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^ That's not what the article says. The dyno test was done according to the NEDC, and I will guarantee that if the proper (prescribed) gear change points are followed and that driving cycle is followed, that engine will never come anywhere close to 3500 rpm in that test! If you follow the NEDC on the road with the prescribed shift points, the results should be close to the same as on the dyno. All combustion engines gasoline and diesel have protection strategies that temporarily emit higher than the prescribed emission limits if driven steadily under the conditions that trigger them (typically high load and high RPM). That's why the standards use average emissions over a driving cycle, not a do-not-ever-exceed limit! I can only surmise that DUH is on a mission to attract attention to themselves.
You want someone to produce a vehicle that runs on a fuel that there is currently no distribution network for, or that requires the operator to fill both a gasoline tank and a diesel tank and not make a mistake? You realize that manufacturers want to sell something in quantities that they have at least a hope of being profitable, right? I think Mazda's Skyactiv-X pre-empts this research, and it runs on fuels available today that everybody is accustomed to, and it's in production (OK, next year, but they're committed). BMW i3 Rex is a series hybrid; when operating on the combustion engine, it is unremarkable in terms of fuel consumption.
I live here. Loudest noise on the subway is the horrendous screeching and clanging from the steel wheels whenever it goes around a bend inside the concrete tunnel, which contains and reflects all that noise. Streetcars produce the same noise, it's not contained and reflected back to its passengers but now everyone gets to hear it. Trucks, buses, construction activity, general traffic sounds contained and reflected within the concrete jungle add to the din. Vehicles with noisy exhausts are a small part of it (and have little or no influence on subway noise since the subways are separated from road traffic); typically in downtown Toronto, the only vehicles with engines running under heavy load when they make lots of noise are the underpowered buses and trucks.
Tesla needs to focus on getting Model 3 production sorted out, and I'm quite sure this will happen within the next few months. They are close. Then they can think about how to build a new model. Exporting manufacturing to Asia doesn't result in getting the vehicle into production any faster (It still takes them time to build stuff and get the bugs out of it), but it DOES alienate customers who want to support jobs in their home market. I don't know why HarveyD is so insistent on putting his neighbors out of work. As for the cameras vs mirrors, I agree that regulations go out of date, but NHTSA is notoriously slow to change, and they recognize that many of the regulations have been put in place for a reason and careful thought is necessary before backtracking or before doing something that may have unforeseen consequences. Cameras and video screens are subject to technical failures that mirrors aren't subject to, and I'm sure this would be a prime area of consideration. In the meantime, Tesla, and the rest of us, have to operate within the regulatory environment as it exists today, and that means ... mirrors. And air brakes. With that central seating position, how do you deal with a toll booth? Or passport control when crossing the border? Or the security guy at the gate of the facility you are going to? Or the chap at the weigh scale booth? It makes for unnecessary awkwardness ... this vehicle has plenty of width; why make it unnecessarily awkward for the driver? It has to interface with all sorts of existing infrastructure ...
^ I doubt if you've set foot in a manufacturing plant lately. I do every day. Tesla's problem at the moment has nothing to do with productivity and nothing to do with robots (they've got plenty of them), and a lot to do with making too many promises that can't be kept, and that's a management issue. The delays aren't because the workers aren't working (Far from it), they're because management has underestimated the monumental task of making everything work together properly. They opted to skip prototype build ... well, guess what, they're doing it anyhow, whether they wanted to or not, and it's to the surprise of nobody who works in the auto industry. They will get it done, but it will be months late (i.e. it will end up taking the normal amount of time, instead of being compressed the way it was promised). In one of the videos that shows the Model 3 being assembled, you can see a piece of equipment that a customer of mine built. And that is about as much as I can say about it. What it means is that I do not want Tesla to fail ... but I do want them to do what they say they will do when they said they will do it, the corollary of that being don't make promises you can't keep.
^ Let's support North American manufacturing, please. Tesla could very well be out of business by 2025 due to committing to too many expensive projects too soon. They really should focus on getting Model 3 production up and running, and leave the pet projects aside for now. The Tesla semi as shown is not production ready; they've got a fair number of visible non-conformances to motor vehicle safety standards in the concept vehicle, in addition to potential ground clearance concerns that someone else mentioned. Mirrors (you are not allowed to substitute them with cameras! - you can have cameras, but you still need mirrors). Air brakes with the associated mandated gauges and handles, at a minimum. The ability to see and inspect the drive wheels and hubs and brakes. Windows that roll down. The ability to see around traffic when making a left turn without relying on cameras (central driving position is not good for this - and it's not such a critical issue with right turns).
I wonder if the "pollution" category includes cigarette smoking. A whole lot of people voluntarily expose themselves to higher pollution levels than found in the worst cities anywhere. A friend of mine just died of lung cancer ... he was a long-time cigarette smoker.
