Su suggerimento di @Vincenzo Cardarelli.

Un articolo pubblicato su Low-Tech Magazine spiega, illustrandone possibilità e problemi, la storia e le caratteristiche dei veicoli a gas d’aria, una miscela di azoto, monossido di carbonio e, in minima parte, anidride carbonica e idrogeno, che si ottiene facendo bruciare carbone o legna in presenza di una quantità d’aria insufficiente a far avvenire una combustione completa.

During the Second World War, almost every motorised vehicle in continental Europe was converted to use firewood. Wood gas cars (also known as producer gas cars) are a not-so-elegant but surprisingly efficient and ecological alternative to their petrol (gasoline) cousins, whilst their range is comparable to that of electric cars. Rising fuel prices and global warming have caused renewed interest in this almost-forgotten technology: worldwide, dozens of handymen drive around in their home-made woodmobiles.

Immagine da Wikimedia.