Toyota Prius Press Kit

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TOYOTA PRIUS PRESS KIT
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1. TOYOTA HYBRID SYSTEM AN AUSTRALIAN FIRST

Toyota is to showcase the world's first volume production hybrid-powered car in Australia.

It uses half the petrol of an equivalent conventional car and emits only half the carbon dioxide on a typical city drive cycle.

Emissions of carbon monoxide, NOx and hydrocarbons are one tenth of the legislated maximum permissable levels.

The Toyota Prius (Latin for forerunner) is powered by an electric motor, power for which is supplied by a 288 volt battery pack and a fuel efficient twin cam multi-valve petrol motor.

The Prius achieves new standards in package efficiency. It has Corolla sized exterior dimensions and a 1992 Camry-sized interior.

The Prius is already on sale in Japan and it is committed for sale in the USA and Europe in 2000.

Toyota has brought seven production models of Prius to Australia for evaluation.

One will go on permanent display in Sydney's Powerhouse Museum.

The others will be used around the country in demonstrations to opinion leaders and fleet and private motor vehicle users.

Toyota has taken a position of world leadership in green-car manufacture, driven by its global president Hiroshi (Harry) Okuda.

The company's Vision 2005 program calls for an aggressive approach to resolving environmental issues.

The production Hybrid System is part of a stepped program which could lead to the introduction of a fuel cell electric vehicle.

Toyota's Hybrid System was first shown at the Tokyo Motor Show late last year, to coincide with the Kyoto Greenhouse Summit.

Prius, the first and so far only vehicle to incorporate the system, went on sale in Japan just one month later.

More than eight thousand Prius have been delivered and production has doubled at the Takaoka plant to two thousand a month.

Toyota announced last month it aims to sell 20,000 Prius in the North American and European markets in 2000.

Toyota is planning to use the next two years to develop a THS (Toyota Hybrid System) vehicle optimised to the conditions of both markets.

Future direction for THS in Australia will depend on the success of the upcoming evaluation.

THS offers a currently unique opportunity to trial viable alternative energy technology both in a technical sense and from a marketing viewpoint, Toyota Australia's senior executive vice president John Conomos said.

On the surface THS can make a substantial contribution to the future of automotive direction in this country.

It can provide a benchmark for local development.

And it can be an important tool in educating consumers - both private and fleet - to the benefits of alternative energy use.

The enormity of the latter task in an entrenched market should not be underestimated.

Mr Conomos said introduction of new technology in viable quantities would require commitment from the car industry and from government.

There is a need to create a new environment in which technology such as THS can be made available and be accepted by the market place, he said.

Ecological and economical rationale must co-exist if take-up of environmentally friendly automotive technology is to succeed.

Buyers may well be influenced by the pure motive of buying green cars but it is unlikely they will be prepared to accept a large economic penalty for doing so.

They will need to be encouraged, both by car makers providing direct benefits such as better fuel economy and by governments offering incentives to move from traditional solutions.

2. TOYOTA HYBRID SYSTEM DOUBLES FUEL ECONOMY

The Toyota Hybrid System, already on sale in Japan in the Prius, can halve greenhouse gas emissions and double fuel economy compared with a conventional vehicle.

Volume-selling Prius has achieved 3.57 litre/100km (79mpg) fuel economy in the Japanese 10-15 test mode.

This is twice the economy of a comparable-sized conventional efficient four cylinder passenger car with automatic transmission.

The doubling of fuel economy means a halving of carbon dioxide emissions.

In addition, the THS reduces emissions of gross pollutants carbon monoxide, hydrocarbons and oxides of nitrogen.

Prius' emissions are around one tenth of the level permitted under the current Australian Design Rule ADR 37/01 for passenger cars.

Toyota Prius achieves these improvements, while offering space for five adults, passive safety to world's best standards and smooth acceleration and response.

Energy-saving features include a state-of-the-art petrol engine which shuts down when not required and regenerative braking.

Hybrid Systems:

Hybrid systems are automotive power plants which use both petrol engines and electric motors for motive power.

Conventionally, there are two kinds of hybrid systems:
i) series hybrids, which use a petrol engine to generate electricity for the electric motor (and sometimes batteries) to propel the vehicle
ii) parallel hybrids, which use both petrol engines and electric motors for motive power, and switch back and forth between them as the situation demands.
The Toyota Hybrid System:
The Toyota Hybrid System combines the best aspects of both series and parallel hybrids, for greater efficiency.

