> To further improve fuel efficiency and output, ZR15DDTe engine uses Nissan's unique STARC*2 concept paired with a large turbocharger.
If we are able to consider fixed RPM operation and are willing to endure turbomachinery, I don't know why we wouldn't just go all in on a gas turbine. You can reduce the number of moving parts dramatically and accept a much wider range of fuels.
Being able to engineer everything around a one fixed operating speed makes a huge engineering difference. Reciprocating engines are responsive to load and speed changes, but there are trade offs in many other categories.
You can also make a gas turbine power module quite small relative to the alternatives. Replacing the it at major service intervals could be made economically viable.
This has been tried, but back in the day the automatic transmissions weren't really up to it, and they don't really like thermal cycling. And they're noisy. Exact opposite of modern stop/start petrol engines for urban driving.
I also suspect all attempts to keep doing combustion engines for mainstream driving are going to get gradually overtaken and lapped by BEVs.
It was tried in the 60s and 70s, most seriously by Chrysler, and the emissions and drivability weren't great because it was in the "we need to get it working good before we go back and mop up all the other stuff" phase or R&D. The fuel crisis plus the state of automatic transmissions at the tie kept it a back burner item so development was slow and not a priority nor did other OEMs invest seriously.
Chrysler flamboyantly gave this back burner project up and promised to halt further development as part of the wrangling around the government loan they got to save them from bankruptcy in 1979.
Basically it was a song and dance to win political points among the same generation of absolute genius environmentalist who thought moving a steel mill from Ohio where you can regulated it to China where you can't is a win.
I suspect that had the project died a natural death in the 80s rather than being publicly executed as a warning we likely would see some trickle of development these days since they see like a nice natural pairing for various sorts of EVs and CVT powertrains.
It's also worth noting the degree to which facilities and talent pool overlapped between Chrysler, Chrysler Defense, how much more porous the corporate world was 50yr ago and that that Chrysler did ultimately get someone else's turbine into a running driving mass production vehicles in the form of the M1 Abrams so it's not like the technology is unsuitable on a fundamental level.
>Think if it like this - is the turbine exhaust hot? Then you are losing energy.
Turbines for land uses have heat exchangers to get a lot of this back. Even after those the turbine is still lighter for a given power output and lifetime. But normal engines are a lot cheaper.
bob1029 · · focus · HN ↗
If we are able to consider fixed RPM operation and are willing to endure turbomachinery, I don't know why we wouldn't just go all in on a gas turbine. You can reduce the number of moving parts dramatically and accept a much wider range of fuels.
Being able to engineer everything around a one fixed operating speed makes a huge engineering difference. Reciprocating engines are responsive to load and speed changes, but there are trade offs in many other categories.
You can also make a gas turbine power module quite small relative to the alternatives. Replacing the it at major service intervals could be made economically viable.
pjc50 · · focus · HN ↗
I also suspect all attempts to keep doing combustion engines for mainstream driving are going to get gradually overtaken and lapped by BEVs.
cucumber3732842 · · focus · HN ↗
Chrysler flamboyantly gave this back burner project up and promised to halt further development as part of the wrangling around the government loan they got to save them from bankruptcy in 1979.
Basically it was a song and dance to win political points among the same generation of absolute genius environmentalist who thought moving a steel mill from Ohio where you can regulated it to China where you can't is a win.
I suspect that had the project died a natural death in the 80s rather than being publicly executed as a warning we likely would see some trickle of development these days since they see like a nice natural pairing for various sorts of EVs and CVT powertrains.
It's also worth noting the degree to which facilities and talent pool overlapped between Chrysler, Chrysler Defense, how much more porous the corporate world was 50yr ago and that that Chrysler did ultimately get someone else's turbine into a running driving mass production vehicles in the form of the M1 Abrams so it's not like the technology is unsuitable on a fundamental level.
actionfromafar · · focus · HN ↗
You can extract more energy by adding stages but that increases weight.
While a small and light weight diesel engine is already very close to the theoretical limit.
cucumber3732842 · · focus · HN ↗
Turbines for land uses have heat exchangers to get a lot of this back. Even after those the turbine is still lighter for a given power output and lifetime. But normal engines are a lot cheaper.