Updated: January 2014
TOYOTA iQ
KEY POINTS
Launched as the world’s smallest four-seat car, less than three metres long
Exceptional packaging achieved through six space-saving innovations
- Front-mounted differential
- Centre take-off steering gear
- Flat underfloor fuel tank
- Ultra-slim seat design
- Ultra-compact heater/air conditioning unit
- Asymmetric dashboard design
Multi-award-winning 1.0-litre VVT-i and 1.33 Dual VVT-i petrol engines with manual or Multidrive transmissions
1.0-litre manual delivers 99g/km and 64.2 combined cycle mpg – road tax-exempt
Five-star Euro NCAP safety rating
Three grades – iQ, iQ2 and iQ3
Nine airbags, stability and traction control, electric windows, heated door mirrors and six-speaker audio system standard on all models
Customisation options – colourful side and roof decals and interior leather upholstery choices allow owners to individualise their car
Introduction
From an environmental perspective, iQ demonstrates how Toyota can offer cars that are exciting and desirable, while still achieving low fuel consumption and emissions.
iQ Chief Engineer Hiroki Nakajima explained: “We wanted to create the world’s first, sophisticated four-seat car, measuring less than three metres long, using ultra-effective packaging, a unique design, ultra-low fuel consumption and high driving and safety performance. To achieve this, iQ had to be similar in size to an A-segment car, its performance would have to surpass B-segment standards and interior and exterior quality would have be on the level of C-segment models.”
Birth of iQ
The iQ story began in 2003 when a team of Toyota engineers, led by Hiroki Nakajima, were given the chance to create one of the most important cars to be launched by the company. Just as Prius set a new benchmark for innovative drivetrain engineering, iQ is intended to act as a catalyst for reshaping thinking about how small, environmentally efficient cars can be packaged. The challenge was to develop a revolutionary, sophisticated compact car with excellent environmental credentials for use in urban areas.
Initially the project focused on packaging and miniaturisation. Later, designers from Japan and Toyota’s European design studio, ED2, worked together to create a sub-three-metre car. Toyota top management gave the project the green light and the iQ concept went on to be presented at the 2007 Frankfurt motor show.
The team targeted commercial success by designing iQ to appeal strongly to customers new to Toyota, principally the kind of people who take a more emotional approach to car buying. While they may have admired Toyota for its success and innovation, they might not have connected with the brand on an emotional level before. iQ was designed from the outset to connect to the needs of these customers.
iQ occupies a key position in Toyota’s range of compact cars. Although Aygo is longer – by 420mm – than iQ, it remains a simple and accessible entry-level model. Yaris, on the other hand, is positioned at the heart of the B-segment, while also attracting family buyers for use as the main car in the household.
iQ is different from these and all other small cars, thanks to radical thinking that has led to a breakthrough in automotive engineering. It also brings a new, high level of sophistication to the market, through the use of advanced features that are typically only found on larger cars.
iQ production began in November 2008 at Toyota’s Takaoka plant in Japan, with Japanese sales starting the same month. Sales in the UK and Europe were launched in January 2009.
ENGINEERED WITH SIX MAJOR SPACE-SAVING INNOVATIONS
- Kakushin – the driving force behind iQ
- Six space-saving innovations
A series of engineering breakthroughs have combined to make iQ the world’s smallest four-seat car. Toyota acclaims iQ as an “engineering jewel” that is capable of radically changing consumers’ opinions on small cars.
“Kakushin” - the driving force behind iQ
Speaking to the Harvard Business Review, the then TMC President Katsuaki Watanabe said: “In today’s world change can be produced by kaizen (continuous incremental improvement), but when the rate of change is too slow, we have to resort to kakushin (revolutionary change or radical innovation). I am trying to get people to make the leap from incremental improvement to radical improvement wherever possible.”
iQ required a drastic change of mindset. Engineers not only had to re-design parts to a smaller size, they had to reconsider their location, too. The result is a leap forward in small-but-spacious packaging, designed also to meet the highest crash test standards.
The car has a 2,000mm wheelbase with comfort ensured thanks to a 710mm distance between the driver and front passenger seat – space comparable to that in a C-segment vehicle.
Even the thickness of the doors has been reduced (compared to Yaris), by using a guideless window regulator structure rather than a conventional cross-arm type, so increasing shoulder room.
To avoid a claustrophobic atmosphere, the A-pillars are positioned forward and slope back. The front passenger seat can be slid far enough forward to ensure that three 190cm (6ft 3in) tall adults plus a child or extra luggage can be comfortably accommodated. Both rear seats can be folded down to increase boot capacity to 238 litres; with both seats in position capacity is 32 litres (VDA measurements).
Space has also been created by locating the gearshift and parking brake almost side by side, giving rear seat passengers more room to extend their feet between the front seats. As there is no fuel tank beneath the rear seats, a handy concealed storage tray has been created so objects can be stowed out of sight.
