418 replies to this topic

[Moon Tricky]

Originally posted by Todd


The Honda has but one electric motor(connected to the drivetrain - unlike the Toyota, Honda has another electric motor driving an A/C compressor as well, so Honda A/C works in traffic, while Prius' does not), and it serves as generator, supercharger, and starter motor. If it could turn faster than the IC engine, then Honda would need a new strategy for their engine stop/start system, which is much of the key to good city mileage for a hybrid. The engine is shut off at traffic lights. The monster electric motor effortlessly starts it when moving off from a stop.

There's not much advantage on being able to drive on electric only, if you ask me. Storing electric energy for later use is just too inefficient. It's already stored as fuel in the first place. But this strategy of Honda's would work perfectly well for a diesel "hybrid". Insofar as it can properly be described as a hybrid simply to stop the engine when the vehicle is stationary and start it again when needed. There would be not so much need for the large batteries.

But can a diesel be stopped and started like that without any problems?

[McGuire]

PSA Peugeot Citroën has a parallel hybrid diesel with start/stop in the pipe, tentatively due in 2010. They have some tall claims but it looks interesting.

[Greg Locock]

That should be good.


It would be interesting to see a study showing which 'feature' of a given hybrid solution is responsible for how much of the fuel savings. This might point the way to a more cost effective solution. For instance the simple rule "Do not run the engine at idle" is a relatively practical one that requires no new technology, at least at an amateur level (for a manufacturer it has serious implications - you do not want to be in court explaining why the 35cent relay failed just as the car load of children were trying to get out of the way of the out of control truck, etc).

I have seen estimates that on the EPA cycle the maximum benefit from a hybrid system is of the order of 50%, but that is a model, not a theoretical limit.

[LS 1]

Originally posted by desmo


I'm up I-5 in Bellingham, somewhere to the political Left of Seattle (if that's possible)

Possible? Three words: Evergreen State College

Sure is a small world, ain't it? You must be the only F1 fan in Whatcom County.

[LS 1]

Originally posted by phantom II
OK, wise guy, how do you get rid of the blinking.

Erm, pull the plug when the movie's over?

[Jerome]

Originally posted by McGuire


That is just another form of commie-ism. No wonder you love electric cars and hate democracy.

That's funny.

[Jerome]

Originally posted by Moon Tricky


There's not much advantage on being able to drive on electric only, if you ask me. Storing electric energy for later use is just too inefficient. It's already stored as fuel in the first place.

That is the most enlightening (not in a buddhist sense ;) post of this thread.

Actually, since I started this thread, I suddenly see a lot of hybrid cars in my neighbourhood. Perhaps I was not paying attention, or there is definitely something going on the auto-business. A lot of articles on hybric cars are also appearing in the Dutch press, while before that was rather rare...

[malbear]

Is this concept similar to the Miller or atkins cycle and therefore most suitable for the Ic component of a hybred?

SWEPT VOLUME

Imagine a four stroke engine single cylinder capacity one litre
Bore 115mm stroke 96.3mm swept volume of 1000cc.
Imagine a Beare Head with a bore of 75mm and a stroke of 56.5mm a swept volume of 250cc.
Imagine that the combustion chamber volume is 100cc. the trapped volume when both upper and lower main piston are at their closest proximity with the top piston down as far as possible and the main piston at TDC.
INTAKE.
The main large piston is at TDC, the upper smaller piston is at the top of its bore or BDC, so the cylinder volume is 250cc plus 100cc equals 350cc.
As the main piston descends it is increasing volume. At the same time the upper piston is descending reducing volume.
At main piston BDC the main piston has swept 1000cc and the upper piston has descended half its bore as it is synchronized at half the main piston rotational speed. It has swept 125cc and reduced the swept volume by 125cc
Therefore the cylinder volume at main piston BDC is 1000cc add the combustion chamber, add the volume left in the upper piston of 125cc so the total volume is 1225cc
So the swept volume of the intake stroke is 1225cc minus the volume at the start of the intake stroke of 350cc
875cc
COMPRESSION.
The cylinder volume is 1225cc
The main piston ascends while the upper piston continues to descend, both pistons are reducing volume.
At TDC main piston has swept 1000cc while the upper piston has swept a further 125cc
Cylinder volume is now 100cc
So the swept volume is 1225 minus 100cc
1125cc.

