The total efficiency is through the in wheel motor-regenerator to the accumulator then back through the in wheel motor.
If we can get the in wheel drives to 95% (very possible) then you have
.95X.99X.95=.893475 or very close to 90% efficiency.
Thats about as good as a conventional drivetrain which only directs power to the wheels with no regeneration.
It will also allow the engine to cycle on and off the maintain the accumulator's level of reserve energy, which allows the engine to only run at its peak efficiency.
Basically this means the very essence of hypermiling can now be incorporated into the vehicle itself, without any special imput from the driver.
You have two pedals, one accelerates and the other decelerates. If you push neither pedal you are coasting. No gear shifter, or clutch, just go coast and slow. You dont even need a shift indicator. No maunals or automatics.
And 25% fewer parts per vehicle.
The only friction brakes you need would be a cable operated emergency brake, in case of a total system failure, which would require the 4 individual wheel circuits to all fail simultaneously. The probablity of that happening would be greater than getting hit by a meteriorite.
at one time, you were talking about a take off assist that would use regenerative breaking to charge an accumulator that would be released when the break is released. I mean the add on version that could be retro-fitted onto an existing auto. is that going to be developed as well? If I remember correctly, didn't you say that it would yield around 30 percent better FE?
I think it is awesome that the ball is rolling on this project. with the reduced gas prices, I was worried that many projects (like yours) would fall along the wayside. I am glad that they aren't. I personally would be interested in the retro-fit if it was actually produced. I think it would be an awesome idea.
IMO the problem with most new technology is that you have to purchase a new car to get it. hybrids? electric? hydrogen fuel cell?....no retro-fit, you have to buy new. I think the retro-fit that you described would make the most difference. it yields less of a gain but it would make the biggest difference now. eventually, the in-wheel trans with accumulator will make a bigger difference but I can't afford a new car (even if it is very reasonably priced) I may be able to afford an add-on piece (depending on price) and with that, you can have the brand car you want and not have to buy the brand that decides to use this new technology.
I hope that 2009 and 2010 will bring even more good news with new technology that will yield better gas mileage and efficiency. I am expecting a daughter before the end of this month and am scared to death of the world that she is coming into. there seems to be some hope that is shining through the madness that we call our lives. that hope is what keeps me going in these difficult times.
keep us posted, we can all use good news.
Be the change you wish to see in the world
There are 3 stages of evolution of the design. These are outlined in the EPA documents.
The Launch assist would be the first configuration available. It would be best on a FWD small sedan, using the rear wheels for the launch assist. The system would recapture braking energy as long as you brake no harder than you would if you used the emergency brake in your car. Hard stops would waste energy beyond the capacity of the rear axle to stop the car with no help form the front wheels. I can drive my car with only the emergency brake, unless some other driver or a yellow light forces me to stop more agressively.
Even the launch assist configuration would be capable of maintiaining speeds by cycling the engine on and off for much better mileage, but it would still retain the conventional powertrain with it's weight penalty and higher parts count per vehicle.
The second stage would be when the powertrain relies on the accumulator for all drive functions. This is when the conventional powertrain is no longer needed, and all breaking forces are recovered at all 4 wheels, hopefully at over 85% efficiency, from wheel to accumulator, back to wheel.
The third stage is a transformation of the engine and powertrain once again. Most people I have talked to think it is too radical at this time, but the success of the first two stages will provide the funding for the third stage.
In the third stage there will be no accumulator. The Engine itself will burn fuel to accelerate its own mass to 4000 RPM, then it will destroke itself and transform into a free spinning flywheel and store energy with its own mass. Regenerative braking will increase the flywheel speed to as high as 10,000 RPM. The engine will need no cooling system other than its own lubricant with a thermostatically operated bypass when oil tempertature exceeds 300 degrees. It will also require no throttle control system since it will either run at max efficiency or not run at all as a flywheel. It will require only one fuel injector, have only one intake and one exhaust port, and warm up within 30 seconds of initial starting.
The engine will be buried in the front crossmember which will do double duty as a scattershield in case of a catastrophic engine failure. It will start in flywheel mode and even have a manual start where the driver can spin the flywheel with his own energy and then switch it to stroked combustion. In other words even if your battery was stone cold dead you could still start the car using you own body strength, like the old days when engines were "cranked up".
The third stage may use a engine-flywheel and a smaller accumulator for greater versatility, or a battery of sufficient capacity to give you a 5 mile range if you run out of fuel.
First stage 30-50% for practically no increase in vehicle cost.
Second stage 100% with vehicle being less expensive to produce
Third stage 150% possibly over 200% with even lower vehicle cost
Of course the vehicle cost is based on mass production afer initial tooling and startup costs .
The final version would probably have 40% fewer manufactured parts per vehicle, with a life expectancy of 500k miles.
Obviously all the mentioned systems that would be eliminated would not exist to break down. It woul take some time to list all the components, but thing of it as systems.
all induction parts related to throttle control
Catalytic Converter light off would be significantly faster since all exhaust gasses would pass through the same port, as well as engine warm up.
Remember the old flywheel toy cars?
Engine size would not really change the systems efficiency so you can have a powerful enigne that just runs a lower percentage of the time.
All vehicles would have 4 wheel drive, that switched to two wheel drive under light acceleration. Suspensions would be hydraulically adjustable, so in deep snow you just increase your ground clearance to 18 inches, then drop it down for better aero when conditions permit.
Acceleration would be at the limit of all 4 wheels traction with the pavement, with ABS and traction control individually applied at each wheel without any connection between wheels being necessary. Each wheel would be its own independent drive system, which gives you quadruple redundancy.