04-07-2010, 09:33 PM
[attachment=3945]
HYBRID CARS (TOYOTA)
Presented By: RAGHAVENDRA B
1BM03ME069
INTRODUCTION
What is a hybrid vehicle
When a vehicle uses multiple propulsion systems to provide motive power, it is called a hybrid vehicle.
WHAT MAKES IT A HYBRID
A hybrid car is a vehicle that uses a combination of at least two different fuel sources for its propulsion. Although many combinations are possible, generally when people are talking about hybrid cars, they are referring to cars with a combination of
a gasoline internal combustion engine
an electric motor
a battery that powers the electric motor and stores energy for future use.
Hybrid cars may also be called gas-electric hybrids.
Examples of current Toyota hybrid cars include the Toyota Prius, Toyota Camry, Toyota Highlander.
HOW IT WORKS
Hybrid cars work by integrating multiple power sources such as a gas engine, an electric motor and a high-powered battery to make motive power. Generally the battery provides power for the electric motor and is recharged by recapturing energy from gas engine that would normally be lost when decelerating. This recapturing of energy is called regenerative braking. If needed, power from the gas engine can be diverted to recharge the battery as well.
To understand how the gas engine, electric motor and battery work together, it is best to divide hybrids into two categories:
Mild hybrids and
Full hybrids
MILD HYBRIDS
Gas engine provides the main force, and the electric motor provides assist whenever extra power is needed.
The electric motor can not operate independently of the gas engine.
The electric motor can generate electricity for the battery or consume electricity from the battery, but not both at the same time
FULL HYBRIDS
The electric motor can operate on its own in certain conditions.
Under low speed or when lower power needed, only electric motor used to run the car.
When higher power needed, both the gas engine and the electric motor can work together to provide the needed power.
Able to generate and consume electricity at the same time.
Examples of full hybrids are,
Toyota prius and
Toyota Highlander.
There are two types of gasoline-electric hybrid cars. They are,
parallel hybrid and
series hybrid.
Both use gasoline-electric hybrid technology, but in radically different ways.
PARALLEL HYBRID CARS
In a parallel hybrid car, a gasoline engine and an electric motor work together to move the car forward.
SERIES HYBRID CARS
In a series hybrid, the gasoline engine either directly powers an electric motor that powers the vehicle, or charges batteries that will power the motor.
TOYOTA HYBRID CARS
TOYOTA PRIUS TOYOTA CAMRY
TOYOTA HIGHLANDER
TOYOTA HYBRID SYSTEM
The Toyota Hybrid System (THS) / Hybrid Synergy Drive mode of operation with only a single power split device is more generically called Input-Split Hybrid, due to the fact that a fixed amount of torque is transferred via the electrical path from the engine to the wheels.
PRINCIPLE OF TOYOTA HYBRID STYSTEM
This system combines the characteristics of an electric drive and a continuously variable transmission, using electricity and transistors in place of toothed gears.
TOYOTA HYBRID SYSTEM CONTINUED
The differing torque vs. rpm characteristics of the internal combustion and electrical motors operate synergistically.
An internal combustion engine's torque is minimal at lower RPMs, since the engine must be its own air pump.
On the other hand, an electrical motor exhibits maximum torque at stall; therefore this engine is well suited to complement the internal combustion engine's torque deficiency at low RPMs, allowing the use of a much smaller and therefore more fuel efficient engine.
THS IN TOYOTA PRIUS
Addition of a fixed gear second planetary gearset as used in Toyota Highlander Hybrid. This allows for a motor with less torque but higher power (and higher maximum rotary speed), i.e. higher power density.
Addition of a Ravigneux-type planetary gear (planetary gear with 4 shafts instead of 3) and two clutches. By switching the clutches, the gear ratio from MG2 (the "drive" motor) to the wheel shaft is switched, either for higher torque or higher speed (up to 250 km/h / 155 mph) while sustaining better transmission efficiency.
TOYOTA PRIUS
POWER SPLIT DEVICE
The power split devise is the heart of the Toyota Prius. This is a clever gearbox that hooks the gasoline engine, generator and electric motor together. It allows the car to operate like a parallel and series hybrid.
WHAT IS POWER SPLIT DEVICE
The power split device is a planetary gear set. The electric motor is connected to the ring gear of the gear set. It is also directly connected to the differential, which drives the wheels. So, whatever speed the electric motor and ring gear spin at determines the speed of the car.
The generator is connected to the sun gear of the gear set, and the engine is connected to the planet carrier. The seed of the ring gear depends on all three components, so they all have to work together at all times to control the output speed.
