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Peugeot showing new 108, new engines, new HYbrid Air implementation at Geneva Show

Peugeot will unveil two all-new models—the 108, successor to the popular 107; and the 308 SW—and two new engine technologies—the 1.2-liter PureTech e-THP three-cylinder turbocharged gasoline engines and new BlueHDi diesel emissions technology, to appear on several versions of PEUGEOT 308, 308 SW and 508—at the forthcoming Geneva Motor Show.

The company will also showcase a 2008 HYbrid Air crossover—an implementation of Peugeot’s HYbrid Air hybrid system (earlier post) in a 2008 Crossover. HYbrid Air is a full-hybrid solution combining compressed air and hydraulic power, with no battery required for energy storage. Hybrid Air combines a PureTech gasoline engine, a compressed air energy storage unit, a hydraulic pump/motor unit and an automatic transmission with an epicyclic gear train.

The Peugeot 108. The Peugeot 108 is an A-segment offering and is the successor to the 107, which has sold 800,000 units worldwide. The A-segment accounts for about 10% of the European new car market.

At 3.47 meteres long and weighing from 840 kg (1,852 lbs), the 108 is a compact and light urban runabout. Available as a three or five-door hatchback, it will also be launched as the 108 TOP! Cabrio version, with retractable fabric roof.

The 108 is primarily a city car, however it is also a key part of PEUGEOT’s move upmarket, so buyers get a comfortable premium cabin. Features available include a seven-inch touch-screen, reversing camera, PEUGEOT Open and Go system (Keyless Entry and Starting), automatic air conditioning, heated electric mirrors and automatic lighting.

Customers will be able to choose from four power units, including 1.0-liter VTi 68bhp and 1.2-liter PureTech VTi 82 bhp three-cylinder units. CO2 emissions are as low as 88g/km.

308 SW. Peugeot is extending the 308 range with a second body style: the SW. It builds on the success of the New 308 hatchback, which has already generated more than 46,000 orders across Europe. The new C-segment offering is built on the new EMP2 platform on which it’s built, and features a 140 kg (309 lb) weight reduction compared to its predecessor.

PureTech. The 1.2-liter 110 and 130 bhp (82 and 97 kW) PureTech e-THP three-cylinder turbocharged gasoline engines are modular and compact. High pressure direct injection and a next-generation high-efficiency turbo provide strong driveability from the lowest engine speed, with 95% or torque available between 1,500 and 3,500rpm. Against engines of equivalent power and driveability, fuel consumption and CO2 emissions are reduced by 21%.

BlueHDi diesel. Peugeot is also unveiling its new BlueHDi diesel emissions technology, to appear on several versions of PEUGEOT 308, 308 SW and 508. Associating Selective Catalytic Reduction (SCR) and a particulate filter with additive, it allows NOx emissions from e-HDi engines to be reduced by up to 90%; CO2 emissions and fuel consumption are optimized while still eliminating 99.9% of particulates. The BlueHDi technology already comfortably meets the Euro 6 emissions standard and will be progressively introduced on all Peugeot’s diesel models.

HYbrid Air. Peugeot’s HYbrid Air technology uses twin sources of power to obtain the best efficiency on the move. They are compressed air, gathered from the recovery of braking and deceleration energy, and PEUGEOT’s latest generation three-cylinder PureTech gasoline engine. This technology will be demonstrated at Geneva in a 2008 Crossover.



if peugeot keeps its promise to put on the road its air hybrid with claimed 96MPG in 2016, we won't see many EVs on the road for quite a while...


Generally speaking, electric drives are considerably more efficient than hydraulic drives and while batteries are are heavy compared to gasoline they will store more energy than compressed air. The only thing that the HYbrid air could possibly have going for it is cost. Hydraulic hybrid trash trucks make some sense as they constantly start and stop so all the energy you need to store is one stop cycle and generally you have other hydraulic functions. Even with the trash trucks, electric hybrids are more efficient.


