Citroën to Show New Rear-Wheel Motor Diesel-Electric Hybrid Concept at Paris Show
06 September 2006
 |
| The sleek C-Métisse diesel hybrid. |
Citroën will unveil a new concept at the upcoming Paris Motor Show—the C-Métisse—with a diesel-electric hybrid powertrain based on that of the C4 HDi hybrid demonstration vehicle shown in January. (Earlier post.)
The performance-oriented C-Métisse combines a 150 kW (201 hp) V-6 diesel engine with two 15 kW motors in the rear wheels. Each motor develops 400 Nm (295 lb-ft) of torque.
The C-Métisse accelerates from 0-100 kph in 6.2 seconds and has a top speed of 250 kph (155 mph). Combined fuel consumption is 6.5 l/100km (36 mpg US) with CO2 emissions of 174 g/km.
The concept uses a diesel particulate filter and a 6-speed automatic transmission. The C-Métisse supports an all-electric range of 3 km at 30 kph (1.9 miles at 19 mph).
A car features a flat underside, enlarged air intakes at the front, two retractable rear airfoils and a rear fixed-fin spoiler, contributing to a Cd of 0.30. With a carbon body and carbon trellis supporting the powertrain and front axle, the C-Métisse weighs just 1,400 kg (3,086 pounds), batteries included.
Awesome, but these guys keep showing model after model, but never bring it into market.
I guess Toyota is going to give them a kick after taking #1 spot in Worldwide sales.
Posted by: Max Reid | 06 September 2006 at 12:33 PM
Citroen left the US market over 30 years ago. I don't see any hope of ever driving a new Citroen again. I'd love to have one of their diesels.
Posted by: Rich | 06 September 2006 at 01:15 PM
What's the point of a concept car not really intended for racing but featuring a carbon-fiber body and retractable spoilers? Citroen could never afford to mass-produce that, and testosterone-challenged males would probably not pick a Citroen anyhow. The company is best known for its ultra-smooth suspension technology.
Also note that this concept vehicle is too light to make full use of the tremendous aggregate traction force of a 150kW diesel and two electric motors. Without electronic torque limitation, your wheels would merely spin like crazy if you floored the gas pedal. As it is, any money is hybrid pocket rocket would save you at the pump would merely go toward higher insurance fees and speeding tickets.
The primary value that hybridization really could add to a turbodiesel with DPF stems from NOx emissions reductions. The objective should be to keep the already frugal diesel engine economically viable in spite of tightening emissions regs. Ideally, a diesel hybrid should meet US Tier 2 Bin 5 emissions without resorting to complex NOx aftertreatment yet offer superior acceleration performance.
Measures to reduce engine-out NOx emissions would include zero idling, electric-only operation at low speed and, acceleration boost at all vehicle speeds. The latter smoothes out the torque demand on the prime mover; emissions spike during step changes in engine load. Note that the January announcement called for a sensible 66kW I4 rather than the over-the-top 150kW V6 in the Metisse.
Moreover, the available electric power could easily support the combustion control measures required for reliable cold starts in spite of a reduced compression ratio, yielding additional NOx reductions after the engine is warmed up. Typical LDV diesel engine designs feature compression ratios as high as 17-21. These increase the cost and weight of the engine, the mounts, the acoustic damping, the frame etc. All of this extra mass must be accelerated, negating the fuel economy gain due the slightly better thermodynamics. Compression ratios of 14-15 are generally considered optimal for LDV engines but fully expoliting this advantage would require a substantial redesign.
Moreover, if the electric drive components are water-cooled, the warm-up period for the ICE can be shorter. This is especially important in hybrids because the prime mover is frequently switched off in stop-and-go traffic. However, integrated cooling is only viable if the electric motor and power electronics are in close proximity to the ICE. The upside is that the electric motor can be attached on the engine side of the transmission.
Posted by: Rafael Seidl | 06 September 2006 at 01:50 PM
It may be too light for the torque available but it is also too heavy for the little power it has if it is meant to be a performance vehicle.
Posted by: Patrick | 06 September 2006 at 02:13 PM
Rafael,
Perhaps they are teasing us with these concepts. A scaled back model might be available, while something similar to this may go towards a rally racing program. Meanwhile, all the features will be added at one time or another as they mature and drop in price and weight, while going up in reliability and performance.
