One big thing about ship diesels nowadays is good monitoring and
control, you can get good reliability, low emissions and low fuel
consumption that way. All meaning lower costs. Also engine starts don't
belch huge amounts of smoke (though that's not important for every
operator).
The difference in rockets compared to most other internal combustion
machines is that rockets operate on a very narrow set of conditions that
are well known beforehand, so benefit from measurement and control are
far less.
Rocket landers have the most variable operation points so might benefit
the most.
What about things like the startup transient? Relatively minor
performance indications for this, but might be a big thing on engine
loads - you can avoid overbuilding the engine if you can guarantee that
the startup is gentle. On the other hand, it should be the same every
time and shouldn't need any sensors or feedback control.
Also if you can see that you accidentally ran lean at some point, there
might be a burnthrough of that engine on the next flight (or if you
haven't yet lifted off, on this flight), so better not do it.
--
Valtteri Maja at gmail com
10.12.2015, 16.57, Paul Breed kirjoitti:
Getting simultaneous propellant depletion at clost to optimum ISP is what matters.... it does not matter if the earlier part of the burn might be slightly off on O:F the steep part of the curve is at the end.
On Wed, Dec 9, 2015 at 9:21 PM, David Weinshenker <daze39@xxxxxxxxxxxxx <mailto:daze39@xxxxxxxxxxxxx>> wrote:
On 12/09/2015 08:59 PM, Monroe L. King Jr. wrote:
I'm not suggesting using car O2 sensors I know they wont work. I'm
looking for something that will work.
Those optical sensors are not the same as O2 sensors.
Engine management in cars is what I know I am speaking
generally in that
direction based on what I know about that.
I see plenty of reasons to want better control over the engine.
Yes, mixture control is a good reason.
A valve can be controlled, pressure/rpm of the power turbine
and many
other factors.
If you want to do closed-loop control of rocket O/F ratio, there
may be
usable methods other than direct flame-chemistry sensing - e.g., using
the pressure drops across the injectors as a proxy for flow
measurement,
and then "closing the loop" to maintain a desired relationship between
those signals.
-dave w