EXPANSION
Cylinder volume is 100cc
The main piston descends while the upper piston ascends.
Both pistons are increasing volume.
At BDC the cylinder volume is main piston 1000cc and upper piston is 125cc.
Total cylinder volume is 1225cc
So the swept volume is 1225 minus 100cc
1125cc

EXHAUST
The cylinder volume is 1225
From BDC the main piston ascends reducing volume while the upper piston continues to ascend increasing volume
At TDC the main piston has swept 1000cc, the upper piston has increased volume by 125cc
The total cylinder volume is combustion chamber 100cc and upper piston volume 250cc
350cc
So the swept volume is 1225 minus 350cc.
875cc


The total swept volume over the four strokes is 4000cc
Intake 875cc add compression 1125cc add expansion 1125cc add exhaust 875cc
Therefore the nominal average capacity of the Beare cycle engine is
1000cc
Similar arguments and dissertations could apply to the miller cycle.

The waters could be muddied somewhat more by considering only the trapped volumes after all the ports have been closed. The Japanese used to apply this principle to two-strokes with corrected compression ratios.
There is a further complication if the upper piston crank is delayed or advanced in its rotational relationship with the main crank, or if it is a conventional crank and con rod or a scotch yoke drive. All have effects on the swept volume in regards to crank angle position.
But the net results are that the Beare cycle has advantages in gaining efficiency, pumping losses are reduced as less energy is expended to suck intake and pump out exhaust. And more energy is extracted during the expansion stroke
If the upper piston is delayed in its rotational relationship by about 20 degrees the maximum volume no longer occurs at BDC but is at173 main crank degrees on intake and maximum volume occurs at 548 for expansion and minimum volume occurs at 361 and the rate of change in volume during combustion is less than the conventional four stroke maintaining a closer relationship to the theoretical ideal of constant volume combustion.. and therefore higher maximum cylinder pressures are achieved even though the compression ratio and open throttle cranking cylinder pressure may be the same as the conventional four stroke.

FUEL CONSUMPTION TEST
ROAD SPEED MPH 4STROKE RUN TIME SECONDS 100cc FUEL 6STROKE RUN TIME SECONDS
100cc FUEL LOADED RPM
In 5th GEAR % LONGER RUN TIME
30 159 216 2000 35.8%
35 138 184 2500 33%
40 107 134 3000 25.2%
45 89 101 3500 13%
YAMAHA TT 500cc
Test by Malcolm Beare, Elliot Munro, Grant Guy, July 1995
The dyno used was an old motorbike dyno with the rear wheel driving a large fan with a speed readout dial. The throttle was opend enough to maintain the designated speed. So the power outputs were identicle
The sixstroke head was designed to as closely match the fourstroke as possible compression ratio , valve timing , port sizes. Not a fully optimised sixstroke much more port area is available.
and compression ratio could be higher.
The sixstroke would run happily at lower revs(1000) than the fourstroke in 5th gear. The fourstroke would pull 4000 RPM at full throttle the sixstroke 3500.
Same gearing same carburetor.
Fuel was gravity fed to the carb from a long clear tube with two level marks to indicate 100cc

http://www.sixstroke...500_burnout.htm

[SphereTL1000S]

Have you guys seen this one?

NEW YORK—Perhaps it was fate—We were walking towards the parking lot to leave the New York auto show’s second day or press previews Thursday as a strong gust of wind blew the cover off of a little, red roadster parked on a side street. We went back to investigate, and discovered the L1X-75, a 600-hp, carbon-fiber rocket that’s powered by nothing more than your 110 outlet.

Sure, the speedster has none of the creature comforts of its Javitz Center brethren (you know, airbags, radio, rear-view mirrors, turn signals), but what it lacks in style it makes up for in function. Hybrid Technologies’ thoroughbred pulls from zero-60 in just 3.1 seconds as it launches towards a top speed of 175 mph and a maximum range of around 200 miles. Forget about our impending deadlines, our editors sending frantic blackberry text messages that we’re overdue in the office. We had to take a test drive. (Watch video of the test drive, story continues below.)

http://www.popularme...ws/4215249.html


That is a sport hybrid really worth having.

