Overview: Mitsubishi iMiEV

Before there was iMiEV there was i. Launched in 2007, Mitsubishi’s i was the first Japanese Kei-car to be marketed in Europe.

The Kei (keijidosha) cars are a legally-defined breed of vehicles in Japan. Restrictions are placed on overall size and engine capacity. The original intention of the Kei-car regulations was to promote cheap four-wheeled transport after the second world war, to get people moving and the car industry working. The European bubble cars, like BMW’s Isetta, were built with the same intentions. As Japan’s cities grew, and grew more crowded, the emphasis changed: Kei cars were given favourable taxation treatment and exempted from some urban parking restrictions to encourage urbanites to run smaller cars. In 2006, Kei-cars accounted for 2.02 million (54 per cent.) of the 3.7 million cars sold in Japan.

Mitsubishi iMiEV.

Mitsubishi’s conventional i model uses a three-cylinder 659cc petrol engine mounted in a rear-mid position — just ahead of the rear axle line. With four valves, intercooled turbocharging and variable timing for the intake valves, the unit delivers 57PS at 6000rpm and 85Nm at 3000rpm. A four-speed epicyclic automatic gearbox is used. Predictably, with this sort of drivetrain, the i’s CO2 result is not startlingly low, at 114g/km.

The most obvious competitors for the conventionally-powered i are the Toyota Aygo and Peugeot 107 — the same car, of course. Toyota’s 998cc atmospheric engine produces more power and torque than the tiny blown Mitsubishi unit, but it’s the smaller engine that returns the better urban fuel economy result. Across all of the standard tests, though, it is the Toyota that wins for fuel economy, proving once again that a small engine working hard is not the best way to save fuel.

The electric version of Mitsubishi’s i model, the iMiEV, is presently being used by the manufacturer for joint research programmes with Japanese power companies. The car is driven by a 64PS electric motor through a single-speed reduction gear. The motor is of the permanent magnet, synchronous type, with a rated maximum speed of 8500rpm. The nominal system voltage is 330V.

Mitsubishi has specified hypoallegenic seat fabrics, but not funky designs. The rear compartment really could be a little more welcoming.

The iMiEV’s powertrain layout is broadly the same as the petrol version’s, with the electric motor, inverter and control electronics mounted just ahead of the rear axle line. The Li-ion battery pack lives under the floor.

The iMiEV’s running gear is the same as the petrol model’s, with McPherson struts at the front and a three-link de Dion arrangement, with non-concentric springs and dampers, at the rear. At 1080kg, the electric car is 180kg heavier than the conventional i.

The combination of quite large (350mm) ventilated discs at the front with 200mm drums at the rear seems at first slightly odd for a rear-engined car, but the engine is ahead of the rear axle line, and the presence of at least the driver on board will shift the weight distribution much closer to 50/50. And when a car is braked, wheel loads shift substantially to the front.

Anti-lock braking with an electronic brake-force distribution function is a standard feature, as is an active stability control system.

The decision not to drive the front wheels has helped the iMiEV’s manoeuvrability. Despite having a longer wheelbase than the Aygo, its turning circle is 0.4m smaller, at 9.0m.

Instrument display.

A domestic 13A 230V input will charge the iMiEV’s Li-ion battery pack from flat to full in six hours. The rapid charging system, relying on a commercial charging station to provide the power, will charge the pack from flat to 80 per cent. full in 30 minutes. An energy-saving drive mode, which reduces the motor’s output to 24PS, can be used if charge is running low.

Although there’s no pretending that the iMiEV’s purchase price of £38,699 — minus the Government’s £5000 incentive grant — is not very substantial, there are some paybacks. The car is exempt from road tax and congestion charges; it qualifies for a first year capital allowance as a fleet vehicle; it attracts zero benefit-in-kind company car tax; and it qualifies for free parking in some areas, including several London boroughs.

Mitsubishi
i
Mitsubishi
iMiEV
Toyota
Aygo
Body type 5-door
hatchback
5-door
hatchback
3-door
hatchback
Length (mm) 3395 3395 3415
Width (mm) 1475 1475 1615
Height (mm) 1600 1600 1465
Wheelbase (mm) 2550 2550 2340
WB/L 0.75 0.75 0.69
Kerb mass (kg) 900 1080 ca. 850
Cylinders 3 3
Valves 4 4
Bore/stroke 65.4/65.4 71/84
Swept volume 659cc 998cc
Compression
ratio
8.8:1 10.5:1
PS/rpm 57/6000 64 67/6000
Nm/rpm 85/3000 180 93/3600
Maximum speed 84 81 98
0-100km/h 14.9s 14.9s
Urban MPG (l/100km) 52.3 (5.4) 51.4 (5.5)
CO2 g/km 114 107
Transmission A4 (1) A5
Driven wheels Rear Rear Front
Fuel capacity 35l 16kWh 35l
(1) Single-speed reduction gearing
Mitusubishi iMiEV.
Text and design copyright Under the Skin 2010. We recommend Firefox.