Contributor
I suspect that when you size a gasoline engine to a specific, essentially fixed load you can get better economy than if you have an engine that can produce a lot of excess horsepower. For most ICE vehicles the engine is much larger than needed for cruising down the highway. In a hybrid vehicle you can use the batteries to make up the extra needed power for peak load which allows you to put a much smaller engine in the vehicle.Originally Posted by Doug Garson
Mike
Go into the world and do well. But more importantly, go into the world and do good.
Contributor
[QUOTE=Jim Matthews;3068665]So many things you've got wrong there.
http://autocaat.org/Technologies/Hyb...0the%20vehicle
The advantage of hybrid systems is that each motor operates in it's most efficient range.
The Kia Optima PHEV illustrates this quite clearly.
Compare the hybrid version to the stock GDI.
https://www.fueleconomy.gov/feg/noframes/39783.shtml[/QUOTE
Agree that hybrids are more fuel efficient, just trying to understand the physics behind it. Not sure the linked sites explain the physics. Suspect it's because the gas engine runs at constant optimized speed like you say and regenerative braking saves lost energy from braking.
Contributor
[QUOTE=Doug Garson;3068725]Yes, there are multiple things going on in a hybrid to make them the most fuel efficient internal engine powered cars on the road:
1. The ICE in a hybrid can be optimized for fuel efficiency, because the hybrid drive train can be optimized for torque, instant availability, etc. That means in a Prius, e.g., using an Atkinson cycle engine, and turning it off whenever the vehicle is not moving, or is coasting for extended periods. In those old Mother Earth News hybrids, they attempted that by using a very small, low hp engine and running it only at maximally efficient RPMs. I say attempted because a 5 hp Briggs is still not a very efficient fuel converter.
2. The selection of power source can be fully optimized by the multiple-input, planetary transmission. A computer can choose the optimal combination of ICE power, battery power to drive train or drive train to battery based entirely on the demand or availability of motive power from the wheels. This drives automotive buffs nuts, because in a hybrid, you have no direct input to the ICE through the controls - you tell the car how fast you want to go, and it decides how to run the ICE and the electrics to move the car, and, of course, the transmission is completely and seamlessly continuous variable, so don't even know it's there.
3. Lower drag coefficient. This is not actually part of the hybrid design, but in the most efficient hybrids available (Prius), it's a major component of their actual fuel efficiency. That is, the Prius gets top line efficiency not just by delivering power optimally, but by needing significantly less energy overall.
Member
These two aspects surprised me most about the Prius : the drivetrain is really clever, they don't look "fast" but the wind tunnel sez otherwise.
https://hybridautopart.com/blog/toyo...-split-device/
Contributor
Yeah, one of the most elegant combinations of mechanical, electrical and computer engineering I've ever seen. I particularly like the way they added 2 electric motor/generators to the planetary transmission. That gives the car direct electric drive through the primary electric motor and a simple gear reduction system attached the ring gear of the planetary, along with very flexible balancing act between the smaller electric attached to the sun gear, and the ICE driving the planetary spider. A naïve implementation would be an ICE, an electric motor, and the output of the planetary system driving the car. The second motor/generator just gives you so much finesse in the power paths.
Moderator
There's no requirement to show a profit in order to claim expenses...in the short term. But longer term, it can become a factor. That's very apt for small businesses, BTW, when the "business or hobby" thing comes into play. That's kinda what Doug was joking about. I guess you can call the space operations a "small business" compared to the rest of Amazon.
--
The most expensive tool is the one you buy "cheaply" and often...
Contributor
A driveover wireless pad for charging your EV vehicle...
https://www.freep.com/story/money/ca...ds/6428778002/
The important thing is that SAE (Society of Automotive Engineers) already has developed a standard for this which should focus implementation rather than everybody trying to develop this on their own.
"Don't worry. They couldn't possibly hit us from that dist...."
Contributor
The IRS says to be not a hobby you must make a profit in 3 of five years, 2 in seven for horses, They do not enforce the must make a profit rules for real estate. ... The assumption is the real estate is increasing in value even when it is not being sold.
Bil lD
Last edited by Jim Becker; 11-28-2020 at 5:02 PM. Reason: removed reference to political figure
Member
Sometimes we see what we expect to see, and not what we are looking at! Scott
Contributor
It's hard to see how this could charge a car in a decent amount of time. Power can be transferred efficiently in a transformer but the two coils are on top of each other and there's an iron core guide the magnetic field. Having the sending coil a foot or more from the receiving coil (and with not core) makes for inefficient coupling. Plus, the car has to carry around the weight of the receiving coil all the time.
Mike
Go into the world and do well. But more importantly, go into the world and do good.
Member
Claim from the article:
"The system delivers DC current up to 11 kilowatts at the maximum voltage the vehicle can accept over up to 10 inches of space between a pad mounted on the floor to a receiver on the vehicle. Charging efficiency is up to 94%, comparable to wired connections."
That's faster than my Siemens level 2 charger.
https://new.siemens.com/us/en/produc...-charging.html
Contributor
I read that claim, also. Just hard to see how they can do that.
Mike
Go into the world and do well. But more importantly, go into the world and do good.
[OP]
Contributor
Would a focused DC pulsing coil have less power loss than a continuous AC coil?
jtk
"A pessimist sees the difficulty in every opportunity; an optimist sees the opportunity in every difficulty."
- Sir Winston Churchill (1874-1965)
Contributor
I can't see how it would make any difference. The way induction coupling works is that a magnetic field is created and then reverses (or collapses). A voltage is induced in the other coil by the magnetic lines of force cutting the wires of the second coil.
In a transformer, the coils are tightly wound around an iron core that directs and contains the magnetic field so that most of the magnetic lines of force cut the secondary coil.
When you have a coil out in the open, the magnetic field would tend to spread out so that some of the magnetic lines of force will not cut the wires of the secondary coil. The further apart the two coils, the worse the coupling will be. With things like an iPhone lying on a charging pad, at least the two coils are pretty close to each other.
But transformer design was not my specialty so there's a lot I don't know. I'm sure the engineers who design this stuff know what they're doing.
Mike
[Assuming that the sending coil is just a coil lying horizontally, the magnetic lines of force will be in the shape of a torus. The closer the secondary coil is to the sending coil, and if the secondary coil is the optimum size, the more lines of force will be cut, and the better the coupling.]
Last edited by Mike Henderson; 11-29-2020 at 5:30 PM.
Go into the world and do well. But more importantly, go into the world and do good.
Contributor
Seems like one of the issues that needs to be addressed is universality of charging stations. Right now, Tesla has built a network of fast charging stations that only Tesla's can use. They can even prevent specific Teslas like those that have been rebuilt from salvage from charging. From one perspective it is free enterprise and they have the right to use their Supercharger network to help promote the sales of their cars, on the other hand if the goal is to promote electric vehicles to fight climate change, exclusive charging stations is counterproductive. Imagine if your Ford could only be fueled at a Ford gas station?
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