Systems and methods to measure or control fuel cell stack excess hydrogen flow using ejector mixing state

Patent metadata

Field	Value
Publication number	US-12500253-B2
Application number	US-202217898070-A
Country	US
Kind code	B2
Filing date	Aug 29, 2022
Priority date	Sep 10, 2021
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

The present disclosure generally relates to systems and methods for determining, managing, and/or controlling excess hydrogen flow in a system comprising a fuel cell or fuel cell stack and ejector based on the internal state of the ejector.

First claim

What is claimed is:

1 . A fuel cell system comprising:
a first flow stream and a second flow stream mixing to form a third flow stream, the third flow stream flowing through an ejector and an anode inlet of a fuel cell stack, wherein the ejector comprises components including a primary nozzle, a mixer region and a diffuser, and a controller configured to compare an excess fuel ratio of the fuel cell system to a target excess fuel ratio of the fuel cell system by determining a pressure change or a temperature change between two locations selected from the primary nozzle, the mixer region and the diffuser, the controller configured to alter a volumetric flow rate of the first flow stream based on the comparison of the excess fuel ratio to the target fuel ratio.

2 . The system of claim 1 , wherein the fuel cell system further comprises a blower, or a by-pass valve.

3 . The system of claim 2 , wherein controller is configured to determine when to operate the blower or a blower speed based on the excess fuel ratio.

4 . The system of claim 2 , wherein the controller is configured to determine operation of the by-pass valve based on the excess fuel ratio.

5 . The system of claim 2 , wherein the fuel cell system comprises at least a first ejector and a second ejector, and the controller determines whether to operate the first ejector, the second ejector, or both the first ejector and the second ejector based on the excess fuel ratio.

6 . The system of claim 1 , wherein the mixer region comprises a mixer length, and wherein the fuel cell system further comprises at least one physical or virtual sensor along the mixer length.

7 . The system of claim 6 , wherein the primary nozzle comprises a nozzle outlet plane at a primary nozzle outlet, wherein the mixer region comprises a mixer inlet plane at a mixer region inlet, a mixer outlet plane at a mixer region outlet, and an end of constant pressure plane, and wherein the ejector comprises an interaction zone that ranges from the nozzle outlet plane to the mixer inlet plane, a mixing zone that ranges from the mixer inlet plane to the constant pressure plane, and a pressure recovery zone that ranges from the constant pressure plane to the mixer outlet plane.

8 . The system of claim 7 , wherein the at least one physical or virtual sensor measures a first pressure of the third flow stream in the mixing zone and a second pressure of the third flow stream at an outlet of the diffuser, and wherein the first pressure and the second pressure are used to determine a mass flow rate of the third flow stream at the anode inlet, and wherein the mass flow rate of the third flow stream is used to determine the excess fuel ratio.

9 . The system of claim 7 , wherein the at least one physical or virtual sensor measures a first temperature of the third flow stream in the mixing zone and a second temperature of the third flow stream at an outlet of the diffuser, and wherein the first temperature and the second temperature are used to determine a mass flow rate of the third flow stream at the anode inlet, and wherein the mass flow rate of the third flow stream is used to determine the excess fuel ratio.

10 . The system of claim 7 , wherein the at least one physical or virtual sensor is located near the mixer inlet plane and used under low flow conditions.

11 . The system of 7 , wherein the at least one physical or virtual sensor is located in a region of highest flow accuracy when the fuel system is functioning under operating conditions that challenge ejector performance.

12 . The system of claim 6 , wherein the fuel cell system can detect the presence of a shock wave in the ejector, and wherein the at least one physical or virtual sensor is located downstream the mixer region and used when the shock wave is present at the beginning of the mixer region.

13 . The system of claim 6 , wherein the at least one physical or virtual sensor determines sound intensity, determines a location of peak intensity or determines an average intensity over a range of frequency, and wherein the controller determines a mass flow rate of the third flow stream using the sound intensity, the location of peak intensity or the average intensity over a range of frequency.

14 . A method of efficiently operating a fuel cell system comprising:
mixing a first flow stream and a second flow stream to form a third flow stream, flowing the third flow stream through an ejector and through an anode inlet in a fuel cell stack, wherein the ejector comprises components including a primary nozzle, a mixer region and a diffuser, determining an excess fuel ratio of the fuel cell system, operating a controller configured to compare the excess fuel ratio of the fuel cell system to a target excess fuel ratio of the fuel cell system by determining a pressure change or a temperature change between two locations selected from the primary nozzle, the mixer region, and the diffuser, and altering a volumetric flow rate of the first flow stream based on the comparison of the excess fuel ratio to the target fuel ratio.

15 . The method of claim 14 , wherein the primary nozzle comprises a nozzle outlet plane at a primary nozzle outlet, wherein the mixer region comprises a mixer inlet plane at a mixer region inlet, a mixer outlet plane at a mixer region outlet and an end of constant pressure plane and, and wherein the ejector comprises an interaction zone that ranges from the nozzle outlet plane to the mixer inlet plane, a mixing zone that ranges from the mixer inlet plane to the end of constant pressure plane, and a pressure recovery zone that ranges from the end of constant pressure plane to the mixer outlet plane, and wherein at least one physical or virtual sensor is located near the mixer inlet plane and used under low flow conditions.

16 . The method of claim 14 , wherein the primary nozzle comprises a nozzle outlet plane at a primary nozzle outlet, wherein the mixer region comprises a mixer inlet plane at a mixer region inlet, a mixer outlet plane at a mixer region outlet and an end of constant pressure plane and, and wherein the ejector comprises an interaction zone that ranges from the nozzle outlet plane to the mixer inlet plane, a mixing zone that ranges from the mixer inlet plane to the end of constant pressure plane, and a pressure recovery zone that ranges from the end of constant pressure plane to the mixer outlet plane, and wherein the method further comprises determining a first temperature of the third flow stream in the mixing zone and a second temperature of the third flow stream at an outlet of the diffuser, and using the first temperature and second temperature to determine a mass flow rate of the third flow stream at the anode inlet, and wherein the mass flow rate of the third flow stream is used to determine the excess fuel ratio.

17 . The method of claim 14 , wherein the method further comprises detecting the presence of a shock wave in the ejector, and wherein at least one physical or virtual sensor is located downstream the mixer region and used when the shock wave is located at the beginning of the mixer region.

18 . The method of claim 14 , wherein the mixer region comprises a mixer length, and wherein the fuel cell system comprises at least one physical or virtual sensor along the mixer length.

19 . The method of claim 18 , wherein the at least one physical or virtual sensor is located in a region of highest flow accuracy when the fuel system is functioning under operating conditions that challenge ejector performance.

Assignees

• Cummins Inc
• Hydrogenics Corp

Inventors

• Ancimer Richard J
• Forte Paolo
• Tripathi Sumit

Classifications

• H01M8/0438

  Pressure; Ambient pressure; Flow · CPC title

• H01M8/0432

  Temperature; Ambient temperature · CPC title

• H01M8/04097 Primary

  with recycling of the reactants (H01M8/04119, H01M8/04104 take precedence) · CPC title

• H01M8/04089 Primary

  of gaseous reactants · CPC title

• H01M8/04432

  Pressure differences, e.g. between anode and cathode · CPC title