Nope. Compression ratio is directly related to efficiency.
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Since the Otto cycle IS a thermal cycle, engine temp has a large effect on efficiency. If one engine is running at 160 degrees coolant temp and another at 220 (assume both are water cooled), the hotter engine will be more efficient since during the expansion stroke less heat is lost through the cylinder walls and head. A cooler engine loses more of the combustion heat, and therefore power, through the cooler cylinder and head. Further. air cooled stationary engines must run cool enough at 105 ambient temp as well as warm enough at 0 degrees ambient temp. The air-fuel mix must also accommodate this but it is open-loop with no mixture feedback from an 02 sensor.
Water cooled engines run at a regulated temp higher than an air-cooled would at less than 105 ambient and regulate the air-fuel ratios in a closed loop fashion. That makes them more efficient.
Except it doesnât run at a single load point. Your home doesnât draw a constant load so the generator will need to vary its load as required to maintain output. Fuel delivery, as I pointed out, varies with engine and ambient temps so a carbureted gennie will always be, at best, only close to 14.0 to 1 (E10s proper a/f ratio).
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So an iron cylinder head would be more efficient since it runs hotter than aluminum, but this requires a lower compression ratio than the aluminum head would offer, since the hot head leads to detonation. So I wonder which is better?
All these super efficient gasoline engines are actually direct injection engines, which is essentially what we call a diesel engine today. Itâs really diesel engine technology made to run on gasoline. A gasoline direct injection hybrid vehicle should be able to average less than 1/50th of a gallon of gasoline per mile. This is bad news for EVs! 25% is at the low end of efficiency for diesels.
But charging your EV with a diesel generator is a viable solution. Thatâs what the power stations in Hawii and Alaska use. The cost of operating an EV is much more the cost of the battery than the cost to charge it.
Say it takes 1 unit of money to charge the EV, and 2 units of money to account for the battery degrading due to that charge. Thatâs 3 units of money. With a gasoline generator it takes 3 units of money to charge the EV and 2 units of money for the battery. Thatâs 5 units of money. The cost isnât even doubled.
This ALL wrong. All of it. Direct injection is NOT the definition of diesel. Compression initiated combustion IS the definition of the diesel cycle irrespective of fuel.
Direct injection has been used on gas engines as well as diesel. Mercedes Gullwings from 1955 used mechanical gasoline direct injection as did some WW2 German aircraft.
Electronic direct injection for diesels was developed over 20 years ago. Using it for gas engines allows compression ratios as high as 13 to 1 with pump fuel because of the cooling effect of fuel evaporation when injected. Much greater efficiency than a 6 or 7 to 1 air cooled stationary engine
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What something is commonly defined as may not be what is most significant in every situation. The EPA now classifies natural gas spark ignition engines in the diesel engine category because their definition is any engine that varies its fuel to air ratio depending on load.
Some may think that compression ignition is significant. The EPA may look at fuel to air ratio. Iâm looking at the injection type. Others may look at compression ratio.
Or crab shell batteries. UMD is working on zinc batteries that use chitosin, made from crab shells, as the electrolyte. Chitosin is not only cheap, itâs biodegradable and the zinc can be recycled. Itâs a newly developed technology and needs a lot of work, but something like this could eventually make large batteries for automotive applications or whole house applications a lot less expensive and easy to dispose of.
Crab shells to recharge the EVâs battery? hmmm ⊠If a recharge includes an order of tasty crab cakes, Iâm in 
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Do you have to kill the little fellas to get their shells? Louisiana doesnât have much gravel but lots of sea shells, so they use them on the roads. Another natural resource.
lol ⊠Iâm going to have to figure out my own method, expect it will several months for me to do that job in my diyâer way. I want to insure I can continue to boast about my record of taking the longest time to rebuild a carburetor. Several years on, carburetor is performing in a like-new fashion.
Any shellfish leftovers can be used. Crabs are abundant in MD and that is no double why the UMD chose to make chitosin from their shells.
To paraphrase a former frequent poster, crabs deserve a place at the dinner table. Right next to the ears of buttered corn! Lay the butcher paper on the table, pour the seasoned and steamed crabs on top and let me at âem. Gimme a knife and a beer and Iâm gonna rip those crabs to shreds.
Now that is complete BS. Prove it. Link that definition from epa.gov.
A compression ignition engine is a diesel no matter what fuel it uses. A spark ignition engine is an Otto cycle engine no matter what fuel it uses. That is the accepted definition by the EPA, SAE and every engine manufacturer worldwide.
It was on some alternative energy website about using natural gas as a fuel. I canât find it now. The EPA does have different standards for lean burn and rich burn stationary natural gas engines. Here is the closest I could find:
Whatâs the big deal? I said theyâre using diesel engine technology. Direct injection is a technology used on diesel engien. Why the non stop picking apart words to try to find fault with everything?
Because so many things you post are just flat out wrong. Like the one below;
I donât need to find fault when you display it so effectively. I donât want you banned but I also donât want these gross inaccuracies to remain unchallanged. Facts matter. Words matter.
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I guess I should have said what I consider the most essential part of a diesel engine.
They have the characteristics of a diesel such as higher compression ratio, direct injection, probably lower exhaust gas temperature due to the higher efficiency, but they donât use compression ignition.
In the past there were diesels that had spark plugs. They would run on gasoline to get started and then the diesel direct injection would take over.
If an engine that burns gasoline was made to be compression ignition, what would you call that?
If the Snowman only posted facts would that be as effective as being banned ?
Yep, because then heâd have little or nothing to post.
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Mustangman,
With gasoline direct injection engines having compression ratios as high as 14:1, wouldnât the gasoline ignite from the compression heat alone and not always need a spark? If so it could in some cases meet the requirement for being a diesel engine.
Gasoline octane rating is a measure of the fuels resistance to compression/heat ignition.
So it could happen, but much more difficult than with diesel fuel, which is high cetane and (would be) low octane rated.
Perhaps 20:1 or more compression.
NASCAR (and other) race engines are running 14 to 1 CR and have been a while but they do not compression ignite. 14 to 1 is not quite enough to compression ignite. It is just a bit too low. While NASCAR does not use direct injection, other race engines do.
There are combined compression ignition/spark ignition gasoline engines in developmemt but none for saleâŠyet⊠as far as I know. They can regulate the combustion process with properly timed multiple direct injections per stroke but I believe the CR is higher than 14 to 1. The spark works well when cold to rapidly heat the cats and transitions to compression ignition once warm. Since it uses gasoline, there is no soot.
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I think a lot of you guys do not know the difference between compression ratio and dynamic compression. Most race engines have a very high compression ratio but their dynamic compression is no higher than a street engine, not much anyway.
Compression ratio is the measurement of the volume of a cylinder at BDC to the volume at TDC. High performance engines have a lot of valve overlap from the long duration cams that effectively reduces the dynamic compression. The dynamic compression can be further changed with cam timing. Variable valve timing actually varies the dynamic compression of an engine.
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