Just reading the engine specs on a 2013 Kia Optima Hybrid I have. Says it has 13:1 compression ratio with multi-port fuel injection. I was under the impression only DI could support such high compression. And it runs on regular gas. Explain.
I don't believe Hyunkia does that, I only know of Toyota, Ford, and VAG doing that.are you sure the 'multiport' injection isn't direct + some port injected fuel to keep the intake valves reasonably clean? (not a KIA expert here)
Yes it is. Does that mean when under load it won't maintain 13:1? Only at cruise or coasting?Is it Atkinson cycle? They often have a higher compression ratio but can still take regular
The intake valve is open during part of the compression stroke making the actual compression ratio lower but the expansion ratio higher during the power stroke, which is supposed to gain efficiency compared to using an equal compression and expansion ratio, I guess when you compare an equivalent engine using the otto cycle with a lower compression ratio equivalent to the effective compression of a comparable Atkinson cycle engine, there's still more power the could be extracted from the expansion during the power stroke but you run out of stroke and have to exhaust thus losing efficiency that is afforded by the Atkinson cycle..Yes it is. Does that mean when under load it won't maintain 13:1? Only at cruise or coasting?
With an Atkinson cycle engine, you will never get close to 13:1 ever due to most of the compression going out the intake valve on the compression stroke.Yes it is. Does that mean when under load it won't maintain 13:1? Only at cruise or coasting?
and mitsubishi. they go even further, it's essentially always running port injected and under certain conditions runs DI aswellI don't believe Hyunkia does that, I only know of Toyota, Ford, and VAG doing that.
Hyundai does MPI + DI now.I don't believe Hyunkia does that, I only know of Toyota, Ford, and VAG doing that.
The engine in the original poster’s car is indeed a MPI engine. Hyundai/Kia only used MPI on their hybrid engines for quite some time.are you sure the 'multiport' injection isn't direct + some port injected fuel to keep the intake valves reasonably clean? (not a KIA expert here)
13:1 compression = high octane fuel.
They can put knock sensors and adjust the timing via ECM but, that guarantees nothing.
Russian roulette. Are you game?