system TOYOTA PRIUS PRIME 2021 (in English) Repair Manual

86
PRIUS PRIME_OM_OM47D71U_(U)
2-1. Plug-in hybrid system
Plug-in hybrid system features
The illustration is an example for explanation and may differ from the
actual item.
Gasoline engine
Electric motor (traction motor)
The plug-in hybrid system is a system excellent in both econom-
ical efficiency of electric vehicles and practicality of hybrid vehi-
cles.
●EV driving can be performed using electricity charged from an
external power source.
*
●If the amount of electricity remaining in the hybrid battery (traction
battery) becomes low, the vehicle is automatically controlled in
such a way that it can be driven as a hybrid vehicle through the
joint use of the gasoline engine.
*: The EV driving range will vary in accordance with conditions such as
vehicle speed, the amount of charge remaining in the hybrid battery
(traction battery) and the usage of the air conditioning system. The gaso-
line engine may also be used simultaneously in accordance with driving
conditions.
1
2

PRIUS PRIME_OM_OM47D71U_(U)
872-1. Plug-in hybrid system
2
Plug-in hybrid system
The plug-in hybrid system operates in the following modes.
The multi-information display can be used to check which mode the plug-in
hybrid system is currently being driven in. (P. 220)
EV mode
When a sufficient amount of electricity is remaining after
charging
*1, EV driving is performed using electricity stored in the
hybrid battery (traction battery).
*2
When in EV mode, the EV drive mode indicator illuminates.
*1: The amount of remaining charge can be checked on the multi-informa-
tion display etc. (P. 231)
*2: Depending on the situation, EV driving may be canceled and both gaso-
line engine and electric motor are used. (P. 95)
Plug-in hybrid system operation mode
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PRIUS PRIME_OM_OM47D71U_(U)
2-1. Plug-in hybrid system
EV auto mode (P. 9 0 )
When a sufficient amount of electricity for EV driving is remaining in
the hybrid battery (traction battery) after charging
*, the operation
mode can be switched to EV auto mode.
Switching to EV auto mode make powerful driving possible by using
both the gasoline engine and electric motor in a driving condition
that requires large driving force, such as when passing a vehicle on
a highway or driving on a steep slope.
When in EV auto mode, the EV auto mode indicator illuminates.
*: The amount of remaining charge can be checked on the multi-informa-
tion display etc. (P. 231)
HV mode
When in HV mode, the vehicle is driven using both the gasoline
engine and electric motor (traction motor). (P. 9 2 )
●If electricity needed for EV driving in EV mode or EV auto mode
is not remaining, the operation mode will be automatically
switched to HV mode.
●The operation mode can be switched to HV mode at any timing
by operating the switch to keep electricity for EV driving etc.
*
(P. 90). Switching to HV mode when driving on a highway or
when driving uphill is recommended in order to conserve battery
power.
When in HV mode, the EV drive mode indicator and EV auto mode indi-
cator turn off.
*: The EV driving range may reduce even after switching to HV mode.
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3

PRIUS PRIME_OM_OM47D71U_(U)
892-1. Plug-in hybrid system
2
Plug-in hybrid system
Hybrid battery (traction battery) charge mode (P. 91)
Electricity generated in the gasoline engine can be charged in the
hybrid battery (traction battery) by switching to the hybrid battery
(traction battery) charge mode when electricity needed for EV driv-
ing is not remaining.
*
●The system may not be able to switch to the hybrid battery (trac-
tion battery) charge mode due to the state of the plug-in hybrid
system. (P. 9 1 )
●Charging time differs depending on the driving state of the vehi-
cle when driving in hybrid battery (traction battery) charge mode.
When in the hybrid battery (traction battery) charge mode, the hybrid
battery charge mode indicator illuminates.
*: When in the hybrid battery (traction battery) charge mode, the hybrid
battery can be charged while driving. However, the gasoline engine runs
to charge the battery and fuel consumption becomes higher compared
with driving in HV mode.
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PRIUS PRIME_OM_OM47D71U_(U)
2-1. Plug-in hybrid system
The plug-in hybrid system operation modes can be switched using the
switches.
If there is not enough charge remaining in the hybrid battery (traction bat-
tery) to allow EV driving, EV/EV auto mode will not be selectable.
The hybrid battery (traction battery) charge mode cannot be selected if the
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■
Switching the plug-in hybrid system operation modes
Press the EV/HV mode selection switch or EV auto mode switch to
change modes as the following table shows.
When in EV mode, the EV drive mode indicator illuminates.
When in EV auto mode, the EV auto mode indicator illuminates.
When in HV mode, the EV drive mode indicator and EV auto mode indi-
cator turn off.
*: If there is not enough charge remaining in the hybrid battery (traction bat-
tery) to allow EV driving, EV/EV auto mode will not be selectable.
Plug-in hybrid system operation mode selection switches
EV/HV mode selection switchEV auto mode switch
Current mode
Switch operated
EV modeHV modeEV auto mode
EV auto modeHV modeEV mode
HV modeEV mode*EV auto mode*

