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Sure, but fully solenoid-controlled has considerable parasitic loss associated with moving the valves themselves. Opening the valve using a camshaft against a spring allows at least some of the energy that it took to open the valve to be returned back to the camshaft. Once you have fired a solenoid to open the valve, that energy is lost and can't be recovered. Sure, it's only a little bit of energy to open each valve, but multiply that by number of valves and how fast the engine is spinning, and it adds up to a big electrical demand and a big parasitic loss. Thus far, it hasn't seen production. There are several ways of being "almost as good" in terms of valve motion while being "nowhere near as bad" in terms of parasitic loss: - BMW Valvetronic (in production, fully mechanical, cams acting against springs, the duration is related to the lift and can't be adjusted separately) - Fiat MultiAir (in production, electrohydraulic but with the hydraulic pressure coming from cam lobes, some but not all of the mechanical energy used to open the valve is returned) - Koenigsegg (sp?) FreeValve - electropneumatic, this seems to have been proven to a pre-production state but I don't think it has seen production yet. - This system - which appears to be mechanical, somehow changing the motion profile of the camshaft. If it works the way I think it does, there may be restrictions on the number of cylinders per bank. - Honda VTEC and several variations of it, which have two discrete cam profiles to choose from. This might be a situation that has 20% of the complexity for 80% of the benefit.
The collision prevention logic has to be sorted out first, including the defensive-driving logic ... and only then, and after an extensive validation period to prove the system as fault-free as possible, the car may be allowed to steer itself under limited circumstances. The other manufacturers understand this. Tesla has put the cart before the horse. There are SO many things that Tesla could do: - Fix obstacle detection and evasion is the obvious one. Until it is bulletproof ... No auto-steer, and with that, no auto-navigate. It's fine for this to be proven out in limited circumstances or limited locations or limited conditions. Disallow operation otherwise! - Defensive driving needs to be implemented. The system needs to recognize other vehicles on a conflicting path, and do something about it. - Stop sign and red traffic signal detection needs to be bulletproof before hands-off operation is allowed on any road that has stop signs or traffic signals. - Any time it is in automatic operation, it needs to have a plan for a graceful exit in case the circumstances allowing automatic operation come to an end and the driver doesn't respond. It follows from this, that for automatic operation to be allowed, it has to be able to respond to all foreseeable panic-emergency situations, because the driver cannot be expected to take over quickly. - The car knows where it is. It knows what sort of road it's on. Disallow self-steer operation unless the car is known to be on a road suitable for its use and in conditions suitable for its use, and with a pre-planned graceful exit in the event that the driver does not respond to a request to take over. (See: Cadillac SuperCruise) It's fine for this to start out in limited circumstances and gradually expand as other locations and other conditions get proven out. I'm not optimistic about Level 5 (full self driving in all conceivable circumstances, the no-steering-wheel scenario) ever happening. Level 4 with planned graceful exits will probably happen on pre-planned repeated routes and in decent weather. Level 3 is extremely dangerous due to lack of ability of humans to pay attention and immediately take over in circumstances when they are generally not doing anything (i.e. they'll be sleeping, or texting, not watching the road). Level 2 is proving to be dangerous when it masquerades as something it is not.
^ That plus a multitude of other reasons are why OEMs in general are not doing it this way. High performance motors need active liquid cooling, too, meaning even more stuff that needs to flex with suspension and steering movement (which it wouldn't have to, if the motor were between the wheels attached to the chassis and driving through CV shafts). Perhaps someone is under the impression that a fixed-reduction gearbox is inefficient and that CV joints are a major source of power loss. They're not. Perhaps someone thinks they are saving space. The space in the middle of the vehicle between the suspension parts is readily utilized for CV shafts and drive components.
GDI savings are somewhere between nothing and several percent depending on the implementation but 4 - 6% is a fair estimate in the absence of knowing details. Turbocharging and downsizing, on the other hand, doesn't seem to work out in reality. There are ample cases of these vehicles doing well in government test procedures but not so well in the real world. Mazda, notably, with their Skyactiv approach, stated that they preferred to let the engine be a bit bigger and *not* turbocharge it in the interest of having a higher compression ratio. Market demands seem to be pushing them towards turbocharging, though. Toyota hypes the Prius and hybrid versions of some other models but they sell an awful lot of base non-hybrid Corollas and RAV4s and Yarises. It's still the highest hybrid percentage of anything in the chart. Tesla isn't on there ... nor is BYD ...
