Possible future engine efficiency enhancements

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labman

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Not enough content or facts to be worth fighting scrolling a slow PDF.

Realisticly, from here we are never going to see the big gains again like the 80's and 90's. My 81 Pheonix and 92 Grand Am were miles ahead of older cars. Even with the new Ecotech, my 02 Cavalier is mostly a different compromise than the Grand Am, not much progress over the Quad 4.

I suspect only $2.50 for gas in 2013 is a dream.
 
Interesting forward looking article on how to make gasoline and diesel engines more efficient and able to meet future emmisions requirements.


Link to article

Wayne
 
quote:
Originally posted by labman:
Not enough content or facts to be worth fighting scrolling a slow PDF.

I suspect only $2.50 for gas in 2013 is a dream.
Click to expand...
A few things to note in the article, $2.50/gallon is referenced in terms of 2003 constant dollars, which means that one discounts inflation in terms of the future price. If you assume a 2003 value of petrol to be $2.50, and inflation at 3% per annum, the pump price of petrol, according to that report, will be $3.36/gallon in 2013. Of course, at the time the report was written, nobody could have predicted the significant loss of value of the American dollar which, of course, places substantial pressure on the overall cost of imported energy including petrol.

The most promising technologies are turbocharging and petrol homogeneous charge direct injection technologies. The paper gives an overall good general overview of some of the technologies, their implementation costs, and some of the risks associated with both implementation and acceptance.

On the powerplant side of things, my quick read of the paper shows that a 20% gain is realistic in the period 2002-2013 in specific fuel consumption -- ie: the amount of fuel required to produce a fixed unit of output.

I personally believe that a 30%-35% gain is realistic for overall efficiency improvements over that same period if the industry makes a diligent effort to adopt energy saving technology insofar as auxiliary loads are concerned, as well as more optimal transmissions, and lighter weight components and use of composites, particularly with respect to certain body components (car floors could be made of lighter weight composite materials quite easily I feel), hydraulics (use of non-hydraulic braking and steering), and electrical (lighter weight electricals due to the use of 42V systems and more advanced digital signalling networks).

Of course, bigger gains are to be had if the industry is forced into a higher degree of agression insofar as reducing fuel consumption. Sidesticks, for example, instead of foot pedals and the steering wheel, form the cornerstone of more advanced energy management systems that could be installed in cars to enable better overall operating efficiency.

[ February 06, 2005, 12:35 AM: Message edited by: pitzel ]
 
will there be a payback. For example in my toyota there is a knock sensor it cost $150.00 plus the wire that goes from the harness to the sensor ,plus the intake manifold gaskete that cost $112.00 for the set . The sensor is located under the intake manifold in the valley and the cam belts have to be removed . IMO the I have not ever saved $$$ with the computerized high efficient crap put on the market.
 
Does anybody here have data on the specific fuel consumption vs. power output for a typical automotive engine (gas and diesel)?

How badly does efficiency suffer when running at 15% of full power, eg. driving slowly down the highway?

My car's engine is rated at 165 hp maximim, but probably only needs to make 25 hp to drive the car at 70 mph. How much better would my fuel economy be if the engine were actually a 25 hp one running at full power?


Minimizing lifetime dollars spent on transportation is a good thing to strive for. This includes the value of the person's time as they sit in transit (eg. 55 mph speed limits).
 
Good point, Steve. It's not miles per gallon that is the ultimate goal, but cost per mile of ownership. What's the point of saving 0.1 mpg if it costs $1000 in equipment to achieve this goal?

Decades ago, we never had to worry about transmissions giving out, head gaskets failing, $900 bill for starter replacements, or using computers to figure out why your car is running rough.

I wonder if 4-, 5-, and 6-speed automatics with locking torque converters, aluminum heads, and expensive engine componentry have really saved the average driver any commuting costs. I know a lot of this technology is emissions related, but not all of it is.

I notice that the article addresses gains in fuel efficiency and costs associated with manufacturing this technology. Nothing is said about increased cost to repair and maintain these vehicles. This report falls short on addressing the real world situation (typical of the Ann Arbor crowd, who live in their own little world). Nobody gives a rats a$$ on the repairability of cars anymore.

