By Rud Istvan,
This possible guest post was inspired by Andy May’s recent post concerning mainly internal engine combustion (ICE) alternatives. Since I am a SME in the general field (including several basic supercapacitor patents), thought I would provide some factual engineering perspectives to WUWT.
First, combustion engines come in two basic forms: internal, and external. External (1819, Sterling) was never proven practical despite Dean Kamen’s fairly recent trying to get me as head of Motorola strategy and innovation at the time to invest. His fundamental engineering problem was simple. In ICE, most of the necessary thermodynamic cooling exhaust heat leaves via the tailpipe. The remainder (about 20%) is in the big car radiator. In a Sterling ECE, ALL the working exhaust heat must leave via a REALLY BIG radiator. NOPE.
Second, ICE engines come in various stroke flavors. For purposes of this simplified discussion, just two fours: Otto cycle and Atkinson cycle. Otto cycle is your ordinary 4 stroke piston car. A compression fuel upstroke, a combustion downstroke, an exhaust upstroke, then an intake fuel downstroke.
An Atkinson cycle uses the same four strokes slightly differently. The compression upstroke air intake varies (via complicated valve timing). So delivers more fuel efficiency (about 15%) but less torque efficiency on the combustion downstroke. (Oversimplified explanation: more uptake air, less fuel, less combustion downstroke torque.)
In what follows, we learn full hybrids can fully compensate for that Atkinson cycle fuel efficient torque deficiency.
Hybrids
There are several flavors:
- Mild
- Moderate
- Full (Prius)
- Plug in (New Prius, Chevy Volt)
We will define all, but only consider to any extent full and plug in.
- Mild hybrids basically just do engine off at idle. NOT simple with conventional automatic transmissions, which is why FORD went with all DCT by 2018. Now this also (as BMW learned) still kills SLA battery life despite DCT. Turns out the necessary additional AH battery sizing (even at low PbA battery cost) “killed” that simple’s application. Valeo’s system is just one ‘dead’ example.
- Moderate hybrids add regen braking. The problem is, unless a really big battery, regen kills PbA even if PbA is oversized for starts) battery life by ‘overcharging’. Kills that application also.
- Full hybrids work, as posted here previously. Downsize the ICE (mine is a small I4 Atkinson cycle), make up the torque loss with the electric machine. Idle off at stop is free, and regen braking is free. For comparison, the HP and towing 2007 equivalent 4WD Ford Escape V6 got about 20 MPG average, our full hybrid equivalent gets about 30. Plus, we use regular, the v6 equivalent used hitest. About a dollar a gallon difference in these parts, and about 1/3 less gallons for a HP and towing equivalent small SUV.
- Plug ins. (like Chevy Volt and new plug in Prius). These by definition have larger, more expensive, and heavier batteries, yet still have all the heavy range extending backup ICE equipment. At the present (unnecessarily elevated) price of gas, still a very bad economic tradeoff. And, there is a hidden subtly. In full hybrids, the traction battery floats between about 60% and 40% charge. Nevermore, never less. That maximizes its life by design.
In a plug in, you drain the battery until the charging engine cuts in. That guarantees a much shorter battery life. Not a good thing economically.
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Nearly all parked cars charging in Paris are hybrids.
And I have never seen as many very large cars! All hybrids of course…
No battery has the energy density of combustible fuel. This means that you are always spending more energy simply carrying the extra weight.
The second issue is how quickly you can re-fuel a vehicle with a liquid combustible fuel vs recharging a battery.
For these two reasons, batteries are simply not appropriate for most vehicle transport. Reference to hybrids as electric vehicles is hiding the fact that the energy source is still a combustible liquid.
Whether there will be an energy system which can compete with an ICE in terms of energy density and refuelling time in the future is unknown. Hydrogen fuel cells have been touted for some years, especially if you can use methanol as the hydrogen source, but it remains unproven.
A diesel electric train locomotive works because the grade is less than 4%. With a mechanical transmission you are never overloaded so long as you have another gear to shift down.
Electric bikes have gears for a similar reason.
