Using a car engine as a generator

[jiminwatford]

Is it a bad idea?

They're a lot quieter than a generator

I have a complete 1.2 Punto I could use

Would it be more fuel efficient?

My generator puts out 3.5kw, how do you get a car engine to do similar or more?

Would you need a governer to operate as a generator?

Is it too simplistic to think this is a good idea?

[Milord]

bookmarked, as I have some extra engines lying around and have been playing with the same idea but lack electrical know how

[jiminwatford]

If I was happy with 4kw what's wrong with connecting something like this www.ebay.co.uk/itm/4000W-Car-Power-Inverter-Pure-Sine-Wave-Converter-DC-12-AC-220V-Invertor-Caravan/293463338037?hash=item4453c72c35%3Ag%3ArbcAAOSwGIJeJsQS&LH_BIN=1 to a car battery (while being charged by the alternator)?

[slater]

Someone asked this a while back and basically no it wouldnt be as good as a proper generator engine. Especially a petrol.

[jiminwatford]

Ok,

Got anymore info on that?

What thread was it in?

There was a recent thread about using a generator for welding but that doesn't seem to be it

[93fxdl]

May have been urban myth, but years ago I was told of some flats powered by a Renault engine,running on gas, driving a generator for electricity and the cooling water and exhaust running through heat exchangers to warm the building. it was not enough power at maximum demand so would draw from the grid and put back any surplus at times of low demand.
Ttfn Glenn

[melle]

Ford Cologne V4 engines (as found in Saabs, Matras and European Fords) were used for all kinds of industrial applications, amongst others coupled to generators. I have a few manuals for this engine on my website.

[Phil H]

Many engines have “industrial” versions but usually very different to their car counterparts, usually the carb is set to be speed controlled (so a mechanically coupled throttle) and the camshaft is usually different to set it to run best at a constant speed (usually 1500r or 3000rpm so the motor attached to it will generate at 50Hz).

[melle]

The industrial Ford Cologne V4 was identical to the car engine, but depending on application often had a Hoof governor fitted on the standard FoMoCo carb.

[comfortablynumb]

Wasn’t there a programme a few years ago with Robbie Coltrane and featured uses of a 350 Chevy engine to power everything from air raid sirens to air con plants? IIRC they ran on lpg?
Of course I could be lying.....

[dodgerover]

I would recommend using either something running on LPG (a bottle can be used but is expensive) or an old diesel running on something other than pump fuel.

[stealthstylz]

It was quite common for air raid sirens in America to be powered by V8 engines. Can't see the point if you're just using the alternator as the generator though, might aswell just run whatever you want to do off the car you're in.

[generallee]

So, to summarise this thread. Car engines; may or may not be any good for generators. Great for air raid sirens.

[Darkspeed]

Feb 14, 2020 15:35:27 GMT 93fxdl said:

May have been urban myth, but years ago I was told of some flats powered by a Renault engine,running on gas, driving a generator for electricity and the cooling water and exhaust running through heat exchangers to warm the building. it was not enough power at maximum demand so would draw from the grid and put back any surplus at times of low demand.
Ttfn Glenn

No myth at all - many flats and offices have CHP (Combined Heat and Power) one of the best small units was powered by an industrial Toyota engine - very efficient system. The small units that the company I worked for sold started with a VW engine and then changed to Toyota as the service requirements were far superior. Micro CHP whereby the majority of homes have a small generator as part of the gas central heating boiler has been around for decades but never really caught on - Honda invested heavily in the tech and --- we are getting way off topic.

[kevins]

Its what most hybrids do, I'm trying a PHEV transit this weekend, it uses a 1.0 3cyl fiesta engine coupled to a generator which charges the battery and the Van is driven by an electric motor.

A car engine will work fine, You just need some sort of governor and a very good cooling pack. Modern engines are pretty efficient anyway, An older engine developed for the job will probably be more efficient though.

[xbl]

They work fine but you need a fair bit of torque to keep up with the instant demand.
If your'e generator is loud you can extend the exhaust, I know mine has a flange as the tailpipe so I can add on a longer length of pipe.

[skkylinedave]

Volkswagen flat fours were/are used as generators and sold in a different format as a bespoke industrial powerplant .

Plenty of US V8's used as well in agriculture for irrigation , again with appropriate mods whatever they may be .

[TessierAshpool]

Not seen one done with a car motor, but saw this cute little 12v generator a while ago made from a strimmer motor and a motorbike stator. Looks very easy to replicate:

[slater]

I think what you need to understand is a engine for a car has vastly different requirements than an engine for a generator. For example the car engine works over a wide speed range where as a generator ideally keeps a constant speed at all loads. It has to react to load quickly (so yes it needs to be governed) to avoid a drop in frequency and power output as the electrical load increases.

A proper generator engine is going to have a vastly different cam profile for example. A diesel is going to be more efficient for the usual diesel reasons. People are right there are industrial stationary versions of vehicle engines but they are more then just bolting a truck engine down to a stand if you know what I mean.

It's likely that a car engine used for generation would need to be much larger and because of that much less efficient than an optimised unit.