I thought of recovering waste engine heat using compressed air, but the numbers did not look good, it did not produce enough power to justify the costs.


Who said (besides you) that electric drives are more efficient than hydraulic?


At this point, it's a pure matter of fuel savings per $/€ of hardware.  If Peugot can use pneumatics to recover braking energy and (especially) slash throttling, friction and idling losses for less than batteries cost, I hope they take over Europe.


The drivetrain of a hydraulic hybrid has the potential to much higher efficiency than an electric hybrid. This is well-known since many years ago. I have chosen a link below that shows this. It is a comparatively old presentation but it is fundamental, clear and shows the potential. The “roundtrip” efficiency for hydraulic hybrids during regenerative braking can be higher than 70%, whereas electric hybrids provide less than 25%. I recognize that Li-ion batteries will improve the latter figure somewhat but the gap would still be substantial. Furthermore, the high efficiency drivetrain could enable series hybrids with high efficiency, an application where electric hybrids cannot provide this efficiency. In addition, a hydraulic drivetrain is ideal for a free piston engine where, again, an electric drivetrain struggle with efficiency and bulkiness. Note that using high operating pressure enables a hydraulic motor of 500 hp to be as small as your fist. Hydraulic hybrids are less complex and costly than electric hybrids. They need no rare metals of elements and are inherently, in this respect, environmentally sustainable. This cannot be said about electric hybrids.

The only drawbacks I can think of with hydraulic hybrids are the lower energy density of the accumulator in comparison to a battery and the simple fact that the development is at an earlier state than what it is for electric hybrids. Energy density is of interest if a plug-in version is the objective and in this application I think that a Li-ion battery must be added. Again the same complexity and cost will be associated as for electric plug-ins which, at the moment, is prohibitive for any larger market penetration anyway. A competitor on the horizon might also be the kinetic hybrid but I will leave that discussion for later…

For sure, Peugeot knows what they are doing.


Beat me to it, Peter. For pure stop-and-go, currently-available technology in hydraulics beats electric hands-down for round-trip efficiency. As you stated, specific energy is the issue (volumetric especially). Another problem is noise. Although the torque to inertia ratio of an hydraulic motor is unbeatable (as you also point out), they make a LOT of racket.

Chrysler was doing some work in this area (see ). I don't know if they were genuinely serious or if it was part of a ZEV credits strategy -- for awhile this kind of research would "buy" credits, but I think that has faded away. In any case UPS and FedEx have been running them in some urban applications, where this technology really shines.



Who said (besides you) that electric drives are more efficient than hydraulic?

John Deere


"Compared to the Caterpillar D7R Series II, the D7E is projected to deliver 25 percent more material moved per gallon of fuel."

Comments from Caterpillar on the Cat 6120B H FS

"Cut your fuel cost per ton by at least 25% compared to other shovel options – without sacrificing productivity – with our diesel-electric hybrid technology."


I work for a start up that is using electric servo drives on a specialized piece of agricultural equipment.
Essentially, an electric gentry robot. Anyway, our fuel consumption is about half that of our competitors who use hydraulic drives. We will be converting more of the machine to electric. We recently had a sales presentation from Parker on the possible use of electric traction drives. Parker build both hydraulic and electric drives but I think that the handwriting is on the wall for the future of hydraulics -- it is on the way out for many applications. Also, if hydraulics were more efficient we would have diesel hydraulic locomotives instead of diesel electric locomotives and this idea was given a serious try back in 50's or 60's.


There's a lot more decades of experience with hydraulics and accumulators and whatnot than with RE magnets and NiMH battery packs, so I'm not sure there's a huge amount of improvement available beyond the current generation of hydraulic hybrids.  What we need is for hydraulic hybrids to become the default.


sd, I don't disagree that the question as posted by Peter ("Who said (besides you) that electric drives are more efficient than hydraulic?") is perhaps not phrased quite right. Converting the output of the ICE to electrical energy, and then in turn to mechanical output through an electric motor, is indeed a winner against hydraulics if we're measuring optimal end-to-end conversion of an electric vs. hydraulic primary drive train. But in a stop-and-go regenerative system, where the measure of "efficiency" is how much of the waste energy is recovered, stored, and reused for acceleration, hydraulics wins (and big time).

