42% efficient IC engine on the horizon...

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http://articles.sae.org/15351/

GDI and HCCI (well without the homgenous part)....

Quote:
Delphi projects that engines employing its coming third-generation gasoline direct-injection compression-ignition (GDCI) combustion system will attain a thermal efficiency of 42%, the company said at the 2017 SAE High-Efficiency IC Engines Symposium in Detroit. That thermal efficiency would top any current production-vehicle gasoline engine, the most efficient of which are claimed to have peak thermal efficiency of about 40%.


Quote:
Major advances over Delphi’s second-generation GDCI system include “wetless” combustion, quicker cold-start operation and an optimized low-temperature exhaust aftertreatment that achieves roughly 90% carbon monoxide conversion in about 4s.

Sellnau said the third-generation system has increased the compression ratio to 16:1 (from 15:1) and its new longer stroke and increased top-dead-center piston clearance enable the wetless operation that sees fuel completely vaporized before it contacts cylinder or combustion-chamber surfaces. Advanced fuel injectors operate at 350 bar (5076 psi) and provide three injection events. The third injection, Sellnau said, is “what differentiates (GDCI) from HCCI (homogenous-charge compression ignition).”


Quote:
The system will require a variety of emissions-reduction measures that, in addition to the newly-formulated low-temperature catalyst, include an intake-air heater, gasoline particulate filter and urea injection. But Sellnau was confident those measures, coupled with the combustion-related design advances of the third-generation system, will enable a production engine to be Tier 3, bin 30 compliant—a vital achievement to advance the system for production-vehicle readiness.

Moreover, he promised the latest GDCI will operate with gasoline at currently-available octane. “We really need to get to market with commercial gasoline,” he said.


It's not much more complex than is already put there, just an adaptation and combination of ideas, which is where people work while building to the next big step.

42% is the power station before in house consumption, transmission and storage...it's really really good.
 
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The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.
 
Pretty interesting. I know that control has been one of the issues facing HCCI - i.e. starting ignition at the right point in the cycle across all temperature & load ranges. Unfortunately they don't comment on that in this article.
 
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.

Assuming Shannow's 42% value is correct and factoring in the average electric losses of 7.4% in Florida, your electric vehicle has a starting efficiency of about 35% without factoring heat loss in the engine. Granted there are additional factors such as transportation and refining of gasoline to truly compare the two to the fullest extent, but it looks to me like you are implying the electric vehicle starts at 100% efficiency which just isn't true.
 
Originally Posted By: MotoTribologist
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.

Assuming Shannow's 42% value is correct and factoring in the average electric losses of 7.4% in Florida, your electric vehicle has a starting efficiency of about 35% without factoring heat loss in the engine. Granted there are additional factors such as transportation and refining of gasoline to truly compare the two to the fullest extent, but it looks to me like you are implying the electric vehicle starts at 100% efficiency which just isn't true.


The problem is that the higher thermal efficiency quoted on a lot of these IC engines is that it is a peak value under certain ideal conditions whereas a power plant can do that consistently. A quick google search says the average thermal efficiency of engines in automobiles is around 20% so maybe this new engine could average 30% at most. New natural gas combined cycle plants are in the upper 50% range.
 
where efficiency = conversion of source energy to usable form.

33% to 48% is what I found for thermal power plant efficiency. Wind power has 45% efficiency and solar has 22% efficiency.

So 42% is very good.
 
Got to do somehow use that heat coming off of IC engines. You can only milk a cow so much.
 
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.


So you're saying electric cars are not subject to driveline, aerodynamic, and rolling resistance? Wake up.
Electric motors are 90+% efficient, but only as long as their power density is low. If the current through the motor is high, the resistance in the windings increases, decreasing their efficiency. And also, the charging process for the battery is not 100% efficient, and the faster you try to charge it, the less efficient it becomes. And there are also resistive losses in the current collectors in the battery when the car is operating, and losses in the power control electronics. Overall, the EPA uses a factor of 2.5 to compare the MPG of gasoline to electric (MPGe).
 
Originally Posted By: Schmoe
Got to do somehow use that heat coming off of IC engines. You can only milk a cow so much.