I wonder what they mean by "fully digital manufacturing". This isn't something that you can do on a computer. Someone or something needs to pick up this piece of steel, and pick up that other piece of steel and hold it in the right spot, while someone or something else takes a physical welding gun and welds them together. (I work in this business) Fully digital inventory control and parts scheduling ... Certainly. It's already pretty much like that and has been for quite a while. Network communication between devices (robots, pneumatic valve banks, weld units, etc)? It's getting there. Everyone is using ethernet or profinet communication these days. Not all the hardware is compatible yet but it's getting close. Collaborative robots ... I've only seen one application; I've talked about 10 customers out of doing it this way because when the process was properly analysed, it didn't make any sense. (It didn't even make sense to do the one that was completed, but someone wanted to do it that way to experiment with it. Their money, not mine ...) I wouldn't exclude this completely, it just didn't make sense for the applications that have come across my own desk. If someone wants to change the design of the car then someone still has to make all the molds, stamping dies, fixtures, and all the automation around them (this is the piece that I do). You generally want robots (and AGVs) to do the same job over and over without "intelligently" deciding to do something else, if you want every car to come off the line the same way ... If the path of a weld is inconsistent then you had better find out why your parts or fixtures are inconsistent, and fix that ...
It will be the same on this go-around as it was the last time: Based on the fuel consumption alone, simple economics will dictate that supersonic aircraft will remain a tiny niche market compared to standard commercial aircraft. If supersonic aircraft account for let's say 0.01% of commercial air traffic, the overall effect of the higher fuel consumption (and therefore CO2) and other emissions are insignificant. Even on a flight from North America to Europe, the time spent waiting in airports is a pretty big percentage of the total travel time ... especially if you need a connecting flight at one or both ends, which is highly likely if the flight across the ocean only goes on an infrequent schedule between specific high-traffic airports that don't happen to coincide with your travel plans.
It looks to me like the motor is always coupled directly to the rear-axle-drive through a planetary reducer, and the whole deal can be engaged to the front axle or not through the multi-plate clutch. Surely the "better fuel efficiency than two-wheel-drive" is relative to a two-wheel-drive system without this transfer case, i.e. non-hybrid; something of an unfair comparison ... A lot of the newer designs of automatic transmissions are designed to allow the torque converter and lock-up clutch to be replaced with a motor-generator and a clutch to couple or de-couple the engine. (The ZF 8-speed is like that.) Doing it that way removes the need to check off the "4 wheel drive" option box in order to get the "hybrid" option, but it means it has to be a "full" hybrid rather than a "mild" hybrid, since the motor-generator would then be responsible for all start-ups from a stop. Chrysler did it a different way, with a belt-coupled motor-generator attached to the engine. Again, no need to check off "4 wheel drive" option box to get "hybrid". But, can't drive electric-only (at all) with that set-up. 4 wheel drive is almost becoming mandatory in that segment anyhow, so the distinction might not matter much.
Right now, there's no reasonable way to make such a comparison, because (A) Autopilot requires drivers to constantly be paying attention and be ready to take over if something occurs that it can't handle, which means Autopilot isn't really responsible for what is happening, (B) Autopilot is only supposed to be used in the circumstances that it can handle, and that does NOT include traffic control devices (it is incapable of properly handling stop signs and traffic signals, nevermind a policeman waving his arms), and does NOT include adverse weather conditions, construction zones, etc. This means it is only supposed to be used in circumstances in which human drivers already have low risk. Most serious collisions happen at intersections which have traffic control devices (stop, yield, traffic lights) ... which Autopilot can't handle. There is a list of vehicles out there which, over a particular study period, had ZERO driver deaths recorded. Some of them are reasonably common cars - this isn't because there are none of them on the road. (Google it.) Tesla is not one of them ...
