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Citroën to Unveil C-Cactus Diesel Hybrid Concept at Frankfurt

Citroën’s C-Cactus diesel hybrid.

Like its corporate sibling Peugeot, Citroën will introduce a diesel hybrid concept car at the Frankfurt Motor Show. Unlike Peugeot’s 308 Hybrid HDi, which is based on a production platform and more oriented toward short-term commercialization (e.g., 2010, earlier post), the C-Cactus concept features a different design approach.

Low on consumption (like the cactus plant, according to Citroën), the C-Cactus offers fuel economy of 3.4 l/100km (69 mpg US), CO2 emissions of 78 g/km and a ZEV (Zero Emission Vehicle) mode. Maximum speed is deliberately capped at 150 km/h (93 mph).

The hybrid powertrain combines a 70 bhp HDi diesel engine with a 30 bhp electric motor. Built on the Citroën C4 platform, the C-Cactus uses only around half the components of a conventional car and incorporates many recycled components.

The design of the C-Cactus is intended to produce a hybrid that would be no more expensive than a mid-range family car. The solutions adopted for the design of C-Cactus also contribute to bringing down fuel consumption and CO2 emissions. Using fewer parts makes the vehicle 15% lighter than a C4 Hybride HDi for a total weight of 1,306 kg.

Citroën engineers streamlined the number of parts and mechanisms required, incorporated several functions into a single part and removed all features that are non-essential to the running of the car or to the comfort and safety of the occupants.

The central console. Click to enlarge.

As an example, the cabin consists of just over 200 parts, only around half that of a similarly-sized conventional car. One of the first moves involved the removal of the dashboard, with the original functions and loudspeakers, gearbox controls and navigation system now grouped on the central console and Citroën’s signature fixed centre controls steering wheel. The ignition key is also an MP3 player.

The front bumper section, which includes the headlamps and trademark Citroën chevrons, also makes up the lower part of the rear tailgate. The design of the car’s front end consists of just two parts: the fixed hood comprising the front wings and a flap giving access to the vehicle maintenance functions.

The door panels are made of just two parts, compared to 12 in a conventional car, and because the automatic air conditioning system virtually makes it unnecessary to open the windows, Citroën’s engineers have removed the opening mechanisms and replaced them with simple sliding panes.

The front seats comprise just two parts: a moulded, integral-skin foam part for the seat and a solid monoblock frame to hold the former in place and fix it to the floor rails.

The C-Cactus uses a significant number of recycled or recyclable materials. The windshield, windows and tires are all recyclable, as are the steel door panels, which are unpainted but have been treated for corrosion. Cork and felt are used for many interior parts and the patterned floor uses recycled leather taken from off-cuts.

Developed in conjunction with Michelin, the large-diameter and low-profile tires help to reduce ground friction area, boost fuel efficiency and keep production costs down.



What a waste of an article. You did not say if this is a serial machine or a parallel machine, the most important piece of information. I really dont want to know about door panels.

Neither did you say if it was a plug-in. But I have to assume it is not.

If you want to be helpful to your readers, say the important things first, and leave the door panels and navigation system to last.

Rafael Seidl

The parts count reduction is probably the least sexy but actually the most important part of this concept. Getting rid of the IP altogether is a bold statement. However, a center console that looks like a giant hairdryer is perhaps a little too metrosexual even for a French car.

Still, systematically reducing both the weight and the cost of the vehicle body and interior is essential for making a sophisticated, high-MPG drivetrain affordable. The diesel might be an inline three with compensation shaft and a single-scroll turbo. Diesel injectors are expensive.

I'm not convinced a relatively heavy diesel engine is the ideal choice, though. For less money, you can get a smooth-running 1.0L inline four Miller-cycle homogenous GDI engine with the smallest available twin-scroll turbo and far lower emissions. Since the power is capped at just 70hp, you could even forgo the water cooling jacket usually required for turbos on gasoline engines. The ECU simply wouldn't give you access to the areas of the engine map that require special measures to protect exhaust system components. More to the point, the cost savings on the engine would permit a wonderful dual-clutch transmission instead of the crappy single-clutch manumatic envisaged in this parallel hybrid concept.

