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Diesels Challenge Hybrid Drivetrains

Posted December 12, 2010 7:00 AM

With fuel and emissions efficiency a priority for auto buyers, hybrid powertrains have garnered much attention. But an article in EE Times contends their fuel efficiency is matched by modern diesel engines using state-of-the-art direct fuel injection and optimized electronic motor control. Which technology will eventually win highway supremecy - hybrids or diesels - and why?

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#1

Re: Diesels Challenge Hybrid Drivetrains

12/12/2010 10:59 PM

Modern diesels are more fuel efficient than gasoline engines for three reasons: 1) There are no pumping losses because the diesel engine does not have a throttle that restricts the amount of air that enters an engine. While a gasoline engine must maintain an air/fuel ratio close to stoichiometry, the chemically correct ratio of air to gasoline, ~14.7/1, the more air you can cram into a diesel the more efficiently it operates. That is why virtually all modern diesel engines use turbochargers to increase the amount of air in the cylinder. By contrast, the throttle of a gasoline engine at cruising speed is open very slightly thus the pistons encounter significant pumping losses as they try to draw air through the small throttle opening. 2) Motor fuel is sold by the gallon and cetane, the chief constituent in # 2 diesel, is a larger molecule than trimethyl pentane (iso-octane) that is burned in gasoline engines and has much more energy per gallon. 3)Diesels inject fuel into the center of a combustion chamber of highly compressed air with an excess of oxygen. This creates a stratified charge and the fuel burns quickly and relatively completely. With the notable exception of the newest direct injection gasoline engines, traditional gasoline engines mix fuel and air uniformly through the combustion chamber. However, after the mixture is ignited by a spark, the flame front does not burn the fuel that is closest to the surfaces of the combustion chamber (head, cylinder walls and piston crown) because temperature of the burning mixture drops below the combustion temperature of gasoline. Consequently there will always be residual unburned gasoline in the exhaust. That is why the State of CA insisted that cars be equipped with catalytic converters, a practice that has spread throughout the industrialized world.

Lastly, the new common rail, direct injection diesels that appear on European cars make multiple injections of fuel during the three millisecond combustion period and they are so timed to maximize combustion efficiency and reduce both noise and particulates. Thus diesels are inherently cleaner and more efficient than gasoline engines and now almost as quiet. However, they are heavier, more robust because of higher peak combustion pressures and much more expensive to build.

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Anonymous Poster
#2

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 12:23 AM

Simple. Just make a diesel hybrid and it shuts everybody up.

I see this as a 2 pointed question. First hybrids are not good on highway tests and diesels are. Second hybrids are good in stop and go city driving and diesels are not.

What exactly is the question? "Which technology will eventually win *highway* supremecy".

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#3
In reply to #2

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 1:29 AM

Diesel engines require more maintenance than petrol and electric, don't they? If you take such costs into consideration, which is the better option?

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#4
In reply to #3

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 4:14 AM

In our experience - having operated a small vehicle hire business with cars and trucks - diesels cost much less to maintain than petrols as they are so much more reliable and the routine work is now minimal.

I drive a VW Passat Turbodiesel which after 150 000 miles has had one cambelt change and 15 oil and filter changes, and nothing else done on the engine. It still achieves 55 mpg in ordinary mixed driving.

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#6
In reply to #3

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 12:11 PM

The maintenance is simpler, but a good (more expensive) oil is a requirement for a really long life.. the life can easily exceed twice that of a comparable petrol engine....

Diesels have VERY long lifetimes if correctly maintained and do not require spark plugs either....glow plugs can last the lifetime of the engine I have found after having many diesel cars.....

Also the Longlife III oil currently used can easily achieve 30,000 Kms in a Diesel.....

In the event of an accident, Diesel burns far less readily than petrol, giving vital extra seconds to exit the car.....petrol can almost "explode" under certain circumstances....Not good......

Plus similar sized/performance cars are mostly far more economical in Diesel versions....difficult to compare but generally accepted as true.....

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#5
In reply to #2

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 7:12 AM

G'day gals, guys & gurus,

"Simple. Just make a diesel hybrid and it shuts everybody up."

Diesel engines are well suited for use in hybrid transmissions and have been used quiet extensively for over half a century now in diesel electric locomotives.