Given that Tesla still (rightfully) insists that drivers have to continue to pay attention and monitor vehicle operation when using autopilot (even though it's quite apparent that plenty of them don't do so adequately), statements about how autopilot affects collision rates aren't meaningful because it isn't really the autopilot in control if it requires the human driver to take control and/or overrule if autopilot does something wrong. With the current situation, it's only a matter of time before a vehicle operating in autopilot mode kills someone outside the vehicle. Maybe a pedestrian, maybe a bicyclist, maybe someone in another vehicle. They've already hit two fire trucks and an unoccupied police car (that we know of). When they hit and kill someone ... look out. Uber was in the unfortunate position of having this happen in a highly publicised case early on. Tesla has just been lucky. Can't rely on luck forever.
^ ... only works for those using a truck strictly as a personal vehicle (in which case, maybe they should just buy something else - but good luck convincing them). For those who use trucks as trucks, for hauling and towing stuff, the most efficient (not the same as "smallest") engine you need for cruising while pulling an 8000 lb trailer might be this one. (I have a Chrysler van with their 3.6 V6, and it's fine for what I use it for, but I wouldn't want to max out the towing ratings with it) Dynamic Skip Fire should solve some of the issues that turned up with the prior VCM system, in that the "dead" cylinders would lead to piston ring sealing issues and thus lead to high oil consumption. Honda had that problem, too. Dynamic Skip Fire allows all cylinders to take their turn, which should help with this. It'll be interesting to see how this compares to the newly-introduced Ram trucks with their mild-hybrid system ... I suspect it will be two different means to the same end.
No misinformation on my part. I call situations as I see them. I understand how cars work. Tesla is building cars that the normal everyday person is going to be driving, and they owe the same duty of care in doing so that anyone else does. If they fail to do so ... they do not get a free pass just because they don't have a tailpipe. As for the claimed "software bug" ... Panic stops exceed (by a lot) the amount of power that can be dealt with by regenerative braking on all current EVs. Therefore, this issue, whatever it may be, has to pertain to the standard braking system, which uses hydraulic brake calipers and disks just like any other car does. I will use the conventional terminology for this system, the "service brakes" (as opposed to the regenerative brakes or the emergency brakes). So, this hypothetical "software bug" IF that were to be the case, would relate to failure of the vehicle to apply the service brakes in a consistent manner. Why would a "bug" cause the service brakes to be fully applied the first time they are used in anger, but fail to fully apply them afterward? That makes absolutely no sense. The more plausible argument ... is that they either selected the wrong brake pad compound (too easily glazed) or undersized the brake pads (too much heat = glazed pad material) or did some other equivalent booboo related to thermal management of the brakes which ends up cooking something the first time they are used hard. Glazed brake pads will behave EXACTLY as Consumer Reports, and other road testers, have reported - the first stop works OK, subsequent stops not so well and they essentially never recover. If it isn't the pads but rather is some other part of the brake system that gets cooked the first time the brakes are used in anger, that's just as bad a fail ... perhaps even worse, since that probably won't get fixed by changing the brake pads. But setting all that aside, let's suppose there is a "software bug". This is in the braking system, which has to be the most FMEA'ed and validation-tested system in the whole car. How would they miss a fault in the braking system that only allows the braking system to perform optimally once and seemingly never again? Oh yeah, someone didn't think they needed to do that validation testing ... Bear in mind that a Tesla weighs ~ 1000 lbs more than an otherwise-comparable normal car, because of its batteries. (So, by the way, does a Chevrolet Bolt.) Means it needs beefier brakes.
HarveyD, why do you want to take away North American jobs?? Mainstream vehicle manufacturers the world over know how to select brake system components. Sometimes the bean counters compromise the engineering choices but they all know how to do it. My experience has been that European vehicles in general have the best brakes (because they have to cope with the German autobahn), but there are many American-designed and -built vehicles with excellent brakes, too. This problem could have very easily been found and fixed had proper pre-production testing be done. Problems like this, are what pre-production validation testing is for! It's too late in the game for Tesla to subcontract-out the design and manufacturing of this vehicle. It's also rather likely that Elon Musk's personality wasn't compatible with contracting-out. He displayed his original attitude towards traditional auto manufacturing quite a while ago. Now, he's finding out the hard way that maybe the traditional auto manufacturers and suppliers know a thing or two about building cars.
