Backing Up a Bit . . .

One of my friends who drops by several times week on the way to work, he works midday to late, has been watching this saga with barely restrained amusement. We talk about various options and their possible effect as he is quite practical in some ways and terrifyingly willing to disregard the strength of materials and their proper use in others. The ideas are often OK but their execution can sometimes leave a little to be desired . . . however, he suggested I try a few other things before I remake everything in sight!
Like maybe I should just try getting a bit more air in and out and see what that does.
Probably a good idea in the grand scheme of things!
So I removed the inlet and outlet grilles to start with . . . what a huge difference!
I could hardly believe just how much restriction there is in these grilles.
He also was convinced that the exhaust was the main culprit in introducing heat and not the cooling airflow. It is hard to tell with the two being mixed together inside the generator.
So the next step should really be to separate them and see if that is true.
This requires a new exhaust pipe attached to the muffler so a bit of machining and some dodgy but serviceable welding and a splash of hi-temp 650deg. C paint and we have a start.























To this a piece of stainless steel flexible exhaust is added and run out through the floor. There is a little bit of fibreglass lagging pushed in to the hole to keep the hot pipe away from the wooden floor in this temporary arrangement. Later the entire pipe will be wrapped to make sure the heat is not radiated inside. Also a piece of the insulating foam with aluminium foil each side is used to deflect the cooling air more directly into the fan outlet. Fairly primitive but enough to conduct a test.


















Close up the compartment and start it up.

Amazing !!

The cooling air is barely warm when you put your hand in the airflow.
The exhaust gas coming out the pipe is considerably hotter but you can still put your hand about 25mm from the end comfortably.
But the part of the pipe which comes out of the truck rapidly becomes too hot to hold!
Very Interesting!!
Also with the grilles removed it is easy to reach inside and feel the various parts.
The generator is now still cool to touch after 30mins continuous running.
The insulation above the cooling air duct is not even getting hot.
In fact I don't think I even need to go to the bother of separating the cooling air from the fan ducting at all. Even the fan motor is still cool to the touch.
What I really need to do is get more air in and not restrict the outlet with the pretty but useless aluminium grille that I had there first time round.
Rolling around in the back of my head is the desire to keep all of these inlets and outlets water proof both while travelling and when parked up and running the generator in bad weather. This and blazing heat when wanting to run the air conditioner are my two main use scenarios. If I enlarge the vents I already have I just make the problem worse. Maybe I can just put doors over the holes and open them when I stop, I don't intend to run the generator when on the move as the 110amp alternator provides the necessary power under those conditions. It would just be part of the setting up procedure then like switching on the fuel and ignition so the remote start can be operated whenever the generator is required. In looking around I remember I have a hatchway which came with the toilet system so the cassette can be removed when required. I never used this as the cassette is accessible through one of the underfloor bin doors with more convenience. This hatch has a nice sealing system and is slightly larger than the opening I already have for the fan. If I mount it horizontally instead of vertically the door will protect the cooling air outlet from most of the rain when it is open. The strong outflow of air and some attention to waterproofing around the area should deal with the small amount of rain which is likely to get in.
What would also be nice is to have the inlet up through the floor so the truck itself provides protection from the rain etc. as air will be being sucked in through this opening. While examining things more closely it becomes evident that in fact the combustion air and cooling air in the generator enter in different places. The combustion air goes in through small slots in the front panel. The size of these openings I now realise was the main culprit in misleading me as to the amount of air required into the box. On closer examination one of the supports under the generator on which the rubber feet are mounted has been cut away at the back and there is a large opening underneath through which the cooling air enters. Very tricky - but silly in my opinion. Given the likelihood that someone could put the generator on some very grubby surfaces including the middle of a sandy paddock it would be very likely that a whole lot of dirt could get sucked in. Put it on wheels and you would have a pretty good vacuum cleaner!
All of this however induces me to make the inlet underneath. The only problems are that this will weaken the floor the generator is standing on and will make closing the opening tricky while travelling. Still these problems can be solved so out with the jigsaw.
A decent sized hole is cut through the floor immediately in front of the generator inlet.
Two pieces of thick wall tube are cut to bridge across the floor to the framework at either side supporting the floor. This will transfer the generator weight to the proper places.


















Next a very open piece of mesh is cut to cover the hole. This is of mild steel as it doesn't need to look as pretty as if it was mounted on the side and it will allow a large piece of "fridge magnet"to adhere to it when travelling to keep out dust and water. It is in a protected area under the body as well.
This is then cleaned and primed for rust protection and later painting.











Some of the ubiquitous foot mounts are screwed to the tubes to keep everything in place and some breeching staples are fixed either end through which some tiedown straps can be fed.
The mesh is fixed in place under the floor and painted black while the rest of the floor is painted in hammertone grey to match the rest of the framework.


















When this all dries the outlet hatch can be fitted and a bit more insulation, to the door, to keep any reverberation at bay and the exhaust lagged for that last little bit of heat protection.

And then maybe I can start going FORWARD again !!