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I think we can debate the reciprocation definition and loose the progression of the concept.
Just agree to disagree.
My conclusion is based on the definition of a rotary engine which is what it was called when it came on the scene.
A radial engine is definitely a reciprocating engine. Reciprocation of the pistons in the cylinders is converted to rotary motion by an oscillating motion of the connecting rod interface with the crankshaft journal.
Any way, back to the Hydraulic Hybrid evolution.
Once I had progressed to the point of focusing on an in wheel hydraulic pump motor. I considered the potential sealing issues of the pistons and cylinders. With displacement changes the volume of fluid in the displaced areas in each cylinder would have caused inherent imbalance of the rotating assembly especially if the displaced area was on the perimeter of the assembly. Trying to seal the connection between the pistons and cylinders as well as the rest of the connection points presented an almost impossible task.
By reversing the pistons and cylinders the passageways for fluid movement would be much simpler. I also came to the conclusion that instead of trying to seal of each individual interface, it would be much easier to just have all the components located inside a closed containment vessel. This way the designed tolerances would allow a very small amount of intentional leakage and the whole containment vessel would be filled with fluid at low pressure directly connected to the low pressure return circuit.
The logic was instead of fighting a small percentage of leakage, make the leakage work for you by using it for lubrication and cooling. So externally the complete component would look like a cake pan spinning around the fixed axle, with only a seal between the axle and hub-drum assembly subject only to low pressure circuit pressure levels. All internal components would be lubricated by the small amount of inherent leakage, which would be offset by the elimination of seal drag friction.
This thing would work completely submerged to a depth that equalled the low circuit pressure level, probably about 30 PSI. Another benefit would be in the event their was any air in the assemble it would be purged by centrifugal forces, also into the low pressure return circuit.
The engine concept went to the back burner due to the fact that a power train design can be quickly incorporated into existing vehicle architecture. My 2001 Echo has rear hub assemblies that bolt to the beam rear axle. This meant I could simply remove the existing hub assemblies and replace them with two of the pump motors. Adding a hydraulic pump to the engine would allow accumulator recharging if I wanted to continue further evolutionary development. In the first implementation it could simply be a launch assist recovery rear axle, capturing and reapplying normally lost braking forces.
It would also make acceleration significant better after a regeneration event, above and beyond the normal powertrain's capability.
The next phase would be to remove the power steering and substitute it with a manual unit. Then install a hydraulic pump with a toothed belt drive, which could recharge the accumulator at constant lower speeds to allow engine cycling while maintaining constant vehicle speed. Power demands above the abilities of the system would require normal engine and transmission supplementation of the standard power train.
The third phase (hopefully after an income stream was created by the launch assist commercialization, would be to build a dedicated vehicle with a pump-motor at each wheel, connected directly to the accumulator, with the engine (or motor) providing replenishment of accumulator storage levels as its sole function. The rest of the conventional power train components would no longer be necessary.
Consider the 5 states of vehicle operation
1.Idling-waste of fuel-eliminated in this design
2.Coasting-engine off-absolutely
3.Acceleration-can be by accumulator or both engine and accumulator. All 4wheels driven selectively together or separately. Each wheel has no connection with other driven wheels. Integration with current anti lock brakes and traction control is easy. Wheel speed sensors would change stroke position to adjust power or regeneration at each wheel individually. Current systems use brake application for traction control, and brake line pressure fluctuations for ABS. Applying brakes to an accelerating vehicle is a waste of energy. This design would control the power application and recovery at each wheel in microscopic increments. without wasteful brake application to control wheel spin on acceleration.
Proper sizing of the accumulator and wheel motor displacements would allow torque to be applied to each tire to the limits of the tires adhesion.
That means acceleration at the limits of all 4 wheels ability to maintain traction with the pavement.
0-60 potential in less than 5 seconds even on highly inflated LRR tires.
4. Deceleration with engine drag-eliminated
5. Braking-normal friction brakes would be eliminated, with the exception of an emergency brake in the even of a total system failure. A total system failure would require all 4 wheel pump motors to fail simultaneous, IE quadruple redundancy, something that exists on no vehicle today. Its not that I am an advocate of high performance 4 wheel drive road rockets. 4 wheel regeneration is essential to maintaining the highest possible energy recovery.
The 0-60 in 5 seconds quote would be from accumulator energy alone, and could be accomplished once while the engine was not even running!
An additional benefit of this system is it automatically compensates for improvements in aerodynamics and rolling resistance. Every vehicle in motion constantly bleeds energy to various sources of losses. Every improvement outside of the power train design would automatically result in less regeneration cycles of the power consuming engine or motor.
In the first link on the first post the INNAS BMW conversion only needed to run the diesel engine 11.9% of the time that the car was running through the test cycle. If the car was aero modded like Basjoos has done with his car that run time would probably drop by 50%.
In areas where you had sustained mountain climbs, it would be necessary to have the ability to bypass the accumulator and drive the vehicle directly with the engine. The sweet thing is the engine size is not really that important. A larger displacement engine would run for s shorter period of time to recharge the accumulator. No matter what the speed of the vehicle the engine would only run at its ideal BSFC with power generation to the accumulator or directly to the wheels regardless of the proportion of supply.
The end result would be a vehicle that was totally practical. It could even be an aero sedan with hydraulic lifting suspension that elevated the vehicle for off road driving or severe weather, like 12 inches of snow on the road. The in wheel drives would be impervious to the elements, capable of operation completely submerged.
Cooling of the hydraulic fluid would be accomplished at each individual wheel. You could even use any heat generated to help with heating the vehicle in winter, by insulating the wheel motors and capturing the heat in a radiator in the low pressure return circuit.
regards
Mech
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