2022 TOYOTA MIRAI Owners Manual

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Owners Manual_USA_M62084_en
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2
Fuel cell system
Fuel cell system
2-1. Fuel cell vehicleFuel cell vehicle characteris-tics ................................ 74
Fuel cell vehicle precautions ..................................... 79
Fuel cell vehicle driving tips ..................................... 89

742-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
2-1.Fuel cell vehicle
The illustration is an example for explanation and may differ from the actual
item.
Fuel cell stack
Fuel cell converter and auxiliary inverter
Hydrogen tanks
Traction battery
Electric motor (traction motor)
Fuel cell vehicle characteristics
Fuel cell vehicles efficiently use electricity, which is gener-
ated by a chemical reaction between hydrogen and oxygen in
a fuel cell stack, and electricity charged in a traction batter y
to drive the electric motor (traction motor).
The fuel is H2 (compressed hydrogen gas), so the exhaust is
only water and water vapor. As they do not release emissions
such as CO
2 (Carbon Dioxide) and NOx (Nitrogen Oxides),
fuel cell vehicles are environmentally friendly vehicles.
Fuel cell vehicle components

752-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
2
Fuel cell system
Tailpipe
*: If equipped
■Sounds unique to the fuel cell vehicle
Due to the design of y our fuel cell vehicle, there are various relays, valves
and pumps which under normal driving conditions will produce so unds. This
is a normal characteristic of th e vehicle and does not indicate a malfunction.
Furthermore, these sounds may differ based on usage environment or con-
dition.
■Maintenance, repair, recycling,
and disposal
Contact your Toyota dealer regard- ing maintenance, repair, recycling,
and disposal. Do n
ot dispose of the
vehicle or any of its components
Noticeable soundsSource of the sounds
Clunking, clicking and
clackingOperation of relays and hydrogen tank valves
(Sounds may be heard wh en starting or stop-
ping the fuel cell system.)
Knocking
The parking lock is engaged
(Sounds may be heard when pressing the P
position switch or stopp ing the fuel cell sys-
tem.)
Whooshing, squealingGas is flowing through the nozzle and valves
(Sounds may be heard when filling the fuel.)
High pitch sound
 Pulsing sound
 Whooshing sound
Operation of the pumps
(In particular, sounds may be heard when
starting the fuel cell s ystem, accelerating from
a stop, or pressing the H
2O switch. The sound
may be louder when in Br mode or when the
vehicle decelerates during dynamic radar
cruise control.)
 Humming sound
 High pitch soundOperation of the motor
(In particular, sounds may be heard when
accelerating or decelerating.)
Blowing and draining
sound
Exhaust water or air is being purged
May also occur periodically while parked when
it is cold to p revent freezing.
(Sounds may be hear d when vehicle is
stopped, fuel cell system is stopped or while
parked)

762-1. Fuel cell vehicle
Owners Manual_USA_M62084_enyourself.
The electric motor (traction
motor) allows smooth, powerful
takeoff and acceleration. This
vehicle drives similarly to a gas-
oline vehicle without any special
actions by the driver. (
P.161)
As there are no engine sounds
and the vehicle is quiet, opera-
tion noises unique to fuel cell
vehicle components may be
heard. ( P. 7 5 )
■Regenerative braking
In the following si tuations, the vehi-
cle generates electricity from the
deceleration of the vehicle while
driving.
●The accelerator pedal is released
while driving with the shift position
in D.
●The brake pedal is depressed
while driving with the shift position
in D.
■Charging the traction battery
Because electricity generated by the
fuel cell stack and regenerative
braking charges the traction battery,
the battery does not need to be
charged from an outside source.
However, if the vehicle is left parked
for a long time, the traction battery
will slowly discharge. For this rea-
son, be sure to drive the vehicle at
least once every few months for at
least 30 minutes or 10 miles (16
km).
If the traction battery becomes fully
discharged and you are unable to
start the fuel cell system, contact
your Toyota dealer.
■Charging the 12-volt battery
 P.473
■Parking
Because there is no engine sound
or vibration, it is easy to mistake the
fuel cell vehicle for being off when it
is actually still running (“READY”
indicator is illumina ted). For safety,
make sure to always shift the shift
position to P and apply the parking
brake when parked.
The system may behave differ-
ently on cold days as it may be
performing a special cold-start
process to improve the start up
performance. ( P.172)
Operation noises ( P.75),
purge process ( P.175), etc.,
may differ from usual. However,
this is not a malfunction.
Compressed hydrogen gas fuel
can be filled at hydrogen sta-
tions.
More information about hydrogen
fuel and fueling can be found in the
“Opening the fuel door” section of
this manual. ( P.203)
Fuel cell vehicles do not have
engine sounds like gasoline
vehicles. Therefore, a sound
that changes in accordance with
the driving speed, will be played
Driving the vehicle
Fuel cell system
Fuel filling
Acoustic vehicle alerting
system