In addition, Toyota has reduced the size and weight of all the components - engine, motor and battery.

The THS divides the engine's power along two paths, one to the generator to produce electricity and the other through a mechanical gear system to drive the front wheels.

Controlling this power split is one of the secrets to THS efficiency.

The primary power source is a specially developed 1.5 litre twin cam multi-valve Atkinson cycle engine, with a high expansion ratio cycle for maximum extraction of combustion gas expansion energy and low pumping and friction losses.

The engine achieves its best fuel consumption per unit of output when operating in the high-torque ranges.

Therefore, depending on conditions, the system controls the division of power between engine and electric motor so the engine always operates in its maximum torque range.

The engine automatically operates in its optimum rpm range to maximise fuel economy.

If extra power is required during acceleration, the THS draws energy from the battery and sends it to the electric motor.

A characteristic of an electric motor is the added benefit for take-off of maximum torque at zero revolutions.

Smooth Acceleration:
The THS therefore offers acceleration which matches or exceeds that of a conventional car with automatic transmission.

Moreover, the THS driveline acts as an intelligent continuously variable transmission.

There are no gear changes and so acceleration occurs without gearshift shock.

When the vehicle is stopped, decelerating or running at a low speed, the engine automatically shuts off after a pre-determined period to save fuel and reduce exhaust emissions.

When the vehicle decelerates, the motor acts as a generator, converting the vehicle's kinetic energy into electricity and sending it through the inverter to be stored in the battery.

3. HYBRID SYSTEM LAUNCH A '90S MILESTONE

The launch of the Toyota Hybrid System at the end of the century has been as important to Toyota as the development and launch of Lexus a decade ago.

Toyota's commitment to environmental technology is as absolute as its passion to achieve quantum improvements in design and manufacturing technology with Lexus.

Toyota Australia senior executive vice-president John Conomos said the strength of dedication to green technology was absolute.

World president Harry Okuda has made harmony with the global environment the priority for Toyota activities, Mr Conomos said.

His view is that unless we act decisively the automobile may cease to be a viable transportation option.

Toyota was seeking to achieve a balance between environmental protection and economic growth.

Mr Okuda says that as an automobile manufacturer Toyota must strike a balance between business and corporate citizenship, Mr Conomos said.

Economic growth that ignores environmental consequences is in his view reckless.

But attempting to resolve global environmental issues without recognising the need for economic growth is unrealistic.

The objective should be sustainable development.

Toyota has encountered an overwhelmingly positive reception to its hybrid technology in its domestic market. Production levels have been doubled to 2000 a month to go part of the way to meet demand.

Toyota became the world's first auto-maker to bring hybrid technology to production with the launch of Prius last December.

The company's commitment to production of 20,000 THS vehicles for North America and Europe in 2000, and its trial of the technology in Australia, were indications of its global intentions.

At the announcement of the North American initiative, Toyota said it wanted to be to the environment what Volvo was to safety and Rolls-Royce was to luxury, Mr Conomos said.

While market perceptions may be open to interpretation, there is no doubting Toyota's commitment.

It took leadership more than a decade ago when it began true global mass production of better-breathing Twin Cam Multi-valve technology.

It has consistently demonstrated environmental commitment at all levels including the development of the patented Toyota Super Olefin Polymer as a recyclable material for many body parts.

Efficiency-improving Variable Valve Timing with intelligence (VVT-i) technology, recently introduced on top line models, will be taken up by many Toyota models in the future.

Mr Conomos said the strength of Toyota as a global supplier and as one of the world's largest car makers added significant impetus to its environmental commitment.

A smaller manufacturer would simply not be able to make such a commitment on so broad a scale, he said.

Toyota's R&D commitment is more than four percent of its turnover and in accordance with President Okuda's direction, priority lies with environmental development.

Toyota has committed over US $1.2 billion in R&D of alternative power sources out of a typical annual R&D expenditure of US $6 billion.

This commitment to alternative energy sources is greater than the total R&D budget of some other carmakers.