PRIUS PRIME_OM_OM47D71U_(U)
912-1. Plug-in hybrid system
2
Plug-in hybrid system
■Switching to the hybrid battery (traction battery) charge mode
Press and hold the switch.
Take your hand off the switch
once the hybrid battery charge
mode indicator starts to blink.
The hybrid battery charge mode
indicator illuminates when the
switch to hybrid battery (traction
battery) charge mode is com-
plete.
When the hybrid battery (traction battery) is fully charged
*, the hybrid
battery (traction battery) charge mode is automatically canceled and the
operation mode will be switched to HV mode.
The hybrid battery (traction battery) charge mode will be canceled by
pressing EV/HV mode selection switch or EV auto mode switch.
*: The maximum charge amount in the hybrid battery (traction battery)
charge mode is approximately 80% of the fully charged capacity for the
charging from an external power source.
■If the plug-in hybrid system operation mode cannot be changed
In the following situations, the plug-in hybrid system operation mode cannot
be changed even if the EV/HV mode selection switch or EV auto mode switch
is pressed. (In this case, the warning message is displayed on the multi-infor-
mation display when the switch is pressed.)
●When electricity needed for EV driving is not remaining (when in EV/EV
auto mode)
●When the traction battery is almost completely charged (hybrid battery [trac-
tion battery] charge mode)
■When switching from EV mode to another mode using the switch
When the power switch is turned off, operation mode switching is canceled
and the system returns to EV mode the next time the vehicle is started.
■Hybrid battery (traction battery) charge mode
●The following may occur to protect the system, etc.
• Cannot switch to hybrid battery (traction battery) charge mode or cannot
cancel it
• Gasoline engine does not start or stops even after switching to hybrid bat-
tery (traction battery) charge mode
●If a load to the system is large, such as when the power consumption of the
air conditioning system is large or when the temperature of the engine cool-
ant is high, it may take longer time than usual to charge using the hybrid bat-
tery (traction battery) charge mode, or charging to the hybrid battery
(traction battery) may not be performed.

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PRIUS PRIME_OM_OM47D71U_(U)
2-1. Plug-in hybrid system
■When in EV/EV auto mode
In EV/EV auto mode, EV driving (driving using only the electric
motor)
* is possible. However, depending on the situation, EV driv-
ing may be canceled and both gasoline engine and electric motor
are used (P. 95). Also, if a little electricity is remaining in the
hybrid battery (traction battery), HV mode is automatically selected.
To drive in EV/EV auto mode long, observe the followings.
●Avoid sudden acceleration and sudden deceleration, and be sure
to drive smoothly.
If you repeatedly accelerate, the hybrid battery (traction battery)
charge will deplete quickly. Also, EV driving may be canceled by
rapid acceleration or vehicle speed.
●Restrain your speed as much as possible. The distance that can
be driven in EV/EV auto mode will reduce considerably at high
speeds.
*: The EV driving range can be checked using the multi-information dis-
play etc. (P. 214, 230, 237, 254)
■
When in HV mode
The vehicle can be used in the same way as a standard hybrid
vehicle.
In HV mode, controls are primarily carried out as follows in accor-
dance with the driving conditions.
●The gasoline engine stops
* when the vehicle is stopped.
●During start off, the electric motor (traction motor) drives the vehi-
cle.
●During normal driving, the gasoline engine and electric motor
(traction motor) are controlled effectively, and the vehicle is
driven with optimum fuel efficiency. Also, when necessary, the
electric motor (traction motor) operates as an electrical generator
to charge the hybrid battery (traction battery).
●When the accelerator pedal is depressed heavily, drive force
from both the gasoline engine and the electric motor (traction
motor) is used to accelerate.
*: When the hybrid battery (traction battery) requires charging or the
engine is warming up, etc., the gasoline engine will not automatically
stop. (P. 95)
Control when driving in each mode