The Prius has many innovative features:
Regenerative braking: The motor recovers energy from the brakes when they slow down or stop the vehicle and uses it to recharge the battery.
Lighter, smaller engine: To improve efficiency, the Prius engine is sized to accommodate its average power load, not its peak load. Most gasoline engines are sized for peak power requirements, yet most drivers need peak power only 1% of the time.
Better fuel efficiency: The Prius consumes less fuel than vehicles powered by gasoline alone â€partly because the engine is turned off when itâ„¢s not needed. Conventional gasoline engines run constantly, regardless of power requirements.
Lower emissions: The Prius reduces regulated tailpipe emissions by up to 90% and greenhouse gas emissions by about 50% compared with Tier 2 standards.
ADVANTAGES
The additional boost in power from the electric motor in certain driving conditions also guarantees maximum performance.
Hybrid cars use much less gasoline than standard vehicles, preserving oil reserves for other uses such as heating oil and polymer synthesis.
The current hybrid cars, emit less pollutants than the market average. For example, Honda Insight has 67% less of annual greenhouse gas emission. Furthermore, car manufactures are exploring way to reduce total emission in future hybrid cars.
In a effort to cut off gasoline consumption in car, research is underway to explore for alternative fuels, such as fuel cells and corn-derived fuels.
DISADVANTAGES
Ecological Disadvantages
More car batteries will need to be made, creating a larger problem for disposal of such batteries.
Consumer Disadvantages
The price range for HEVs is $17,400 -> $26,000. The current price range does not target an average household
The manufactures have gone through considerable pains to reduce the weight of the vehicle so that it burns less gasoline while achieving a reasonable acceleration. This has raised questions as to how safe the car is when it is involved in an accident.
HEVs are smaller, less comfortable, and provide much less storage space than an average conventional automobile.
CONCLUSION
Hybrid cars are definitely more environmentally friendly than internal-combustion vehicles. Batteries are being engineered to have a long life. When the hybrid cars become more widespread, battery recycling will become economically possible. Research into other energy sources such as fuel cells and renewable fuels make the future look brighter for hybrid cars.
REFERENCES
hybridcars.com
howstuffworks.com
allabouthybridcars.com
wikipedia.org
greenercars.com
toyota.com
greenhybrid.com
automotivenew-cars/28/hybrid/toyota
THANK YOU
HYBRID CARS (TOYOTA)
Presented By: RAGHAVENDRA B
1BM03ME069
INTRODUCTION
What is a hybrid vehicle
When a vehicle uses multiple propulsion systems to provide motive power, it is called a hybrid vehicle.
WHAT MAKES IT A HYBRID
A hybrid car is a vehicle that uses a combination of at least two different fuel sources for its propulsion. Although many combinations are possible, generally when people are talking about hybrid cars, they are referring to cars with a combination of
a gasoline internal combustion engine
an electric motor
a battery that powers the electric motor and stores energy for future use.
Hybrid cars may also be called gas-electric hybrids.
Examples of current Toyota hybrid cars include the Toyota Prius, Toyota Camry, Toyota Highlander.
HOW IT WORKS
Hybrid cars work by integrating multiple power sources such as a gas engine, an electric motor and a high-powered battery to make motive power. Generally the battery provides power for the electric motor and is recharged by recapturing energy from gas engine that would normally be lost when decelerating. This recapturing of energy is called regenerative braking. If needed, power from the gas engine can be diverted to recharge the battery as well.
To understand how the gas engine, electric motor and battery work together, it is best to divide hybrids into two categories:
Mild hybrids and
Full hybrids
MILD HYBRIDS
Gas engine provides the main force, and the electric motor provides assist whenever extra power is needed.
The electric motor can not operate independently of the gas engine.
The electric motor can generate electricity for the battery or consume electricity from the battery, but not both at the same time
FULL HYBRIDS
The electric motor can operate on its own in certain conditions.
Under low speed or when lower power needed, only electric motor used to run the car.
When higher power needed, both the gas engine and the electric motor can work together to provide the needed power.
Able to generate and consume electricity at the same time.
Examples of full hybrids are,
Toyota prius and
Toyota Highlander.
There are two types of gasoline-electric hybrid cars. They are,
parallel hybrid and
series hybrid.
Both use gasoline-electric hybrid technology, but in radically different ways.
PARALLEL HYBRID CARS
In a parallel hybrid car, a gasoline engine and an electric motor work together to move the car forward.
SERIES HYBRID CARS
In a series hybrid, the gasoline engine either directly powers an electric motor that powers the vehicle, or charges batteries that will power the motor.