In the search for space, Toyotadeveloped an ultra-compact air conditioning unit and repositioned the heater blower from its usual position in the front passenger footwell to the centre of the instrument panel. Designers then went so far as to make a detachable glovebox (the glovebag accessory). This created a significant amount of space for the front passenger seat to slide forwards. Thin front seatbacks were also developed, giving them a concave form to increase rear seat legroom.
iQ’s six space-saving innovations:
- Front-mounted differential
- Centre take-off steering gear
- Flat underfloor fuel tank
- Ultra-slim seat design
- Ultra-compact heater/air conditioning unit
- Asymmetric dashboard design
1. Front-mounted differential
Positioning the differential in front of the engine means the distance from the tip of the bumper to the accelerator pedal could be reduced by 120mm. This brings three main advantages: the under-bonnet area is made more compact; the front wheels can be placed at the very corners of the car, drastically shortening the front overhang, and the passenger compartment gains 120mm in length (compared to Yaris).
2. Centre take-off steering
iQ has a central take-off steering gear, positioned higher and further back in the engine bay. This meant the size of the engine compartment could be considerably reduced, further shortening the car’s front overhang.
This is made possible because the steering rack tie-rods are connected to the centre of the rack, rather than both ends, as in Yaris and Aygo. This gave the engineers room to accommodate the engine underneath.
3. Flat under-floor fuel tank
The conventional fuel tank located under the rear seats has been replaced by an ultra-slim underfloor tank that is only 120mm high. This means the rear wheels can be brought 440mm further forward. In addition, the rear shock absorbers are angled backwards, so they don’t encroach on rear seat space.
Traditionally a flat tank was considered difficult to engineer, because the fuel surface level would vary depending on the angle of the car, for example when parked on a slope. Persistent efforts to reduce size and find the best position for functioning parts has resulted in success and a flat fuel tank that brings significant space savings and also lowers the car’s centre of gravity.
Toyota engineers developed a special horizontal fuel pump. Fuel suction inlets in both the fuel pump and canister and fuel level indicators are located in the centre of tank and ensure an accurate fuel level. The tank’s 32-litre capacity is enough to give iQ a range of around 435 miles.
4. Ultra-slim seat design
The slimness of the seatbacks releases a further 40mm of rear passenger room at knee height. An all-new structure and optimal adjustment of ancillary parts ensure the new design saves space without sacrificing comfort. In its drive to reduce weight, Toyota created high-tensile frames that save 1kg per seat.
5. Space-saving heater/air conditioning unit
Toyota engineers have succeeded in significantly reducing the size of the heater/air conditioning unit, without diminishing performance. As a result, the passenger side of the asymmetric dashboard could be moved forward and centrally towards the base of the windscreen, freeing up extra cabin space.
The size of the unit has been reduced by 20 per cent without losing performance, thanks to a smaller blower fan, re-routing of passages to improve air flow inside the unit and a more compact air filter.
6. Asymmetric dashboard and sliding seat configuration
iQ’s innovative asymmetric dashboard design takes advantage of the relocation of the smaller air conditioning unit to open up more space for the front passenger, with an extra 130mm of legroom. Comparable to the space available in Yaris, it allows for generous back and forward seat adjustment. When the seat is in its furthest forward position, there is sufficient space for the front passenger and comfortable room for an adult sitting behind.
Instead of a conventional glovebox, iQ saves more space by using a soft ‘briefcase’ that can be detached from the fascia if desired, available as an accessory option.
DRIVING PERFORMANCE
- Strong body with short overhangs
- Weight-saving engineering
- Compact, lightweight MacPherson front suspension
- Torsion beam rear suspension
- Electric power steering
- Vehicle Stability Control with steering assist (VSC+) standard
- 15 and 16-inch alloy wheels
More than just the world’s smallest four-seat car, iQ delivers driving performance that is almost unheard of in its class. It is quick and nimble for around-town driving and great fun to push along twisting roads, while at motorway speeds it displays a level of stability that was previously unimaginable for a car of its size.
The excellent driving dynamics have been achieved by the combination of a new platform, suspension and steering engineering and leading-edge aerodynamics. High stability at all speeds is maintained thanks to characteristics such as the front suspension’s high caster angle and reduced torsional stiffness, and the amount of roll steer and rigidity maintained in the rear suspension. In spite of its very short wheelbase, straight line stability is maintained under emergency braking.
Thanks to the repositioning of the engine and front wheels, iQ has an extremely tight turning radius of 3.9 metres, ideal for manoeuvring in citystreets.
Strong body, short overhangs
Toyota engineers reduced iQ’s overhangs to a minimum and located most of the car’s mass between the front and rear wheels to improve handling and vehicle controllability, a design philosophy borrowed from racing car design that also makes iQ great fun to drive.
The prototype model underwent thousands of hours in computer simulation and wind tunnel testing to achieve class-leading aerodynamics. The 1.0-litre VVT-i with manual transmission has a 0.30 drag coefficient, which boosts high-speed stability and top speed while also reducing fuel consumption and wind noise.
