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I looked through the document you provided Robert. While the average of motor and inverter efficiencies looks like it is about 70%, that does not cover the wheel to wheel efficiencies.
The example you provided (Honda Accord) also has a CVT transmission which has its own losses, as well as the battery which also has losses. Manuals have losses as well in both directions (application and recovery).
Consider the Insight you and I drive, which can only recover half of the energy it can generate electrically. Also consider that it is generally accepted that best efficiency is achieved by minimizing the battery use in the Insight.
That puts the Insight at 50% recovery, with additional losses in reapplication that further reduce the efficiency to close to the percentage I provided.
That's wheel to wheel. including all of the cumulative losses. While we can debate the percentage of cumulative losses, you can not debate the fact that batteries will not accept energy input at the same rate as they will output the same level of energy.
That's a non issue with hydraulics.
In your provided example, the energy pathway is wheel, to axle, to differential, to transmission, to motor, to controller, to cables, to battery. Each component compounds to totality of cumulative losses as you know. The same pathway is duplicated in reapplying the power which effective doubles the cumulative losses. In any process where the steps in energy conversion are many, even the smallest losses are compounded.
Another disadvantage of the Accord configuration is the motor can only spin with the engine, which is solvable by placing another clutch between the IMA and engine.
Electric motor efficiencies are best in a certain range of speed, while in-wheel drives are most efficient at the lower speeds of the wheels. In the referenced photos the bent axis pump is spinning at the same speed as the propeller shaft, which kills its efficiency. In- wheel drives at all 4 wheels suffer from no such issue and can recover energy to the last revolution of the wheel itself and at efficiencies that are their highest when fluid flow rates are lowest.
Compare the cycle life expectancy of any battery to an accumulator. There is no comparison and rebuilding an accumulator is a simple process that is very inexpensive compared to rebuilding or replacing a battery.
The cumulative losses of electric configurations do not allow P&G operation of the system.
The INNAS link clearly states that engine to accumulator P&G is an essential part of the operational strategy.
The bent axis pump used in the comparison (photos provided) is not designed specifically for the application. The rest of the components are also off the shelf.
My design was from the very beginning conceived for the specific purpose of replacing the power train in vehicles, at a cost that makes an inexpensive basic vehicle possible at $10K newly produced. That amount wont cover the cost of the battery in the Nissan Leaf, with a 100 mile range.
Even in the Leaf a launch assist rear axle with my in-wheel drives and an accumulator of two gallons capacity would extend the range by possible 50%.
That's a prediction I can not back up with concrete data, but I must emphasize this point. If you can P&G any vehicle in its current configuration, you can improve its mileage by incorporating P&G into the vehicle itself.
Some may consider that an over simplistic statement, but I maintain it as a fact that seems to be largely misunderstood today.
I hope our conscientious debate contributes to the knowledge base of everyone who reads this thread, my friend.
regards
Mech
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