Diesels are great for large, heavy vehicles. For something this small and equipped with an electric hybrid to boot, a spark ignition engine just makes more sense IMHO.


The point is that these folks have taken a whole vehicle approach to maximize economy. I thought it was a good review.


Did a giant step on a MINI?


As Rafael said a diesel isn't the best choice,in fact except for fuel economy it isn't the best choice for anything green.
Exhaust emissioms have been proven over and over again to be cancerous,but europe continues to embrace them because of fuel costs in their lovely socialistic society


Exhaust emissioms have been proven over and over again to be cancerous,but europe continues to embrace them because of fuel costs in their lovely socialistic society

The vast majority of commercial surface and waterborne transport in the United States runs on diesel, as does much of the offroad use. Does that make us a "lovely socialistic society" as well?

Yes exactly how does diesel equate with socialism? It would be nice to know how it's drive train works, but the previous article covers that:

"The demonstrator’s parallel hybrid powerplant uses an 80 kW (107 hp) 1.6 HDi DPFS diesel engine coupled with a 16 kW (continuous) electric motor providing a maximum power output of 96 kW (129 hp)—comparable to that of the 308 with the 2.0 liter HDi DPFS 100 kW (134 hp) diesel engine—and a 6-speed electronically controlled manual gearbox. A 200V, 5.5 Ah NiMH battery pack provides energy storage, and is recharged via regenerative braking."


Unlike Europe, we use catalytic systems, and will do so with the upcoming 50 state diesels.

So, yes, we are very much looking forward to high-mileage clean diesels (hybrid or not) in all our vehicles, small and large, here in the U.S.


Jack wrote: The vast majority of commercial surface and waterborne transport in the United States runs on diesel, as does much of the offroad use. Does that make us a "lovely socialistic society" as well?

Jack, if you need it spelled out, Europe has very high fuel taxes, which encourages the use of high mileage diesels instead of less polluting but lower mileage gasoline engines. The original poster apparently equates taxation with socialism. This is a common mindset among right wingers who seem to prefer large balance of payments deficits and oil wars to gas taxes.


The best diesel hybrid would have a two-cylinder, opposed, two-cycle, air-cooled diesel.


Remember George the diesel produces less CO2 (due to efficiency) so you could say they pollute less, of course you got to forget about the NOx and particulates to make that work.


1.1 KWh NiMH battery? My e-bicycle is close to that and its lithium.

Figures - these people are utter socialistic losers. This is 5 years old technology and then they call it a "concept car"? For the French it must be.

I dread the future with such engineers around.

All the other stuff they claim is utterly uninteresting and redundant. 6 speed transmission when it could have been a serial hybrid with 0 speeds and 0 weight of transmission? What is so "cost reducing" and interesting about that?

And then a 107 hp diesel limited to 70 hp when you could get away with 30 hp diesel in a serial?

Gimmie a break!

Bill, to the best of my knowledge, off-road and especially sea-going ships don't use any kind of emission control; the latter even use heavy crude, and are currently the most prominent source of sulphuric components in the atmosphere globally...

Many of the things you imagine US road diesel engines must be equipped with don't work with the current (and even less so) or former diesel fuel available in the US due to it's extreme sulphur content (which readily poisons catalytic converters based on noble metals). Even the current diesel fuel standard in the US is problematic for most catalytic converter systems...

BTW: I like the western european "socialist" way, as this obviously means much less expensive health care (compared to the US), coverage of virtually the entire population (despite the much less costly system) and a more or less ok pension system (again, everybody is covered), and a minimum income for the unemployed which can be enough to live with (when being very frugal)...


...the most important think on this car is the speed limit set to 150Km/h. So, the company could optimize the power pack. This limit should be mandatory for all car companies. There should also be a limit for accelaration. Almost everythink in a car is set by law. Unfortunately not these two very important aspects.


""This is 5 years old technology and then they call it a "concept car"? For the French it must be.""

JD, i'm french (please forgive my mistakes) and i can't let you say that. It's insulting.
French engineers from PSA have a great savoir-faire about creating hybrid cars. They first introduced a start & stop system, it was on the Citroën C3, and will probably introduce the first diesel-electric hybrid.

