HYBRID VEHICLES

What are Hybrid Vehicles ?

A hybrid vehicle is a vehicle that uses two or more distinct power sources to move the vehicle.

Power Source

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Power Source

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Hybrid Vehicle

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The term most commonly refers to hybrid electric vehicles (HEVs), which combine an internal combustion engine and one or more electric motors.

Power Sources for Hybrid Vehicles :

• Coal, wood or other solid combustibles• Compressed or liquefied natural gas• Electricity• Electric vehicle battery• On-board or out-board rechargeable energy storage system (RESS)• Petrol or Diesel fuel• Solar• Wind

Need of Hybrid Vehicles :

• Declining fuel reserves • Increasing Demand • Environmental Degradation

An electric-powered car cannot go more than 100 miles (161 km) between recharging, is difficult to re-charge and doesn't drive beyond 60 mpg, although it emits little pollution Hence, Hybrid Vehicles.

Components of Hybrid Vehicles :

• Conventional Car Engine • Fuel Tank • Electric Motor • Generator• Batteries • Transmission System

Conventional Car Engine :

• Gasoline Engine ( also Petrol or Diesel respectively )• Smaller in size• Greater Efficiency and Lesser Emission

Fuel Tank :

• Stores the fuel needed to run the car engine

Electric Motor and Generator :

• A motor will be needed to take energy from the batteries and accelerate the car. • Generators are needed to produce the electrical power.

Batteries :• Stores and releases energy as required by the car • Energy from the battery is taken by the motor• Wide acceptance as a recyclable battery from the environmental standpoint• Examples : Pb-acid, NiMH, and Lithium (Li)-ion batteries• Long cycle life with maintenance free and high safety mechanisms built into the battery

Nickel Metal Hydride Battery Advantages :

• Energy Density of 30-80Wh/kg • Can have exceptionally long lives if used properly • Faster charging

Disadvantages :

• Poor efficiency • High self-discharge• Poor performance in cold weather

Lithium Ion Battery Advantages :

• High energy density• Solid electrolyte • Typically 40% smaller and weigh half than NiMH • Open circuit voltage (OCV) of approximately 3- 4V at full charge• Lesser charge discharge time• More environment friendly

Disadvantages :

• Overcharging may cause damage to electrodes • Dangerous if not handled carefully • Safety features required for both cell and battery pack

Classification of Hybrid Vehicles :

Drive Train Structure

Series Hybrid

Parallel Hybrid

Power Split or Series-Parallel Hybrid

Degree of Hybridisation

Mild Hybrid

Full Hybrid

Plug-In Hybrid

Series Hybrid :

Series Hybrid :Advantages :

• ICE running mostly at optimal speed and torque • ICE can be turned off in zero emission zone • Low floor possible • Low fuel consumption • High fuel efficiency

Disadvantages :

• Many energy conversions owing to loss of energy• More suitable for city driving

Chevrolet Volt

Parallel Hybrid :

Parallel Hybrid :Advantages :

• ICE directly connected to wheels -> fewer power conversions• Electric machine and gearboxes present -> ICE working pt. can be chosen freely

Disadvantages :

• ICE & electrical machines must be mounted together -> no low floor

Honda Civic Hybrid

Series-Parallel Hybrid :

Series-Parallel Hybrid :Advantages

• ICE can be turned off • ICE speed can be chosen by adjusting generator speed

Disadvantages• Power vicious cycle may occur leading to low efficiency • Relatively complex • Expensive

Toyota Prius

Degree of Hybridisation : Mild Hybrid• IC Engines equipped with an electric machine allowing the engine to be turned off whenever the car is coasting, braking, or stopped, yet restart quickly.

