Fuel cell system, fuel cell-mounted vehicle and method of controlling fuel system

Patent metadata

Field	Value
Publication number	US-9793562-B2
Application number	US-201514934717-A
Country	US
Kind code	B2
Filing date	Nov 6, 2015
Priority date	Nov 14, 2014
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

When a first timing at which a fuel gas is injected to a fuel gas supply flow path by an injector and a second timing at which water residing on a circulation flow path is discharged by controlling rotating speed of a circulation pump coincide with each other, a controller performs either: (i) a first process of operating the circulation pump at a preset RPM without injecting the fuel gas to the fuel gas supply flow path by the injector; or (ii) a second process of injecting the fuel gas to the fuel gas supply flow path by the injector and operating the circulation pump at an RPM lower than the preset RPM.

First claim

What is claimed is:

1. A fuel cell system comprising:
a fuel cell;
a fuel gas supply flow path configured to supply a fuel gas to the fuel cell;
an injector configured to intermittently inject the fuel gas to the fuel gas supply flow path;
a fuel gas discharge flow path configured to discharge a fuel exhaust gas from the fuel cell;
a circulation flow path connecting the fuel gas supply flow path and the fuel gas discharge flow path to each other;
a circulation pump provided on the circulation flow path and configured to supply the fuel exhaust gas to the fuel gas supply flow path; and
a controller configured to control a rotating speed of the circulation pump to a preset RPM (Revolutions Per Minute) to discharge water residing on the circulation flow path, wherein
when a first timing at which the fuel gas is injected to the fuel gas supply flow path by the injector and a second timing at which the water residing on the circulation flow path is discharged by controlling the rotating speed of the circulation pump coincide with each other, the controller performs either:
(i) a first process of operating the circulation pump at the preset RPM without injecting the fuel gas to the fuel gas supply flow path by the injector; or
(ii) a second process of injecting the fuel gas to the fuel gas supply flow path by the injector and operating the circulation pump at an RPM lower than the preset RPM.

2. The fuel cell system in accordance with claim 1 , wherein
when the first process and the second process are not being performed, and power of the fuel cell is equal to or lower than a predetermined power value, the controller performs a third process of increasing a fuel-gas injection quantity per stroke from the injector in comparison to that of the case where the power of the fuel cell is greater than the predetermined power value, and intermittently injecting the fuel gas at a injection cycle longer than an injection cycle preset for injection of the fuel gas.

3. The fuel cell system in accordance with claim 2 , wherein
in the third process, the controller multiplies the injection quantity per stroke r-fold and multiplies the injection cycle r-fold (where r is a real number of 1 or more).

4. A fuel cell-mounted vehicle comprising:
a vehicle; and
a fuel cell system comprising a fuel cell; a fuel gas supply flow path configured to supply a fuel gas to the fuel cell; an injector configured to intermittently inject the fuel gas to the fuel gas supply flow path; a fuel gas discharge flow path configured to discharge a fuel exhaust gas from the fuel cell; a circulation flow path connecting the fuel gas supply flow path and the fuel gas discharge flow path to each other; a circulation pump provided on the circulation flow path and configured to supply the fuel exhaust gas to the fuel gas supply flow path; and a controller configured to control a rotating speed of the circulation pump to a preset RPM (Revolutions Per Minute) to discharge water residing on the circulation flow path,
when a first timing at which the fuel gas is injected to the fuel gas supply flow path by the injector and a second timing at which the water residing on the circulation flow path is discharged by controlling the rotating speed of the circulation pump coincide with each other, the controller performs either:
(a) executes either the first process or the second process if a running speed of the vehicle is equal to or lower than a predetermined low-speed threshold; and
(b) operates the circulation pump at an RPM preset for blowoff of the liquid water if the running speed of the vehicle is higher than the low-speed threshold.

5. The fuel cell-mounted vehicle in accordance with claim 4 , wherein
when the first process and the second process are not being performed, and power of the fuel cell is equal to or lower than a predetermined power value, the controller performs a third process of increasing a fuel-gas injection quantity per stroke from the injector in comparison to that of the case where the power of the fuel cell is greater than the predetermined power value, and intermittently injecting the fuel gas at a injection cycle longer than an injection cycle preset for injection of the fuel gas.

6. The fuel cell-mounted vehicle in accordance with claim 5 , wherein
in the third process, the controller multiplies the injection quantity per stroke r-fold and multiplies the injection cycle r-fold (where r is a real number of 1 or more).

7. A method of controlling a fuel system, wherein the fuel system comprising an injector configured to intermittently inject a fuel gas to a fuel gas supply flow path supplying the fuel gas to a fuel cell, and a circulation pump provided on a circulation flow path connecting the fuel gas supply flow path and a fuel gas discharge flow path discharging a fuel exhaust gas from the fuel cell and configured to supply the fuel exhaust gas to the fuel gas supply flow path, comprising:
when a first timing at which the fuel gas is injected to the fuel gas supply flow path by the injector and a second timing at which the water residing on the circulation flow path is discharged by controlling the rotating speed of the circulation pump coincide with each other, performing either
(i) a first process of operating the circulation pump at the preset RPM without injecting the fuel gas to the fuel gas supply flow path by the injector; or
(ii) a second process of injecting the fuel gas to the fuel gas supply flow path by the injector and operating the circulation pump at an RPM lower than the preset RPM.

Assignees

• Toyota Motor Co Ltd

Inventors

• Yamamoto Kazuo
• Imanishi Hiroyuki

Classifications

• H01M8/04753

  of fuel cell reactants · CPC title

• H01M8/04298

  Processes for controlling fuel cells or fuel cell systems · CPC title

• H01M8/04082

  Arrangements for control of reactant parameters, e.g. pressure or concentration · CPC title

• H01M8/04156

  with product water removal · CPC title

• H01M8/04776 Primary

  at auxiliary devices, e.g. reformer, compressor, burner · CPC title