[ February 24, 2005, 01:59 PM: Message edited by: Kestas ]
 
quote:
Originally posted by Kestas:
Good point, Steve. It's not miles per gallon that is the ultimate goal, but cost per mile of ownership. What's the point of saving 0.1 mpg if it costs $1000 in equipment to achieve this goal?

Decades ago, we never had to worry about transmissions giving out, head gaskets failing, $900 bill for starter replacements, or using computers to figure out why your car is running rough.

I wonder if 4-, 5-, and 6-speed automatics with locking torque converters, aluminum heads, and expensive engine componentry have really saved the average driver any commuting costs. I know a lot of this technology is emissions related, but not all of it is.

I notice that the article addresses gains in fuel efficiency and costs associated with manufacturing this technology. Nothing is said about increased cost to repair and maintain these vehicles. This report falls short on addressing the real world situation (typical of the Ann Arbor crowd, who live in their own little world). Nobody gives a rats a$$ on the repairability of cars anymore.
Click to expand...
Absolutely correct. One of my vehicles is a 1982 Ford F250 truck. I am not afraid to drive it anywhere. But it has no A/C, which is not a good thing in South Central Texas. It was GIVEN to me free, gets about 15 miles per gallon. Starter replacement is under $30. The ownership cost of this vehicle, to me, far exceeds what a new hybrid would be. Eventually, I will use it up, and then I can just park it (recycle it). I enjoy keeping up with all of this new gadgetry, and fuel efficiency increases, but am put off by the cost of it. There has to be a balance somewhere. Its not the auto makers fault, as they are required to build vehicles which have to do three things:
be more fuel efficient
be more non-polluting
be safer and surviveable in a crash

Each of these takes away from the other, a fine balance is needed. If we could wipe the slate clean (of all old vehicles) things would be immensly different. A Civic driver would not have to worry about a head-on crash with a 1971 Lincoln Continental. Eventually time evolves everything. But cost-efficiency is whats most relative to everyone. There will always be a market for cheap vehicles, that are able to be fixed cheaply.
 
quote:
Anyone interested in hearing more? if so, where might I start (the beginning)? [/QB]
Click to expand...
I am, for sure. For one, I have a question about the volumetric efficiency difference between diesels and GDI (gasoline direct injection) engines. The later do not have butterfly valve (BMW), so their cycle are much more like diesels now, except for ignition and fuel/air management? Are they equivalent in efficiency?
 
quote:
Originally posted by Curious Kid:

1.) Aside from leverage gains between crank and connection rod which is relative to a piston's stroke, a spark ignition engine at low throttle, is theoretically running as though it were a low compression engine
Click to expand...
I should dig up some equations on theoretical efficiency vs compression ratio. The 5-10% loss of an electric dive might be offset by the doubling of efficiency, by running a full throttle engine at low duty cycle. Battery/hybrid designs suffer from a large energy loss in each charge/discharge cycle. There must be a better way. Diesels are much more efficient at reduced power, but even they have one point where efficiency is best.
 
Off the wall -

1.) How about a check valve within the oil pump pick-up, just behind the screen? This would maintain the pumps prime during times of inoperation, minimizing delay in pressure build upon start-up.

2.) Has anyone tried applying ionization charges to fuel and air to posibly help with economy? How might these attractive forces play in the dynamics? Fuel negatively charged as is the engine block (thus representing repulisve effects, helping to keep fuel in suspension), the air positively charged (because of the opposit polar charge as fuel, it would present an attractive force between the two). Concerns I have are with self-discharge via spark...for obvious reasons. Turbulent flow in itself may present ionization processes, but I don't yet understand the effect(s).

The more I ponder the operating efficiencies between spark and compression ignition engines, the more I find in favor with compression ignition engines.

1.) Aside from leverage gains between crank and connection rod which is relative to a piston's stroke, a spark ignition engine at low throttle, is theoretically running as though it were a low compression engine - a partial vacuum exists upon completion of the intake cycle, leaving an overall lower compression pressure prior to ignition, unlike a compression ignition engine. This would relate to what is called the volumetric efficiency of the engine at that point.