4. GOVERMENT HELP FOR CLEAN AIR TECHNOLOGY

Toyota intends to lodge a position paper with various departments of State and Federal government proposing a range of possible assistance measures.

According to Toyota senior executive vice-president John Conomos, government incentives would accelerate the introduction of global developments to the Australian market.

It would represent a partnership between world car makers and the government to create a viable eco-car market.

Australia is in danger of being overlooked in the formative stages of clean-car production, Mr Conomos said.

Government co-operation would enable benchmark vehicles to become an important early component of local green-vehicle market development.

Toyota has proposed green cars be offered incentives not available to conventional cars.

In Japan, where the Toyota Prius hybrid car is on sale, Toyota had already absorbed substantial development costs to bring the vehicle's list price close to public expectation.

The Australian government is serious about greenhouse improvement, Mr Conomos said.

It should therefore seriously consider a co-operative program aimed at developing a viable alternative to conventional technology.

There is an important market development role which must run in parallel to the technical program.

To ensure consumer support, green technology needs to be introduced at a price consistent with that of conventional vehicles.

Mr Conomos said without co-operation Australia could be overlooked in upcoming green-car development.

For the future of our own domestic industry it is imperative that benchmark world developments are made available here as soon as they come on stream, he said.

A viable local eco-car industry depends on the incentive of international example.

5. HYBRID TECHNOLOGY HIGHLIGHTS CARBON AWARENESS

The world's first production hybrid car has been chosen as the centrepiece of Australia's first Carbon Awareness Day.

The Toyota Prius has been demonstrated to national environment minister Senator Robert Hill in a ceremony in the Great Hall of Parliament House, Canberra.

Carbon Awareness Day is as important going into the next decade as Clean Up Australia Day was in the last, John Conomos, senior executive vice-president of Toyota Australia said.

Major world companies are now paying substantial attention to environmental care.

It is up to every citizen to follow suit.

Carbon Awareness Day is an initiative of the Foster Foundation, a not-for-profit organisation founded to promote environmental awareness, especially in the transport industry.

An immediate thrust of the organisation is to encourage Australian motorists to each pay $25 annually to have seven trees planted to compensate for the carbon dioxide emissions of their vehicles.

The Carbon Awareness Day tree planting project, called GreenFleet, has appointed Peter Brock as its patron.

GreenFleet calculates it will take the carbon cleansing properties of seven trees over their 20 to 30-year growing span to neutralise one year of emissions from each vehicle.

Under the pine tree model used by GreenFleet, the trees grow fastest and absorb the most carbon during their first 15 years and become carbon neutral between 20 and 30 years.

National environment minister Senator Robert Hill inaugurated Carbon Awareness Day in the Great Hall of Parliament House.

Third-year environmental law student Claire Crocker, the co-ordinator of the Australian Youth Parliament for the Environment, invited Senator Hill to plant a tree and to drive Toyota's new hybrid technology car, Prius.

Prius is a big step forward because it uses half the petrol and emits only half the carbon dioxide of an equivalent conventional car, Claire said.

It shows what can be done by car makers to make our air cleaner.

According to Mr Conomos, the concept of Carbon Awareness has far broader implications than the GreenFleet carbon-neutral target.

Australia's carbon emissions would be significantly improved by a reduction in the age of the vehicle car park.

Australia has 10.5 million registered vehicles, with an average age over 10 years, he said.

Modern, comparatively environmentally efficient cars have the potential to reduce harmful exhaust waste.

Voluntary, or enforced, reduction of the age of the vehicle car park would be a significant move in reducing not only emissions but also to improving road safety. Mr Conomos said Australia had one of the oldest vehicle fleets amongst its contemporary nations.

A joint venture project about to be undertaken by Toyota and Japanese partner Mitsui may make an incremental contribution to the GreenFleet goal.

Toyota has chosen Australia to trial its Forest of Toyota project intended to cultivate fast growing high-photosynthesis (high carbon absorbing) trees.

The pilot program intends to grow more than six million trees in Australia in the next 10 years.

FOOTNOTE: There are currently about 1.4 billion trees being grown on plantations in Australia.

6. PRIUS OFFERS SEAMLESS OPERATION

Toyota's Prius Hybrid technology vehicle offers seamless matching of petrol engine and electric motor power, for smooth, low-emission, low fuel consumption driving.

