Diesels went through a rough patch, but the SCR diesels are the best engines ever conceived of. The problem was meeting the NOx emissions requirements. The first iterations lowered combustion temperatures to reduce NOx, increasing soot. Fuel economy was terrible and the DPF units clogged. The introduction of urea catalyst allowed all time high combustion temperatures without soot or NOx. I have an SCR diesel with 700k on it, no issues whatsoever. I run synthetic diesel, renewable. The EGR valve is as clean as it was when new. #diesel #engines #renewablefuel #engineering