It has been noted that an expected volumetric efficiency of an unmodified production engine is around 80%, meaning that at full-throttle, the intake charge is around 80% of the engine's actual displacement. Even though the mechanics of the engine have a defined compression ratio, the compression ratio of gases within the combustion chamber above atmospheric pressure is much less definable. Factors such as intake restrictions (butterfly, air cleaner, valves, etc.), air raming, valve actuation, exhaust scavenging, intake resonance, and turbo/super charging, can all have an effect on the engine's volumetric efficiency, even having it exceed 100% (raming, resonance, turbo/super charging). One may now understand how volumetric efficiency also varies with rpm, and start to see how compression ignition engines are less effected and more efficient.

I feel like I'm spilling my brains, needing to make an order before presenting all this.

Anyone interested in hearing more? if so, where might I start (the beginning)?
 
I meant not to tease anyone with the closing, "Anyone interested in hearing more? if so, where might I start (the beginning)?." I was finding myself in a moment where things seemed to make a lot of sense. A moment of enlightenment I suppose. And the "where should I start" part, well that just seems like a smart^#*, egotistical remark now that I think about it (where's that soap box charactor?).

What "knowledge" I have comes form tinkering, repairs, modifications, and in some cases a revamping. I've always been fascinated with machinery - especially engines. I have many text resources and like the rest of you, web access. Mostly theory and hypotheticals on my part however.

It's been some time since I have done research on engine design since I found myself with a rather depressing love-hate relationship with my last vehicle all of my own doing. I will say that It was something I had to experience.

Most of my "research" has delt with gasoline engines of the carburated sort, because that was what I had been working with. Around the time prior to the release of hybrid vehicles, I was mulling over the processes from a few publishings - one I believe from the magazine in Popular Science/Popular Mechanics, or was it Scientific America? I'd have to dig it up from the basement.

It's astonishing when working with the subject "efficiency" and "systems", just how defined everything becomes and in clock-work like fashion everything works. One cannot get more out of a system than one puts in. There is an order, a decision tree in design and operation, and for even the interaction of the human operator to be taken into account. It all seems integrated, harmonious, and in remote explaination of so much more...as I see it anyway.

Before putting things "on the shelf", I started to look into DGI engines, which I believe was in-step with releases in the media of potential up coming designs in the automotive field. I believe the engine(s) I viewed at the time were from Mitsubishi. I stopped before anything really struck me. I guess this would put me with being out of touch, though it might be argued that the ICE is the oldest technology appearent in the everyday passenger vehicle.

I'll see if I might be able to dig up a few things.
 
quote:
Originally posted by oilyriser:
Does anybody here have data on the specific fuel consumption vs. power output for a typical automotive engine (gas and diesel)?

How badly does efficiency suffer when running at 15% of full power, eg. driving slowly down the highway?

My car's engine is rated at 165 hp maximim, but probably only needs to make 25 hp to drive the car at 70 mph. How much better would my fuel economy be if the engine were actually a 25 hp one running at full power?


Minimizing lifetime dollars spent on transportation is a good thing to strive for. This includes the value of the person's time as they sit in transit (eg. 55 mph speed limits).
Click to expand...
I don't know about modern cars with their steep gear ratios, but the 65hp Ford V4 engine in the 1967-1973 Saab 95/96 (I used to drive a 1969 96) actually had a published specific fuel consumption curve, as it was also used by Ford for stationary powerplant. Low point on the curve was 2800-2900rpm with no load (corresponds to about 50mph). I used to get about 30-32mpg @ around 58mph (3200rpm) and it went down from there. My parents 1979 900 got it's best mpg at around 65mph (again, about 3200-3500rpm).

My wife's new Accord, on the other hand, only runs about 2800rpm at 70mph.

so; looking at all highway driving (we actually got these number on long highway-only trips):

1969 Saab 96 : 65hp :
~3200rpm = ~58mph = 31+ mpg hwy : 27 city

1979 Saab 900 : 105hp :
~3300rpm = ~65mph = 32+ mpg hwy : 27 city

1991 Honda Prelude : 140hp :
3500rpm = 70mph = 30+ mpg hwy : 25 city

2005 Honda Accord : 160hp :
2800rpm = 70mph = 25? mpg hwy : 23 city

Anyone notice a trend? What happened with the Accord? We haven't yet done a full-tank highway drive in it to find its true mpg, but what we have done has no impact on the fuel usage. From what I see, it is geared wrong. 4th gear in the Accord is the same road speed as 5th gear in the Prelude. All the other gears are spread out more also to compensate. This car is an absolute pain to drive in the city.

