why can’t we have diesel hybrids?
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The diesel emissions scandals have more or less destroyed the market for diesel cars – there isn’t enough of a market for diesel cars right now for a single manufacturer to be making one for the US market. Diesel engines are also more expensive than gas, while hybrid engines are significantly more expensive than non-hybrids. So you’re basically making a more expensive version of something that there already is no market for.
You also have to question who the target market of a diesel hybrid would even be in an emissions scandal free world. While diesels produce a bit less CO2 than gas engines, they produce hundreds of times as much organic pollutants, which are the cause of smog. So while they’re more efficient than gas, they’re not more environmentally friendly. And people looking to buy environmentally friendly cars are the target market that is willing to pay the already steep premium to get a hybrid vehicle.
Hybrid automobiles are kind of a funny thing. They get gas milage advantage purely from storing and reclaiming the energy used two slow down the car which is normally wasted. Gas engines are well suited to this because they can be easily started and stopped.
Diesel engines are most efficient 6 when they can be run at a single, optimum speed. This is why diesel transmissions usually have more gear ratios than gas, to keep the diesel at a given RPM.
Actually, all your train locomotives, these days are diesel/electric. The diesel engine runs an electric generator,which powers electric motors. The diesel motor gets to run at a more constant RPM and the electric motors are great because they are produce the most torq at low RPM. The electrical motors can also act like breaks. Now that battery storage has gotten cheaper, I can see trains carrying battery cars that would store this braking energy that they’re currently throwing away as heat.
You can. There’s a decent selection in Europe. It’s just diesel isn’t that popular in the US.
There are quite a few diesel hybrids cars?
Diesel is more expensive for the extra mechanical bits and heavier construction of engine parts. And you want to ladle electric bits on top? Too expensive to manufacture. There is 20% more energy in the same volume of diesel versus gas. The VW thing was political. The whole thing was stupidity beyond belief if you look at the net result. I still drive a VW diesel as does anyone outside the US. Nobody considers the vehicles where diesel emissions are “not applicable”. Compared to the amount of emissions from a bunch of tiny VW’s? Ridiculous. You do know they wanted to crush all the non compliant cars? Not so thankfully they are being retro fitted and on sold.
There’s no reason we can’t, they should honestly be the norm at this point. Diesel generators function much better than gas.
Because petrol engines produce maximum torque at higher rpm, whereas diesel engines produce max torque at lower rpm. Therefore, when you pair an electric motor with a petrol engine they synergise well. The electric motor fills in the torque curve at low rpm and the petrol engine can take over at high rpm. Both systems work nice and smoothly together over the whole power band.
If you pair a diesel engine with an electric motor they are both producing huge torque at low rpm, which leaves a gap in the power band at high rpm. It’s just not an efficient use of both technologies. Modern engineering can mitigate this difference to a certain extent at the expense of cost and complexity, but generally it’s just not worth it.
What scale are we talking about? Do you mean like almost every train in North America, or like some cars in Europe?
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