""6 speed transmission when it could have been a serial hybrid with 0 speeds and 0 weight of transmission? What is so "cost reducing" and interesting about that?""

The 5-speed electronically controlled manual gearbox is very interesting. It's the same comfort as an automatic gearbox but with about 97 % efficiency : far better than a CVT or an automatic. Additionnally, it is the same components as a manual gearbox, so it IS "cost reducing" ! (In Europe, the vast majority of cars are with manual gearboxes)
A serial hybrid is a lot more expensive, not because of the light engine or the gearbox, but because of the much more powerful electric motors and controls ! And it is nonsense on highway.


I'm beginning to wonder if anyone in Europe understands that we here in the U.S. have always emphasized emissions over mileage.

This will continue with the upcoming 50 state diesels, which will have substantially fewer emissions than anything sold in Europe.

The biggest question is how much will the new emission control systems de-rate the mileage.

And everybody does understand the U.S. switched to ultra-low sulfur diesel (15 ppm) a year ago for on-road diesel?


Series hybrid can be better on the highway too because you can use an engine with a completely undriveable map but with sky-high efficiency at certain rpms. Atkinson engine that can't idle or accelerate properly, or silly forced induction levels with 20 second boost-lag? Can't be used with a gearbox but no problem at all in a series-hybrid!

As for French hybrid expertise, remember Renault also had the plug-in series hybrid Electroad on sale for a while here in Europe years ago too. Long before any of this stuff anyway.

Rafael Seidl

@ JD -

the nature of the hybrid drivetrain is explained in the link to the earlier post. Please make more of an effort to track back the information before lambasting Mike Millikin who manages this blog. He provides a free and IMHO very valuable service.

European manufacturers are indeed behind the curve on hybrid technology relative to the Japanese, mostly because wrt fuel economy it's no better than a diesel. It's only now that the EU is insisting on extremely low fleet average CO2 emissions that car makers are beginning to accept that they also need to develop hybrid expertise. There is also a different emphasis here than in the US: the climate is considered a common asset and reducing CO2 emissions a *collective* responsibility. Ergo, everyone is expected to chip in, not just the green fringe. In that sense, a super-duper fuel economy concept such as this one is already well beyond what most people would be prepared to pay a premium for.

Btw: serial hybrid architectures, such as the GM E-Flex and the Subaru SSHEV before it, generally deliver fairly poor fuel economy once the optional grid charge is depleted. Electric-only drivetrains with battery buffering are very exoensive and feature aggregate transmission efficiencies of just 55-65%. Compare that to 95%+ for a modern purely mechanical drivetrain. The very efficient operating point of a small genset does compensate the electric drivetrain losses to some extent, especially in stop-and-go traffic, but the overall result is still worse.

@ michel -

limiting acceleration by law is difficult because it is hard to measure externally. You'd need surveillance points equipped with Doppler radar or something similar. A crude but simple approximation is to base vehicle license fees on engine horsepower, as some European countries do. However, if improved fleet average fuel economy is the goal, nothing beats higher fuel taxes.

Note also that greater acceleration is one of the visceral/emotional aspects that entice people to trade their old clunker in for a new model, which is important if you care about keeping people employed in your automotive industry. Politicians in Germany, France, Italy, Sweden and a few other European countries most certainly do!

hampden wireless

The country vs country bickering is silly.

This concept advances technology and gas hybrids could learn from some of the part/cost reducing tricks and the transmission. Hopefully this concept will bring forth more real world choices in the future. Well at least its not only GM that gets bashed.


Bill, the largest difference between CA and EU diesel emissions regulations is that over here we are relatively stringent when it comes down to small passenger vehicles and lenient with larger passenger vehicles (specifically MDPVs at nearly a g/mile of NOx) and HDVs. In the EU, larger commercial vehicles (N1, Class III >1760 kg) are allowed at most .15g/km, while over here we allow big pickup trucks (HDLTs) nearly four times that amount.

