Commutamatic IV


APUs (Auxilliary Power Units)

Last updated Spetember 2009

APU #1

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. Great luck.

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 running sound.

side view of apu

Here's a side view of the Aux Pwr Unit.

- 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 apu

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.

APU #2

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.


APU #3

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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