However, in a diesel electric locomotive the mass of the diesel engine and electric motors is actually a benefit as it give the locomotive more traction, but in a motor vehicle mass is a negative. As a result the added mass of the diesel combined with the batteries and motor generator set makes the whole process just that much more difficult. But that doesn't make it impossible.

I think a diesel electric car possibly with capacitive rather than batteries for short term storage would work. Although the super cap technology isn't there yet so in the short term you would more than likely still need to have batteries.

What do others think?

Regards, masu

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#11
In reply to #5

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 5:46 PM

Use a 30-40KW electric motor to drive the vehicle and regenerative braking to recharge the batteries. use a 7-10KW diesel engine-generator to charge the batteries. Should be able to get 70-80 mpg.

Similar system was installed in an Opel back in the late 1970s.

http://www.motherearthnews.com/Green-Transportation/1980-09-01/Mothers-Own-Hybrid-Car.aspx

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#7

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 1:40 PM

Diesel engine is bad by design and should be placed in museum. It inherited many causes of inefficiency from Otto design patented in 1876. The causes have been handed down from generation to generation and still penetrate into engines under development for the future. The inventor of gun-engine spotted the causes and eliminated all of them by combining operation of diesel with gun. Thus inventor called the invention "gun-engine". The found needed design changes eliminated need for external cooling, thus eliminated radiator, as the gun-engine is only cooled by expansion of exhausts below atmospheric pressure, because exhausts when expanding produce work and cool down. The new design delivered practical engine, the efficiency of which matches the efficiency of ideal Carnot engine. I also detonates vaporized or gaseous fuels, which speeds up energy release from fuel about 1000 times and that is important, because power available from fuel is defined as energy release from fuel, thus less fuel consumption delivers better power and mileage.

The inventor converted small Suzuki into gun-engine that detonates vaporized fuel, which yields about 14 times higher pressure than max pressure Suzuki cylinder could withstand, so he lowered fuel supply to only 10% fraction of originally intended to prevent cylinders from bursting. Nonetheless the measured power output was read 40% higher than max power of the original Suzuki that was fully fueled. Zero toxic emissions were always observed and GHG emissions were cut by 95%. While measured torque was about 100 times higher than max torque of diesel consuming the same fuel, the gun-engine could be directly clutched to wheels, thus no need for energy wasting transmission. Who needs hybrids when gun-engine has improved mileage by 15 times?

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#8
In reply to #7

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 3:30 PM

Such posts, especially from Guests only serve to make me believe NOTHING good will ever come from the "Gun" engine.

So please do not waste my/our time posting such rubbish......

If you REALLY want to impress us in a positive manner, get a name and post with reliable links to videos and other factual information.

Your present method works very negatively on many of us.......

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#9
In reply to #8

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 4:24 PM

Worry not Andy - last time guest trotted this rubbish out the claim amounted to 11 times the available energy in the fuel. I.e. 10 "over unity's" - a record of some sort I think, even by Hendrick standards.

I guess that has now become 15 times the mileage, to fool us that 'sums', or 'tests', have been done.

Must be one hell of a crankshaft in that Suzuki too.

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#14
In reply to #9

Re: Diesels Challenge Hybrid Drivetrains

12/14/2010 3:36 AM

LOL!!

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#12
In reply to #8

Re: Diesels Challenge Hybrid Drivetrains

12/14/2010 12:21 AM

Hey - not all guests are idiots and not all posts from named users are golden eggs. Don't lump us all in with the dipstick....

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#13
In reply to #12

Re: Diesels Challenge Hybrid Drivetrains

12/14/2010 2:39 AM

"not all guests are idiots"

I agree and there have been many informative, constructive and discussion initiating posts by guests to CR4, however in this case it is none of the above.

Being curious by nature and sceptical at heart I tried to find further information on this so called gun­‑engine and I unfortunately have nothing more to report than a repeat of the guests clams over and over. Not only was there a lack of hard data but the descriptions of the engine's function were nebulous and uninformative and did not lead to an understanding of the concept.

I am sorry, but the performance claims sound too good to be true and when that happens they nearly always are.

However, I would love to be shown to be wrong, so I invite the guest or anybody else for that matter to post an informative description of the gun‑engine's operation and hard data on the performance claims.

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#18
In reply to #13

Re: Diesels Challenge Hybrid Drivetrains

12/21/2010 1:12 PM

My findings almost to a "T", many thanks.