772-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
2
Fuel cell system
in order to warn people nearby
of the vehicle’s approach. The
sound will stop when the vehicle
speed exceeds approximately
23 mph (37 km/h).
■How to hear the warning
In the following ca ses, the acoustic
vehicle alerting system may be diffi-
cult for surrounding people to hear.
●In very noisy areas
●In the wind or the rain
Also, as the acoustic vehicle alerting
system is installed on the front of the
vehicle, it may be m ore difficult to
hear from the rear of the vehicle
compared to the front.
*: This function can only be used in
the mainland U.S.A. It cannot be
used in other states and territo-
ries, including Alaska and Hawaii.
This system operates based on
the driving situation to enhance
fuel economy. For details about
Predictive efficient drive, refer to
“NAVIGATION AND MULTIME-
DIA SYSTEM OWNER’S MAN-
UAL”.
■Predictive deceleration sup-
port
 When the vehicle approaches
to predictive deceleration sup-
port points registered in the
navigation system, the refer-
ence operation range of the ECO Accelerator Guid-
ance (
P.102) on the multi-
information display will be
turned off to encourage the
driver to reduce excessive
acceleration.
 The regenerative braking
force will be increased
according to the driving condi-
tions to more efficiently
charge the traction battery
after the accelerator pedal is
released.
■Predictive SOC* control
The following types of controls
are performed based on data
such as road information during
route guidance by the naviga-
tion system to help ensure that
the vehicle effici ently uses elec-
tricity.
 When there is a long downhill
slope along the route, the sys-
tem reduces the traction bat-
tery level before reaching the
slope to help ensure charging
capacity for regenerative
braking while traveling down-
hill.
Predictive efficient drive
(vehicles with navigation
system)
*

782-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
*: SOC means state of charge

792-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
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Fuel cell system
■Hydrogen-related components
The fuel cell vehicle has hydrogen tanks (10150 psi [70 MPa, 71 4
kgf/cm
2, 700 bar]), fuel cell stack, and hydrogen pipelines as hydro-
gen-related components. Pay attention to all warning labels att ached
to the vehicle.
The illustration is an example fo r explanation and may differ from the actual
item.
Warning label
Fuel cell stack (fuel cell and hydrogen pump)
Hydrogen detectors
Hydrogen tanks
Hydrogen tank valves
Hydrogen pipelines
Hydrogen supply unit
*: If equipped
Fuel cell vehicle precautions
System components

802-1. Fuel cell vehicle
Owners Manual_USA_M62084_en
■High-voltage and high-temperature components
The fuel cell vehicle has high-voltage components (about 650 V
maximum) such as a fuel cell stack, traction battery, power con trol
unit, fuel cell converter, high-voltage cables (which are distinguished
from low-voltage cables by their orange covers), electric motor (trac-
tion motor), etc., and high-temperature parts such as the radiator for
cooling. Pay attention to all w arning labels attached to the vehicle.
This diagram is for illustrative purposes only and may differ f rom the actual
vehicle.
Warning label
Radiator for inverter cooling
Radiator for fuel cell stack cooling
Fuel cell water pump
Fuel cell converter and auxiliary inverter
Power control unit
Cabin coolant heater
Traction battery
Service plug
Electric motor (traction motor)