APUs (Auxilliary Power Units)
Last updated Spetember 2009
Diesel-Fired Generator Trailer
The cherry on the top, as it were: I bought the piece of highway
equipment whence came the APU's prime mover, the diesel, sight unseen.
(It was a shared purchase with a really cool guy I know from New
Hampshire, the kind of guy to whom you can say something like "hey, I
am in the market for a one cylinder diesel..." and he will know of a
couple options right of the top of his head!) And when I got to it, I
discovered the machine was made by a company called Lombardini, an
Italian company! (A division of Briggs & Stratton, now, but still
based and built in Italy.) Perfect to accompany the 40-year-old Lambro.
At Microcar Day 2005, I was running the diesel behind the host's house
and a guy came around the corner of the house grinning, pointing,
nodding, and declaring "Lombardini!" Turns out he's Italian, and grew
up in southern Italy, and worked with Lombardini equipment when he was
young. He was sure (and showed) that the Lombardini has a very distinct
Here's a side view of the Aux Pwr
- The brown rectangular tank low and left at the back of the trailer is
the petrodiesel and biodiesel tank. It has a lift pump to push fuel to
the engine. In typical fashion, the engine starts on petro- or
biodiesel and runs on it until the engine is at operating temperature,
then the operator can switch over to vegetable oil.
-The retired propane tank up high holds the vegetable oil. Gravity
drives the fuel to the engine through the copper lines wired snug to
the exhaust, thus using the exhaust from the engine to heat the
vegetable oil. (Straight veg oil won't work well in a diesel engine
unless it is heated to at least 160F, otherwise it is too viscous.)
- Note the fire extinguisher at the right of the control panel... who
knows, you know?
- There's a small car battery (12v lead acid) low and right; that
battery starts the diesel.
- On the control panel are three switches (diesel fuel lift pump
switch, generator field control, generator armature control), fuses,
stuff like that.
Rear view of the APU.
You can see the copper vegetable oil lines running to and from the
engine on top of the flexible exaust tubing.
Skip over to the other page to see the trailer with the Lambro itself.
Propane-Fired Removable APU.
This Auxilary Power Unit rides on the back deck of the vehicle. It
employs a Honda 5-hp internal combustion engine (I.C.E.) that I
converted, with some students back in about 2000, using a kit, to run
on propane. It delivers current at ~52VDC to charge the battery pack
directly, or, at times of peak demand, to support the current delivery
by the battery pack.
Gasoline-Fired Removable APU.
This Auxilary Power Unit rides on the back deck of the vehicle, too. It
employs an off-the-shelf Colman 4kW generator, featuring an 8-hp
Briggs&Stratton I.C.E. This unit is about 10 years old already, but
has little run-time on it. It provides 110VAC; I can plug the wall
charger into this unit as if it were the wall!
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