How is your Mossie coming along, any new fotos?

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#19
In reply to #18

Re: Diesels Challenge Hybrid Drivetrains

12/22/2010 12:51 AM

My apologies to those involved in this thread as this is somewhat off topic.

"How is your Mossie coming along, any new fotos?"

The mozzie project is on hold while I finish the 1/350 scale model of the Star Ship Enterprise from the first Star Trek movie. So far it has consumed over 200 LEDs, 2 LASER modules and 200 metres of Kynar wrap wire. It also needs 5 microcontrollers to control all those LEDs which means a total of 6 one off handmade printed circuit boards. I have one finished and installed with the second one ready to go while a third is almost ready for printing, but there are still three boards that I haven't started on yet and they are all double sided boards so it could take me a while.

I've been taking lots of pictures during the construction and will write it all up for the mozzie blog when I get it finished. In the meantime here is a photo of one of the shuttle craft sitting on the shuttle bay fantail.

It's very much a work in progress but it will give you an idea of what the model will look like.

Back on the subject of the RC mozzie, I've flown both powered aircraft (Piper and Cessna single engines) and gliders but haven't flown models before so diving in with something as complex and expensive as the mozzie is probably not a good idea. However, my wife got me a 1/24 scale radio controlled flying model of the SR-71 Blackbird for my birthday so the plan is to learn first on a basic unbreakable trainer then practice on the blackbird before moving onto the mozzie. The flying experience will also help with the actual construction of the mozzie especially with the relatively new digital controllers that I plan to use. The one I am looking at is a two way system that utilizes two separate receivers in the aircraft to ensure a constant data stream. It also has a single back channel for telemetry on things like engine temperature, engine speed, battery temperature and voltage etcetera. All together much more sophisticated than the old analogue one model per frequency 27 MHz no telemetry or feedback system.

There is something that others might be able to help with. I plan to install a camera in the mozzie, probably a cut down web camera with a USB interface on it so I need a small wireless USB link that I can connect the camera to that will link back to a laptop PC on the ground. The idea being that it will make it easier to fly by giving you a pilots eye view of what's going on. If anybody knows of an appropriate wireless USB system I would appreciate any info you could supply.

Regards

Masu.

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#20
In reply to #19

Re: Diesels Challenge Hybrid Drivetrains

12/22/2010 9:05 AM

Good move - learn cheap before flying expensive.....thanks.

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#21
In reply to #19

Re: Diesels Challenge Hybrid Drivetrains

12/22/2010 9:27 AM

A dumb question from an interested pilot, What is a "Mossie"?

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#22
In reply to #21

Re: Diesels Challenge Hybrid Drivetrains

12/22/2010 9:42 AM

The Mozzie is a 1/8 scale radio controlled model of the DeHavilland Mosquito from WWII that plan to build. You can read about how far I got before putting things on hold by following this link to my blog on the subject.

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#23
In reply to #22

Re: Diesels Challenge Hybrid Drivetrains

12/23/2010 10:09 AM

I have a "coffee table" photo book of DeHavilland aircraft. Very beautiful aircraft! (IMHO!) Somehow, your blog link does not work for me. I will try to link again after work.

Ried

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#24
In reply to #23

Re: Diesels Challenge Hybrid Drivetrains

12/24/2010 12:19 AM

If that doesn't work here are the links to the individual threads on the subject.

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#17
In reply to #12

Re: Diesels Challenge Hybrid Drivetrains

12/21/2010 1:10 PM

There are two reasons to post as guest:-

1) sheer cowardice 2) stupid remarks.

Please be so kind as to make your choice!!

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#10
In reply to #7

Re: Diesels Challenge Hybrid Drivetrains

12/13/2010 5:34 PM

And when you add the defragmenting encabulation system previously covered in a video shared on the CR4 site several years ago, the homogenous synergism can become spectactular to resonate!

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#15

Re: Diesels Challenge Hybrid Drivetrains

12/20/2010 12:18 PM

Mexican engineers are getting 10% more power and 35% better fuel performance on big diesels (trucks and such like).

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#16
In reply to #15

Re: Diesels Challenge Hybrid Drivetrains

12/21/2010 5:05 AM

Ok Raknruin I'll bite, how are they achieving these improvements in performance and efficiency?

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