Fuel cell engine system and load increase and load decrease control method

The invention relates to a fuel cell engine system and a load increase and load decrease control method. The system comprises an air system, a hydrogen system, a cooling cycle system, a galvanic pile module and an electric control system, wherein a buffer tank arranged on a pipeline between a control valve and a galvanic pile hydrogen inlet is additionally arranged in the hydrogen system; the volume of the buffer tank is greater than or equal to that of air flow required by an anode at limit loading speed. The load increase and load decrease control method of the system comprises the following steps: controlling the load increase and load decrease of a cathode by taking the air flow in the buffer tank as an upper limit during the load increase and load decrease processes of a fuel cell engine; and performing stepped load increase and load decrease control by taking a set upper limit value of load increase and load decrease speed of the cathode as the maximum load increase and load decrease speed. The system and the method which are provided by the invention have the beneficial effects that air lacking phenomenon of the anode is effectively avoided due to introduction of a hydrogen buffer tank; through the control for load increase and load decrease, the fluctuation of voltage is reduced, and the service life of the engine system can be effectively prolonged.