Home-built hybrid

"no_name" wrote

I might. But I need some help. See bottom.

So, the small diesel engine indirectly provides the motive force of the car. In other words it drives a generator to provide electricity to the electric motor?

In the article he mentioned a pulser which is simply a combination of a reworked car generator and an old fan motor which he can keep the draw within limits and effectively control the car's acceleration.

What is this combination of a reworked car generator and an old fan motor?

But the real technology is in the control electronics. One has to generate a profile or schedule of the charging. When to start the IC engine, when to turn it off, how to partition energy from generator between driving vehicle and charging batteries.

The speed controller needs to be a bit more sophisticated than for a pure electric, because it has to feed data to the scheduler/controller. A good speed control has some pretty fancy high power semiconductors.

The electronics is what keeps me from trying this, even though I retired a couple of years ago as an avionics engineer.

But the real technology is in the control electronics. One has to generate a profile or schedule of the charging. When to start the IC engine, when to turn it off, how to partition energy from generator between driving vehicle and charging batteries.

The speed controller needs to be a bit more sophisticated than for a pure electric, because it has to feed data to the scheduler/controller. A good speed control has some pretty fancy high power semiconductors.

The electronics is what keeps me from trying this, even though I retired a couple of years ago as an avionics engineer.

It sounds like a fun project, but may run into some frustrations and money.

My son in Europe has an Escort station wagon that came with a little diesel engine. It gets good mileage, is reliable, and is pretty darn peppy. If I could get my hands on one of those little engines, I might forget the hybrid concept.

If I understood the article, the "pulser" was a mechanical control to chop the DC when the motor was first starting to to keep it from drawing too much current. Homebrew using 1979 junkyard technology.

I think it was some kind of rigged up rotary "on/off switch" to modulate the current draw. The DC motor draws a lot of current when it's just starting to spin, so he applies a little current & chops it off, applies a little more current & chops it off ...

Instead of real DC you'd get something like:

_ _ _ _ _ 28 VDC | | | | | | | | | | _| |_| |_| |_| |_| |_ 0 VDC

Even though the motor draws a whole lot of current, it's prevented from drawing too much by the repeated chopping of the voltage.

As the DC motor gets spun up, it draws less current to keep spinning and the duty cycle of the chopper would increase so the current was on more and more of the time.

From the DC motor's point of view, it starts out with a low voltage that builds up as motor speed increases. And the initial low voltage limits the current the motor draws.

But, that is, again, **If I understood the article ...**

"Don Stauffer" wrote

The solid state speed controller could cost up to $800. But, the rotary "on/off switch" speed controller can be built at for $25.

"no_name" wrote

Thanks. The rotary "on/off switch" is just what I was looking for. If I understand correctly, this device is a mechanical one. I needed to built a mechanical controller that I can fix when it breaks. A mechanical controller will produce a lot of arching during acceleration which could build up a lot of heat. I'm not certain how I can suppress the arching or cool it down.

The Lupo 3Liter TDI engine is a 3-cylinder diesel. Diesel makes sense if you're in California - you don't need a smog inspection.

A hybrid is much more interesting that the motor can act as a generator during braking. The battery can be charged at home using solar panels. Three deep cycle battery can range up to 15-25 miles is pretty much my daily commute. In effect, I may never have to go to a gas station.

Maybe when the plans get here there will be some explanation.