Lexus launches hybrid limo
GS 450h gives 'performance with low emissions'
Lexus GS 450h
Drive train
Following the hybrid RX 400h SUV, the GS 450h has a new, front engine, rear-wheel drive, series/parallel hybrid powertrain. It uses a 3.5-litre V6 petrol engine with a new D-4S (Direct-injection 4-stroke Superior-version) twin injector system with Dual VVT-i (Variable Valve Timing – intelligent), developing 292bhp and 271lb-ft of torque, mated to a compact, high-output, permanent magnet electric motor that generates 197bhp and 203lb-ft of torque from standstill.
With its combined power output of 341bhp, Lexus claimed the GS 450h is the world’s most powerful production hybrid car. It also includes electronically-controlled continuously variable transmission – E-CVT – with sequential shift mode. According to Lexus, each of the six sequential ‘steps’ gives sharper engine braking force, in the manner of a conventional automatic gearbox in sequential mode.
Performance is reasonably brisk: 0-62mph in 5.9 seconds and from 50 to 75mph in 4.9 seconds, maintaining linear acceleration all the way on to a top speed of 155mph. At the same time, the GS 450h returns a claimed 35.8mpg in combined cycle driving. Carbon dioxide emissions are 186g/km, which matches the performance of four-cylinder economy diesels in the premium segment, and combined emissions of nitrogen oxides (NOx) and hydrocarbons (HC) are lower than for any other vehicle powered by a combustion engine at 0.01g/km -- according to Lexus at least.
Handling
The GS 450h has 50:50 front-to-rear weight distribution and a better moment of inertia compared to the GS 430 model, as the 3.5-litre V6 is 17 per cent lighter than the 4.3-litre V8. The electric power steering incorporates variable gear ratio steering which alters the steering gear ratio according to vehicle speed, giving minimal steering effort at low speeds, with improved feel and feedback as speed increases. The system is linked to the adaptive variable suspension and Lexus’ vehicle dynamics integrated management system -- essentially the company's version of stability control.
The front double wishbone and rear multilink suspension design includes an adaptive variable suspension system, offering sport and comfort settings. Sport mode increases the difference between inner and outer shock absorber damping through corners to help reduce body roll.
Safety
SE-L versions of the GS 450h feature Lexus’s systems that prime the front seatbelts and emergency braking when a frontal collision is detected. This works in tandem with adaptive cruise control which automatically matches the speed of the GS 450h to that of the vehicle ahead, maintaining a safe distance.
The GS 450h also co-ordinates the ABS, electronic brakeforce distribution, traction control and vehicle stability control with the active variable suspension, electronic power steering and variable gear ratio steering to improve vehicle stability and handling. Passive safety features include a class-leading complement of front, knee, side and curtain airbags, augmented on SE and SE-L versions by additional rear side airbags.
For the remainder of 2006, Lexus said it expects to sell 700 GS 450h models, accounting for 30 per cent of all GS sales and 750 in 2007. It's on sale now.
But just how 'green' is it, really...?
The Article said:Nice car, and I'm glad that hybrid powertrains are finally finding their way out of liberal-teacher-car-hater-mobiles and into something remotely interesting.
the GS 450h returns a claimed 35.8mpg in combined cycle driving
Unfortunately I doubt many will see 35.8mpg. The the concept of a hybrid is that it relies on having periods of sedate driving, when only a small amount of the power is used, so it can run on the motors. But what actually happens is that people say "Wow, 35.8mpg! I'll be able to get my foot down all the time and not drink any fuel!!". Which is far from true. When the engine is revving they drink worse that if it wasn't a hybrid, because they've got to lug all the motors and batteries around.
http://hybridcars.about.com/od/hybrid
r988 said:
Surely this is the first hybrid Limo?
http://hybridcars.about.com/od/hybrid
Nope - the LS600h is not out yet. The GS450h is.
It's a storming car. The positioning of Lexus hybrids is there an alternative to diesel, not purely for economy. Basically, you get 4.5l V8 performance with a 3.5l V6.
Remember, electric motors give all their torque from 0 revs too. In gear acceleration is amazing.
Apparently they've made a one-off diesel Cayenne mule using a Toureg diesel unit so that they can test back-to-back and ensure the hybrid is more fuel-efficient.
That may not actually be true - it'll be interesting to see how the big Lexus really does perform in the real world.
A friend with a Prius has found that it yields its best economy on any journey that involves significant braking. Meaning that he was surprised to find that it actually does better MPG on twisty A and B roads than at constant speed on the motorway or uncongested town driving.
Electric motors are very efficient but can't operate at high power levels for long because not enough power can be stored in the batteries, so the efficiency gains in hybrids come in low power applications such as town driving. Motorway slogging takes a lot of power (wind resistance being the square of speed), as does heavy acceleration, so hybrids are poor in these two areas.
Unfortunately Fat Cat executives like to do both high-speed cruising and heavy acceleration, so it'll be interesting to see what happens.
stig said:
Surely this is the first hybrid Limo?
http://hybridcars.about.com/od/hybrid
Nope - the LS600h is not out yet. The GS450h is.
But it's stretching things (pun not intended) to call the GS450h a limo though, unless you're French or German.
80 mph on the motorway fuel consumption was not much different to most big 4.0ltr cars but round town it was giving well over 30mpg and in almost total silence as well. Should think the claimed 35mpg shouldn't be to far off the mark in normal mixed reasonable speed driving but it can still perform when called on.
Take a look at the BMW 535d
Whilst it's not going to be perfect and it won't suit everyone, I think the idea is to be applauded as a first step into bleeding edge technology. People laughed at the idea of a performance diesel not so long ago (and I know some still do :P). I think it'll be interesting to see how far hybrids can go once they've had the same level of investment and research as diesels have had over the last 10 years.
3, They launched this thing at Bathhurst in Australia. Not really sure why, maybe to demonstrate it rather shifted somewhat. One Journo took an E55 along for comparison and called them rivals. Not quite buddy.
Like the idea though, no emissions is good, even if during build it's more costly vapours-wise than a conventional one, due to extra build time and other factors. The IS version will sell massively.
Ali.
Andrew D said:
Apparently they've made a one-off diesel Cayenne mule using a Toureg diesel unit so that they can test back-to-back and ensure the hybrid is more fuel-efficient.
The thought of a Diesel Porsche is too much to bear!
As for the Lexus, top marks to Toyota for trying to be different and not going down the derv route.
Andrew D said:
The Prius has rheostatic brakes, which basically entails the motor becoming a generator under braking, putting load on the wheels to slow the car (in addition to conventional brakes), so it recycles some of the kinetic energy back into the batteries.
Electric motors are very efficient but can't operate at high power levels for long because not enough power can be stored in the batteries, so the efficiency gains in hybrids come in low power applications such as town driving. Motorway slogging takes a lot of power (wind resistance being the square of speed), as does heavy acceleration, so hybrids are poor in these two areas.
Unfortunately Fat Cat executives like to do both high-speed cruising and heavy acceleration, so it'll be interesting to see what happens.
lol - of course, the engineers won't have considered any of this
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