The pick up truck with a small diesel engine concept has merit, I’ve recently acquired a Mercedes Sprinter 4x4 dually van with a 3.0l turbodiesel and am getting way better fuel economy with it, to the tune of 25% or better (based solely on litres used, not noting fuel cost which varies). This is great considering that compared to my outgoing long wheelbase GMC Savana that it has much greater GVWR, twice the cargo volume, I can stand up in it and it has a real selectable 4x4 system. Usually each of those improvements would be detrimental to fuel economy so it makes me wonder about how economical their shorter 2WD models with the 2.1l 4 cylinder turbo diesel are?
6.31 km/l versus 4.55 km/l, about 28% better.