Fuel supply device

1. A fuel supply device to supply fuel to an engine comprising:

a fuel passage portion having a first passage to send supply fuel to the engine, and a second passage to communicate with the first passage;

a first electric pump to send fuel into the first passage;

a second electric pump to send fuel into the second passage;

a relief valve to discharge fuel from the second passage when a fuel pressure of the second passage is higher than a predetermined relief pressure;

a pressure regulator having a fuel chamber to communicate with the first passage, and a backpressure chamber to communicate with the second passage; and

a controller to switch control mode of the first pump and the second pump between a low pressure mode and a high pressure mode based on an operation state of the engine, wherein

the pressure regulator discharges fuel from the fuel chamber when a fuel pressure of the fuel chamber is higher than a regulation pressure in a state that a fuel pressure of the backpressure chamber is equal to the relief pressure, the regulation pressure being higher than the relief pressure,

the controller controls the first pump to stop, and controls a pressure of fuel discharged from the second pump to become higher than the relief pressure, when the low pressure mode is selected, and

the controller controls a pressure of fuel discharged from the first pump to become higher than the regulation pressure, and controls a pressure of fuel discharged from the second pump to become higher than the relief pressure, when the high pressure mode is selected.

2. The fuel supply device according to claim 1 , further comprising:

a check valve to disconnect the first passage from the second passage when the fuel pressure of the first passage becomes higher than the fuel pressure of the second passage.

3. The fuel supply device according to claim 1 , wherein

the pressure regulator discharges fuel from the fuel chamber when a fuel pressure of the fuel chamber becomes higher than a low regulation pressure in a state that a fuel pressure of the backpressure chamber is lower than the relief pressure, the low regulation pressure being higher than the relief pressure and being lower than a high regulation pressure corresponding to the regulation pressure,

the control mode switched by the controller further has a middle pressure mode other than the low pressure mode and the high pressure mode, and

the controller controls the pressure of fuel discharged from the first pump to become higher than the low regulation pressure, and controls the second pump to stop, when the middle pressure mode is selected.

4. The fuel supply device according to claim 3 , further comprising:

a check valve to disconnect the first passage from the second passage when the fuel pressure of the first passage becomes higher than the fuel pressure of the second passage.

5. The fuel supply device according to claim 1 , further comprising: a reservoir cup arranged in a fuel tank of the engine so as to store fuel to be suctioned by the first pump or the second pump; and

a jet pump to send fuel from the fuel tank into the reservoir cup by injecting fuel flowing through the second passage.

6. The fuel supply device according to claim 1 , further comprising:

a reservoir cup arranged in a fuel tank of the engine so as to store fuel to be suctioned by the first pump or the second pump; and

a jet pump to send fuel from the fuel tank into the reservoir cup by injecting fuel discharged from the fuel chamber through the pressure regulator.