Engineering TV

The actual energy storage is in the gas in the bladder of the hydraulic accumulator.  Why not have a pneumatic hybrid?  Way back in 1930, a diesel-pneumatic was more efficient than a diesel-electric, and air is cheap and easy to store.

This is the most well executed production I have seen yet.  Good video, good audio, two cameras with interspersed clips of the product, well thought out questions, and enough time allotted to actually let your audience learn something.  Kudos.  Where do I send my resume?

Fantastic concept. What about oil leaks from the hydraulic systems and the resulting fire hazards? I have seen Industrial hydraulic systems over-time that tend to get leaky.  

Stewart, thanks for the positive feedback!  More to come from Lightning Hybrids this week and a few next week.  Every once in a while we'll do these in-depth productions on location - glad you like them!

Eric:

The Hydraulic Hybrid in this configuration is essentially a pneumatic hybrid as mentioned.  The energy is in fact stored by compressing air.  The air that is compressed is nitrogen gas which is held in the accumulator bladder.  The advantage of the hydraulic system is that you are pumping

an incompressible fluid which allows you to achieve higher flow rates in a smaller package.  A one hundred horsepower compressor that would allow you to compress and store enough energy to accelerate the vehicle from a stop would be half the size of the vehicle itself.  Imagine an industrial air compressor.  As I understand most pneumatic hybrid vehicles use a smaller compressor that runs continuously at a low power setting.  The one hundred horsepower hydraulic pump occupies much less than a cubic foot of space and only weights 45 pounds.    

Brian:

Certain types of seals work better than others.  If you are clever enough in how you design your manifold you can eliminate most of the hoses or piping in the plumbing.  By sticking to mainly o-ring and mechanical seals in the few seals that you have you can largely eliminate leaks from the system.  

We did, in fact have a hydraulic fluid leak during one of our test drives.  It was messy, but no more so, or more dangerous than a typical oil leak.

My biggest question, what is the duration of the hydraulic accumulator's accleration.  From a stop, full PSI charge in the accumulator.  If you get the engine to full power, and accelerate how long does the charge last and at what speed does it drop off to being engine only - hydraulic loss.

I think the concept is excellent, providing the short duration high torque required for most driving situations, such as over taking at highway speed, or accelerating from a stop light, where the length of time the pressure differential at the pump is large enough to increase the usable power.

Just curious as to how long that lasts, and in the typical automotive tests how the system performs, those being the ones automotive readers look at.

Standing quarter mile, zero to 60, zero to 100, 60 to 100,etc.

Final question re: braking control, as a driver who constantly times lights to not have to stop, and downshifts to engine brake and cut the fuel consumption during decelleration, I would personally enjoy braking feed back re: how much was being provided by hydraulic regeneration and how much braking was being provided by the car's brakes themselves.  This would allow the user to modulate the brake such that they were maximizing efficiency.  I realize that in the current rear wheel drive variant you are limited to the ~20% braking effort possible, perhaps utilizing ABS wheel speed sensors to control a pressure release on braking in combination with the front axle brakes to allow maximum regeneration?  I really have no clue how far you've come since these videos were posted.

Great ideas!