[Jerome]

Now I am completely flumoxed... a range of 200 miles!!!?? I thought I understood the whole electric debate after this thread, but now I can start over again!

[Todd]

Originally posted by Jerome.Inen
Now I am completely flumoxed... a range of 200 miles!!!?? I thought I understood the whole electric debate after this thread, but now I can start over again!

The published range for battery electrics has always been 200 miles.

[Jerome]

yeah but it was never true, was it?

Oh darn, it's you, McGuire! Bloody Irony!

[Moon Tricky]

Originally posted by SphereTL1000S
Have you guys seen this one?
That is a sport hybrid really worth having.

It's not really a hybrid though, if it's just electric. Or is it?

[J. Edlund]

Originally posted by imaginesix

Doesn't that make the Honda a series hybrid since power must be delivered through the engine and motor to drive the wheels?

No, it makes it a parallel hybrid. The Honda is using what is essentially a conventional drivetrain, with the addition of an integrated starter generator which sits between the engine and gearbox. This ISG can boost power during load and create electricity during braking.

A serial hybrid works according to:
engine -> generator -> battery -> motor -> wheels
or
engine -> generator -> motor -> wheels

This means that a serial hybrid always convert mechanical power to electricity, all moving power is generated by electric motors. Parallel hybrids create moving power by both engine and motors, "excess" power (mainly thought braking) is used to create electricity for motors. Parallel hybrids so far offer a better mileage due to the large losses between engine and wheels in a serial hybrid.

Originally posted by Moon Tricky


There's not much advantage on being able to drive on electric only, if you ask me. Storing electric energy for later use is just too inefficient. It's already stored as fuel in the first place. But this strategy of Honda's would work perfectly well for a diesel "hybrid". Insofar as it can properly be described as a hybrid simply to stop the engine when the vehicle is stationary and start it again when needed. There would be not so much need for the large batteries.

But can a diesel be stopped and started like that without any problems?

At low speeds the fuel consumption of a car driven by an engine starts to increase. So electric only at low speeds is beneficial. Storing energy for later use is also not that inefficient (the loss is about 20% if I remember correctly). But plug-in-hybrids are from a CO2 standpoint not beneficial as long we have coal fired power plants (about 40% efficient + 8% grid losses). The emissions from using extra fuel to power a car is smaller than from using more electricity (the same is true for electric vs. diesel trains). Plug-in-hybrids could however improve the air quality in big cities since the emissions are moved from the cars to the powerplants.

[imaginesix]

Pretty much says it all right there

[Calorus]

Originally posted by J. Edlund

The emissions from using extra fuel to power a car is smaller than from using more electricity (the same is true for electric vs. diesel trains). Plug-in-hybrids could however improve the air quality in big cities since the emissions are moved from the cars to the powerplants.

Perfectly true, however the significance of move from the motor engine, to the power station is that it allows the technology to be availble, refined and inplace to ensure that as hydro-electric, geothermal, and nuclear are refined and optimised, the transport energy emissions are reduced directly with the grid's rather than requiring an independent path of research and development.

[crono33]

in europe in some cities we still have something called "filobus", which is an electric bus, and there is an infastructure of wires along the bus routes

http://ratb.stfp.net...z/5002-73:1.jpg


i wonder if something like this could be applied for city private transport. of course overtaking could be a problem ;-) but with onboard batteries the vehicles would have a level of freedom from the wired network and overtaking capability.

[J. Edlund]

Originally posted by Calorus


Perfectly true, however the significance of move from the motor engine, to the power station is that it allows the technology to be availble, refined and inplace to ensure that as hydro-electric, geothermal, and nuclear are refined and optimised, the transport energy emissions are reduced directly with the grid's rather than requiring an independent path of research and development.

What you mention is not a problem, and may also hurt future development.

Fossil fuels will not be replaced by hydro-electric, nuclear or geothermal power sources in the near future. Nor can we say that grid powered electric cars is the future, and saying so will certainly hurt the development of new technologies. It's always important to be goal orientated and technology neutral for future energy solutions.

There is currently no environmental reason to go for plug-in-hybrids, and it's therefore also no reason for governments to subsidize them. If people buy them for any other reason, it's however ok to let them do that.

[LS 1]

Originally posted by J. Edlund


It's always important to be goal orientated and technology neutral for future energy solutions.

Amen.