Hyper hybrid EV
This is a product proposal, an attempt to explore a potential electric vehicle with an extender that operates in series hybrid mode to optimize cost and range while minimizing emissions.Original document here.
We still do not have an affordable EV that can be as capable and dependable as any ICE car
Tesla is probably the best bet EV but they are expensive for regular people
Tesla did not commit to right-to-repair, so no freedom or fun
Batteries are still expensive, charge times are high and range-anxiety is real
Teslas cannot go off road, Rivian can but that is even more expensive
Build a (kit) car that can sell for $20K and up, range starting from 50 miles to 400+ adding battery modules in 10kwh increments (like in DELL PC business model of ‘build your PC online’)
Introduce a fixed RPM high efficiency 40 KW gasoline range extender for those who want to stay in budget but go beyond 50 miles (1000 mile extended range), add provision for other power plants (future batteries, H2?)
Energy buffer (ultra capacitor) between power plant and motors, to decouple power delivery (performance) from power plant capability (change motors not changing plant), and to improve regen to 90% recapture
In wheel hub motors for true off road 4x4 capability, fuel efficiency and power/weight ratio and min 100 KW
5 mile/kwh efficiency at 65 mph, using large front grill that opens its flaps to let air in, above 35 mph, that hides an ugly half-tear-drop shaped frunk (like in a boat hull), to minimize drag, increase efficiency, reduce battery cost
1.2 KW Solar roof, to trickle charge daily commute fueling needs up to 30 miles, and to enable remote camping
Series hybrid model, electric motors connect to energy buffer (ex: supercapacitor) and energy buffer gets filled by power plant
This is the equivalent of RAM memory in computers. CPU runs at higher speed than what an SSD or HDD can supply data bytes at, so the programs are first copied from SSD or HDD to RAM, then into L3/L2/L1 cache, then CPU registers, etc. This model can be copied over to any areas where we have speed/demand mismatches.
Think of it as a tank with big inlet/outlets, which can be filled and drained quickly as per the needs of driver at the motors, and the tank slowly filled from power plant (well), but the tank can only hold so much of energy that you cannot drain fast and for long, but is big enough for small bursts of power needed for say a quarter mile run
During breaking all that energy can be re-captured and then slowly used for further driving or charging batteries, increasing efficiency. Batteries cannot capture full regen due to charging current thresholds. Regen during long downhill trips cannot benefit much here as buffer size is small.
Buffer will be partitioned to 2 parts, one for charging and the other for draining,
A partition switches from drain to charge when empty, and charge to drain when the other one is empty
Motor power supply is routed to charged partition when current partition is near empty, making the charged partition as active drain
Passive or drained partition is immediately connected to power plant and starts charging
The power plant will charge batteries, idle, or turn off when there is no energy demand for reasonable amount of future period (based on navigation data), from energy buffer
Potential buffer option
The power plant can be anything that can take in a widely available fuel and produce 40 KW of electricity. During cruising, the energy demand will be under 20 KW and the surplus will be used to charge the battery. If no charging is needed, the plant should be moved to standby or off.
It should allow standby (cut off load and fuel) and constant switching operations
In future the power plant can be replaced by a cheaper high density battery (ex: Aluminum air battery) and the car will not go extinct because of the modularity of power train
Potential power plants
A typical car has 10m2 worth of roof area which can be used to generate up to 1.2 KW solar electricity. For an average 5 hours of parking in the sun, this can amount up to 6 KWh energy or 30 miles of range at 5 miles/kwh.
For sunny areas, this mean fuelling free commute to office for the average American
This comes really handy when camping in remote areas with no electricity. You can use AC, do cooking, or run electronics without worrying about depleting your battery/gas and getting stranded
Coefficient of drag
Tear drop like shape will reduce CoD but makes car look ugly (ex: Aptera) or impractical (rear ceiling height)
What if we can hide the tear drop shape with a mesh around it that can trick the eyes to make it appear like regular car with a large grill, but the grill opens up as the air drag picks up, to let air pass through and around the teardrop shaped hull inside (paint it in deep black)
Open flaps will not be noticeable at high speeds (look at existing gas cars with grill openings in front of radiators), and will only cause minimal drag themselves, and they remain closed at low speeds where the drag is minimal anyway (drag force is proportional to the cube of velocity) to maintain aesthetics
Grill flaps can be mechanical (right weight and hinge) or electrically opened/closed (solenoid based, activated based on speed).
ICE power trains are tuned for good performance over a range of RPM/torque values. This is needed as the engine is directly powering the wheels.
Instead we should let the engine operate at maximum efficiency, store the energy produced in large buffers and consume energy from this buffer as needed.
This is only possible if the energy is converted to electric form and stored in battery/ultracapacitor buffers, and use electric motors to move the wheels.
Power plant operates only at maximum efficiency (sweet spot of RPM) to minimize emissions and to maximize fuel economy.
This model is a win-win for the environment and wallet.
Unable to deliver high performance or regen for extended time. You can do a drag race, quarter mile run, but not 200 mph for 20 minutes, as the energy buffers will run out (Buffer Under Run) of juice and the plant cannot produce enough to meet demand. The car is still quick and fast but not for long stretches, but who needs that!
People may choose to buy the cheapest model and may run on extender for long trips, beating emission goals. But the car is still more efficient than any regular hybrid and long trips amount to <50% of total annual mileage on average. Eventually alternate power plants will be made available (Al-Air battery?) that are cheaper and more efficient than gasoline and then those folks might switch over.