If I follow the trend above, then we need to drive this car at 85-90mph to get into the 'sweet spot' for the RPM, but then we get into high-speed wind drag, not to mention the fact that I WILL NOT drive that fast on any highways around here, as I just don't feel comfortable at those speeds. It is too easy to lose control crossing a windy bridge, hitting a pothole, etc....

As manufacturers keep increasing power output and pushing the gear ratios to make the RPMs as low as possible at highway speeds, I think they are pulling the engines out of the consumption curve and increasing actual fuel usage at current highway speeds by, as you said, not fully utilizing the potential of the engine.

Technology has allowed us to increase power output wigh minimal impact on fuel consumption, but I think the transmission/final drive gearing has more impact on the final mpg.
 
quote:
As manufacturers keep increasing power output and pushing the gear ratios to make the RPMs as low as possible at highway speeds, I think they are pulling the engines out of the consumption curve and increasing actual fuel usage at current highway speeds by, as you said, not fully utilizing the potential of the engine.
Click to expand...
I seem to agree. Cars of the late seventies, early eighties had V-8, with carburetors and no overdrive. Most had 3 speed autos. Heavy cars, that could regularly get 20-25 mpg when driven right, and in the "torque band" of these engines. Of course most were geared toward the federal mandated national "55" speed limit. I drive a 82 Ford F-250, 351 V-8, with a 1:1 final gear ratio with a carburetor. I also drive a 96 Chevy C-2500, 350 V-8, with throttle body fuel injection and an overdrive final gear ratio. Similar vehicles, and they get equal mpg readings. So wheres the supposed improvement the newer truck should get?
 
RE your accord, do take a nice spring highway drive now that the weather is getting nicer and motor is broken in. I hope it gets good MPG at 65-70. The newfangled variable valve timing should make better torque down low. Plus you want the throttle open more, the car bogging, to minimize pumping losses. Set the cruise if you have it for the ECM to have the most predictable circumstances to work with.

I think the difference between it and your prelude are weight, frontal area, and hopefully better low down torque with the VVT.

Shoot, the accord hybrid gets 37mpg and has 100 more ponies.
 
It seems that in general, U.S. drivers have the heaviest cars, and the least maintained, in the world.
Europeans are not ashamed to drive smaller cars - I applaud them.
 
quote:
Originally posted by kreigle:
[1969 Saab 96 : 65hp :
~3200rpm = ~58mph = 31+ mpg hwy : 27 city

1979 Saab 900 : 105hp :
~3300rpm = ~65mph = 32+ mpg hwy : 27 city
Click to expand...
2004 Saab 9-3 : 175hp
~2400rpm = ~65 mph = 34+ pg hwy : 29 city

There are improvements to be had... I can push 40 mpg in this car on an all highway cruise control @ 65 drive.

But the manufacturers have to appeal to the idiots in the crowd, effectively ruining economy and everything else for the rest of us who are actually looking for value and life cycle cost lowering.

At the same time, I for one dont mind the expensive technologies put in, to a point. If 1 million cars save 0.1 mpg each, thats a lot of fuel saved. The more this happens, the longer there will actually be fuel to be had (save syntroleum, etc.).

JMH
 
Jon good point about the emmisions vs. milage thing, injection keeps cars right around 14.7AFR at cruise not for milage but because of emmisions leaner means hotter and hotter leads to more NOX. I have to wonder though if the ppm increse is enought to offset the lesser volume. This is something all too often forgotten in the overly burocratic world of environmental controls. Example 15 years ago while in NJ my Mom had a mid-80s Towncar got 18mpg come winter and oxygenated fuel she got 9mpg or close to it, luckily we lived right on the Deleware so PA and good gas were a short drive short enough to actually be worth the trip.
 
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