The challenge with any hybridization is that it becomes very mission-dependent when measuring relative figure of merit. Caterpillar's Heavy Shovel is a great place for electrical conversion because when the shovel is not carrying load, the electric motor driving the hydraulic pump can be idled, turning the pump just enough to overcome system losses. In turn the diesel-driven generator is unloaded; add in the supercapacitors that are used for energy storage and the engine operates the engine can be operated much closer to optimum. A direct-driven hydraulic pump must be run at engine speed -- further any accumulator large enough to make a meaningful flow contribution to operate a 50-60m^3 shovel is just too effin' big (hence no regen). So yes you are right.

In an urban hybrid application, the accumulator is sized only for a burst of power (seconds), and the motor/pump operates only briefly as refill/additive power. They are not the primary means of power conversion.

Hydraulics definitely has a place in a dense stop-and-go environment; I'm not sure it belongs in saloon (and smaller) sized private automobiles with a broad usage. But it is fantastic in the urban delivery truck, bus, or taxi application if you can stand the noise.

BTW, if you think I'm anti-electrification, please understand I have a 2012 Leaf sitting in my garage right now. Mr. Clipper Creek will send some leptons starting at 0430, and heaters will kick in at about 0640 so I'll have toasty toes and a charged battery right on time. No need to sell me on electrical goodness (for the right usage). I just think hydraulics deserves a shot.


I believe that a hydraulic hybrid may be more cost effective than an electric hybrid for some stop and go applications. A trash pickup truck is an obvious example where the truck accelerates to the next stop which may be only 30 m away and then brakes. These trucks also have other hydraulic functions so a hydraulic hybrid makes sense. However, while it may be more cost effective in the current market, it is not more thermal dynamically efficient. We had a meeting last week with some sales engineers from Parker Hannifin, Parker is big in hydraulics and builds some of the hydraulic trash truck hybrid systems. However, they are working on electric traction drives which is what they were trying to sell us. They told us that they are working on electric hybrids for trash trucks because of greater efficiency.

There are a number of problems with the efficiency of hydraulic systems. Most hydraulic accumulator are gas over hydraulic. When you compress a gas, it heats up. If any of this heat is lost, it is an efficiency loss. A bigger problem is flow loss especially thru flow control valves (throttling loss). Modern digital Pulse Width Modulated (PWM) electric controls do not have this problem as the power is either full on or full off and do hot have the equivalent of a throttling loss. Also, in general, electric motors and alternators are more efficient than hydraulic motors and pumps.

Now, why is Peugeot building their air over hydraulic system? Maybe they think that it is less expensive and they will have a cost niche. Maybe, they just want to be different.


@ sd.... Yes, Peugeot and specially Citroen liked to be different and sometime leaders with short lived innovations.

Improved ultra caps/batteries will eventually capture as much braking energy and store more energy than equivalent size hydraulic accumulators. Secondly, electric drive trains are easier to control and maximize.

Electrified vehicles are here to stay and prosper.

Richard C Burton

great discussion you guys-thanks for your well thought out reasoned info, and with no name calling or slurs! great job, and I mean that!


@sd & others
Do you think the fuel consumption cited by Peugeot indicate low efficiency? I would say high efficiency… With an open mind other solutions than electric drivetrains might be considered and developed. I cannot understand why any other option than electric must be scorned all the time on this site. Since EVs and plug-in hybrids have been a total failure so far, and seem to remain so in the foreseeable future, other solutions must be developed. This is one. I can think of other solutions as well…


Who's scorning the non-electrics?

sd, the actual pressure ratio in hydraulic accumulators doesn't have to be very large as they are pre-pressurized.  The temperature swing can be reduced by using a gas with a lower Cp/Cv, such as methane instead of nitrogen.