PRIUS PRIME_OM_OM47D71U_(U)
932-1. Plug-in hybrid system
2
Plug-in hybrid system
■When braking (regenerative braking)
The electric motor (traction motor) charges the hybrid battery (trac-
tion battery).
The EV driving range can be extended by actively using this regen-
erative braking to store electricity in the hybrid battery (traction bat-
tery).
Moreover, as fuel consumption is also reduced when in HV mode,
the regenerative braking system can be used effectively.
In order to make EV/EV auto
mode available, charge the hybrid
battery (traction battery) from an
external power source before
using the vehicle.
Even if charging the hybrid battery
(traction battery) has not been
completed, the vehicle can be
driven. However, if there is not
enough charge remaining, it is pos-
sible that the vehicle cannot be
driven in EV/EV auto mode or the
EV driving range will become
shorter.
When driving with the gasoline engine stopped, a sound, which
changes in accordance with the driving speed, will be played in order
to warn people nearby of the vehicle’s approach. The sound will stop
when the vehicle speed exceeds approximately 22 mph (35 km/h).
Charging (P. 1 1 0 )
Vehicle proximity notification system

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PRIUS PRIME_OM_OM47D71U_(U)
2-1. Plug-in hybrid system
■Regenerative braking
In the following situations, kinetic energy is converted to electric energy and
deceleration force can be obtained in conjunction with the recharging of the
hybrid battery (traction battery).
●The accelerator pedal is released while driving with the shift position in D or
B.
●The brake pedal is depressed while driving with the shift position in D or B.
■EV driving range
●The EV driving range is displayed on the multi-information display etc.
(P. 214, 230, 237, 254)
●The EV driving range changes in accordance with the charge status of the
hybrid battery (traction battery), the speed of the vehicle, etc.
●Even if there is enough charge remaining in the hybrid battery (traction bat-
tery), EV driving may be canceled and both gasoline engine and electric
motor are used depending on the situation. (P. 95)
■After EV mode has switched to HV mode due to low hybrid battery (trac-
tion battery) charge
If the hybrid battery (traction battery) is regenerated by driving continuously
down a long slope, the EV driving range etc. will be displayed on the multi-
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If EV mode is not switched to even though EV driving range is being dis-
played, EV mode can be switched to by pressing the EV/HV mode selection
switch.
■Refilling fuel
Plug-in hybrid vehicles can be driven using electricity charged from an exter-
nal power source. However, as the gasoline engine is used depending on the
situation even if in EV mode, and the gasoline engine is provided on board as
a power source for driving in HV mode, it is needed to refueling the vehicle.
Check the fuel amount and refill immediately when the fuel level becomes
low. (P. 371)

PRIUS PRIME_OM_OM47D71U_(U)
952-1. Plug-in hybrid system
2
Plug-in hybrid system
■Gasoline engine operation in EV/EV auto mode
Even if there is a sufficient amount of electricity remaining in the hybrid bat-
tery (traction battery) and EV driving range (P. 214, 230, 237, 254) is being
displayed on the multi-information display etc., EV driving (driving using only
the electric motor) may be canceled and both gasoline engine and electric
motor are used depending on the situation (EV driving will be returned to
automatically after EV driving becomes possible again).
EV driving may be canceled automatically in the following circumstances:
●When vehicle speed is more than approximately 84 mph (135 km/h).
●When power is needed temporarily, for example when the accelerator pedal
is depressed firmly or when accelerating suddenly.
*
●When the temperature of the hybrid system is high.
The vehicle has been left in the sun, driven on a hill, driven at high speeds,
etc.
●When the temperature of the hybrid system is low.
●When the heater is switched on when the outside temperature is below
about 14°F (-10°C).
●When the windshield defogger switch is pressed. (P. 515, 527)
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The gasoline engine may also operate in circumstances other than those
listed above, depending on conditions.
*: When traveling in the EV auto mode only
■Conditions in which the gasoline engine may not stop
The gasoline engine starts and stops automatically. However, it may not stop
automatically in the following conditions
*:
●During gasoline engine warm-up
●During hybrid battery (traction battery) charging
●When the temperature of the hybrid battery (traction battery) is high or low
●When the windshield defogger switch is pressed. (P. 515, 527)
*: Depending on the circumstances, the gasoline engine may also not stop
automatically in situations other than those above.