From the perspective of AQ, I imagine that CARB and to a lesser extent the EPA, has to crack down on LDV diesel emissions before going after HDV emissions so that vehicle manufacturers/the HDV lobby can't claim the LDV is the source. The EU seems to be a bit more reasonable wrt emissions from different sources. For instance, LDV diesels are allowed greater NOx and PM emissions, while LDV petrol vehicles are allowed greater CO and HC emissions. They don't have the same holes for large passenger vehicles and HDVs that we have over here.


I wonder how they got to the 78 g/km CO2 emissions. According to my calculations at 3.4 l/100 km (diesel) you get aroung 92 g/km CO2 emissions. That is utterly unimpressive for a supposed 'car of the future'.

Btw I find a weight of 1306 kg equally unininspiring.


Hmmm... The 3L Lupo is around 81g/km so that's likely a typo unless it's plug-in.

Rafael Seidl

@ Anne -

good catch on the gCO2/km emissions, there does appear to be a discrepancy there. 1 liter of diesel/100km is generally reckoned to equal 26.5gCO2/km (vs. 24 for petrol). Maybe they cheated and allowed the battery state of charge to decline during the test.

1306kg even after all the simplifications in the bodywork and interior is also not all that stellar. Just goes to show how heavy the combo of a diesel engine and a full hybrid electric drivetrain are. Besides, Citroen aren't exactly renowned for their ability to add lightness.


Rafael, good point about labour force and consumer interests.

But the thing is that auto-industry is not only answering the demand of people for mobility and prestige but also stimulating new demands and altering the reception of prestige. If a induvidual has a certain desire, ok: his/her problem. But there is my induvidual desire too. It is clean fresh air. Consuming this air does not harm anyone. But burning dirty fuels like patrol and diesel does harm for selfish base motives of the otheres. This is not very nice. To find a compromise between my/others supply needs of clean air and others for prestige, we have to compromise. That means, we do not ban induvidual transport and certain concepts of living (Suburbia) but arrogate clean state of the art and beyond transport devices. People, who are ready to pay money for induvidual transport have to pay for clean technology. There is no harm for the auto-industry as their lobby is eagerly to claim. This is no problem for people loving cars. It´s just a minor contribution that easly can be turned in a advantage for all of them. Unfortunately, auto-industries and their beloved and trusted customers belive something else. The very point seems to be a lack in education and potential of education. It took Liberals quite a while to convince the town dwellers of the 19th century to invest in municipal waste water system and to use it.
Still, we are trying to convince people to invest in technologies that should enable us to breath crisp fresh air. And that clean air is a remarkeble thing attests by everyone who spent some days in the country side, the mountians or the sea side. (Oh yes, it seems to be a reason why people like to dwell in Suburbia).
Maybe, this French design is a educated and responsible contribution to my and other needs (depends on the exhaust gas after treatment, noise levels).


I hate to say it, but if new car designs don't play to base impulses then green tech is going nowhere. I know it's not as popular to state mainstream beliefs here as it is to say that I can't wait to spend $30,000 on a 2 seat, 3 wheel hybrid dorkmobile, but it's got to be said that forcing people to go slowly in a whimpy looking car is shooting the movement in the foot.

If they sold Citroens in Texas (a big, polluting state) they'd sell maybe 10 of these cars if they're anywhere close to this concept, and that's being generous. So we've established that France is nothing like Texas, no surprise there.

But the notion that limiting acceleration, and a governor of less than 100mph, is not going to sell cars to a very large segment of the population. If it's a niche ride then fine, but it's not going to change opinions about green tech, it's going to reinforce the idea that they have to be small and slow.

How are you going to outrun an axe murderer, a carjacker (as if they'd want it), a tsunami, a tornado, or even a geo metro in something like this?

America has to stop polluting, but they've still got to be allowed to be Americans, and lots of Americans really, really like to drive. Not to pollute, but to drive. I'm guilty of it as many of you have to be. There's a few ultra-liberals out there that'd buy a car like this, but there's a lot more middle of the road and conservative people that need to be sold on hybrids. I'm liberal. This is a joke. Give me something sporty, or luxurious, or at least slightly better looking and performing than a civic or Accord. Even an ultra cheap, economy ride should at least look better than this.

In short I don't like it. ; )

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