Aims and Objectives

Aim

To be able to describe the operation of a vehicles hybrid system

Objectives

To recognize the need for alternative fuels To be able to describe the operation of a hybrid systemTo be able to comment on the use of hybrid systems

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Why do we need alternative fuels?

We need alternative fuels as our supply of fossil fuels (that make petrol and diesel) are becoming less and less.

To make an effort to reduce our carbon footprint.

To reduce the amount of harmful gases produced by vehicles.

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Question

In pairs discuss some other reasons why we might benefit from alternative fuels.

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Alternative Fuels

Ethanol

Reduces the green house gases produced by vehicles, is commonly mixed with petrol to run motor vehicles:-

E10 10% Ethanol 90% Petrol

E85 85% Ethanol 15% Petrol

(no difference in performance to the two)

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Alternative Fuels

Ethanol Plus points

Lower EmissionsMore resistance to engine knockAdded vehicle cost is minimal

Ethanol Negative points

Flex fuel vehicle Lower energy contentLimited Availability

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Alternative Fuels

Bio Diesel

Is made up of crops, or even old restaurant oil

Can be used on its own or blended with petrol

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Alternative Fuels

Bio Diesel Plus points

Can be utilised in most diesel enginesLess air pollutantsBiodegradableNon-toxicSafer to handle

Bio Diesel Negative points

May not be approved by the manufactureLower fuel economy More nitrogen oxideNot suitable in lower temperatureConcerns over engine durability

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Alternative Fuels

Natural Gas

Can be used to fuel the car as a gas or a liquid

Can be utilised within duel fuel vehicles

Stored in high pressure tanks (therefore two fuelling systems are required within the vehicle)

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Alternative Fuels

Natural Gas Plus points

60-90% less smoke producing emissions30-40% less Green House gasses emittedLess expensive

Natural Gas Negative points

Fewer miles per tankLess available Limited to the type of vehicles it is available on

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Alternative Fuels

Propane LPG

Clean burning fossil fuel

Contains fewer toxins

Must have a separate fuelling system for the two fuels (petrol and LPG)

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Alternative Fuels

Propane Plus points

Fewer toxins and smog emitting pollutantsLess expensive

Propane Negative points

Not currently readily available on newer modelsFewer miles available per tank of fuel

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Alternative Fuels

Hydrogen

Hydrogen is been readily looked at as an alternative for petrol/diesel.

Environmentally friendly fuel, however, there are challenges that stop this fuel being currently widely used.

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Alternative Fuels

Hydrogen Plus points

Produced from several sourcesNo air pollutants producedProduces only NOX

Hydrogen Negative points

ExpensiveFuel cells can be expensiveLower energy density then fuel

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Alternative Fuels

Questions

Give two advantages and disadvantages of hydrogen fuel?

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Can be split into two sections:-

Series and Parallel

Series

The vehicles Engine will drive the generator which in turn powers the vehicle.

Parallel

Engine and motor can be used to drive the vehicle, this system employs brake energy regeneration.

This is the most favoured amongst manufactures.

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Question

What are the two sections that hybrid vehicles can be split into?

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The main components include:-

Motor

High Voltage Battery

Power drive Unit

DC converter (direct current)

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Toyota Prius

Uses a Power Split system

the high voltage battery provides power to the motor to drive the wheels

2)Wheels are driven by engine to power splitting device. The generator is driven by planetary gears to provide the motor with electricity to drive the wheels

3)During de-acceleration energy is recovered at the wheels, the energy in converted to mechanical energy to charge the vehicles high voltage battery

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Toyota Prius

Power Splitter

Is a epicycle gear box, that transmits energy in main components.

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Toyota Prius5 Operating Modes

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Question

Name one of the five modes that hybrid vehicles use.

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Toyota Prius

Start up

Under normal conditions the motor will start the engine

Under poor start up conditions the 12v starting system will start the vehicle

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Toyota Prius

Acceleration

DC is converted to AC via the power drive unit

This is used as supply to the motor

It is also used to supplement engine output

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Toyota Prius

Cruise

Engine drives the motor (which acts as a generator)

The output current drives the motor

Converted to 12v DC supplies the vehicles charging system

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Toyota Prius

Deceleration

Motor is driven by the wheels under deceleration conditions, regeneration takes place

Power drive unit converts AC current to DC current to charge the batter module.

Some energy is then used to charge the 12v electrical system.

If ABS senses wheel lock up, a signal is sent to the ECU and re-generation stops to prevent interference.

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Toyota Prius

Idle

The flow of energy is similar to that of cruising

If the charge of the battery is low, the ECU will raise the vehicles idle speed to compensate for this.

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Summary - have we ?

Recognized the need for alternative fuels ?

Can we describe the operation of a hybrid system ?

Are we able to comment on the use of hybrid system ?

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Any Questions ?

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