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Old 03-04-2021, 03:13 PM   #11 (permalink)
It's all about Diesel
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Originally Posted by octinum View Post
I'd prefer some boot between the rear bumper and the child seat at the back.
No wonder some models available only as a hatchback in Western Europe often had a sedan bodystyle for markets such as Turkey.

Never driven a deux chevaux myself.
Neither did I.

Small turbo engines rely on very rich mixtures under high load conditions to prevent preignition.
Direct injection became so prevalent on newer generation of turbocharged engines because it doesn't require such a very rich air-fuel ratio. Downside is an increase to NOx emissions, and even some particulate matter buildup which used to be previously seen as more troublesome to Diesel engines than to spark-ignited ones.

LPG as vapor also replaces some of the air in the intake charge. So less oxygen to burn an already low energy content fuel.

What I'm thinking is to use the cooling effect of LPG as it vaporizes in the intake manifold. This should also be a simpler system without the need for the evaporator.
Either going through the evaporator or being allowed to vaporize naturally at the intake manifold, an amount of the charge air would always be replaced at a port-injection engine operating with LPG. With the cooling effect, there is a lower NOx emission, even though the AFR could still be leaner than with a vapour-phase injection.

As you said, some manufacturers just use the original gasoline injectors for two purposes, so a common, cheap injector from a gasoline car should work.
I have only found mentions to the usage of stock injectors for direct-injection engines. Port-injection ones may still require supplemental injectors only for the LPG, just like the 5th-generation CNG conversion setups.

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