ilPistone.com: Lexus RX400H

E' una delle tanto attese novità. Non tanto per la vettura in se stessa, quanto per la tecnologia che la fa muovere. Con la Toyota Prius, abbiamo visto applicare con successo il concetto del funzionamento ibrido su una vettura pensata appositamente per lo scopo. Questa volta pero' e' decisamente diverso, la RX non e' certo leggera (1980kg) ed il motore termico non e' un 1.5 ma un V6 da 3.3 litri. La potenza complessiva e' di ben 268cv, lo 0-100 compiuto in un miracoloso 7.4 secondi. Ma il vero prodigio viene dai consumi (dichiarati)... 9 litri/100km in citta e 7.8 litri/100km in autostrada.

canadiandriver.com

Kohala Coast, Hawaii - Hawaii and Canada may have very little in common, especially the weather. But what Hawaii and Canada do share is high gasoline prices.

The average price of gasoline on the Big Island of Hawaii today is US$2.41 a gallon. That's about 80 cents per litre Canadian, and admittedly not a huge price to pay considering the prices we're used to. But Hawaii is the most expensive US state in which to buy gasoline - forty cents a gallon more than New York, the next most expensive state to buy fuel, and 50 cents a gallon more than Alaska.

Hawaii depends almost exclusively on imported diesel fuel to generate electricity and its electricity rates are also among the highest in the US. So naturally, the people of Hawaii are more energy-aware than other US residents. Unlike the other 49 states, diesel-powered vehicles are abundant. In Canada, compacts and sub-compacts are more popular than in the US.

But for most people, whether in Canada or Hawaii, the cost of fuel is just the price one must pay to have the vehicle they feel they need. Research conducted by Lexus has shown that buyers are not prepared to give up performance, safety and comfort and convenience to save fuel, even if they are predisposed to consider an environmentally friendly vehicle.

Gasoline electric hybrids offer greater fuel savings but among luxury car buyers and SUV owners have suffered the same stigma as sub-compacts.

David Brimson, Lexus Canada's public relations and advertising manager says, "They perceive hybrids as under-powered and lacking in performance and luxury amenities."

Time for a reality check. The RX 400h - as well as a number of other hybrids arriving this year and next - is about to change that perception.

The RX 400h has everything a luxury SUV owner would want. Not only is it considerably more fuel efficient than the RX 330 on which it is based, but it is more powerful and every bit as luxurious.

Total system power - the combined power of the 3.3-litre V6 and the hybrid transaxle - is 268 horsepower. Zero to 100 kilometres per hour is estimated to be 7.4 seconds, compared to about 8.0 seconds for the 230 hp RX 330.

On a test track in Hawaii, the RX 400h turned consistent 95 mph quarter mile speeds. The timing lights weren't working that day, but my rudimentary hot rodder math tells me that is about 15 seconds - or pretty quick for a V-6 powered, 1,980 kg (4,365 lb.) vehicle.

RX 400h fuel consumption is estimated to be 9.0 litres per 100 kilometres in the city and 7.8 L/100 km on the highway. The RX 330 is rated by Natural Resources Canada at 12.0 L/100 km in the city and 8.6 L/100 km on the highway.

Another comparison: the combined city/highway fuel consumption of the RX 400h - 8.4 L/100 km - is less than the 8.5 L/100 km for the average compact sedan.

With the RX 400h, it is no longer necessary to ignore your social and environmental conscience to drive a luxury sport utility vehicle.

The RX 400h could have been even more fuel efficient, but the hybrid is equipped with 18-inch wheels and beefy P235/55R18 tires, rather than small, low rolling resistance tires. The bigger tires help put the RX 400h's ample power to the ground and maintain the capable look buyers expect in an SUV.

As well, the 3.3-litre engine, which has been specially tuned for the hybrid application, could have been more fuel efficient but at the expense of power. By itself, the 24-valve six-cylinder engine develops 208 hp, about 10% less than the RX 330 due to intake and exhaust changes.

But the hybrid system more than compensates for the lower power from the engine. The Lexus Hybrid Synergy Drive system uses not one but three electric motors - two which work with the engine to provide power to the front wheels and a third which drives the rear wheels.

The system is a "full hybrid," meaning that the RX 400h is capable of operating in separate gasoline or electric modes, as well as one that combines power from both. On take-off, the vehicle is powered exclusively by electrical energy. The engine cuts in seamlessly when more power is required to accelerate. On deceleration or at rest, the engine will shut off, with the vehicle and its accessories running exclusively on power from the battery or the electric motors.

When battery power drops off, the electric motors operate as generators, reversing the flow of energy to recharge the battery pack stored under the rear seat. Energy captured from the brakes also helps charge the battery pack. The RX 400h battery pack consists of 30 nickel metal hydride modules, each with 8 cells. Peak power is 45 watts, 80% more than the battery pack in the current Prius.

Like the RX330, the RX 400h has full-time all-wheel drive, but with a difference. The rear wheels are powered solely by an electric motor and are not connected by a drive shaft or other mechanical means to the engine or front transaxle. The electric all-wheel drive is principally an on-road traction enhancer. It is not intended for off-road ventures. It also allows all four wheels to capture energy through regenerative braking.

