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Out of curiosity, how do they handle the transmissions in self-driving trucks? My guess was automatics, but torque converter automatics aren't strong enough for

by scurvy 7y ago

Out of curiosity, how do they handle the transmissions in self-driving trucks? My guess was automatics, but torque converter automatics aren't strong enough for use in a big-rig like this. DSG? Fully "automatic" clutch-based manuals? These things have to be pretty expensive.

anticensor 7y ago
Series hybrid aka diesel-electric may work.
loeg 7y ago
With a diesel you can pretty much drop it into the appropriate adjacent gear and let the synchros handle it. The RPM band is pretty narrow.
rightbyte 7y ago
European heavy trucks are automatic. It's a robot pulling the gearstick and pushing the clutch under the hood. I guess some US brands offer it too? Even though I know manual is popular in the US. It's kinda funny how the automatic is so popular for cars in the US but not for trucks while in Europe it is the opposite and trucks are automatic and uptil recently cars were manual mostly.
deleted 7y ago
[deleted]
joshuahaglund 7y ago
They've got electronically controlled clutches, no torque converter. Yeah, probably more expensive than a manual but they save gas which will cost much more long term. https://www.ttnews.com/articles/manual-transmissions-rapidly-becoming-thing-past https://www.ttnews.com/articles/manual-transmissions-rapidly...
jillesvangurp 7y ago
When trucks go electric, they'll be a lot easier to control. Current trucks are optimized for truck drivers. They become a lot simpler if you no longer need to worry about transporting humans. IMHO autonomous ICE vehicles on the road will probably not happen because they are getting replaced with cheaper EVs in roughly the same time frame that autonomous driving is happening and not having to worry about complex engines simplifies the job of automating things.
- gambiting 7y ago
  >>When trucks go electric, they'll be a lot easier to control The big elephant in the room is of course the fact that no one can actually explain how you'd make trucks electric. Cabs aren't fitted with dual 300 litre diesel tanks for show - moving 40+ tonnes takes a lot of energy and a battery that would provide a similar range to what we have now would be gigantic, meaning both very heavy and very expensive.
  - jillesvangurp 7y ago
    Tesla is planning to ship a truck soon and they've been driving the prototypes around for a few years now. So they seem to have a plan for this with all these boxes ticked (class 8 heavy duty truck, check, 500 miles, check, etc.). Also other's are already producing electric vans, trucks, buses, as well. And I think there was a story about some ginormous heavy duty mining ore EV trucks https://hackaday.com/2019/08/22/electric-dump-truck-produces-more-energy-than-it-uses/ https://hackaday.com/2019/08/22/electric-dump-truck-produces.... Takeaway point is that if you need heavy duty engines with insane amounts of torque, electric is the way to do it. Most modern oil tankers are electric engines powered by diesel generators for the same reason. Batteries are not cheap of course. But then the life time consumption of diesel for a Truck is not exactly cheap either and probably buys you a lot of battery and power to charge them. Assuming a million miles (which is what Tesla is shooting for with their drive trains) and a generous 6 miles to the gallon, we're talking about 0.5M fuel cost at 3$/gallon. Your mileage may vary a little of course but it's a nice round number. If you'd buy Tesla 3's at 50K each and stripped their batteries you'd end up with with 10 x 75kwh = 750kwh (and a lot of premium cars). So, lets just say that amount of money easily gets you into mwh territory which fully explains why Tesla can advertise a 500 mile range, which in a truck doing 50m/h is about ten hours of driving, which I'm sure legally requires taking some breaks in the US as well (i.e, plenty of opportunity for charging, just in case you'd bring up range anxiety as a thing). As the whole point of a truck is to move heavy loads, adding a few tonnes of battery that you would need for this should not be a problem. Torque is superior with electric. I doubt moving 40+ tonnes is going to be much of a problem given that they routinely demonstrate the torque of EVs by having them pull e.g. freight trains, large jets, or whatever. Also, EVs can do regeneration downhill or when braking and they barely use any power when idling (unlike Diesel engines).
SigmundA 7y ago
>but torque converter automatics aren't strong enough for use in a big-rig like this. Not true Allison makes pretty standard 6 speed automatics with torque converters that can handle class 8 trucks, look at the 4500 series. They aren't the most efficient for long haul steady state highway though, Allison introduced a sort of hybrid 10 speed with torque converter back in 2012 for highway use called the TC10. Other makers of automatics are Detroit, Eaton and Volvo I believe they are all dry clutch designs. The automatics can have better efficiency do to fast optimized shifting and are of course easier to train. I believe that majority of newer trucks (2015+) are built with automatics now.

