1.11 - Renewal and Retrofitting Fleets

Version 3



    Today’s most recent vehicles show a sharp drop in polluting emissions. What needs to be done to speed up the spread of such progress to the entire fleet?


    In highly-motorized countries 10 % of the most polluting vehicles – generally the oldest – are responsible for most of the local pollution!

    This situation exists, in varying degrees, in countries with a lower vehicle ownership rate.

    Fleet renewal


    Clearly, we can imagine speeding up the fleet renewal rate and taking the oldest vehicles out of circulation, by offering a scrappage bonus or cash for clunkers in the US. Such a selective policy would be difficult to impose especially in developing countries, where the fleets are generally older and the citizens’ purchasing power modest. In motorized countries the average natural fleet renewal rate is 15 years.

    Retrofitting vehicles


    Another solution would be to equip these vehicles with more recent devices to treat tailpipe gases and particles. Such a retrofit would result in an important reduction in local pollution, and could be deployed rapidly compared with the 10 to 20 years necessary for fleet renewal, and for a relatively limited cost, which would be inferior to that of purchasing a new vehicle.


    Retrofitting in English refers to the addition of new technology or features to older systems (Wikipedia).


    Retrofitting has been used for some time now for example by private car owner or professional car service technicians to give the mass produced vehicle a new more stylish or sporty look: wider tires and rims, modifying the aerodynamics of the bodywork…

    The object of reducing a vehicle’s environmental footprint, especially emissions, has led component suppliers to propose retro equipment, for example tailpipes for trucks. Some countries are currently preparing legislation to make certain evolutions obligatory. 

    The case of passenger cars is a more delicate issue because of the additional cost when compared to the initial cost of the vehicle, especially if it is an older one. The most common kind of retrofitting is to change the coolant gas of air conditioning systems to protect the ozone layer, but this operation is often done when the state of the air conditioning requires it.

    Some research workers are going much further to develop solutions which radically change the vehicles. This is the case of Dr Charles Perry and his team from Middle Tennessee State University in the United States who have developed a plug-in hybrid thermal-electric* retrofit kit for an ICE car.

    An electric motor is fitted to the hub of each rear wheel and an electric battery is positioned at the rear of the vehicle. For these additions no changes have to be made to the brakes, bearings, suspension or other shock absorbers. The point of the conception of these two electric motors is that they are perfectly adapted to the technologies of the vehicle. The cost is 3,000 US dollars but it is a prototype.

    * http://oilprice.com/Alternative-Energy/Renewable-Energy/New-Retrofit-Kit-can-Turn-Any-Car-into-a-Plug-In-Hybrid.html   


    Initiatives like this which are liable to generate genuine industrial projects are rare in the retrofitting world of second-hand vehicles… but could perhaps attract the attention of some automaker?