I was thinking. Now people plan to build factories to transform wood to liquid fuels. But why not run a motor on solid fuel. A diesel spread diesel to a fine particle dust so it burn faster and better. But you can get a explosion by sawdust. Is it not possible to get sawdust in to the motor? Does the exhaust from sawdust damage the motor? But is it possible to build a engine that don’t need a fast burning fuel? Lets say I take a gas tube and put in a sawdust burner with glow wire. I increase the pressure like in a engine and burn the sawdust. (The tube is heat isolated.) This increase the pressure and temperature. I now lead the pressure to a air engine. But I don’t want to let out hot air, so I have a chamber before air engine, were I spray in water that transform to steam and increase pressure and lower the temperature to 120-150 degrees. Now I build 6-8 similar tubes that in turn give pressure to the air engine with an automatic system that remove the ashes and load a tube with sawdust. The air motor is connected to a generator and a compressor to give pressure to the loading of the tube. Can I with this system get a working cheap effective engine system that need only solid fuel like saw dust and similar? Would it work? Could it get effective?