Tesla is paying for their failure to do proper validation testing. A good first-time stop followed by inability to repeat it is indicative of overheated "glazed" brake pad surfaces - which may be sub-optimal brake pad material choice, or undersized brake calipers/pads/rotors. Regenerative braking won't fix this. No EV uses the regenerative brakes (appreciably) in panic stops. Perhaps Tesla is counting on regular drivers not using the friction brakes much, and thus not encountering brake pad glazing in normal driving ... but that's not the right way to address this. It means if they need to do a panic stop, and it's the first one those brake pads ever did, it will work, but if it's the second (or subsequent) ... maybe not so well. The rear-drive configuration of the Tesla is not advantageous for regenerative braking. (Of course, the upcoming and $$$$ all-wheel-drive model fixes that.) Improving braking performance through an over-the-air recalibration is a joke. If the brake pads use the wrong material, you have to open the toolbox and take the wheels off and change the brake pads to a different material. Just wait until it becomes apparent that Tesla's "hardware for full self-driving capability" isn't actually sufficient for doing that (which many people already suspect) ... Will they offer refunds for those who bought that expensive option, or offer to buy back cars because they can't live up to that promise? Ouch ... I really want to like the car, but until (A) they shut up about self-driving, (B) repair parts are available through the aftermarket, (C) repair procedures are available on AllData just like they are for any other car so that you are not locked into having repairs done only at a Tesla service center, I'm not buying one. The ones that you can actually get, are out of my league anyhow ... The location of the manufacturing plant is the least of Tesla's worries. I'd rather have its assembly support North American jobs. Relocating the assembly plant won't fix flaws that are baked into the design of the vehicle - like undersized brake pads. What Tesla probably should have done was contract detailed design and manufacturing of the entire bodyshell and undercarriage and all of the associated mfg and assembly tooling to someone who already does this (e.g. Magna) ... but that's water under the bridge at this point ...
Perhaps the existence of Tesla as a competitor gives some motivation, but this will be commercially available before Tesla gets theirs in production. It also remains to be seen if Tesla's system lives up to its promise in the real world. All of this is contingent upon the availability of suitable batteries in large enough quantities and low enough cost, and that threshold is somewhere near being crossed right now. Electric powertrains are already on the market in buses, and trucks in the next smaller class (MitsubishiFuso Canter). MercedesBenz has been quite a bit more conservative in their performance promises ... It's one thing for it to be available, quite another to get actual customers to buy into the concept.
This has nothing to do with Tesla. If you read the article, aspects of this have been in real-world proving (something Tesla doesn't seem to realize that they need to do) since 2013 and the production components were revealed last year with production starting next year. Meritor being involved in this, is huge, given the number of on-highway trucks in North America that use Meritor suspension and brake components. I am sure the outcome of this will be functional and reliable, will be offered with realistic performance expectations, and will actually be available on the market roughly on the stated timeline. Waste-collection trucks are a good application for this due to relatively short daily mileage but a tremendous number of starts and stops.
It is a whole lot easier and less troublesome in most applications to do what's shown in the bottom illustration: Have the motor and gear reducer assembly fixed to the chassis (generally as part of a subframe that also hangs onto suspension attachment points) and run the shaft power out to the wheels through halfshafts and CV joints. This way the motor doesn't have to move relative to the chassis, so there is no flexing of the high-power cables, it doesn't add unsprung weight, it doesn't try to share space with suspension and brake components, and the space between the wheels is generally more or less available due to suspension components anyhow so you might as well use it. Halfshafts and CV joints are very efficient and there is essentially no downside to doing it this way ... which is why all current EVs from volume manufacturers do it this way. Whether you use a single motor and an open differential, or two separate motors and drive units to give built-in "limited slip" and "torque vectoring", is a cost versus benefit decision. Installation of the powertrain components on a subframe that in turn bolts to the bodyshell means that it is even possible to have both arrangements, i.e. lower end models can be single motor and open diff and higher end versions of the same vehicle can be dual motor. 'Course, doing it that way (which is conventional) means there would be no subject for this article ...
BEVs using lead-acid batteries were never commercially successful in this or any other application outside of golf carts and forklifts, and are now of only historical interest for vehicle propulsion. Over and out.