TOYOTA HYBRID CARS
TOYOTA PRIUS TOYOTA CAMRY
TOYOTA HIGHLANDER
TOYOTA HYBRID SYSTEM
The Toyota Hybrid System (THS) / Hybrid Synergy Drive mode of operation with only a single power split device is more generically called Input-Split Hybrid, due to the fact that a fixed amount of torque is transferred via the electrical path from the engine to the wheels.
PRINCIPLE OF TOYOTA HYBRID STYSTEM
This system combines the characteristics of an electric drive and a continuously variable transmission, using electricity and transistors in place of toothed gears.
TOYOTA HYBRID SYSTEM CONTINUED
The differing torque vs. rpm characteristics of the internal combustion and electrical motors operate synergistically.
An internal combustion engine's torque is minimal at lower RPMs, since the engine must be its own air pump.
On the other hand, an electrical motor exhibits maximum torque at stall; therefore this engine is well suited to complement the internal combustion engine's torque deficiency at low RPMs, allowing the use of a much smaller and therefore more fuel efficient engine.
THS IN TOYOTA PRIUS
Addition of a fixed gear second planetary gearset as used in Toyota Highlander Hybrid. This allows for a motor with less torque but higher power (and higher maximum rotary speed), i.e. higher power density.
Addition of a Ravigneux-type planetary gear (planetary gear with 4 shafts instead of 3) and two clutches. By switching the clutches, the gear ratio from MG2 (the "drive" motor) to the wheel shaft is switched, either for higher torque or higher speed (up to 250 km/h / 155 mph) while sustaining better transmission efficiency.
TOYOTA PRIUS
POWER SPLIT DEVICE
The power split devise is the heart of the Toyota Prius. This is a clever gearbox that hooks the gasoline engine, generator and electric motor together. It allows the car to operate like a parallel and series hybrid.
WHAT IS POWER SPLIT DEVICE
The power split device is a planetary gear set. The electric motor is connected to the ring gear of the gear set. It is also directly connected to the differential, which drives the wheels. So, whatever speed the electric motor and ring gear spin at determines the speed of the car.
The generator is connected to the sun gear of the gear set, and the engine is connected to the planet carrier. The seed of the ring gear depends on all three components, so they all have to work together at all times to control the output speed.
The Prius has many innovative features:
Regenerative braking: The motor recovers energy from the brakes when they slow down or stop the vehicle and uses it to recharge the battery.
Lighter, smaller engine: To improve efficiency, the Prius engine is sized to accommodate its average power load, not its peak load. Most gasoline engines are sized for peak power requirements, yet most drivers need peak power only 1% of the time.
Better fuel efficiency: The Prius consumes less fuel than vehicles powered by gasoline alone â€partly because the engine is turned off when itâ„¢s not needed. Conventional gasoline engines run constantly, regardless of power requirements.
Lower emissions: The Prius reduces regulated tailpipe emissions by up to 90% and greenhouse gas emissions by about 50% compared with Tier 2 standards.
ADVANTAGES
The additional boost in power from the electric motor in certain driving conditions also guarantees maximum performance.
Hybrid cars use much less gasoline than standard vehicles, preserving oil reserves for other uses such as heating oil and polymer synthesis.
The current hybrid cars, emit less pollutants than the market average. For example, Honda Insight has 67% less of annual greenhouse gas emission. Furthermore, car manufactures are exploring way to reduce total emission in future hybrid cars.
In a effort to cut off gasoline consumption in car, research is underway to explore for alternative fuels, such as fuel cells and corn-derived fuels.
DISADVANTAGES
Ecological Disadvantages
More car batteries will need to be made, creating a larger problem for disposal of such batteries.
Consumer Disadvantages
The price range for HEVs is $17,400 -> $26,000. The current price range does not target an average household
The manufactures have gone through considerable pains to reduce the weight of the vehicle so that it burns less gasoline while achieving a reasonable acceleration. This has raised questions as to how safe the car is when it is involved in an accident.
HEVs are smaller, less comfortable, and provide much less storage space than an average conventional automobile.
CONCLUSION
Hybrid cars are definitely more environmentally friendly than internal-combustion vehicles. Batteries are being engineered to have a long life. When the hybrid cars become more widespread, battery recycling will become economically possible. Research into other energy sources such as fuel cells and renewable fuels make the future look brighter for hybrid cars.
REFERENCES
hybridcars.com
howstuffworks.com
allabouthybridcars.com
wikipedia.org
greenercars.com
toyota.com
greenhybrid.com
automotivenew-cars/28/hybrid/toyota
THANK YOU
