Toyota Hybrid Synergy Drive

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Toyota Hybrid Synergy Drive

• Why I dont have to plug in my car

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Hybrid Components
Internal Combustion Engine
Electric Motor
First we have to get familiar with the hybrid
components.
The Prius is front-wheel drive, so well only
show the front wheels.
There is an internal combustion engine. But
Toyota moved the engine over to make room for the
electric motor.
And theres the battery pack.
But for illustration purposes, well keep it near
the other components.
Its really in the back.
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Standing Still
Whats Happening Under the Hood

• Nothing

Well start with Standing Still. For example,
sitting at a stop sign.
Whats happening under the hood?
Absolutely nothing.
The internal combustion engine is shut off and
the car is silent.
Because of this, there is no wasted gasoline and
no emissions.
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Light Acceleration
Whats Happening Under the Hood

• ICE off
• Battery turns electric motor
• Electric motor turns wheels

The Internal Combustion Engine is still not
running.
The battery is supplying enough power to move the
car.
This consumes energy from the battery.
When taking off from a stop, there is light
acceleration.
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Increased Load
Whats Happening Under the Hood

• ICE engages
• Some power diverted to the electric motor
• Battery not being used

When accelerating more or going up a hill, the
battery is no longer solelycapable of sustaining
the increased load.
The engine engages to power the wheels.
To help the engine, some of its power is diverted
to the electric motor. As a result, the
electric motor assists in turning the wheels.
The battery is not being used at this time.
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Heavy Load
Whats Happening Under the Hood

• ICE engages
• Extra effort used to turn electric motor
• Battery turns electric motor to assist

Heavy load conditions include heavy acceleration
or going up steep hills.
The engine turns the wheels and diverts some
energy to the electric motor.
For extra effort, the battery also supplies power
to the electric motor.
Together, the engine, battery, and motor provide
maximum power.
However, this consumes both gasoline and battery.
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Maintaining Speed 42 mph
Whats Happening Under the Hood

• ICE powers wheels
• Any extra effort turns motor, generates
  electricity, and charges battery

42 mph
Above 42 miles per hour, the electric motor alone
can not propel the car.
The engine will power the wheels.
Since the engines full power isnt needed, left
over energy turns the electric motor to
generate electricity. This will recharge the
battery.
Once the hill is crested, its time to cruise.
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Maintaining Speed Whats Happening Under the Hood

• ICE off
• Battery turns electric motor
• Electric motor turns wheels

Below 42 miles per hour, the Prius can operate on
pure battery power.
The engine completely shuts off. In this mode,
no gasoline is consumed.
The only limit is the charge level of the battery.
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Regenerative Coasting
Whats Happening Under the Hood

• Wheels turn electric motor generating electricity
• Electric motor regenerates battery

When coasting, the wheels turn the electric motor.
This generates electricity which recharges the
battery.
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Regenerative Braking
Whats Happening Under the Hood

• Wheels turn electric motor generating electricity
• Electric motor regenerates battery

Braking works just like coasting.
Anytime the wheels are moving and the car is not
accelerating, energy is being stored as battery
charge.
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Exceptions

• Cold Engine
• ICE will operate to warm up
• Turns electric motor and recharges battery
• Self-Preservation
• When battery is low, ICE will operate to recharge
• Wet Road and Low Tire Pressure
• Increased friction and surface area reduces
  overall coasting ability
• More effort required to maintain speed
• Effects all cars

All cars in this situation must work harder to
maintain cruising speed.
When driving on wet roads, rolling resistance of
the tires is increased.This is also a problem if
your tires are under-inflated
When the engine is cold, it will run to warm
itself and the catalytic converter.
While it is running, it will turn the electric
motor to recharge the battery.
If the battery ever gets too low, the engine will
run to recharge it.
Even if the car is standing still.
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Toyota Hybrid Synergy Drive

• Why I dont have to plug in my car