What to warm up manually to switch to gas quicker
 

I have a V70 bi fuel factory fit and finding in winter when starting up first thing in the morning I am running on petrol for about a mile and a half. I use about 2 galls of petrol a week because of the time spent running on petrol. I see no reason why, when I pour warm water over my windscreen first thing, I shouldnt be able to lift the bonnett and pour hot water over the sensor that switches the car over to gas. At least then I could reduce my petrol consumption.
Can someone please tell me in laymans language where this part is I have to heat up or possibly send a picture.
Many thanks

In hot water
 

My LPG conversion needs to warm for about a mile or so before switching to gas, so I'd guess a factory bi-fuel would be the same.

The reason for this is because the LPG has to be vapourised before it gets via the injectors and into the combustion chamber. This vaporisation is achieved by warming the LPG as it reaches the engine bay.

This is done by passing the LPG through a regulator that is heated by means of a water jacket. The hot water to heat this jacket is provided by the engine's cooling system - which only gets hot enough to do the job once the engine has reached operating temperature and the thermostat is fully open.

If the temperature isn't high enough then the vaporisation doesn't happen efficiently enough and thus trying to run the engine on LPG (Liquid Petroleum Gas) that is more L than P means it will do a pretty good impersonation of a three-legged dog!

I do know that it is possible to start and run an engine on LPG from cold, and one or two posters on here do have older LPG-only cars. Classicswede will be able to explain more fully, but I'm not sure it's possible on more modern engines with sequential injection LPG systems.

As far as I'm aware though, modern sequential injection LPG systems do need the engine to be fully warmed up before they'll run on gas.

Useful link: http://www.autogas.co.uk/converting.htm

You might be able to get an LPG expert to twiddle things a bit, and I guess anything you can do warm the engine up quicker will help.

One cheap and easy thing you could fit is a new thermostat. The other would be to change the LPG filter. It won't do any harm, and might indeed help a bit.

Cheers

Jack

Thanks Jack. I dare not let anyone tinker adjusting anything while she is purring along on gas.
So we are all using more petrol during cold weather waiting for the gas to kick in.
I am obsessed with using least petrol as possible. Does anyone know if I could get her onto lpg sooner were I to pour hot water over the round cylindrical thing to which water hoses from the radiator connect. Is this the place that needs warming or is there anywhere else??

If you assume that your car does 25mpg and that fuel costs £1.20 per litre it will cost you 22 pence to drive a mile.

How much will it cost you to boil a kettle of water?

I don't think there is a big annual gain to be made here.

My guess is that the 'round cylindrical thing' is your gas regulator. Pouring hot water over any part of a car, and especially into the engine seems to me to be a bit of a bad idea - downright dangerous in fact. On a frosty morning you'd actually run the risk of having that water freeze around the regulator before it got chance to warm up. And the chances of water getting into something electrical would be a cause of serious concern.

You need the engine as a whole to warm up as quickly as possible.

To do this, you need to make sure that it's running as efficiently as possible.

Get a new thermostat fitted and a new LPG filter. You could also use the old trick of blanking out a section of the front grille, although you'd need to be very careful that this didn't cause the engine to overheat. I'm not sure that car makers support this idea these days. There was a time when every Cortina or Morris 1300 owner religiously fitted a bit of old lino across the grille at the end of November, and took it off again in March!

Other measures would be an oil and filter change, a new air filter, new spark plugs and leads. This would all help to optimise the engine's efficiency.

You could also make sure that the car is garaged at night, you could cover the engine overnight with blankets, or you could even use an engine pre-heater.

Other things to do are all about your driving style. Start the car and drive off immediately, and don't let the engine idle when cold and running on petrol. It won't warm up any quicker.

You could also shut the heater down so that the heat from the engine stays in the engine, and isn't being usd to heat up the car. This does seem a bit extreme however, and you risk not being able to clear the windows on a damp or frosty morning.

It's a fact of automtive engineering that in cold conditions, internal combustion engines take longer to warm up, and thus use more fuel. If the engine is in good condition and correctly serviced I reckon there are better ways to save fuel costs than trying to 'cheat' the LPG system into thinking it's warmer than it is.

If your LPG is kicking in after just one and a half miles, and everything is working well I reckon you're probably already getting the best out of your car.

Cheers

Jack

Agreed: on a cold morning 1.5 miles before a switch to gas is fine - that's what I achieve with my S60 bifuel. I have no reason to think that this is longer than it should take so why fiddle if there's nothing wrong? Sounds like a recipe for disaster - the kettle and an open bonnet though....

1.5 miles per morning x 7 = 10.5miles/ 2 gallons petrol = 5.35mpg = something wrong with something but not the gas system....

Are your numbers right?

Then 7 evening trips too, making your calculation nearer to 11mpg.....

Of course if your drive to work is only a few miles then you're not really getting the best out of an LPG car! SWMBO's S70 does the school run - 2 miles each way twice a day, plus shopping trips. Precisely because of this it's never been worth an LPG conversion.

I reckon my converted V70 will use about one gallon of petrol per week - that would typically be 5 morning cold starts, 5 evening cold starts, plus maybe another half dozen over a weekend. 16 x 2 miles each = 32mpg, 16 x 1.5 miles each would mean around 24 mpg. My feeling is that it's somewhere between these two extremes.

Typically I drive 2000 miles per month, which means that my 221,000 mile 2.5 litre petrol auto will do around 500 miles per gallon of petrol!

Cheers

Jack

But surely those first few miles warming up in winter the car would do a lot less mpg than it would when running at normal temp. Hence my allowance for rather a lot of petrol to get down the road before gas kicks in

>>Then 7 evening trips too, making your calculation nearer to 11mpg.....

My assumption was that since the OP didn't refer to this that this wasn't seen as such an issue. Either way 11mpg is still awful IMHO!