• May employ regenerative brake and some level of power assist to the IC Engines

Degree of Hybridisation : Mild HybridAdvantages :

• More fuel efficient (10-15%) compared to conventional gas powered car• Less expensive than fully hybrid

Disadvantages :

• Less fuel efficient than fully hybrid

Example :

• Chevrolet Silverado• Honda Civic

Degree of Hybridization : Plug-In Hybrid Key Features: • Rechargeable batteries • Electric motor -> primary power source, gasoline engine -> supplemental motivation • Require deeper battery charging and discharging cycles than conventional hybrids• Charging topologies ―On-board chargers ―Off-board chargers ―Using electric motor's inverter and inductance • Modes of Operation ― Charge-depleting mode ― Charge-sustaining mode ― Mixed mode

Available Hybrid Cars Models :

Indian Hybrid Car Model :

• Speed : 104 km/h • Distance : 160 km • Weight(empty) : 700 kg • E - motor : 13 kW ( max.) • Battery : 72 V ( 14 kWh) Li-ion • Energy Recuperation

Mahindra Reva NXR

Features and Working of Hybrid Vehicles :

Advanced Technology :Hybrid-electric vehicles (HEVs) combine the benefits of gasoline engines and electric motors and can be configured to obtain different objectives, such as improved fuel economy, increased power, or additional auxiliary power for electronic devices and power tools.Some of the advanced technologies typically used by hybrids includes :

Regenerative Braking. The electric motor applies resistance to the drivetrain causing the wheels to slow down. In return, the energy from the wheels turns the motor, which functions as a generator, converting energy normally wasted during coasting and braking into electricity, which is stored in a battery until needed by the electric motor.

Electric Motor Drive/Assist. The electric motor provides additional power to assist the engine in accelerating, passing, or hill climbing. This allows a smaller, more efficient engine to be used. In some vehicles, the motor alone provides power for low-speed driving conditions where internal combustion engines are least efficient.

Automatic Start/Shutoff. Automatically shuts off the engine when the vehicle comes to a stop and restarts it when the accelerator is pressed. This prevents wasted energy from idling.

Regenerative Braking :

Limitations :

•The regenerative braking effect drops off at lower speeds •Friction Brake required as backup • Friction based braking required in cases of adverse conditions in two-wheel drive vehicles • It is normal to also incorporate dynamic braking to absorb the excess energy • Friction braking is required to absorb the surplus energy in order to allow an acceptable emergency braking performance

Selecting a Hybrid Car :Certain Basic Parameters to look out for while buying a Hybrid car :

Price :

As told earlier hybrid cars have a much more initial expense than the ordinary ones. Hybrid cars range in prices from $20,000 to $50,000. The price varies according to the size of the car and also the style. So, decide wisely as this is a lot of money.

Mileage :

Clearly, hybrids have a lot more mileage than the conventional cars. But still try to buy cars that have better mileage among the category. There are cars with mileages varying from 65mpg to 28 mpg.

Travel comfort :

For long distance traveling, travel comfort plays a very important role. There are cars with comfortable hatchback and others with leg room, boot capacity and overall space.

Advantages of Hybrid Vehicles :• Very less pollution.• Better mileage.• More reliable and comfortable.• Very clean cars due to less emissions.• Batteries need not be charged by an external source.• Warranties available for batteries as well as motors.• Less dependence on fuels.

Disadvantages of Hybrid Vehicles :• The initial cost will be very high – higher than other cars.• Since a lot of batteries will be needed, the car will be very heavy.• As there are electrical components, there is risk of shock during an accident.• The vehicle can be repaired only by professionals.• Spare parts will be very costly and rare.

Future of Hybrid Vehicles :• Toyota continues to build momentum as a leader of the hybrid industry.

• Next generation of hybrids will feature improved batteries with higher density.

•The next-generation Prius, specifically, will combine our advance battery technologies with new electric motors that are smaller in size, and feature improved power density

• While the adoption rate for hybrids in the US is small today (2.2% of new car sales in 2011),] this compares with a 17.1% share of new car sales in Japan in 2011, and it has to potential to be very large over time as more models are offered and incremental costs decline due to learning and scale benefits

• These analogs collectively suggest it would take at least 30 years for hybrid and electric vehicles to capture 80% of the US passenger vehicle stock.

• Don't get us wrong, save the trees and the environment, but we still prefer our burners any day of the week.

Thank You

Presented By :

Chanchal Krishna2k12/AE/26

DTU