A bit of a rant that’s been stuck in my head for a while:
Rudolf Diesel would be devastated to see what the diesel engine has become, an engine originally pioneered for it’s ability to run alternative fuels and operate entirely without electricity (A mechanical diesel engine is completely EMP proof).
Diesel engines have now become an overcomplicated mess, heavily reliant on electronics, sensors and are equipped with emission systems that ruin efficiency and reliability. EGR, SCR, DPF, I know these things are neccesery to meet modern emission standards, but they often contradict purposes.
Examples:
- EGR reduces NOx, increases PM, CO, BSFC (alters A/F ratio) and causes the turbo to take longer to spool (less airflow).
- DPF captures PM, increases BSFC (exhaust backpressure, regeneration), large soot particles are burned during regeration, turning them into smaller (more harmful) particles. Each regeration dilutes the engine oil with diesel on engines that use post injection for regen, NOx output is high during regen.
- SCR, probably the most effective emission control technology yet, it’s tried and tested, has been in use on lorries in Europe for the past decade. However I doubt the manafacture, packaging and transport of urea soloution (AdBlue) offsets the NOx reduced in vehicles using SCR.
- These emission systems usually require ULSD to avoid damage to components, which rules limits the use of alternative fuels.
Despite all this I don’t dislike the common rail diesel (without emission systems), it’s design resolved a lot of long standing issues with the diesel engine and is perhaps the one of the most underappreciated technological advancements in modern history; hard to believe it was originally developed by Fiat.