At the moment I’m teaching my son to drive in my Electric Car. Like my daughter before him it’s his first driving experience. Recently, he has started to drive his grandfathers pollution generator, which has a manual transmission. So I was trying to explain why the clutch is needed, and it occurred to me just how stupid internal combustion engines are.
Dad: So if you dump the clutch too early the engine stops.
Dad: Well, a petrol engine needs a certain amount of energy to keep it running, for like compression for the next cycle. If you put too big a load on the engine, it doesn’t have enough power to move the car and keep the engine running.
Dad: Oh yeah and that involves a complex clutch that can be burnt out if you don’t use it right. Or an automatic transmission that requires a complex cooling system and means you use even more (irreplaceable) fossil fuel as it’s less efficient.
Dad: Oh, and petrol motors only work well in a very narrow range of RPM so we need complex gearboxes.
Dad thinks to himself: WTF internal combustion?
Electric motors aren’t like that. Mine works better at 0 RPM (more torque), not worse. When the car stops my electric motor stops. It’s got one moving part and one gear ratio. Why on earth would you keep using irreplaceable fossil fuels when stopped at the traffic lights? It just doesn’t make sense.
The reason of course is energy density. We need to store a couple of hundred km worth of energy in a reasonable amount of weight. Petrol has about 44 MJ/kg. Let see, one of my Lithium cells weighs 3.3kg, and is rated at 100AH at 3.2V. So thats (100AH)(3600 seconds/H)(3.2V)/(3kg)=0.386MJ/kg or about 100 times worse than petrol. However that’s not the whole story, an EV is about 85% efficient in converting that energy into movement while a dinosaur juice combuster is only about 15% efficient.
Anyhoo it’s now possible to make EVs with 500 km range (hello Tesla) so energy density has been nailed. The rest is a business problem, like establishing a market for smart phones. We’re quite good at solving business problems, as someone tends to get rich.
I mean, if we can make billions of internal combustion engines with 1000’s of moving parts, cooling systems, gearboxes, anti-pollution, fuel injection, engine management, controlled detonation of an explosive (they also make napalm out of petrol) and countless other ancillary systems I am sure human kind can make a usable battery!
Internal combustion is just a bad hack.
History is going to judge us as very stupid. We are chewing through every last drop of fossil fuel to keep driving to and from homes in the suburbs that we can’t afford, to buy stuff we don’t need, making plastic for gadgets we throw away, and flying 1000’s of km to exotic locations for holidays, and overheating the planet using our grandchildren’s legacy of hydrocarbons that took 75 million years to form.
Oh that’s right. It’s for the economy.