The simplest thruster fuel consumption control! No combinators, only 1 wire.

[Eimas]

TL:DR Use a pump and connect either fuel or oxydizer to an empty tank. Wire the pump to the tank and set to only turn on when there is less than 125 units of your chosen liquid. Connect all the engines AFTER the tank, other liquid can flow freely to the thrusters. Thats it

Hey

So I've been using the method for controlling thrust from this genius thread viewtopic.php?f=193&t=118009
Also started seeing some more setups pop up in my youtube recomendations. And I started thinking.

After thinking for a solid 5 minutes I've come up with a system worthy of all that thinking. It's as simple as it gets. Only consisting of 1 Tank, 1 Pump and one wire.
Screenshots now, explanation below:

Screenshot 2024-11-14 165757.png (74.25 KiB) Viewed 741 times

Screenshot 2024-11-14 165714.png (2.73 MiB) Viewed 741 times

I use an empty tank for measuring how much fuel is currently in the system and turn the pump on when it falls below a certain amount. The measuring itself is not the main thing here, since the fuel is constantly being used. It's just a controlled bottlenech of sorts. After some testing I settled on turning a pump once there is less than 125 units of fuel in the tank, this gives me 32u/s of fuel consumption and ~89% efficiency. For less efficiency but more speed use a higher value like 250 or something. I hope this helps and you find it useful!

Notes:
Yes the thrusters fill up when stationary, but once moving they quickly burn off the excess fuel and reach cruising speed faster. Like an older or chip tuned diesel flooring it from the intersection leaving a cloud of smoke lol.
Since the thrusters are using both fuel and oxydizer at the same rate, limiting only one is enough.
Tried using another pump to only supply the engines with the fuel when the speed of the hub is above 0, but it did not work as expected.
Tested with 1, 3, 5 and 7 engines and the consumption per second differs only by a few units so it's pretty much negligible.

[dragon_gawain]

After looking at the other topic you mentioned and double checking the factoriopedia graphs, I came up with pretty much this exact same solution - add an extra tank after my main storage tanks, hook it up to a pump from the main storage tanks, and set the pump to only turn on if the extra tank is below 250.

To prevent the initial inefficiency caused by the engines filling up when stopped, I added this very simple combinator

Screenshot 2024-11-14 125326.png (1.64 MiB) Viewed 684 times

hooked up to the hub and the extra tank, and outputting to the pump (requires the engines to be primed, but only once for the same reason as the other post mentioned - since I'm relying on V (this ship velocity) to be greater than 0, the engines need to be able to activate, but they can't activate if they're fully empty).
So in total I'm using 2 DCs (one for each tank).
Combinators just save a bit of extra fuel, the full simple version that you stated works as well, you just lose that bit of efficiency at the start.

edit: forgot to mention, my version with it at 250 runs the engines at 75% efficiency, but I wanted to get that bit of extra speed cause this particular ship I'm using to transport some stuff from Gleba, so speed is important. What you set the value to is your decision on the speed/efficiency tradeoff.

second edit: yes, my version also suffers some inefficiencies cause I'm doing it based off of V > 0, and as the ship slows down, the engines still fill up. I haven't fine tuned the V value yet.

(the extra green wires hooked up to my main storage tanks are reading the fuel and only allowing the ship to depart if there's enough fuel to make it to the destination, so it's part of a different system and can be ignored. Just look at the highlighted green wires connects to the DC for my take on this simpler version)

[Eimas]

Yeah I was thinking of ways to stop overfilling the engines at standstill, but since my goal was to keep this as simple as possible I stuck with this one. The initial burst of speed is quite a nice bonus allbeit inefficient.