Accumulators reach efficiencies of 99%.
Hydraulic rams are very close to the same.
Green Car Congress: Innas and NOAX to Show Hydraulic Series Hybrid Drivetrain at Hannover Messe
Here is a similar system, but mine needs no transformers since the stroke on the in wheel drives is variable and reversible.
If you are really interested read the whole article and remember it was published 3 years ago. We're still waiting for the miracle battery breakthrough.
The First generation Honda Insight is still the mileage champion among cars ever sold in the US, even though it has not been built since 2006. The battery in the Insight was not powerful and only provided assist and regeneration of a small portion of the acceleration and braking forces. Even today to get the best mileage from an Insight you minimise battery usage.
Pulse and glide is not better for fuel economy in any gas electric hybrid due to the sum of losses involved in energy conversion. I know from driving my Insight for over 30 k miles what works and what doesn't work, having average 67 MPG for that distance.
I could have achieved better mileage with an accumulator and a hydraulic drive like I am describing here and my Insight had a dead battery at 45k miles, replaced by Honda under warranty. Cost out of warranty would have been close to 1000 gallons of fuel.
The drive in this discussion has a life expectancy of 500k miles, and the accumulator would be close to the same.
Most people here understand the massive increase in fuel economy of pulse and engine off glides. This design allows you to do exactly the same thing, with on huge exception.
In the pulse you store energy in the mass of the vehicle itself, energy you recover in the glide with no fuel consumption with the engine shut off.
The vehicle I am going to build will do exactly the same thing with one difference. You pulse the engine to restore the pressure in the accumulator and use the energy in the accumulator to continue at exactly the same speed, using no additional fuel, until the accumulator pressure has dropped by 66%. Then the engine turns back on and you repeat the process.
In conventional pulse and glide you encounter exponential increases in total aero drag as you speed climbs in your pulse. My system has no such issue since the pulse is directed to increasing accumulator pressure, while the infinitely variable drive continues to apply the exact same power to the wheel, by constantly changing the stroke position and the resulting displacement. When the accumulator pressure is depleted the engine starts and re pressurizes the accumulator while the stroke position of the drive is reduced as that pressure rises in the accumulator.
Pressure drops, stroke increases.
Pressure rises, stroke decreases.
The engine or any other fuel supplied power source you choose, is the servant of the accumulator. It is not directly connected to the wheels, unless you eliminated the accumulator. This allows the engine to either run at best BSFC or shut down and use no fuel. It doesn't matter what speed you are going, what grade you are climbing, or what you average speed is, the only difference is the time the engine is running. Stuck in crawling stop and go traffic and it might only run 5% of the time. Climbing Pikes Peak it would run 100% of the time. The engine needs no throttle plate, so pumping losses are reduced and throttle control is eliminated altogether.
The whole system is configured and designed from the principle of the lest amount of parts for the greatest benefit, which means a vehicle that cost less to build than anything current available. Not $100k, $50k, or even $20k vehicles. The cheapest new car today in the US market is the Nissan Versa at $10,900. This vehicle would cost less, because it would use 25 to 30% fewer parts. Parts that cost a lot to repair and replace would simply not exist.
My reason for building this myself, is the claims I have just made are, quite frankly, hard to believe. Only when companies actually experience first hand the demonstration of the technology and it meets expectations will they begin to consider building vehicles.
I went through a Nissan factory shop manual for a 1983 280ZX and what I am describing would eliminate over half of the parts and repair procedures in the shop manual.
All manifold throttle controls.
Clutch or torque converter, including controls and clutch hydraulics.
transmission
differential
prop shafts
brake system (except for emergency brakes)
The engine can be redesigned for producing power at a precise RPM and load range, with reduced strength in connecting rods, bearings, pistons, as well as many other components that must handle much higher stresses involved in high speed operation. Max engine speed would be about 3500 RPM, and this allows applications of current HCCI (homogeneous charge compression ignition). This is currently under development by Argonne labs with thermal efficiencies approaching 60%, compared to your vehicles average thermal efficiency at 17%.
My goal is to build a vehicle that can travel a mile on one ounce of gasoline at speeds averaging 40+ MPH. I have the funds,technology, and the machine shop working for me today.
Battery-electric power could also provide accumulator pressure, so don't think for a second that this design does not include that configuration. In fact as previously mentioned, since the motor has few connections to the vehicle, you could use either batteries and electric motors gasoling engine (or diesel) or a combination of those power sources.
regards
Mech