The petrol engine is the key component, along with a continuously variable transmission (which doubles as a power-splitting device), generator, electric motor and reduction gears.

The petrol engine drives through the power-splitting device, (an advanced type of planetary gear assembly), which sends part of the power to the wheels and part to a generator.

Electricity from the generator can be fed directly to the electric motor to help propel the car, or through the inverter - to be converted into direct current and stored in the battery.

The combination of the Toyota Hybrid System's electronically controlled continuously variable transmission and electric motor assistance gives Prius smooth acceleration and deceleration, and excellent response.

The high torque of the electric motor from zero revolutions gives Prius excellent initial acceleration.

For maximum acceleration, the system uses power from both the petrol engine and electric motor (using energy stored in the battery).

How Toyota's Hybrid System Works: 1) When moving off, moving at extremely low speeds, descending long gentle hills and for other conditions where the petrol engine would not operate at peak efficiency, the engine is turned off. The electric motor alone propels the car.

2) During normal operations, the engine's power is split, with some power used to propel the car and the remainder used to generate electricity. The electricity is fed to the electric motor and/or the batteries, to assist in powering the car. The Toyota Hybrid system computer controls the ratio of power to each path, for maximum efficiency.

3) During full-throttle acceleration, additional energy is drawn from the battery to boost the electric motor's output.

4) During deceleration or braking, the electric motor acts as a generator, transforming kinetic energy from the wheels into electricity. The recovered energy is stored in the battery.

5) The battery is regulated to maintain a constant charge. If the battery charge is low, the Toyota Hybrid System sends more engine power to the generator to generate electricity and recharge the battery.

6) The petrol engine shuts down automatically after a period of time when the vehicle is stopped.

7. PRIUS HAS PARALLEL HYBRID DRIVELINE

Toyota's Prius has a sophisticated petrol-electric parallel hybrid powertrain for reduced environmental impact.

It is the world's first production hybrid passenger car.

The THS (Toyota Hybrid System) driveline consists of a purpose-developed 1.5-litre petrol engine, a continuously variable transmission (CVT) which also functions as a power-split device, a generator, an electric motor and reduction gears to the front axle.

The CVT/power-split device divides the power from the petrol engine into two paths.

One goes directly to the electric motor and the reduction gears (which are on the same drive shaft), the other to the generator.

Engine power can be transmitted to the front axle via a mechanical path and an electrical path, or a mixture of both.

The continuously variable transmission smoothly adjusts the speed of the engine, generator and motor when the vehicle is accelerating or decelerating.

Some of the engine's power output is transmitted to the electric motor, via the generator, as supplementary power for vehicle acceleration.

A single electronic control unit for the THS controls the engine, power-split/power transmission device, generator, motor, inverter and battery.

As well as propelling the vehicle, the THS driveline allows for energy saving regenerative braking.

Constantly Variable Transmission:

The Toyota Hybrid System transmission acts as an electronically controlled continuously variable transmission (CVT) which can freely vary the engine speed.

It achieves this by controlling the generator's revolutions.

Therefore, the vehicle does not need a conventional transmission.

The power-split device operates via a planetary gear system, in which the engine output shaft drives the planetary gear carrier, and uses a set of pinion gears to simultaneously transmit power to the outer ring gear and the inner sun gear.

The shaft of the outer ring gear connects directly to the electric motor and (through the drive shaft), to the reduction gears and hence the front wheels.

The shaft of the sun gear drives the generator. The planetary gear set therefore acts as both power-split device and CVT.

The result is a significant saving in weight and space under the bonnet, compared with either a traditional automatic transmission or a belt and pulley type CVT.

8. PRIUS HAS HIGH EFFICIENCY, LOW EMISSION ENGINE

Toyota Prius' petrol engine is state-of-the-art for efficiency and low emissions in a volume-production reciprocating power plant.

Toyota has adopted leading-edge engine technology throughout the 1.5-litre Prius engine for maximum fuel and package efficiency and minimum emissions.

The Toyota 1NZ-FXE engine was developed specifically for use in the Toyota Hybrid System.

The 1496cm3 engine delivers 43kW of power and 102Nm of torque, both at 4000rpm.

