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Sotaro
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Harvey, Your comments demonstrate great ignorance. Write about what you know. Don't advocate for mass slaughter.
Barbar, are you sure about the insufficiency of the air spring for the exhaust/compression stroke?Also, I see no reference to a need for a compressor. It would seem possible that they have not gotten that far, but perhaps the linear piston could be the compressor and just a reservoir would be sufficient. Not to be raining on your parade, but a suspension/shock absorption based system of range extension would clearly depend on how bumpy the road is. Probably great in the boonies!
Barbar, are you sure about the insufficiency of the air spring for the exhaust/compression stroke?Also, I see no reference to a need for a compressor. It would seem possible that they have not gotten that far, but perhaps the linear piston could be the compressor and just a reservoir would be sufficient. Not to be raining on your parade, but a suspension/shock absorption based system of range extension would clearly depend on how bumpy the road is. Probably great in the boonies!
In California motorists are often required to go to "Test Only" Smog test stations. These stations are not allowed to adjust nor repair vehicles. The car and truck manufacturers should not be allowed to self certify. They seems to spend large amounts of time gaming the system which benefits only their bottom line, not the asthmatics who are coughing their lungs out.
The technology needed for the return of the two stroke?
Hopefully you naysayers gleaned more than that from the article...
Mahonj, I think that a policy promoting a consistent annual increase in the gas tax is required. The revenues should be split between tax reductions for the lower income groups and spending for infrastructure and social security. The most important thing is to have a dependable increase in fuel costs. If for political reasons it needs to be mostly revenue neutral then so be it.
It takes 10 minutes to charge and can deliver 110 kw! My question is how much energy can it hold, and for how long, or what is it's self discharge rate?
Does this paragraph make any sense to you? "The cylinder bore was decreased by 2 mm (to 74.5mm) while the stroke was increased to 80mm, a change which not only helps compactness, but also increases torque and presents an ideal platform for adding boost (turbocharging or supercharging)." Since the cylinder spacing is unchanged at 88mm, only the outer 2 cylinders would affect the length and width. The maximum potential reduction in radius would be 1 mm twice equaling 2 mm shorter and 2 mm narrower. From what engine is the reduction of bore of 2 mm measured? And the stroke increase? torque has little to do with a longer stroke. Longer stroke has a lot to do with combustion efficiency, especially at higher compression ratios. "...presents an ideal platform for adding boost (turbocharging or supercharging)." I assume this has is artistic license and has no basis in science. Other than the article, it sounds like a nice engine. It would be nice to have more than a press release. How about weight, cost, size, and brake specific fuel consumption?
Thomas, now, don't be a doubting... according to the website, it uses a Rolloff Speedhub which retails for about $1500. Considering the number of links in the swing arm, I would raise that cost to $2000, plus the motor, battery which goes 130 km? I agree though, stunningly expensive.
I love the two stroke. alas only direct injection can save it... or can it? Help us please Orbital and Rotax!
@Peter XX, Do keep in mind that this is Mazda, a rather small car company. They are broadening their line up of high technology diesels. That is about it. As for 3 cylinder engines, is their a 3 cylinder diesel in automotive use? A 1.5 liter 3 cylinder is going to have some larger NVH than the 1.5 BMW gas. I assume that Mazda didn't just slice off a cylinder from their 2.2 because of NVH. That would have been quite a bit cheaper than what they did.
The picture is of the motorcycle engine cut away a DOHC engine of 1.35 litres. The cranks seem to be single sided for both cylinders and it is 360 degree crank ie both pistons rise and fall together, just like the Norton, BSA, Triumph, Royal Enfield twins of old. So the exhaust note, that escapes the turbo, will have the regular beat! This is going to be interesting! The weight of the cruiser is 295 kg.
Dursun, Evinrude spark ignited normally aspirated multifuel two stroke 55 hp weighs 250 lbs. The Yamaha spark ignited normally aspirated gas 4 stroke weighs 250 also. 40% more weight for a compression ignited turbo charged with 2 cranks! It will be interesting.
EMM, It is my understanding that the tires are more efficient when they are all driven. Otherwise, 1-2 tires are driven with more power, which is less efficient per tire and the other 2-3 tires are just dragged along which consumes energy. As far as the drive train your statement maybe correct, because a 4 wheel drive train weighs more and has more rotational drag. However, an electric drive train may be more efficient and certainly allows for better traction control etc with less weight and space consumption, especially if it is already a hybrid.
the use of the word associates in place of workers or employees is misleading. Furthermore, it would be nice to know if the workers are unionized or not.
SD, the reason they didn't do that is multiple, but fuel economy is most important and disconnecting the drive shaft et al saves more than disconnecting the front drive axles. Also, fwd is easier for neophytes than is rear wheel drive.
Hello All, In the discussion of diesel versus gasoline engines keep in mind that the differences are shrinking. The compression ratios of gasoline engines are now commonly 11-12:1 with Mazdas 13-14:1 being the highest. Mazdas diesel is also 14:1, so weight and cost ranges will begin to narrow. Homogenous Charge Compression Ignition maybe the future! Also, maybe someday two stroke direct injection will be environmentally friendly enough for on road use.
what is new about this system, is the roller cam follower, as the press release says. As one might expect from GM, it is less expensive and more efficient. Other than that, it uses 2 different cam profiles and it electrohydraulically switches from one to the other. There is also a cam phase advance/retard mechanism that is probably at the end of the cam near the chain drive (not shown above). So, from what I understand, this is rather like the VTEC in that it changes from one cam lobe to another to change lift, duration etc. So, does GM do this for each intake valve? I assume so as I imagine they are all 4 valve cylinders and have the same for both intake valves. Other than the roller cam follower, is this really cheaper than the VTEC, is it more compact? It has 3 cam faces, one low lift, and 2 high lift per valve. Multiair is a hydraulically controlled intake valve that on an individual or group basis can have it`s lift reduced. That seems more capable than the VTEC or GM for lower speed engines.
I imagine the reason for the electrical turbocharger is a way to provide intake pressure at start up. This is needed because the Ecomotor cannot use crankcase scavenging. The description of the ecomotor mentions uniflow air flow as well as assymetric port timing. I assume that in the practice of Junkers et al, the airflow thru the engine is along the axis of the cylinder from intake port at one end controlled by one piston to the exhaust port at the other end controlled by the other piston. I assume that the intake piston lags the exhaust piston by about 11 degrees a la Jumo 205 (11 degrees). Two things concern me: One is the distance between the main bearings. There are 3 throws with 4 connecting rods in between. The other is the imbalance in the reciprocating weights. The inner pistons are on a common pin and oscillate together. The outer pistons weigh more (I assume given their length) and lag the inner pistons, so it seems vibration is unavoidable. Given the popularity of opoc in tank engines and it's stellar performance in the Deltic and Jumo engines I am excited to see how this pans out.
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Jan 8, 2011