The electric all-wheel drive system is managed by a new advanced stability control system which Lexus calls Vehicle Dynamics Integrated Management or VDIM. The system is designed to anticipate vehicle stability problems and intervene with braking, throttle control and steering assist to correct the problem. Elements controlled by VDIM include a small army of active safety features - electronic braking control (and the regenerative braking system), anti-lock brakes, electronic brake force distribution, brake assist, traction control, vehicle stability control and interactive steering boost.

We didn't encounter any snow covered roads on the Big Island of Hawaii, but we did spend considerable time on the winding and often rough roads that criss-cross the island. We found that despite pushing the RX 400h hard and even, at one point, catching air over a road mogul, the hybrid SUV remained composed and stable. If VDIM intervened, it was largely transparent. A warning light briefly illuminates on the dash when the system is active.

In fact, in day to day driving there is nothing to really differentiate the RX 400h from the RX 330. The hybrid's continuously variable transmission provides more linear acceleration than a conventional transmission and largely masks the enhanced performance of the RX 400h.

VDIM is a significant advancement in active safety technology. But the technological innovation doesn't stop there. The RX 400h is the first Lexus to come equipped with electronically controlled brakes and electric power steering. The latter is not "steer by wire," rather an electronic controller boosts steering based on speed and input from the VDIM. There is no power steering fluid.

Other neat technology includes electric air conditioning - climate control is operative even if the engine is not - and an optional new enhanced navigation system that is equipped with voice recognition and "bluetooth" phone capability.

One knock against Prius is that it is instantly recognizable as a hybrid. Other manufacturers have opted for hybridizing existing models. It may be the future for Lexus too. No one need know you care about the environment. The RX 400h looks much like an RX 330 and a casual glance might miss the RX 400h-specific bumper, grille and fog lamps. The additional opening in the front bumper helps cool the hybrid components. The hybrid also has different LED taillights, which use less power and have a longer life than conventional units. Underbody covers and small front and rear tire fairings help improve aerodynamics. Dimensionally, the RX 400h is 25 mm longer (one inch) and microscopically higher (7 mm) than the RX 330.

Inside, brushed aluminum accents replace the wood accents and a power metre replaces the tachometer, but buyers will find the same level of luxury found in the RX 330. In Canada, the RX 400h will be available equipped only with the premium and ultra premium packages currently available with the RX 330. Briefly, the premium package adds 6-disc in-dash CD player, power rear door and sunroof, and auto leveling and adaptive high intensity discharge headlamps to the base package, while the ultra premium package adds Mark Levinson audio, rear DVD entertainment system and navigation system.

Prices for the RX 330 with these option packages are $55,780 and $63,335 respectively. Prices for the RX 400h are expected to be announced at the Canadian International Auto Show in Toronto later this month, but buyers can expect a premium over and above these figures for a similarly equipped hybrid RX.

The Lexus RX 400h goes on sale in Canada in March

channel4.com

Here is a list of things that it is no longer acceptable to do in public: smoking, spitting chewing gum to the pavement and driving a 4x4. A slight exaggeration, to be sure, but not that much of a stretch. It has long been fashionable to be sniffy about school-run Mums and their Chelsea tractors gumming up our roads and pavements, but the greenies have become even more hysterical of late. Take the Alliance Against Urban 4x4s, a campaigning group that's taken to sticking spoof parking tickets on the windscreens of off-roaders, with phrases such as 'axles of evil' and 'poor vehicle choice'. So if you fancy running a 4x4 how do you respond to such attacks, apart from telling these folk to mind their own sodding business?

Lexus just might have the answer. In the warm afterglow of Toyota's Prius, winner of Car of The Year gong and vehicle of choice amongst enviro-poseur celebs, Lexus has given the RX300 the same hybrid treatment. The result is the RX400h, which will go on sale here next May. The 'h' is for hybrid and the '400' is meant to represent the 4.0-litre V8 output that the hybrid Lexus aspires to. In fact, the RX400 is powered by a 3.3-litre V6 that receives a helping hand from two powerful electric motors.

The result is a powertrain that develops 272bhp. As with the Prius, at low speeds around town the RX is powered exclusively by battery, but once speeds rise or more acceleration is called for, the petrol engine comes on line. When serious performance is demanded, both electric motors and the engine step up to the plate. And the driver gets performance potential that translates to 0-62mph in just 7.6secs and a top speed of 125mph.

And the payoff for Mother Earth is fuel consumption of 34.8mpg combined, a very good figure for a big petrol-powered off-roader, and remarkably low CO2 emissions of 192g/km. To put that in perspective, that's almost exactly the same polluting output as a Vauxhall Vectra 1.8 16v estate, which has far less than half the power of the Lexus. In fact, Lexus reckons that an owner doing 22,000km a year in an RX400h will produce 2.6 tons less CO2 than somebody driving a similarly powered non-hybrid 4x4. We did the math for ourselves and found, if anything, Lexus is being conservative.

« Ultima modifica: Febbraio 01, 2005, 15:40:02 pm da alura »