Lead-acid batteries have about 40 Wh/kg ... a 160 kWh battery pack would weigh an astonishing 4000 kg (Comparable to the weight of the cargo!) and take 1600 litres of space. And don't forget that carrying such a heavy battery would require the chassis to be strengthened and then the suspension beefed up and next thing you know it's doubled the mass of the vehicle and now you don't need 160 kWh any more, you need a lot more than that to get the range, which ends up even heavier ... and it doesn't work. The cargo ends up being just the weight of the batteries with nothing left for the cargo itself. Lead acid is good for normal automotive starting batteries, and forklifts (that need to be heavy to perform their function anyhow), and golf carts (that don't need to go very fast or very far). That's it.
... back before suitable batteries had been developed to the point of being suitable for commercial production?? The previous best choice, NiMH, has about half the energy density of Li-ion. Li-ion was not commercialised until the 1990s, and it's only in the last few years that costs have come down and production volumes have gone up enough for them to be suitable for motor vehicles, and that process is still ongoing. NiMH itself was only first commercialised in 1989 and took a few years after that before being ready for use in motor vehicles (e.g. Prius). School buses are a good BEV application but it couldn't have happened "decades" ago, because batteries adequate for the job were not ready for prime time yet.
The hard part is convincing the public. The even harder part is ensuring that politicians keep their hands off the money. Here in Ontario, the carbon cap and trade system is regarded by the general public as a tax, and a very unpopular one. In Alberta, where the carbon cap and trade system was brought in with the promise of being revenue neutral, and the government that brought it in apparently attempted that, but the successor government simply uses it as general revenue; i.e. it is a carbon tax. It is highly likely that the (very unpopular) government in Ontario which brought in the carbon tax - which is what everyone calls it! - will be given the boot in a couple of months, and the likely winner of the next election is already promising to revoke it. South of the border, higher gasoline prices are seemingly the only way to get Americans to drive anything other than the biggest possible trucks and SUVs. Good luck with that. I don't know how any sort of carbon cap and trade scheme could be sold to the public in a scenario where there is general distrust of government and all that it entails. It's unpopular, and if it is unpopular enough, another political party will promise to revoke it and they'll get elected ...
I hate the "MPGe" notation; just give me kWh / 100 km ... The prime-mover thermal efficiency is already baked into the electricity supplied to the vehicle but it's not baked into fuel consumption ratings using normal combustion-engine powertrains, and it's not correct to compare them directly. The Transit's chassis layout isn't the best for shoving batteries underneath; the driveshaft up the middle is a nuisance which this retrofit has evidently kept. The Fiat Ducato (front wheel drive!) doesn't have that issue, and it could be addressed on the Transit by integrating the drive motor and gear reducer into the rear axle or placing it further back in the chassis with a short drive shaft, but evidently Lightning did not go to that much re-engineering of the base vehicle (probably the budget was limited). As with cars, the outcome will be best when the vehicle has the space for the battery pack designed in from the outset. The new Sprinter will have an electric version from Mercedes, which they will certainly have designed in.
We can backtrack the usable battery size from the statement that it will charge in 6 hours with a Level 2 charger. A Level 2 charger generally means 40 amps give or take at 240 volts, i.e. 9.6 kW (most are less, but let's use the higher number since it gives a shorter charging time). That means 57 kWh useable ... about the same as a Chevrolet Bolt battery pack. A Bolt battery pack in a Bolt is good for 200 ish miles. A Bolt sized battery pack in a Transit will give ... a lot less. Judging by the "mpge" it's using around twice the electricity of the cars, which makes sense given the size of the vehicle, so the range is probably 100 ish miles. Local deliveries only, at that range.
Long-haul trucking will be diesel for decades to come ... but cold-start is a pretty small part of their operation.
This will not appeal in the slightest to H-D's traditional customer base ... which is aging fast. Hopefully it will appeal to a new customer base - which H-D desperately needs to happen. Another big question is whether the dealers will accept it. H-D's dealers have a history of rejecting anything that didn't fit the traditional H-D mold. Buell - Fail. V-Rod - Fail. MV Agusta - Fail. There is a strong possibility that the dealers won't know what to do with this.