The California plant was a joint venture with GM. California is an expensive place to do business. And Tesla is hardly eating Toyota's lunch.
Ethanol does not make for a good compression-ignition fuel ... the octane rating is too high! Mazda has stated that this new engine is designed for use with regular gasoline (referred to as 87 octane in US and Canada, 91 RON elsewhere). If premium fuel is used, it operates in spark ignition mode - for the simple reason that the higher octane rating resists self-ignition due to compression. Now, yes, it is still operating at a higher compression ratio than a normal gasoline engine; the slower combustion (relative to partial compression ignition) would probably reduce efficiency a bit. Ethanol has a higher octane rating than premium pump gasoline and will resist compression-ignition even more.
The various systems used in F1 are only applied at part load (to save fuel during the parts of the lap where the driver can not use full load). And, these engines are not called upon to conform to any emissions regulations. The chart in the article showing relative BSFC is obviously only illustrative, since the Y axis is not provided with any units. It is obvious that the bottom of the graph is not at zero BSFC. If we accept the "concept" shown in the BSFC chart, if not the scale or the numbers, this engine has BSFC better than Skyactiv-G under all conditions and pretty much equal to the diesel engine up to moderate load on the engine ... which accounts for the majority of real world driving anyhow. Only in acceleration or hill climbing is it not matching diesel BSFC but it's still better than prior Skyactiv-G under all conditions (that the chart shows) and that in turn was better than their old port-injected conventional gasoline engine under all conditions (that the chart shows). On the other hand, this hopefully won't need the complex and expensive (and potentially troublesome) exhaust aftertreatment system that the diesel needs. And the hardware is familiar to any mechanic that knows modern gasoline engines. With regards to BSFC still being better with the diesel engine under heavy load ... the only conclusion that I would draw is that the diesel engine will remain the engine of choice for heavy trucks and buses.
Not sure what the point is of the above post, aside from general ranting. Magnesium has been in use for decades but typically in parts manufactured by casting or forging. Notably, the old air-cooled VW Beetle used cast magnesium crankcases. Fire resistance can be a problem area. The good thing is that magnesium conducts heat quickly, so if the part has a decent thickness to it (e.g. crankcases produced by casting) it is pretty resistant to catching fire from a local hot spot (e.g. match or lighter or burning piece of paper or some such). If the whole part is surrounded by fire so that there is nowhere to conduct the heat TO, then yes, it's going to catch fire - and when it does, look out. Water will not extinguish burning magnesium. In the case of sheet metal, the (presumably) thin cross section will allow it to heat up quickly and catch fire more easily ... Magnesium is not good for corrosion resistance, either. It can be painted to prevent corrosion but anything that disrupts the painted surface will lead to corrosion. Probably this new manufacturing process will have some applications but don't expect entire bodyshells to be built from magnesium any time soon.
This suffers from quite a few of the same bad design aspects that a Wankel does, plus a few new ones (even though it isn't a Wankel). Rotor sealing, and tip seal lubrication, will be issues just like they are with a Wankel. The main combustion chamber to rotor seals have combustion spaces on both sides (unlike in a piston engine, where the rings have combustion space on one side and lubrication on the other side). And, as with a Wankel, the combustion chamber is a horrible shape with a lousy surface-area-to-volume relationship (think: lots of heat transfer, i.e. poor efficiency). Having the induction and exhaust go through the rotor means even that space will have limited lubrication ... and a lot of thermal loading. Too good to be true, indeed.
People are confusing particulate filters with NOx control measures (SCR). Particulate filters don't require any additives. SCR is the one that requires the special fluid and dosing system. It's currently thought that the higher exhaust temperature from a gasoline engine during cruising conditions will keep the particulate filter hot enough (unlike diesel applications), and the frequent short periods of coasting (which shuts off the fuel completely but need not shut off air supply) will provide sufficient oxygen for passive regeneration without needing any active method of regeneration, aside from perhaps holding the throttle open a bit during coasting to pump air through (this is a trivial matter for drive-by-wire, which everything has nowadays). If that proves to be the case, the filter is unlikely to require any maintenance until the engine gets old enough to start consuming lubricating oil ... then, look out.
Plenty of bumper crash bars are already made from aluminum extrusions (although I don't know what alloy they use).
It's very difficult to compete with the mainstream players in the pickup truck market. Yeah, they don't offer EV yet ... GM tried offering hybrid; very low take rate; they gave up. "Composite body with carbon fiber" is gonna be expensive. I see 4 wheel independent suspension with coil springs on their drivable chassis. The rear strut towers will intrude on the cargo area - unless the cargo floor is very high, which is an objection that I have to all of the current pickup trucks on the market. Using IRS has an opportunity for improving this because it no longer needs space for the differential to bounce around underneath there ... but those strut towers throw this away.