My experience: I started in 2006 making blends of vegetable oil and kerosene for a diesel vw jetta 2000 and a 2006 Mercedes benz. It was messy but I saved thousands on gas in the 10 years I did it. I got a Nissan leaf in 2012 and got rid of the mercedes.If I had kept the mercedes I would probably still be doing it but the vs died because a timing belt. I got a 2005 prius after that that was great but my kids destroyed it. Replaced with a 2010 prius that I liked even better but had head gasket problems and died. Replaced it with a Kia optima plug in hybrid that is pretty fantastic. At 60000 miles this 2017 Kia has no noticeable battery degradation. I think that is mostly because it has a liquid cooled battery. The leaf on the other hand that has 107000 miles on it will only go about 50 miles now instead of 73 when new because the battery is air cooled. Still we drive it about 45 miles on weekdays to work and the combination of the Kia and leaf we figure save us at least 200 a month on gas. I wanted to get tesla but my wife does not want to sit there and wait to charge on road trips.
I was surprised by point 2:
“battery life by ‘overcharging’. Kills that application also.”
Uncontrolled current flowing into a battery!!
Don’t car companies employ electronic design engineers yet?
You would think a decent battery monitor could sense the battery approaching max charge and divert the energy to a resistor. You lose the energy, but you don’t kill the battery.
How many people have commented here about “Climate Change Mental Disorder Madness Insanity, Derangement etc” even before we encounter Brandon, Greta and (self-inflicted via pasta and booze) Boris?
We should be eating Lithium, not making cars out of it.
Quote:“A fourteen-year study in England that analyzed the health records of 30,000 adults over age 50 demonstrates that the people who took lithium prescribed by their doctors to help them cope with depression and other mental issues were significantly less likely to develop dementia than the people who didn’t take the mineral.
https://jamanetwork.com/journals/jamapsychiatry/fullarticle/2649277
https://www.nature.com/articles/s41386-018-0289-0
https://www.nature.com/articles/s41398-021-01329-3
ICE HEV PHEV or BEV 68% of sales have to be zero emissions by 2030 in Californy-
California Proposes 68 Percent Zero-Emission Vehicle Sales By 2030 (msn.com)
There’s a bit of catching up to do-
Is This The Future? Waiting To Charge At Tesla Supercharger Station (insideevs.com)
Now I know you’re wondering why only 68% and not 70% zero emission cars by 2030 but not everyone will be able to afford them right away-
‘A metastasizing crisis’: can Karen Bass end street encampments in LA? | California | The Guardian
They’re going to change the climate.
If they’re going to mandate zero emissions it should be for the full life-cycle of the vehicle, from mining the materials through disposal of the vehicle at end-of-life plus the total amount and source of energy used at each step. It would be quite interesting to watch the legislative discussions as the actual data came in.
To increase efficiency why has no one tried hooking a steam turbine into the exhaust system , there is enough heat and redesign of traditional cooling systems could make even more heat down the exhaust to drive a turbine . Stop wasting all that lovely heat .
Most diesel motors and quite a few petrol motors already use turbochargers.
Actually there is at least one company that makes thermocouple generators that simply attach to the tail pipe and hook to the battery. They replace the alternator.
I will never buy an electric car. Ever.
Good article although full hybrids have a couple of sub-flavours: series hybrids where the ICE drives a generator and the electric motor drives the wheels. The Volt can, I believe, operate in both modes.
Agree with his comments on Pb. Leads acid has an absurdly short cycle life in this type of application
These climate changers sure do love their computer models-
“World first” trial to integrate electric bus charging with grid in Sydney (thedriven.io)
Maybe one day someone will explain to them the lesson of the tale of the tortoise and the hare with their constant oohing and aahing-
Victoria reaches record wind and solar share of 83.8 per cent | RenewEconomy
In a plug in, you drain the battery until the charging engine cuts in. That guarantees a much shorter battery life. Not a good thing economically.
I’d love to see some backup for that. It makes sense to me that such frequent charges would reduce battery life, maybe radically. To my knowledge, which might very well be woefully lacking, each recharge is a cycle, and there are a limited number of cycles.
But I’m not seeing any evidence from the field on the longevity of the batteries of plug-in hybrids. I am all about the facts, so if you have backup then please present it. For what it’s worth, you could have an impact.
Efficiency increases with compression ratio which was reduced to prevent nitrogen fixation. So they burn more fuel to avoid making fertilizer. Then they use more fuel to make fertilizer.
What’s wrong with this picture?
stirling engine submarines for sweden – Search (bing.com)
I think this works.