WTF Internal Combustion?

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.
Son: Why?
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.

4 thoughts on “WTF Internal Combustion?”

  1. The bad thing about lithium batteries, is there is no standard of manufacture, so recycling is very difficult (no standard way to recycle), and most battery manufacturers don’t have an easy way to return the battery after they no longer charge.

    Then too, Lithium mining affects someone, somewhere, just as oil wells every 50 feet in Texas affects people.

    If we could build small nuclear based jet engines, it would revolutionize air and train travel. I believe it is possible to protect the public, even if these crash and disintegrate in their backyards. The space industry has been using nuclear power for years successfully. They seal the engines real good.

    Lithium, to me, is just another dirty energy solution. We really need to start thinking about adding wireless power to the expressways, and turnpikes. Everyone’s going in the same direction anyway. Switch to the cars own energy at the exit or on-ramp. Then power the wireless via nuclear waste power cells.

  2. Hi David,

    Very good points. One way to look at an electric is miles per cell. Gotta wonder if one HUGE cell would be simpler?


  3. For better or worse, the whole lithuim thing is one of the reasons people are (were?) so excited about fuel cells. Instead of storing your energy in a battery, you store it as a big pile of hydrogen (or whatever), and you run it through a fuel cell. Some of these fuel cell designs seem to be somewhat less toxic, but that’s the real key, isn’t it? How ‘simply’ can we make these things?

    Lithium is terrible, we all know that. But the lifetime-miles-per-cell metric is probably a quite useful one. What’s the total embodied energy & environmental impact of:

    Lithium Battery, electric motor, charging infrastructure construction, lithium battery minig/construction +
    “Power generation” for the electric car over it’s lifetime (which may but needn’t include petroleum usage)


    Engine construction, gasoline/petrol refinery construction +
    petroleum extraction, gasoline/petrol refinery operation, for all fuel, plus materials for antifreeze, engine lubricant, catalytic converter guts etc.

    So it does seem possible that the aggregate results of an entire car’s lifetime worth of resource chomping electric vs. petrol could swing either way, depending on how badly we do the various parts, and how much petroleum we’re using in the production of the car guts (embodied energy). But my suspicion is that the electric one still wins out in terms of less overall toxicity released to the world, even with all the gross crap required to make the magnets, coils, batteries, and charging infrastructure.

    Here’s the thing about all of this that really sucks: It’s 100% optional. We’ve been operating like this for less than a hundred years; we just don’t want to STOP because it’s less convenient, and unless serious economic (or safety ala Resource War) pressures come to bear, nobody’s going to switch to a “less convenient” technology.

    Know what works fairly well with existing engines, is carbon neutral & renewable, but super inconvenient? (And probably not well suited to large scale use due to the limited space for forests and hour horrible history of responsible forestry): Wood gasifying internal combustion engines. They take 15 minutes or so to warm up, and they’re less powerful per engine size, but you can run an internal combustion engine on WOOD.

    Perhaps a better approach to sunlight-to-movement, though, is the horse-drawn carraige? Or even bicycle… but it’s less convenient!

  4. It’s not always the case that manual transmissions are more fuel efficient than automatic ones. The CVT in my Subaru was rated more fuel efficient than the manual transmission.

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