State-of-the-art features include:
* an all alloy construction cylinder head and engine block for maximum thermal efficiency and minimum weight
* a Twin Cam Multi-valve cylinder head with oblique squish combustion chambers
* variable valve timing with intelligence (VVTi)
* high-expansion ratio Atkinson operating cycle with long piston stroke (bore and stroke dimensions are 75mm x 84.7mm)
* low-rpm engine operation
* full sequential fuel injection with multi-point fuel injector nozzles mounted in the inlet ports
* an offset crankshaft centreline
* reduced reciprocating mass and lightweight valve train components, low friction pistons, piston rings and low-load valve springs.

Additional fuel and emission saving technology includes computer engine management, individual Toyota Direct Ignition for each of the four cylinders, electronic spark advance with a knock control system and an electronically-controlled throttle (drive by wire).

Many of these features, including multi-point fuel injection, and Twin Cam Multi-valve cylinder heads are already standard equipment on all Toyota passenger vehicles, whilst direct ignition is available on most passenger models.

The Prius engine is red-lined at 4000rpm, to maximise fuel efficiency.

The low-rev philosophy has allowed the design engineers to use mild valve timing, lighter moving parts, a smaller diameter crankshaft, less tension in the piston rings, reduced valve spring load and smaller bearings (for significantly reduced internal friction).

The crankshaft is offset 12mm to the thrust side of the cylinder bore centre line.

This reduces the side force generated at maximum compression, for reduced friction and maximum torque.

The offset crankshaft configuration reduces fuel consumption by between one and three percent, based on the petrol-only operation.

Toyota's 1NZ-FXE has an aluminium alloy cylinder head for maximum thermal efficiency.

It has four valves per cylinder and vertical intake ports for maximum engine breathing.

The fuel injection nozzles are located in the inlet ports, to prevent fuel wetting and adhesion to the walls of the port, thereby reducing hydrocarbon emissions.

In addition, the Prius engine has variable valve timing with intelligence, a flow-down from the Lexus luxury car program.

VVTi provides continual variations of the intake valve timing, to match the engine's operating conditions, particularly relevant and important to an Atkinson cycle engine.

It improves performance and fuel efficiency, and reduces vibration on engine start-up and shut-down.

Inlet timing can be varied over a range of 40 degrees in the Prius engine.

The Prius engine has a compact cylinder head design, with an included valve angle of 33.5 degrees, for maximum efficiency.

The combustion chambers are almost entirely machined, to ensure minimum variance in combustion chamber volume across the four cylinders.

The compression ratio has been set at 13.5 to 1- a high figure for an engine operating on unleaded petrol - to improve combustion efficiency and power output across the revolution range.

The combustion chambers in the Prius engine employ a slanted squish design, to improve thermal efficiency and reduce the chance of engine knock.

The squish angle has been shaped obliquely along the wall surface of the combustion chamber, to improve airflow, promote swirl and speed flame travel.

Special attention has been paid to cooling the combustion chamber, including provision of a water jacket between the exhaust port and the spark plug boss, to lower the operating temperature at the exhaust valve seat and improve cooling performance.

Engine package efficiency has been maximised and weight minimised by adopting an aluminium cylinder block and compact intake manifold design.

Engine service weight is just 88.3 kilograms.

9. ATKINSON CYCLE BOOSTS ENGINE EFFICIENCY

Toyota's advanced Prius four stroke reciprocating engine was designed for maximum efficiency rather than maximum power.

The Toyota Hybrid System's electric motor can provide added power of up to 30 kilowatts, when required.

The Toyota 1NZ-FXE all-alloy engine employs the Atkinson, or high-expansion, cycle for improved efficiency.

It has smaller combustion chambers and a higher expansion ratio than a conventional Otto cycle engine.

The Atkinson cycle design makes full use of combustion energy, by keeping the exhaust valves shut until the end of the expansion stroke.

The expansion stroke is extended until the expansion pressure has virtually dissipated, converting more of the combustion energy into torque on the crankshaft.

Toyota has combined the Atkinson cycle with a long-stroke engine design and offset crankshaft, direct ignition and variable valve timing with intelligence, to further improve efficiency.

The reduced power output of the Prius' Atkinson cycle engine (43kW versus 69kW from the same capacity Paseo engine) is also as a result of a lower engine rpm limit imposed. This enables the use of smaller, friction-reducing main, big end and little end engine bearings.