This thing is still not dead?
Reality check: The things that can be powered with a Duramax are things that an EV is not a good match for. Your windmills and solar panels were delivered by a diesel powered truck. Before your charging station existed, the parts and materials to build it were delivered by a diesel powered truck. Before we arrive at tomorrow, we have to get through today. And we had to get through yesterday in order to get to today. We are going to need diesel power for quite some time in the future.
Opposed-piston, across-chamber-injection, two-stroke, uniflow-scavenged engines are not a new invention. Those who believe the Achates engine is going to revolutionize the future of transport, would do well to study the design, and the fate, of the Commer TS3. Look it up. They were in production for a couple of decades ... around fifty years ago.
There isn't crankcase scavenging, I know that. Detroit Diesel engines didn't use crankcase scavenging, either. That's not the issue. The issue is that one way or the other, a certain amount of oil needs to get to the piston rings. Those piston rings cross the port openings in the cylinder wall. Every time they do ... a little bit of the oil on that piston ring escapes out the port opening and thus either goes out the exhaust (if it is the exhaust ports in question) or into the cylinder and thus into the combustion system (if it is the inlet ports in question - on Detroit Diesels it only involved inlet ports because of the layout of the engines in question). Scavenging is coming from a mechanical blower ... conceptually much like Detroit Diesel did it. 4-stroke engines - or, more properly, engines that don't have inlet or exhaust ports in the cylinder wall that are crossed by piston rings - don't have this issue because the oil supply stays on the bottom of the oil control rings and the tiny film necessary to lubricate the compression rings stays put against the cylinder wall.
Piston porting + lubrication = lube oil getting somewhere it shouldn't. Detroit Diesel couldn't figure out out ... Same issue ... We'll see.
James, the vehicles in question, which are all model year 2015, came originally equipped with SCR - not a LNT. The earlier-generation models that used LNT (without SCR) are still in limbo, but the proposed solution (yet to be approved) involved a different LNT, not a SCR retrofit. VW was the only auto manufacturer to attempt to use LNT on its own in the North American market. Some BMW models use LNT in conjunction with SCR. Quite a few manufacturers have used LNT elsewhere in the world. California will NOT be withholding registration of the vehicles in question if owners choose to do nothing. That's what the huge compensation payment to the government by VW was for. Any state that took part of that compensation money is required to allow the cars to continue to be registered unmodified if users choose not to have them modified, and California was one of those (there are 5 states that did not but I don't know which they are - Calif is not one of them).
This article is rather short on suggestions. Alternative materials? Durability ... cost ... weather ... traction? Ignore it completely and let pavement degrade faster and have to do a major asphalt reconstruction project (not an environmentally friendly process) more frequently because of it? Dirt roads? Aside from some obvious safety implications, think about particulate matter. And materials put down to control the dust might have side effects, too.
350,000 km divided by 150 vehicles is just over 2000 km each. I am underwhelmed.
This is not a simple matter. The two-stroke concept - a further development of it which does not use air-assisted injection - is in current production by Rotax/Bombardier for snowmobile and outboard motor applications, but a piston-ported two-stroke will always have a trade-off between adequate lubrication of the piston rings for long life, and oil escaping either into the combustion system from the intake ports or out into the exhaust from the exhaust ports, leading to HC and PM emissions. Exhaust temperature tends to be low with a lot of dilution on two-strokes, which is not good for catalyst light-up after cold start. These applications do not require compliance with automotive emission standards nor is the engine expected to last 300,000 km with only basic maintenance. For applications requiring compliance with automotive or Euro 4 motorcycle emission standards, piston-ported two-stroke is not the answer. The Mahle pre-chamber is a lean-burn application which is evidently being used in Formula 1 to reduce fuel consumption at part load. This is also troublesome if you have to meet modern automotive emission standards. If you have to run stoichiometric to keep a catalyst happy, it's doubtful that this acoomplishes anything. Maybe if the prechamber is stoichiometric without a lot of recirculated exhaust and the main chamber is where the EGR is kept, it might be of some benefit. What needs research, and is surely the focus of this, is somehow addressing the fine particulate emissions that have become apparent with direct-injection four-strokes, improving the speed of combustion without encountering detonation so that the compression ratio can be increased for better efficiency and so that combustion is completed at that higher compression ratio, and controlling piston and exhaust valve temperatures to reduce the need for enrichment under load - the latter being a particularly significant issue for downsized forced-induction engines. Advanced engines that rely on HCCI under at least some operating conditions will be relying on this, too.
To me, this thing looks like a sealing nightmare (inside-out version of Wankel but same issues), and a cooling nightmare, and a lubrication nightmare, and a horrible-combustion-chamber-shape nightmare (read: lousy emissions and thermal efficiency), all rolled into one.