I am not scorning other solutions. As I said hydraulic hybrids may make sense for start stop applications with trash pickup trucks being the most obvious. But in general, hydraulics are not more efficient. As I said, I work as an engineer (and also part owner) of a start up building a specialized self-propelled agricultural harvester. The machine is part hydraulic and part servo electric. We use hydraulics for some functions as they are more cost effective but they are not more efficient. We just changed one function from hydraulic to electric. The electric drive cost more but the performance was better. In the future, we anticipate changing more functions to electric and would like to go to electric traction drives but we currently use hydrostatic drives with a variable displacement pump and 2 speed motors. Why? Because the hydrostatic drives are less expensive but they are not more efficient. It is also not where most of the power s being used during normal operations. We do use electric drives for some of the high power consumption functions and it makes a major difference in fuel consumption.

The Peugeot air/hydraulic hybrids will be more efficient than non-hybrids but I would not expect them to be more efficient than electric hybrids. However, the air/hydraulic system may be less expensive.


sd, I think we are pretty much of a mind here. As your professional experience bears out, the word "efficiency" is the rub here. Your explanation is good. If I might add... the Cat Heavy Shovel that you referenced in your earlier post is a another illustration. When Cat engineers decided drive the main hydraulic pumps with an electric motor, they added an additional conversion step. The diesel now drives a generator that powers a motor that drives the pumps, rather than directly. This is, strictly speaking, "less efficient". But the ability to optimize pump speed, recover energy when lowering the load, and most importantly operate the engine within a narrower band allows the machine to do the same actual work with less fuel. Operationally, it's "more efficient".

The Boeing 787 does something similar with its hydraulic system, replacing the large two per engine hydraulic pumps with four variable speed, electrically-driven pumps and only one much smaller engine-driven pump per side. Since the aircraft is designed around the long-range cruise condition, in which hydraulic loads are very low for 90+% of the mission, the net OPERATIONAL weight of the more-electric system (hardware PLUS fuel to drive it) is less for the more-electric solution in cruise over 8 hours. So the idea of "efficiency" is very mission dependent. Earlier you had used the trash pickup as an example of near-ideal for the hydraulic hybrid: absolutely correct. In practice, UPS reports fuel savings of 50-60% on their urban routes. The very short burst of power really favors hydraulics.

It is numerically arguable that ultracapacitors should be even better, what with Coulombic efficiency at 99+%. But there are some reality challenges. Even Maxwell's pitch states a round-trip efficiency (RTE) of 70% in the case of "discharging to ½ voltage in 5 seconds, and recharging at the same rate until fully charged." But the inverter isn't able to make use of a 2x voltage range. The motor is also operating away from its peak efficiency, and rotor inertia is considerable greater than its hydraulic cousin. The reality is capacitor-based system RTEs much lower -- around 30-40%. Conversely an hydraulic solution can be 10-15 points higher (again, in a short duration, high-power application). I also don't think the accumulator thermal issues are an issue at all. Nitrogen-pressurized accumulators for aircraft applications run very active duty cycles (see Parker's EHAs on the F-35) and heat is not a problem.

Again, like you I question the value of the technology for an automobile for all the reasons we both addressed earlier. The relative silence from Chrysler (Fiat) since 2012 hints at how problematic their minivan system might have been despite very promising fuel efficiency improvements in trials. In general I think hybrids as we know them are very much a stopgap measure, and I see a much larger role for ultracapacitors as you do.

Enough from me already. I'll shut up. I am envious of what you're up to in your work. Best of luck.


Herman, I worked on a small piece of the 787 but I never learned that bit about the hydraulics (the HVAC I knew about).  Thanks for that bit of enlightenment.

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