High-Expansion Ratio: In a conventional four stroke (Otto) cycle engine, the compression stroke volume and expansion stroke volume are practically identical, and hence the compression ratio and expansion ratio are identical.

Any attempt to increase the expansion ratio results in an increase in compression ratio, and hence greater likelihood of engine-damaging engine knock or pre-ignition.

The Atkinson cycle engine solves this dilemma by delaying the closing of the intake valves.

The intake valves remain open for the initial stage of the compression stroke (when the piston is ascending), effectively delaying the start of compression and hence reducing the effective compression ratio.

The small combustion chamber volume in Prius still ensures a relatively high compression ratio of 13.5:1.

A small portion of the intake air that has been drawn into the cylinder during the intake phase is returned to the intake manifold.

This slight amount of back-flow into the intake manifold provides benefit in partial load conditions.

It allows for an increase in throttle valve opening, thereby reducing intake manifold vacuum and hence reducing intake pumping losses.

Two Ratios:

The expansion and compression ratios are determined by these formulae.

Expansion ratio equals (expansion stroke volume + combustion chamber volume), divided by combustion chamber volume. Compression ratio equals (compression stroke volume + combustion chamber volume), divided by combustion chamber volume.

Atkinson And Miller:

The Atkinson Cycle was proposed by English engineer James Atkinson, to enable the compression stroke and expansion stroke to be set mechanically independent of each other.

Later, this concept was extended by the American R.H. Miller, who developed a system called the Miller Cycle, in which the opening and closing of the intake valves was made adjustable. The system offers high thermal efficiency but does not generate high output, so until now any practical application involved the addition of a supercharger.

10. THS USES ADVANCED ELECTRICS

The Toyota Hybrid System uses advanced electrical components, designed to maximise operating and package efficiency.

Development work for Prius led to performance improvements, plus reductions in size and weight in components such as the electric motor and battery.

THS Battery:

The THS battery marks a further advance in sealed nickel-metal hydride (Ni-MH) technology, which was originally developed for electric vehicles.

The THS battery offers three times the power output of EV batteries, coupled with improved sealing and durability, and reduced weight.

The THS ECU controls the generator and motor to ensure the battery maintains a constant charge - so there is no need for recharging from an outside source.

Electric Motor:

The THS uses a compact, lightweight, high-output AC permanent magnet synchronous electric motor.

The 30kW electric motor provides shared power with the petrol engine, ensuring smooth starts and responsive acceleration.

In addition, the motor is part of the THS regenerative braking system.It converts the kinetic energy of the decelerating vehicle into electricity, for storage in the battery.

Permanent Magnet Generator:

The THS has a high-efficiency AC permanent magnet synchronous generator, to run the electric motor and charge the battery.In addition, the THS system uses the generator to control the ratio of power distribution from the power-split device.

This is achieved by controlling the amount of electricity the generator produces and hence generator revolutions.

The generator also serves as a starter motor for the petrol engine.

Inverters:

The Toyota Hybrid System inverters turn direct current from the battery into alternating current for the drive motor, and convert alternating current from the generator and motor (in regenerative braking mode) into direct current for storage in the battery.

The inverter circuitry features an intelligent power module for increased reliability.

11. PRIUS USES REGENERATIVE BRAKING

Toyota's Prius petrol-electric hybrid powered vehicle has a regenerative braking system.

The regenerative braking system delivers a number of significant benefits over a conventional car.

It recovers energy and hence improves fuel economy and lowers greenhouse gas emissions.

The regenerative braking system can provide the majority of the total braking force in low-speed, stop-start traffic, where little deceleration is required.

This significantly improves the fuel economy and emissions of a hybrid vehicle and further enhances the attractiveness of hybrid vehicles for city driving.

Regenerative braking also contributes to improved economy and lower emissions at higher speeds, with increases in fuel economy of up to 20 percent.

The electric motor acts as a generator, converting kinetic energy from the vehicle's motion into a reusable form, electricity, which is stored in the battery.

The brake system in Prius has its own electronic control unit, which networks with the Toyota Hybrid System ECU to determine the best balance of regenerative and friction braking for the driving conditions.

The Prius gear shift pattern includes a B setting, to maximise the utilization of regenerative braking.

