a brake booster.

Assignees

• Ford Global Tech Llc

Inventors

• Pursifull Ross Dykstra

Classifications

• F02M35/10229 Primary

  the intake system acting as a vacuum or overpressure source for auxiliary devices, e.g. brake systems; Vacuum chambers (air storage chamber F02B21/00) · CPC title

• F02D41/0002

  Controlling intake air · CPC title

• F02B37/16

  by bypassing charging air · CPC title

• F16K15/00

  Check valves (valves specially adapted for inflatable balls A63B41/00) · CPC title

• Y10T137/0391

  Affecting flow by the addition of material or energy · CPC title