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Pusher trailer
I calculated 7.5kW to keep a light streamlined car (based my calculations on a Porsche 924 I am electrifying) traveling at 110kph on flat ground which is a pretty small gen-set. Hydraulic regen is planned for my range extender trailer/sleeper and a permanent magnet generator from a wind turbine is a very efficient generator which could also provide regenerative braking power. Ideally a lightweight small as possible aeroplane alternator (PMG and small gas turbine) would be the power source of choice or a hydrogen to electric cell but I will use a small lightweight 2-stroke rc plane motor. I would like to experiment with an exhaust heat generator to supplement the power output using thermal generators as about 50% of the wasted energy for an ICE is heat. I estimate at least 50% efficiency of converting the fuel energy to motion, rather than the 25-30% of a conventional car as it would be running at optimal rpm the whole time and be mainly a source of heat for power. The idea of a large infernal combustion engine and gearbox in the drive train of a hybrid seems silly to me as electric drive train is so much more efficient. Modern Hybrids have it the wrong way round. The weight saved using a small gen-set to keep the batteries near topped up would in turn require a lot less energy to roll. A cost comparison of replacing the complex and weighty ICE/gearbox in the Prius with a small generator and slightly chunkier electric motors would show it; too heavy to be efficient. There are a lot of small purely conventional cars that get a lot better fuel efficiency with no added complexity. Aerodynamics, lightweight materials, low rolling resistance tyres... no end of ways to improve the car. I don't see the big car makers really trying.
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