Regenerative Operation:

The regenerative braking system in Prius is a function of the drive axle connected to the electric motor, and acts on the front wheels (the most effective wheels for braking effort).

The system can be activated in either of two ways.

When the accelerator pedal is released, the absence of pressure triggers a response from the THS electronic control unit to begin regenerative braking.

In this example, the friction brakes are not engaged.

If greater braking effort is required, the brake pedal is depressed and the braking ECU engages both braking methods.

Friction Brakes And ABS: Prius has impressive hydraulically boosted friction brakes, in addition to its regenerative braking system.

A leading Japanese motor magazine achieved a 0.9G retardation when testing Prius.

Prius has ventilated 255mm x 22mm front disc brakes, and 200mm ID rear drum brakes.

ABS anti-skid brakes are standard equipment.

12. PRIUS MEETS WORLD SAFETY STANDARDS

Toyota's Prius hybrid technology car meets crash safety standards which have not yet been mandated in Australia.

It has a strong body, with a reinforced cabin, dual airbag SRS and force-limiting front seatbelt pretensioners.

Prius has passed a 40 percent offset deformable barrier test at an impact speed of 60km/h - 15 percent greater than the world test standard of 56km/h and Australian Design Rule Requirements.

It has also met European 50km/h dynamic side impact regulations (at 300mm impactor height), and US rear moving barrier and rollover tests.

A dual, electronically controlled airbag supplementary restraint system is standard equipment.

Electronic control provides more accurate sensing and improved deployment.

The airbags are the latest-generation, non-aggressive type, with non-azide and hybrid type inflators.

GOA Safety Body:

Prius' body was developed using Toyota's Global Outstanding Assessment (or GOA) process.

In the GOA process, Toyota reviews current and anticipated safety standards and designs the vehicle to meet or exceed those standards in addition to its own strict in- house standards.

Prius has been tested to new European standards, and Japanese and US requirements, as well as Toyota's strict in-house goal of having the highest passive safety in class.

The body has collision energy absorbing crumple zones front and rear, and a high-integrity cabin section.

Finite Element Method analysis and numerous on-vehicle tests were used to achieve maximum side impact integrity.

High-tensile steel is used extensively in body panel pressings.

In addition, Prius has significant body reinforcement for both frontal and side impact protection.

Energy-absorbing material has been incorporated into critical areas in the doors, to absorb any loads at those points.

In addition, Prius has the latest head impact protection (HIP) measures, including soft upper interior sections on the roof side rails and inner B-pillar.

The four-way collapsible steering column has a collapsible lower bracket, break-away bracket, energy-absorbing plate and a contractile section.

13. PRIUS OFFERS MAXIMUM PACKAGE EFFICIENCY

Toyota's Prius hybrid technology car offers medium-car levels of interior space in the overall length of a small car.

Its key design thought in packaging was optimum inside, minimum outside, to provide comfort for four adults while protecting the environment and conserving resources.

Prius' compact drivetrain design and short rear overhang maximises cabin space within its overall length of 4275mm.

The short overhangs also contribute to improved handling.

Prius is 5mm longer than the soon-to-be-released Corolla Liftback, but has Camry class levels of interior space.

It has a wheelbase of 2550mm (120mm shorter than Camry) and a height of 1490mm (70mm more than Camry).

However, special attention to front wheel turning angle gives Prius a turning radius of just 4.7 metres.

Vehicle entry and exit has been optimised by the 1490mm roof height, which allows for higher door openings.

The front door hinges have been angled, thereby allowing the doors to open wider.

The seat hip point is 575mm, to minimise bending when entering or leaving the vehicle.

Prius' upright driving position also improves vision and aids city driving.