Weight-saving engineering
Almost every part of iQ underwent sophisticated computer simulation in the quest to reduce weight and so achieve more rewarding driving performance and lower fuel consumption.
Particular effort was made to lighten the torsion beam and 3.5kg was saved. Another kilo of metal was saved by using a new cross-shaped rear wheel flange.
Toyota engineers also created the world’s lightest exhaust for a front engine/front-wheel drive car, weighing only 6kg. This was achieved by using a long tailpipe and a single, low-resonance silencer, with no additional sub-silencer. This design also contributes to iQ’s low floor and low overall height.
MacPherson front suspension
iQ uses a specially designed MacPherson strut front suspension that gives a high level of handling stability and smooth ride comfort, in spite of the car’s short wheelbase. Compact and lightweight, it provides appropriate control for the 15 and 16-inch wheels while still returning a class-leading turning radius.
The system features a high, 8.3-degree caster angle for more toe-out when lateral forces are applied, giving the front wheels a more stable stance. By decreasing the stiffness of the steering arm, toe-out is added, too, when lateral forces increase. This again adds to stability and both measures increase understeer, while optimised geometry and damping force give maximum ride comfort and driving stability.
Torsion beam rear suspension
The torsion beam rear suspension was also developed exclusively for iQ and it gives excellent stability at high speeds and through bends. A high level of rigidity minimises steering changes from the rear suspension. Rear-end lift is also limited under heavy braking, while bushes and shock absorbers have been optimised for ride quality and low NVH performance.
The suspension plays its part in the car’s compact packaging concept by giving a class-leading rear track. Toyota has also been able to slant the rear shock absorbers backwards, allowing for a wider load space to be designed.
Electric Power Steering
iQ is equipped with a centre take-off steering rack and a speed-sensing electric power steering (EPS) system of the kind more commonly found on larger cars. The power to the steering is controlled according to vehicle speed, giving light response for low-speed manoeuvres and added weight as speed increases.
Unlike traditional hydraulic systems, power is only used when steering assistance is required, which supports fuel economy as the engine does not have to maintain constant hydraulic pressure. The 15:1 steering gear ratio gives quick response to driver inputs and good steering feel, and ensures yaw rate gain during urban driving at low to medium speeds. A low yaw rate gain at motorway speeds contributes to stable handling and safe braking performance.
The EPS is also interlinked with the steering assist Vehicle Stability Control (VSC+). The steering column is tilt-adjustable to suit different driver seatingpositions.
15 and 16-inch alloy wheels
iQ is fitted with large diameter wheels that are suited to its super-stance design. The 15-inch alloys are fitted with 175/65R15 low rolling resistance Bridgestone tyres; the 16-inch alloy wheels on iQ use 175/60R16 tyres.
The combination of advanced tyres and alloy rims gives a refined drive, unlike the quality typically found on compact cars with small wheels. In place of a spare wheel iQ is equipped with a tyre repair kit.
DRIVETRAIN TECHNOLOGY
- Toyota Optimal Drive concept
- 1.0-litre VVT-i petrol engine
- 1.33-litre Dual VVT-i petrol engine
- Toyota Multidrive, or five and six-speed manual transmission
- CO2 emissions from 99g/km, exempt from annual VED/road tax
Toyota’s drive for lower CO2 emissions from its vehicles is supported principally by a new range of hybrid models and Toyota Optimal Drive petrol and diesel engines and transmissions.
Toyota Optimal Drive technologies are designed to reduce harmful emissions and increase fuel efficiency with no compromise on driving pleasure and have been made a standard feature of all Toyota’s new-generation petrol and diesel models.
Unlike many other carmakers, Toyota has chosen to develop new technologies, rather than simply downsize or de-tune existing ones. Following the concept of kaizen – continuous improvement – Toyota engineers have improved combustion efficiency and reduced engine and transmission weight and friction. The result is new powertrains that are more powerful, yet also more efficient and economical.
UK versions of iQ are offered with a choice of a 1.0-litre VVT-i petrol engine that with manual transmission produces 99g/km of CO2, the first four-seat petrol car to break the 100g/km mark. This was joined in July 2009 by a 1.33-litre petrol engine.
1.0-litre VVT-i petrol engine
The three-cylinder 1.0-litre VVT-i petrol engine has an output of 67bhp (50kW) and produces 91Nm of torque at 4,800rpm. With the high-ratio five-speed manual gearbox it returns official combined cycle fuel economy of 64.2mpg and CO2 emissions of 99g/km. The engine can also be specified with Toyota’s Multidrive continuously variable transmission, which raises emissions to 110g/km.
Also featured in Aygo and Yaris, the unit has been a multiple winner of the sub-1.0-litre class in the Engine of the Year awards. To suit the specific requirements of iQ, the engine was adapted to slant 21.5 degrees forwards. The intake manifold was reshaped, an air cleaner was integrated into the fan shroud and the air conditioning compressor was relocated as part of the car’s packaging concept.