That's my point, the Lycoming (while an old design) is not all that inefficient.
A Cessna 172 burns about 8 gallons per hour and travels at 125 knots, or about 140 mph. That's the equivalent of about 18 mpg.
There's been an enormous improvement in automobile engine efficiency in the past 30 years, and most of that has come from optimizing engines and transmissions to minimize their fuel consumption under light load, while still giving them enough peak power capacity to accelerate quickly, tow a heavy load up a hill when needed, etc.
In comparison, an aircraft engine spends very little time "idling" and sees very little change in load over the course of a flight. It just runs at a fixed speed and power setting for most of the time. There isn't that much to optimize or improve.
Timing is a big one; magento fired engines have fixed timing. The engines can't remove or add timing to get more power.
Fuel ratios are determined by the pilot with current Lycoming and Continentals. Why should the pilot need to worry about this? EFI has been around for 40 years now and would help decrease the cognitive load on the pilot. Like, how many engines have cooked valves because the pilot (or student) forgot to richen the mixture before descending?
Cooling is a huge one. There are a few liquid cooled aircraft engines and they just make everything easier. The engines are more reliable, and it also removes a carbon monoxide poisoning risk due to corrosion in the exhaust cuff.
Yeah, a Cessna can get better fuel economy than a car traveling at 140mph but it could be _so much better_ than what it is. And not just better fuel economy, but better all around experience for the pilots (lower cognitive load), and owners (lower cost of living, more reliable engines).
Many racecars and boats also run fixed timing. Variable timing is needed when the load is variable. If the load is constant, the timing can be fixed.
Modern engine monitors have given us more insight than ever into engine operation and I don’t find the engine management particularly taxing.
After initial takeoff, I’m likely to set the power (throttle, RPM, and fuel mixture) at 1000’ above the ground and not touch it again for 4 hours (when it’s time to transition to landing).
That's still not particularly efficient. There's still variable load: circuit work, obstacles to climb over, flying around (or into) airspace. Air density isn't fixed, your engine may be running richer or leaner than you need to be. Pilots aren't nearly as efficient as setting the mixture as a computer, nor are the currently used single injector (or carburetor) as efficient as multi-point, or direct, fuel injection.
GAMI got their start selling more balanced fuel injectors, but there's only so much you can do when you squirt gas into a tube and hope that it makes it equally to all cylinders.
There's a _lot_ on the table in terms of efficiency and it puzzles me why there has been almost zero progress on this front.
I’m not disputing that GA engines could be significantly improved and modernized in numerous ways. But none of the improvements you mention actually relate to efficiency at cruise power.
I feel like I've said this already but carbureted and mechanical FI in aircraft often do not have even fuel distribution; that is not all cylinders receive the same amount of fuel. If you have an injector on (in) each cylinder, you do. If you have O2 sensors on each sensor the ECU can adjust mixture on the fly and ensure that each cylinder is running optimally
The SDS EFI people claim up to a 20% fuel effiency gain by going to multipoint fuel injection on existing engines.
If you have consistent cooling (hey, guess what, those rear cylinders on an O-540 are running hotter than the fronts), you can run more timing and more compression.
More timing, more compression, less fuel = more efficiency. Basically everything I'm talking about is more cruise power efficiency!
The premise of GAMI injectors is that not all cylinders are supposed to receive the same amount of fuel, because they don’t all receive the same amount of air. The intent is to achieve the same air-fuel ratio, which means having different injector sizes for different cylinders.
I have GAMIs; they are one per cylinder, just like the factory injectors were, but provide closer matched air-fuel ratios. I also have per-cylinder EGT and CHT instruments and have measured less than 0.3gph spread (about 2%) between the leanest and richest cylinder. Modern cars are rarely measuring per-cylinder fuel, but rather measuring the average of half or all the cylinders and using that to adjust short and long term fuel trims.
Lower cognitive load because you as the pilot wouldn't need to manually set the fuel mixture
In the gallery here: https://cessnaowner.org/pilots-perspective-cessna-340/
The red controls are the mixture and have to be manually adjusted by the pilot, so you could potentially remove 1/3 of the controls from that area
"The eDA40 will compete with Bye Aerospace’s new all-electric eFlyer 2 and eFlyer 4 aircraft, which have been securing significant preorders in the flight training market."
Sort of. One feature of fuels is that the planes gets lighter as you burn it. You can also choose not to fill it up in order to have more cargo (or passengers). Batteries don't offer the same flexibility, so they will have to be pretty power dense to provide the same utility.
I'm still rooting for electrification there too. I can't imagine an electric drive train to cost as much as a Lycoming/Continental engine overhaul.
A Cessna 172 burns about 8 gallons per hour and travels at 125 knots, or about 140 mph. That's the equivalent of about 18 mpg.
There's been an enormous improvement in automobile engine efficiency in the past 30 years, and most of that has come from optimizing engines and transmissions to minimize their fuel consumption under light load, while still giving them enough peak power capacity to accelerate quickly, tow a heavy load up a hill when needed, etc.
In comparison, an aircraft engine spends very little time "idling" and sees very little change in load over the course of a flight. It just runs at a fixed speed and power setting for most of the time. There isn't that much to optimize or improve.