Posted by: allen Z | 06 September 2006 at 02:19 PM
A 15 - 25 hp turbodiesel driving a generator is all that's needed to keep the battery pack charged.
All that extra power and transmission is just a waste of fuel.
Posted by: Lucas | 06 September 2006 at 02:51 PM
Lucas, along the same lines: If you just do basic office routines on your computer having a high end processor and lots of RAM with a huge harddrive is just wasting electricity. Are you indicating your PC is only just barely powerful enough to run your common day to day tasks?
Posted by: Patrick | 06 September 2006 at 02:58 PM
Rafael; good to see you are back. I have missed your insightful comments.
Posted by: Richard C Burton | 06 September 2006 at 03:08 PM
Patrick - It takes 15 minutes for my ancient computer to reboot. I doubt it's wasting nearly as much fossil fuel as these overpowered autos are.
Yes Rafael - Very happy to see you posting again. I missed your insightful comments.
Posted by: Lucas | 06 September 2006 at 03:23 PM
An ancient computer is likely to waste more energy than a newer computer chosen with low-end specs in mind (such as a low-power consumption laptop processor). Efficiency doesn't just take place in the autombile but should be in everything you do if you really want to make a difference but lets do some quick math:
70% of the US electrical generation comes from fossil fuels, 67% of that generated electricity is wasted in losses generating the energy and getting it to your house. Your computer (lets say you have an LCD monitor and assume you are not using a wireless connection) will use around 400W for the power supply to run everything in the computer and consider the monitor's power useage in that to. You use the computer for 8 hours a day (3.2kW-hrs) for 260 working days a year (832kW-hrs). That means the powerplant is using around 2500kW-hrs of energy in a year to provide power for your computer...~1750kW-hrs coming from fossil fuels or 6.3 billion joules of energy. Which is roughly the energy content of 48 gallons of gas. A 17" CRT monitor easily pushes that number up by 20-25%. Insignificant compared to the fuel used by a vehicle, but it is still wasted energy. You could cut that energy use by 1/2 to 2/3 by using a modern low power "throttling" processor and motherboard in your tower and appropriately sizing a modern hardrive for your needs. Older mechanical equipment (the harddrive and optical drives) will be drawing more power than when they were new.
Only addressing one aspect of inefficiency creates a tunnel-vision approach that will fail to completely reach goals of energy independence and arresting environmental damage, etc.
Given this is a bit extreme but I'm not the one who believes a vehicle could adequately run on public roads & highways with a small gen set and nothing more. It would get you where you need to go but unless you have a battery storage setup to store energy from home you won't get very far and are likely to have better performance on a bicycle.
Posted by: Patrick | 06 September 2006 at 03:41 PM
A small gen set,, a Lithium Ion Battery pack and PHEV will meet all our needs for personal transport.
(Other important things would occur also.)
Posted by: Lucas | 06 September 2006 at 04:26 PM
Well, if you mean for the stock battery pack that wouldn't work. If you mean to put in a battery pack separate from what may be found on this concept car then that would be a different matter.
Posted by: Patrick | 06 September 2006 at 04:34 PM
Isn't it remarkable how unimpressive this car's statistics are? All-electric range of 1.9 miles at 19 mph. No plug-in option. Overall gas mileage of 36 MPG. More than 6 seconds to reach 0-100 km/hr. It gets humiliated by the PML Mini QED in every possible way -- and the Mini isn't even made out of carbon fiber.
And this is a concept car? I mean really, this is supposed to show off the best technology Citroen have got? It doesn't make sense. It must have been designed on purpose to be limp-wristed and not threaten gasoline-powered cars.
Posted by: Zobeid | 06 September 2006 at 05:31 PM
Omg carbon body still 1400kg?
Reduce the engine power, reduce the rim size, reduce the top speed, and make a 0-100kmph in 20 secs car with 100 mpg.
G-force? Forget about it.
Posted by: rexis | 06 September 2006 at 05:42 PM
BTW, this is surely a unique motoring blog that everybody is not interested to a sport car :D
Posted by: rexis | 06 September 2006 at 07:28 PM
With that V6 engine and torque of diesel it could haul 34 feet boat or trailer house. Impressive. Sorry is it Toureg? No it's a roadster, but doesn't looks like Audi's Lemans car. What was the purpose of this vehicle? Either i am short minded or these French engineers are.
