Abstract: A controller of a fuel cell system executes at least one of a first control and a second control. The first control is executed when a value of current is raised in association with an increase in flow rate ratio of cathode exhaust gas flowing into a bypass, the first control is executed by which the value of the current is raised to boost discharge pressure from a compressor and subsequently, an opening degree of a flow dividing valve is changed so as to increase the flow rate ratio of the cathode exhaust gas flowing into the bypass. The second control is executed when the value of the current is lowered in association with a reduction in the flow rate ratio of the cathode exhaust gas flowing into the bypass, the second control is executed by which the opening degree of the flow dividing valve is changed so as to reduce the flow rate ratio of the cathode exhaust gas flowing into the bypass and subsequently, the value of the current is lowered so as to lower the discharge pressure from the compressor.

Abstract: A fuel cell system includes: a turbine including a changing mechanism that adjusts a pressure difference between an upstream pressure and a downstream pressure of the turbine, the turbine recovering at least a part of energy of the cathode off-gas using the pressure difference and assisting driving of the motor with the recovered energy; and a control unit configured to drive the changing mechanism to increase or decrease the recovered energy. The control unit acquires a correlation temperature correlated with a temperature of the cathode off-gas discharged from the turbine and performs freezing avoidance control of not setting the degree of opening to be equal to or less than a predetermined degree of opening when the correlation temperature is lower than a predetermined threshold temperature at which the turbine is able to become frozen.

Abstract: A fuel cell system includes: a fuel cell; a compressor; a turbine; an electric motor; a first transmission configured to change a gear ratio between the compressor and the electric motor, the first transmission being linked to the compressor rotating shaft and the motor rotating shaft; and a second transmission configured to change a gear ratio between the turbine and the electric motor, the second transmission being linked to the turbine rotating shaft and the motor rotating shaft. A gear ratio of the first transmission and a gear ratio of the second transmission are set such that a rotating speed of the electric motor is lower than a rotating speed of the compressor and a rotating speed of the turbine and such that a rotating speed of the compressor is higher than the rotating speed of the turbine.

Abstract: A controller of a fuel cell system executes at least one of a first control and a second control. The first control is executed when a value of current is raised in association with an increase in flow rate ratio of cathode exhaust gas flowing into a bypass, the first control is executed by which the value of the current is raised to boost discharge pressure from a compressor and subsequently, an opening degree of a flow dividing valve is changed so as to increase the flow rate ratio of the cathode exhaust gas flowing into the bypass. The second control is executed when the value of the current is lowered in association with a reduction in the flow rate ratio of the cathode exhaust gas flowing into the bypass, the second control is executed by which the opening degree of the flow dividing valve is changed so as to reduce the flow rate ratio of the cathode exhaust gas flowing into the bypass and subsequently, the value of the current is lowered so as to lower the discharge pressure from the compressor.

Abstract: A fuel cell system includes: a turbine including a changing mechanism that adjusts a pressure difference between an upstream pressure and a downstream pressure of the turbine, the turbine recovering at least a part of energy of the cathode off-gas using the pressure difference and assisting driving of the motor with the recovered energy; and a control unit configured to drive the changing mechanism to increase or decrease the recovered energy. The control unit acquires a correlation temperature correlated with a temperature of the cathode off-gas discharged from the turbine and performs freezing avoidance control of not setting the degree of opening to be equal to or less than a predetermined degree of opening when the correlation temperature is lower than a predetermined threshold temperature at which the turbine is able to become frozen.

Abstract: A fuel cell system includes: a fuel cell; a compressor; a turbine; an electric motor; a first transmission configured to change a gear ratio between the compressor and the electric motor, the first transmission being linked to the compressor rotating shaft and the motor rotating shaft; and a second transmission configured to change a gear ratio between the turbine and the electric motor, the second transmission being linked to the turbine rotating shaft and the motor rotating shaft. A gear ratio of the first transmission and a gear ratio of the second transmission are set such that a rotating speed of the electric motor is lower than a rotating speed of the compressor and a rotating speed of the turbine and such that a rotating speed of the compressor is higher than the rotating speed of the turbine.

Abstract: A cooling system for an engine system includes an engine coolant path inside an internal combustion engine and a turbine coolant path inside a turbocharger. A switching section is selectively switched to one of a first operation mode, in which coolant in the cooling system is permitted to flow through the engine coolant path and the turbine coolant path, and a second operation mode, in which the coolant in the cooling system is permitted to flow only through the engine coolant path, while not being permitted to flow through the turbine coolant path. When the switching section is in the first operation mode and a basic flow rate calculated based on an engine operating state is larger than an actual flow rate detected by a flow rate sensor by at least a determination amount, the switching section is switched to the second operation mode.

Abstract: A cooling system for an engine system includes an engine coolant path inside an internal combustion engine and a turbine coolant path inside a turbocharger. A switching section is selectively switched to one of a first operation mode, in which coolant in the cooling system is permitted to flow through the engine coolant path and the turbine coolant path, and a second operation mode, in which the coolant in the cooling system is permitted to flow only through the engine coolant path, while not being permitted to flow through the turbine coolant path. When the switching section is in the first operation mode and a basic flow rate calculated based on an engine operating state is larger than an actual flow rate detected by a flow rate sensor by at least a determination amount, the switching section is switched to the second operation mode.

Abstract: A main CPU determines whether or not there is a request for one valve driving based on an engine operating state such as an engine speed and a load factor, with reference to a control map. When it is determined that there is a request for one valve driving, it is determined whether or not there is an overlapping period between opening periods. When it is determined that there is no overlapping period, a high speed control is performed for controlling electromagnetically driven valves. When it is determined that there is no request for one valve driving, or when it is determined that there is the overlapping period, a low speed control is performed for controlling electromagnetically driven valves.

Abstract: A main CPU determines whether or not there is a request for one valve driving based on an engine operating state such as an engine speed and a load factor, with reference to a control map. When it is determined that there is a request for one valve driving, it is determined whether or not there is an overlapping period between opening periods. When it is determined that there is no overlapping period, a high speed control is performed for controlling electromagnetically driven valves. When it is determined that there is no request for one valve driving, or when it is determined that there is the overlapping period, a low speed control is performed for controlling electromagnetically driven valves.