Petrol Feed Heater

[Strongio]

Does anyone know about drip fed petrol heaters??? I have a steel box under the van which I was told was a heater that could be used while static.There is a control box on the dash with settings 1-6 and a switch? On the box under the van there is a foam filter and also a pipe leading from the box facing the ground.There are cables leading to the box under the van and to the contol panel on the dash.Any ideas what this is or how it works would be great.