Yes, the latest generation diesel engines have lower compression ration than engines from a couple decades ago. Maybe something like 16:1 instead of 19:1. But a

Yes, the latest generation diesel engines have lower compression ration than engines from a couple decades ago. Maybe something like 16:1 instead of 19:1. But also exhaust gas recirculation: https://en.wikipedia.org/wiki/Exhaust_gas_recirculation https://en.wikipedia.org/wiki/Exhaust_gas_recirculation