Then drive the wheel to turn and drive the vehicle through the transmission system
and drive axle. The energy conversion process of hydrogen fuel is shown in
Fig. 13.4.
A certain mass of hydrogen fuel contains a certain amount of chemical energy.
Fuel cells have a certain energy loss when converting chemical energy into electrical energy. When the motor converts the energy of fuel cell into mechanical
energy, there is also a certain energy loss. Among them, the energy transfer link
(DC/DC converter, mechanical transmission system, etc.) is more complex, and its
energy loss can be expressed by total energy efficiency.
(2) Mathematical model
1. Electrical energy and power converted by fuel cells:
E ¼ geM
ð13:1Þ
dE
dt
¼ geQ m
ð13:2Þ
where
E
Electric energy converted from chemical energy of hydrogen fuel cell
(kJ);
M Hydrogen mass (kg);
e
Energy produced by reaction of hydrogen and oxygen per unit mass (kJ/
kg);
Q m Hydrogen mass flow rate (kJ/kg);
g
Fuel cell energy efficiency.
2. Traction force of a car while it is running. According to the principle of
automobile dynamics, when a car is running at a certain speed, it needs to
overcome wind resistance, ground resistance, climbing resistance, etc.
Resistance F W is mainly composed of wheel rolling friction F RO , aerodynamic resistance F L and climbing resistance F st . The equations for calculating various resistances are as follows:
Hydrogen storage
cylinder
Fuel cell
Chemical energy
Hydrogen transportation
system
Motor
Wheel
Electric energy
DC/DC converter, etc.
Mechanical energy
Mechanical transmission
system
Fig. 13.4 Schematic diagram of energy conversion and transfer of hydrogen fuel
336
13 Application of Pneumatic Technology in Fuel Cell Vehicles