07 July 2008

Improving car efficiency

This is an idea I had recently for improving the efficiency of internal combustion engined vehicles. 'Green' is becoming the watchword of the decade (rightly so), and anything that can reduce fuel consumption is a good thing whether your car burns petrol, diesel, or biofuel.

Engines run much more efficiently when they are at their working temperature. Every increment in starting temperature will increase initial efficiency and reduce the time required to reach full working temperature, a double benefit by starting 'further up the curve'.

For very little extra manufacturing expense I suggest fitting a network of piping between the roof of a car and its internal lining. The network would be fed engine coolant by flow and return pipes that could be concealed inside the front pillars between the windscreen and side windows. The coolant would be warmed by solar energy and would flow to the cold engine when the vehicle is idle, returning to the roof network to pick up more heat.

A miniature pump in the engine compartment would keep the fluid flowing slowly, I suggest the pump should be controlled by temperature sensors so that when the water in the roof network is not warmer than the engine block the pump does not operate.

This scheme would improve the efficiency of any internal combustion powered vehicle, cars (including hybrids), lorries, buses, boats, aircraft etc. It would work while your car was parked in town or at the office or outside your home. On a hot day it would have the added benefit of keeping the car slightly cooler, on a cold day it would enable the heater to start working a little sooner. And the fuel efficiency would increase - especially for those short journeys.

There - I've published it. It cannot now be patented (at least in the basic form described here). It's available to any vehicle manufacturer or add-on kit maker that cares to use it.


  1. Hi Chris,

    I like this idea of trying to somewhat warm a cold engine by this method, but my first thought is that of safety. Would a network of piping that contains coolant and extends up the front of the vehicle and across the roof be sufficiently secure in an accident?

    I wonder if a better approach may be to arrange the necessary piping just under the bonnet of the car (perhaps along the sides to avoid complication with the hinged bonnet itself). Not only would the piping be kept further from the occupants of the vehicle, but it would be less far from the engine compartment, allowing for more efficient temperature transfer from the warm outside air and potentially lower design costs.

    Still, it's a neat idea! Are you hawking it out to anyone else who may be interested in prototyping such an arrangement?


  2. Thanks Gavin,

    I envisage a network of quite narrow bore tubing so the total quantities of coolant in the roof space would be small. The circuit would also be closed when the engine is hotter than the roof network (which would be normal while using the vehicle) so there'd be no pressure and no flow.

    But safety is important and you raised a good point. I'll leave it as an exercise for the manufacturers :-)

    In haven't sent the idea off to manufacturers, I thought a good first move would be to get some comment from readers. Yours is first - thanks! If there are any potential prototypers out there, go ahead, be my guest, and let me know how it works out.




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