Why are all modern hybrid and plug in hybrid cars paired with gas engines rather than diesel engines? The diesel and hybrid pair seem like a great idea in theory.

Question

A lot of people see hybrids and plug in hybrids as a great middle ground between ICE and EV, so why not make a diesel hybrid. They can be used in a variety of vehicles, and can reduce the nox and particulate emissions diesels are known for. So why isn’t there a modern diesel hybrid being produced, at least as a passenger car?

In: Engineering

Answer 1

It is only great if the driver is an engineer and understand the drawbacks and benefits of the Powertrain. Also you need a specific use cycle.

Let’s imagine I live 50 km from my work and my diesel-hybrid has an electric range of 45 km. This sucks and I will just torture the diesel engine unless I don’t use the battery and run it like a non hybrid diesel which means I get no hybrid benefit..

If my daily commute is well within range of the battery and I drive carefully so I don’t even start the diesel engine daily I have a great car that can also run long journeys on a weekend with its efficient diesel engine.

I have used a Merc E300de for a 30km commute and I drove it electric 90% of the time. When temperature dropped to -15C it usually started the diesel instant as I hit the start button because the car judged it better get it heated up, now the diesel engine wouldn’t really turn off again even if I had battery power available. But this was probably for the better on those really cold days. Drove the same car Stuttgart to Stockholm with 5.x L/100km don’t remember exactly but it was a good number considering its a large car we never stopped to charge it and we did 140-180 kph all the time in Germany 😄

But it’s really obvious in the Merc 300de anyway that once the engine starts it stays on for longer than in a gas hybrid. It is programmed to maintain engine temperature and also tries to predict the user so it avoids to many start/stops. But the car is fine to drove fully electric if destination is in range imo and the electric engine is strong enough to not test my patience anyway!

If your the kind of hybrid user that will do a kickdown on every major acceleration and start your engine 5 times in your daily commute the Mercedes diesel hybrid is not for you.