by scurvy 7y ago

anticensor 7y ago

Series hybrid aka diesel-electric may work.

loeg 7y ago

With a diesel you can pretty much drop it into the appropriate adjacent gear and let the synchros handle it. The RPM band is pretty narrow.

rightbyte 7y ago

European heavy trucks are automatic. It's a robot pulling the gearstick and pushing the clutch under the hood. I guess some US brands offer it too? Even though I know manual is popular in the US. It's kinda funny how the automatic is so popular for cars in the US but not for trucks while in Europe it is the opposite and trucks are automatic and uptil recently cars were manual mostly.

deleted 7y ago

[deleted]

joshuahaglund 7y ago

They've got electronically controlled clutches, no torque converter. Yeah, probably more expensive than a manual but they save gas which will cost much more long term. https://www.ttnews.com/articles/manual-transmissions-rapidly-becoming-thing-past https://www.ttnews.com/articles/manual-transmissions-rapidly...

jillesvangurp 7y ago

When trucks go electric, they'll be a lot easier to control. Current trucks are optimized for truck drivers. They become a lot simpler if you no longer need to worry about transporting humans. IMHO autonomous ICE vehicles on the road will probably not happen because they are getting replaced with cheaper EVs in roughly the same time frame that autonomous driving is happening and not having to worry about complex engines simplifies the job of automating things.

gambiting 7y ago
>>When trucks go electric, they'll be a lot easier to control The big elephant in the room is of course the fact that no one can actually explain how you'd make trucks electric. Cabs aren't fitted with dual 300 litre diesel tanks for show - moving 40+ tonnes takes a lot of energy and a battery that would provide a similar range to what we have now would be gigantic, meaning both very heavy and very expensive.
- jillesvangurp 7y ago
  Tesla is planning to ship a truck soon and they've been driving the prototypes around for a few years now. So they seem to have a plan for this with all these boxes ticked (class 8 heavy duty truck, check, 500 miles, check, etc.). Also other's are already producing electric vans, trucks, buses, as well. And I think there was a story about some ginormous heavy duty mining ore EV trucks https://hackaday.com/2019/08/22/electric-dump-truck-produces-more-energy-than-it-uses/ https://hackaday.com/2019/08/22/electric-dump-truck-produces.... Takeaway point is that if you need heavy duty engines with insane amounts of torque, electric is the way to do it. Most modern oil tankers are electric engines powered by diesel generators for the same reason. Batteries are not cheap of course. But then the life time consumption of diesel for a Truck is not exactly cheap either and probably buys you a lot of battery and power to charge them. Assuming a million miles (which is what Tesla is shooting for with their drive trains) and a generous 6 miles to the gallon, we're talking about 0.5M fuel cost at 3$/gallon. Your mileage may vary a little of course but it's a nice round number. If you'd buy Tesla 3's at 50K each and stripped their batteries you'd end up with with 10 x 75kwh = 750kwh (and a lot of premium cars). So, lets just say that amount of money easily gets you into mwh territory which fully explains why Tesla can advertise a 500 mile range, which in a truck doing 50m/h is about ten hours of driving, which I'm sure legally requires taking some breaks in the US as well (i.e, plenty of opportunity for charging, just in case you'd bring up range anxiety as a thing). As the whole point of a truck is to move heavy loads, adding a few tonnes of battery that you would need for this should not be a problem. Torque is superior with electric. I doubt moving 40+ tonnes is going to be much of a problem given that they routinely demonstrate the torque of EVs by having them pull e.g. freight trains, large jets, or whatever. Also, EVs can do regeneration downhill or when braking and they barely use any power when idling (unlike Diesel engines).

SigmundA 7y ago

>but torque converter automatics aren't strong enough for use in a big-rig like this. Not true Allison makes pretty standard 6 speed automatics with torque converters that can handle class 8 trucks, look at the 4500 series. They aren't the most efficient for long haul steady state highway though, Allison introduced a sort of hybrid 10 speed with torque converter back in 2012 for highway use called the TC10. Other makers of automatics are Detroit, Eaton and Volvo I believe they are all dry clutch designs. The automatics can have better efficiency do to fast optimized shifting and are of course easier to train. I believe that majority of newer trucks (2015+) are built with automatics now.