Method for preparation for the start of a parked fuel cell system
A method for the start preparation of a fuel cell system in a vehicle having a fuel cell and a system bypass where an air flow is conveyed by parts of the fuel cell system in order to dry the fuel cell. In a first temporal phase of the method, a larger part of the air flow is led through the fuel cell and a smaller part of the air flow is led through the system bypass, after which, in a second temporal phase, a larger part of the air flow is led through the system bypass and a smaller part of the air flow is led through the fuel cell.
1. A method of a start preparation routine of a fuel cell system in a vehicle, wherein the fuel cell system has a fuel cell and a system bypass, comprising the steps of:
conveying a larger part of an air flow through the fuel cell and a smaller part of the air flow through the system bypass in a first temporal phase; and
conveying a larger part of the air flow through the system bypass and a smaller part of the air flow through the fuel cell in a second temporal phase which is after the first temporal phase;
wherein a heating device in the fuel cell system is operated before the first temporal phase in a pre-switched heating phase.
2. The method according to claim 1 , wherein the heating device is operated until an end of the second temporal phase.
3. The method according to claim 1 , wherein the air flow at a start of the first temporal phase is increased to a constant pressure and is held at the constant pressure until an end of the second temporal phase.
4. The method according to claim 1 , wherein a cathode side of the fuel cell system is flowed through with the air flow.
5. The method according to claim 1 , wherein during the first temporal phase and the second temporal phase, an anode chamber of the fuel cell is provided with hydrogen at a pulsating pressure when an anode outlet valve is open.
6. The method according to claim 5 , wherein the air flow at a start of the first temporal phase is increased to a constant pressure and is held at the constant pressure until an end of the second phase and wherein the pulsating pressure is set to a value of the constant pressure.
7. The method according to claim 6 , wherein an average of the pulsating pressure is greater than or equal to the value of the constant pressure.
8. The method according to claim 1 , wherein a start of the first temporal phase depends on a temperature threshold value.
9. The method according to claim 1 , wherein a start of the heating phase depends on a temperature threshold value and wherein the first temporal phase is started depending on a time after the start of the heating phase.