Posted by: Art | 06 September 2006 at 08:08 PM
Patrick:
Parallel configuration is proved to be more efficient for HEV then in-series hybrid. For high-range PHEV, especially when used primary for everyday commuting, not highway driving, I am not sure. I believe when PHEV will appear in numbers, small genset in series could be more economical. It does not imply lethargic driving: regular car at highway speed requires only 25-30 hp. High power demand is needed only for couple of seconds during sharp acceleration, which could be carried out by battery.
Posted by: Andrey | 07 September 2006 at 12:06 AM
2 things:
If you are worried about PC power buy a laptop. They consume about 30 watts.
Another thing alluded to by zobeid - what is enough performance ?
Patrick is not impressed by 0-100 in 6 seconds, Zobeid wants 20 seconds. There is 14 seconds between these two.
The question is - what is enough - say we called it 12 seconds - which I think most people could live with.
If you try to build a car for the real world with 0-100kmph in 12 seconds and 160 kph top speed, you have a reasonable chance of success ( at >60 mpg ).
If you try to build a car with 200 kph & 0-100 in 8 or 9 seconds you have an uphill task.
But moderating acceleration is fighting against all marketing and male impulses. So you have a hard problem building a car that is "good" and that people will buy and be proud to drive.
Posted by: mahonj | 07 September 2006 at 01:44 AM
Mahoni:
Sustained top speed is not an issue. 60 hp is enough to travel with 100 mph, which very fast land you in county jail here in US. Acceleration in 8 sec to 60 mph lasts, well, 8 seconds, which could be accomplished by battery (or better yet – super capacitor) without much hesitation. Hybrid technology allows us to have high fuel efficiency and high-power boost for acceleration without compromising both. This is the beauty of hybrids we are praising about on this blog for a long time.
Posted by: Andrey | 07 September 2006 at 02:21 AM
rexis, you read my mind. How can they seriously say that this car weighs "only" 1400 kg. The 0.3 drag coefficient is also not really something to boast about.
Nice to see they used in wheel motors though.
Posted by: anne | 07 September 2006 at 03:55 AM
Anything to make hybrids (and other energy efficient forms of propulsion) more exciting and fun in the eyes of the average person should be good. Also, the economy it offers for the performance is very favourable compared to cars on the road. I, for one would love to drive it (yes, I do enjoy driving).
"this is surely a unique motoring blog that everybody is not interested to a sport car"
so true.
Posted by: Sunny | 07 September 2006 at 05:07 AM
Andrey, 60hp may be able to SUSTAIN 100mph but there is no way it will EVER be enough to get to 100mph and that is the part of the equation you are overlooking. You are taking the energy required to sustain a speed and forgetting that it takes far more energy to accelerate up to that speed in the first place.
A 15-20hp genset without a plug in capability (providing power directly to the motors) would get you no where fast.
I said a 6 second 0-60 (or 0-98kph) time is slow for a sports car not that it is slow for the average vehicle. Considering that it is lower than a ferrari, has awkward lamborghini style doors, and carbon fiber construction I would have expected better performance but atleast it does achieve 36mpg with the performance it does have. A Mustang with similar 0-60 times doesn't get anywhere even close to that type of fuel economy (of course a mustang is also around 500-600 pounds heavier)
Posted by: Patrick | 07 September 2006 at 08:46 AM
The Yaris has a Cd of 0.3 because they did wind tunnel testing and fitted diffusers on the underside and at the rear... so yes, don't really know what's up with this design.
Posted by: yep | 07 September 2006 at 09:14 AM
yep, you can have a sleek appearing design with a higher Cd than a more "boxy" looking design. The frontal surface area of a Yaris will more than make up for it's low Cd.
Posted by: Patrick | 07 September 2006 at 03:29 PM
Folks, this is a concept car. It doesn't have to be practical, it'll never hit the road. All it's intended to do is attract attention to what a diesel hybrid can do for performance and fuel consumption. Hopefully they'll have practical diesel hybrid options on the Xsara, C4, etc.
Posted by: dt | 07 September 2006 at 03:57 PM