Yes, many companies have been working on exhaust waste heat recovery. You can see real examples of that in F1 and WEC races. Those cars use turbines in the exhaust to turn electrical generators and feed power to the electrical hybrid system. It's really old technology, but worth another look. Curtiss-Wright had R3350 radials in production in the 1940's that used Power Recovery Turbines to feed mechanical power into the crankshaft, boosting output by ~600HP. Still other companies are working on Rankine-cycle, where exhaust heat is used to boil a liquid that turns a turbine. I know Cummins and Navistar were working on such systems for the EPA's Supertruck project. The goal of the Supertruck project was to demonstrate 50% thermal efficiency from the combined powerplant, with 55% as a stretch goal. I sat through a presentation by a Cummins VP about 5 years ago where he said they had achieved 50%. 42% efficiency from diesel engines is nothing new. Detroit Diesel's Series 60 was achieving that when it was first introduced in the the late '80's. Large ship engines do that all the time. And there were even some opposed piston 2-stroke diesels making about 40% efficiency in the 1940's. Since the EPA has been aggressively ratcheting down on NOx and particulate emissions, thermal efficiency has suffered. (Then they complain about CO2 emissions!) If NOx standards were relaxed, engines could be made more efficient, and at a lower cost.
 
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Originally Posted By: Alfred_B
where efficiency = conversion of source energy to usable form.

33% to 48% is what I found for thermal power plant efficiency. Wind power has 45% efficiency and solar has 22% efficiency.

So 42% is very good.


48% is too low for the maximum. That's what a combined cycle plant was doing 10 years ago. Siemens can build you a combined cycle plant right now with a 5700 btu/kwh heat rate. That's 60% efficiency.
 
Originally Posted By: Alfred_B
where efficiency = conversion of source energy to usable form.

33% to 48% is what I found for thermal power plant efficiency. Wind power has 45% efficiency and solar has 22% efficiency.

So 42% is very good.

For wind and solar the "fuel" is free so you can't really compare them to fossil fuels, in terms of fuel input to energy conversion efficiency. I suppose you could argue that the environmental cost to having more turbines and panels is "inefficient" but the environmental cost of fossil fuel extraction and processing probably always loses that comparison as well.
Anyways, 42% for internal combustion is good I guess, but as also noted that would be under high load and unless paired with a hybrid system, most people will never see it in normal driving.
 
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.


I think at 60 mph it more or less 90% of the energy is used to overcome wind resistance, and I believe resistance increases at the square of the speed. Wheres mechanical losses through the drive train are more or less constant.

Claud.
 
Originally Posted By: Claud
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.


I think at 60 mph more or less 90% of the energy is used to overcome wind resistance, and I believe resistance increases at the square of the speed. Whereas mechanical losses through the drive train are more or less constant.

Claud.
 
GDCI? Hmm... Sellnau seems to be trying to re-brand modern HCCI efforts, since basically all of the current prototypes employ GDI making them all qualify for this new GDCI term. And what the heck is "Wetless" supposed to mean? Is it a buzzword simply refering to a staged multi-hole injection optimized to prevent chamber wetting? I can't find anything defining the word "wetless". Reminds me of not long ago when Delphi had their own promotion literature describing a Honda-VTEC style VVL system (a direct copy, really) as soon as Hondas VTEC patent expired. I get it, Delphi wants to sell technical solutions.

Toyota's new Prius engine peaks at 41%, while there are quite a few ~40%ers out there right now.
Quote:
the hybrid variant of this engine is the most thermally efficient gasoline engine ever produced, at 41% peak thermal efficiency. In addition, the standard variant is 40% thermally efficient at peak, matching the previous best production gasoline engines (which, if I recall correctly, are the Gen 4 Prius’s variant of the 2ZR-FXE, and some of the Mazda SkyActiv-G engines).


While 1-3% over 40% is still huge, maybe Delphi should aim a little higher because they may be simply outclassed when their systems hit the market.
 
Hey, if you gotta sacrifice energy to the friction gods, you might as well divert some that otherwise wasted thermal energy towards the altar, right?
 
Amen
laugh.gif
 
Originally Posted By: Blueskies123
The engine might some day 42% efficient but then you lose power thru the transmission, differential, wind resistance, and tires. I do not know if it is true but I read somewhere that if you are driving at 60 mph less than 10% if the energy is propelling the car.
Another reason for electric cars.
Where will the electricity come from to charge the batteries? I like the idea of electric cars because I worked for years on electric forklifts and the advantages of electric drive trains are well worth it in certain operational areas and not the false tree hugging reasons because electric vehicles are very polluting.
 
Originally Posted By: A_Harman
If NOx standards overall emissions restrictions were relaxed, engines could be made more efficient, and at a lower cost.


Fixed that.

I would LOVE to see how far fuel mileage can be increased with current auto technology, if emissions were no concern.
 
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