14. TOYOTA PRIUS TECHNICAL SPECIFICATIONS/

Prius Technical Specifications

Model Code: HK-NHW10-AEEEB

ENGINE
Designation: 1NZ-FXE
Type: Front transverse-mounted all-alloy water-cooled in-line four-cylinder double overhead camshaft Atkinson Cycle petrol with four valves per cylinder, variable valve timing with intelligence, electronic engine management, electronic fuel injection, electronic direct ignition with knock control system and electronic throttle (drive by wire).
Fuel: Regular unleaded petrol
Displacement: 1496cm3
Bore x stroke: 75.0mm x 84.7mm
Compression ratio: 13.5:1
Maximum power: 43kW at 4000rpm
Maximum torque: 102Nm at 4000rpm
Valve mechanism: Two overhead camshafts and direct valve actuation, camshaft drive by compact short pitch chain and scissors-gear, continuously variable inlet camshaft timing over a range of 40 degrees
Fuel system: Multi-point sequential electronic fuel injection into the inlet ports

MOTOR
Designation: 1CM
Type: Lightweight, high-output AC permanent magnet synchronous electric motor
Maximum power: 30kW from 940 to 2000rpm
Maximum torque: 31.1kg.m from 0 to 940rpm
Generator: High-efficiency AC permanent magnet synchronous

BATTERY
Sealed nickel-metal hydride (Ni-MH)
Modules: 240
Module Voltage: 1.2 volts
Total Voltage: 288 volts
Linkage: Series
Capacity: 6.5(3) Amp/hour

TRANSMISSION
Type: Electronically controlled continuously variable transmission (CVT), using planetary gear set and electronic control of generator speed
Final drive ratio: 3.927

CHASSIS
Steering: Electric power-assisted rack and pinion
Front suspension: MacPherson strut
Rear suspension: Twist beam with twin trailing arms, coil springs, double acting hydraulic dampers and a stabiliser bar
Brakes: Regenerative circuit and hydraulically controlled friction brakes
Front type: 255mm x 22mm ventilated disc
Rear type: 200mm ID leading and trailing shoe drums

DIMENSIONS AND CAPACITIES
Overall length: 4275mm
Overall width: 1695mm
Overall height: 1490mm
Wheelbase: 2550mm
Front track: 1475mm
Rear track: 1480mm
Ground clearance: 140mm
Interior length: 1850mm
Interior width: 1400mm
Interior height: 1250mm
Vehicle weight (tare): 1240kg
Gross vehicle mass: 1515 kg
Minimum turning radius: 4.7m
Fuel efficiency (Japanese 10-15 test mode): 3.57litres/100km (79mpg)
Seating capacity: Five adults
Petrol tank: 50 litres

15. FUEL CELL ELECTRIC VEHICLES OFFER ZERO EMISSIONS

Toyota is working towards a zero-emission vehicle, using two types of fuel-cell technology.

Toyota began fuel-cell vehicle research in 1989 and in October 1996 displayed its first fuel-cell electric vehicle.

The company's vision for personal transport in the future is a vehicle which is kinder to the environment while maintaining the same level of comfort, convenience and safety as today's vehicles.

The fuel cell electrochemically converts hydrogen to electrical energy.

Water is the only by-product, so the cell itself offers zero-emissions energy.

However, there are challenges in the generation and storage of hydrogen.

Toyota has adopted two strategies to meet these challenges.

One is the development of a hydrogen-absorbing alloy (metal hydride), which was exhibited at the 13th International Electric Vehicle Symposium in Osaka in 1996.

The second is methanol reformer technology, in which hydrogen is derived from methanol.

Toyota's Fuel Cell Electric Vehicle (FCEV), exhibited at the 1997 Frankfurt and Tokyo motor shows, features this technology.

The 25kW fuel cell-powered a 5-door RAV4 recreational vehicle.

What Is A Fuel Cell?

Fuel cells work on the chemical principles of reverse electrolysis.

Applying an electric current to water splits it into its constituent elements of hydrogen and oxygen. The reverse process can be used to derive electricity.

The principles involved have been understood for 150 years - using a fuel supply (hydrogen), an oxidant (oxygen), and two electrodes (negative and positive) on either side of an electrolyte (usually a solid).

Toyota's fuel cell consists of hundreds of layers of solid-polymer membranes, known as proton exchange membranes (PEMs), stacked one atop the other.

The PEM fuel-cell process is simple: the inputs are hydrogen and air, and the outputs are electrical energy and water vapour.

The fuel cell stack, rated at 25kW, is sufficiently powerful to drive the FCEV's permanent-magnet synchronous electric motor.

It can develop a maximum of 50kW and 190Nm of torque for full-throttle acceleration and hillclimbing.

The additional energy comes from battery power, which is continually replenished by diverting any excess output from the fuel cell and by regenerative braking.