kabu,
some one has explained it before me. FYI, muatan haba tentu is "specific heat capacity".
I have done some researched on the water vapour injection as well. And i already have the components in my store. It's a matter of time to assemble it.
As you know, what we need to do is to unplug the crankcase ventilation hose, and connect the intake hose (just before the TB) to the water reservoir using a longer hose.
The air will be drawn-in via a small filter and bubbled through the water using a fish-stone. Since the air is hot, it will transfer some heat to the water and eventually evaporates it. The vapour of water is then collected at the top of the container and is sucked into the manifold.
Yes, the vacuum effect will be greatest at part-throotle, but not at idling nor full-throttle.
The amount of air being sucked-in can be controlled using a valve just after the filter. For safety reason, an additional valve after the container can be added.
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*the reason why I am still thinking of whether to do it or not:
Injecting additional air (with water vapour) AFTER the MAF will just lean up the mixture.
This is not a problem at idling because: 1. engine idling runs on closed-loop, 2. the injection point is before the butterfly. Any variation in A/F ratio during closed-loop can be rectify by the ECU as long as the variation is not too large.
But this is a problem during part-throttle, i.e. during highway cruising, because the engine is running on open-loops (for Siemen's ECU) now. During open-loop, the engine runs on default mapping. The variation in A/F ratio will not be rectify.
The results of this could be either (depends on the design of the ECU):
1. leaner burning that create more heat, but is 'cooled-down' by the water vapour. So overall effect will be better fuel economy at highway cruising due to a 'better' burning ---> the objective of this modification is achieved. But how much is the ratio of H2O/air to be injected (which is hard to control) to justify the additional heat (lean burning) and cooling effect (H2O high heat capacity) is a BIG QUESTION.
2. Well, some ECUs learn. These ECUs are mainly closed-loops ECUs. During part-throttle situation as i have described above, the ECU will make correction on the A/F ration based on the mapping, and if the 'error' occurs everytime, the ECU will make that as the defaut setting, and a new map is refered ---> You will just lean-up everything!
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I have no idea how exactly my ECU works.. that's why the project is still on-hold.