Could this technology be used or adapted for larger 7-seat VUS for the American market?

No batteries and no FCs is interesting?

How about just an 860kg car with carbon composites used for the body panels, sides, doors and roof and the coil springs.

That would give low fuel consumption, but would it be affordable? Probably not.

Adding the compressed air hydraulic system will add cost and weight along with the better MPG. Also not likely to be affordable.

And they imply that the engine somehow supplies compressed air directly. Does the system actually just pump the oil into the tank and compress the air?

I also think it "sounds as though it really should not work"

This appears to be a hydraulic hybrid, using standard hydraulic accumulators.  The language of the article suggests that the storage medium is ambient air; the previous articles don't support that.

The fuel economy does not appear to be unrealistic.  The study of London diesel cabs a while ago (I'd have to dig, no time) found that a hydraulic drivetrain could double fuel economy by allowing the engine to operate in a highly efficient low-RPM, high torque region that conventional transmissions rarely if ever reached.  Combined with downsizing the engine, 2 liters appears to be quite doable.

The wonderful part of the hydraulic hybrid is that it needs nothing of the supply chain of batteries and high-power electronics needed for electric hybrids.  By going to a supply chain already established for other things, years can be cut off the time needed to ramp up production.  Frankly, I'm shocked that these things haven't hit the market already.

HarveyD

The idea is that it should be cheaper and more efficient than a PHEV, compressed air based energy recovery can swallow better burst of energy from breaking than a 1.5KW battery like the one use on a Prius. An Hybrid air-hydraulic can return 70% of the initial breaking energy where the Prius only return 30%. And for only half of the cost of a PHEV transmission. In city driving this car would out-beat the Prius by a long shot in term of not only efficiency but also driving fun, the hydraulic-air system provides a lot of torque at low speed. And I think this system would work better on a heavy pick up truck or SUV than a PHEV system, PHEV don't work well for heavy vehicle because you need a too big battery which would be too costly

The pneumatic/hydraulic combination is brilliant,
I wish them all the best.

I must hasten to add that at 40 C discharge capability, solid-state Lithium battery will be very powerful and will be able to beat anything a hydraulic hybrid system can do. For example, a 1.3 kWh solid-stare future Prius battery at 40C is capable of 50 kW, which is twice that of current Prius. However, due to the light weight and compactness of this battery, a 2-kWh pack can be used to boost power to 80 kW, which will give very spirited acceleration boost as well as very efficient braking energy recuperation. Adding to this a 70-kW engine and you will have 150 kW, or over 200 hp of power...in a car under 3,000 lbs, this will give very spirited sport-car performance at very high efficiency, while the reliability will be unbeatable!

Let’s not get ahead of ourselves here.

1. This Peugeot 208 Hybrid Air 2L will be just a Demonstrator.

2. Its claimed capabilities, at this point, are vapor.

3. It uses compressed air which loses much energy to heat during compression - but maybe not an issue if all it provides is IMMEDIATE and very SHORT bursts of power - see #4 below.

4. The hybrid capacity is apparently closer to “just 10 seconds” than to 10 minutes.

5. The future improvements of the Prius might come at to high a cost but the existing Prius is much more car (and more for the money) than this 850kG future car is likely to be.

@Harvey,
Toyota already has an HEV capable of 112 mpg, it is known as the Ft-Bh, and it doesn't even have solid state Lithium battery nor SiC inverter, but simply depends on lightness and downsized engine.

If you would apply fundamental understanding of physics, there is nothing that would permit a comparable hydraulic hybrid vehicle to be more efficient than an electric hybrid. Future high-powered, light-weight, and compact solid-state battery and SiC inverter will make electric hybrid even more efficient.

sd, there are variable displacement hydraulic pump/motors.  Throttling is not necessary.

The virtue of the hydraulic hybrid is that it has a completely independent supply chain from the electric hybrids.  This allows rapid expansion without running into shortages of components or manufacturing capacity.

The air part can capture a lot of braking energy, not so much with less than 1 kWh of batteries. Those batteries degrade in performance over time and use, not so with air/hydraulics. As long as the seals last, the device works the same as the first day.

RP:

Let's hope that Toyota will soon produce their 'better than' 118 mpg HEV soon.

Reduced 'dead weight' may indeed be one of the best way to reduce the energy required to move a vehicle from A to Z.

When Toyota comes out with this super HEV, We would change our Prius and Camry Hybrids fast enough.

Engineer-Poet

Your are right in that power is pressure * flow rate and with a variable displacement motor, it is possible to reduce power without throttling losses by changing the flow rate. You do need a variable speed transmission as the pressure gives you torque and the displacement gives you rotational speed.

No matter what you do, you will have a less efficient system with hydraulics than you would with electric. However, the hydraulics may have a lower initial cost but would probably require more maintenance.

Roger Pham

I work as an engineer and am also a principal of a small company that builds a relatively high tech agricultural harvester. We use a hydrostatic transmission which is what you are describing for the wheel drives. Electric would be more efficient but a relatively small amount of the total power is used for traction. We also use some hydraulic motors and cylinders for other functions such as conveyor drives and lifts but where we are different is that all of the high speed positioning is done with 375 V electric servo motors. The use of the electric drives gives us a substantial efficiency and maintenance advantage over our competitors. As we go forward, we will be electrifying more of the functions and may add ultracaps to recover some of the available power from deceleration.