Monday, August 08, 2011

Some considerations about the Nissan LEAF

Starting to have some cult-follow as the first pure-electric vehicle released to the regular market by a major player in the industry, the Nissan LEAF actually doesn't look so revolutionary. As some friends of mine said, at a first sight it doesn't seem to be nothing more than "a regular car body relying on the drivelines of a golf-cart" just like all those tiny electric vehicles from smaller manufacturers.
OK, sometimes a so-called "revolution" is not a complete solution in terms of real-world conditions. For example, cab heating is an essential feature in some places. As far as the Brazilian market goes, even in some southern regions with a cold winter, no-frills versions of the 1-litre cars are often available without cab heating provision to reduce the cost. The elimination of the heater core and secondary cooling fluid lines represents some savings for the automakers, and lower price tags for the customer who doesn't care about all those amenities and just wants something safer and more comfortable than a motorcycle.

As far as electric cars go, it's not so easy to have this feature in a way that wouldn't sacrifice the overall efficiency with an electric heater, then some vehicles have supplementary heating units such as those gasoline-powered or diesel-powered ones used in Europe. However, while a lot of electric vehicles, either dedicated or converted ones, don't have a water-cooling circuit for the motor, the LEAF has it, so can use the waste motor heat to make the cab more comfortable in the winter, just like a regular internal-combustion vehicle. OK, it ends up adding weight and some mechanical complexity when compared to its opponents in the electric cars scene, but was an effective way to deal with the comfort issue.
Its engine bay actually doesn't look so different of an average gasoline-powered hatchback. But it has noticeable differences on the transmission due to the absence of a gearbox. Some electric motors allow the reversibility by their own, so there is no need to have a reverse gear, and since there is no idling they can even be coupled permanently, without the need of a clutch or any torque converter.
Even with a joystick featuring the usual P, R, N and D, with an "eco" mode, its motor is directly bolted to the differential, reducing the friction losses. Except for the "eco" and the P, the same setup as a golf-cart or some pure-electric or series-hybrid transit buses. However, some people who test-drove it in Porto Alegre, my hometown, thought it had either a CVT or a regular "hydramatic" with sequential 2-speed mode...

Only problem with the LEAF, actually, is its range, limited to 160 kilometers/100 miles. Considering its more compact design than the serial-hybrid Chevrolet Volt, one of its opponents in the American market, it would be hard to fit an on-board genset to act as a range-extender. However, if hub-motors were used, bolted to the rear wheels to avoid higher efforts for the steering system due to the increasement on the non-suspended mass, the space currently occupied by the differential and the single motor could leave room either to supplementary batteries or a "range-extender". However, instead of the 4-stroke gasoline-powered setup found on the Volt, a smaller and lighter 2-stroke would have noticeable advantages on packaging. Another good option could be diesel power, allowing the biodiesel as a clean option. But since it was developed to be purely electric, the front compartment could be used for more batteries and maybe even a spare tyre...
Some customers still prefer to have a spare tyre than just these lighter, space-saving quick-sealing setups.

There is already a gap in the automotive market that can be filled by the LEAF, but some reviews on its current concept could make it wider...