Re: I/o Engine Technology....Outdated?
Yeah, not sure what he was smoking on this fine holiday, but open vs closed loop is not specific to turbo vs normally aspirated engines, it is specific to fuel injection strategy, and closed loop at full load is common on most modern automotive engines for fuel economy and emissions.
Further, while the physical restriction that the turbo represents to the exhaust stream can elevate exhaust gas temps, turbos make their power from increasing intake density (boost), not from heat. In fact, they need to operate in a very controlled temperature range or their delicate internals can go molten very quickly.
Modern automotive engines run higher exhaust gas temps in general to produce cleaner emissions burn off, and direct injection helps greatly in controlling detonation and hot spots in the combustion chamber. Water cooled turbos run just as hot as air cooled, but they tend to last longer and suffer less from turbine oil coking after shut down, if there is an auxiliary after run pump in place. Their turbines would have to be jacketed just like current boat exhaust manifolds to ensure heat control.
All doable, but technology is lagging in the boat world in that regard. Possibly related to lower incidence of warranty failures and less required maintenance for the less complicated normally aspirated engines.
These threads are so weird to me. Someone mentions high tech four valve engines, another reminds of OB technology, and then we say those four valve multi cam engines can't work in a boat? Huh?
And someone says that turbos can't be cooled in a boat? Uh, water cooled turbine housings are on every diesel marine engine in the world, even little ones. And turbo engines always get worse fuel efficiency at high load? Huh? smoke is smokin' sumpin', you are so much better than that. One example doesn't a bad technology make . . .
One poster nailed this. Cost, cost, cost, oh and maybe cost.
Yeah, not sure what he was smoking on this fine holiday, but open vs closed loop is not specific to turbo vs normally aspirated engines, it is specific to fuel injection strategy, and closed loop at full load is common on most modern automotive engines for fuel economy and emissions.
Further, while the physical restriction that the turbo represents to the exhaust stream can elevate exhaust gas temps, turbos make their power from increasing intake density (boost), not from heat. In fact, they need to operate in a very controlled temperature range or their delicate internals can go molten very quickly.
Modern automotive engines run higher exhaust gas temps in general to produce cleaner emissions burn off, and direct injection helps greatly in controlling detonation and hot spots in the combustion chamber. Water cooled turbos run just as hot as air cooled, but they tend to last longer and suffer less from turbine oil coking after shut down, if there is an auxiliary after run pump in place. Their turbines would have to be jacketed just like current boat exhaust manifolds to ensure heat control.
All doable, but technology is lagging in the boat world in that regard. Possibly related to lower incidence of warranty failures and less required maintenance for the less complicated normally aspirated engines.