No inlet fouling on propane or natgas.
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Circlotron
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No inlet fouling on propane or natgas.
A lot of talk around regarding inlet valve fouling on direct injection gasoline engines because of no fuel being sprayed on the back of the inlet valve to keep it clean. What about engines that run on propane only, or large stationary engines that run on natural gas. Or for that matter, what about diesels? None of those have gasoline sprayed on the back of the inlet and yet there doesn't seem to be the same issue with inlet valve fouling. What's going on then?
Re: No inlet fouling on propane or natgas.
A lot of those engines don't have EGR.
Few of those engines are high-performance engines that have moderately aggressive cam timing. If there's no overlap, there (pretty much) can't be backflow of burned gases past the intake valve.
They are using a fuel which, when set up properly, produces very little soot.
Few of those engines are high-performance engines that have moderately aggressive cam timing. If there's no overlap, there (pretty much) can't be backflow of burned gases past the intake valve.
They are using a fuel which, when set up properly, produces very little soot.
Re: No inlet fouling on propane or natgas.
No LIQUID fuel sprayed on the valve. They don't need any accelerator pump or other enrichment either because the fuel's not ever liquid.Circlotron wrote:A lot of talk around regarding inlet valve fouling on direct injection gasoline engines because of no fuel being sprayed on the back of the inlet valve to keep it clean. What about engines that run on propane only, or large stationary engines that run on natural gas. Or for that matter, what about diesels? None of those have gasoline sprayed on the back of the inlet and yet there doesn't seem to be the same issue with inlet valve fouling. What's going on then?
Mark
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Circlotron
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Re: No inlet fouling on propane or natgas.
^^ My point was that neither GDI or the others except PFI have liquid fuel sprayed on the back of the inlet valve but only GDI gets clogged up. Have been using propane since 1978 so am well acquainted with it.
Re: No inlet fouling on propane or natgas.
Propane is still a hydrocarbon that can wash away any oil mist before it has a chance to bake on.
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Circlotron
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Re: No inlet fouling on propane or natgas.
What about diesel, with only dry air coming in? Being unthrottled, is the air velocity in the port often fast enough to blow the oil off the back of the valve?
Re: No inlet fouling on propane or natgas.
Well, if nothing else, in a diesel there's no manifold vacuum sucking on the valve seals..
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user-23911
Re: No inlet fouling on propane or natgas.
Diesels with EGR block up.
Diesels without EGR don't.
As far as CNG goes, I've run 2 V8s on CNG over about a 10 year period, I've also had a Nissan that ran entirely on CNG over many years. NO, they didn't have EGR, no they didn't have ports blocking up either.
Some diesels DO have a throttle, it's tied in with the emission controls and the EGR.
Diesels without EGR don't.
As far as CNG goes, I've run 2 V8s on CNG over about a 10 year period, I've also had a Nissan that ran entirely on CNG over many years. NO, they didn't have EGR, no they didn't have ports blocking up either.
Some diesels DO have a throttle, it's tied in with the emission controls and the EGR.