3 ms·
It sounds like 7 percent of the 10 percent efficiency gains are from aerodynamics. I expected (probably naively) engine changes to play more of a role.
by jrmg 2y ago
It sounds like 7 percent of the 10 percent efficiency gains are from aerodynamics. I expected (probably naively) engine changes to play more of a role.
- SAI_Peregrinus 2y agoDiesel engines already have very high compression ratios. Compression ratio directly correlates with the ratio of temperature at combustion to the temperature outside the engine, which is the limiting factor in the Carnot efficiency. A gasoline engine will be able to get up to maybe 12:1 before knock is an issue, high-efficiency diesels can hit 25:1. Gas turbines can hit even higher ratios, but are far more complex & expensive (e.g. the GE GEnx-1B78/P2 turbofan has an overall compression ratio of 58 and thermal efficiency of 58%, but it has a list price somewhere around $20 million and is bigger than the entire truck cab).
- uticus 2y agoIf you noticed, the article talked about aerodynamics in terms of frontal area and side fairings - on other words, the parts of the tractor interacting with the airstream. The trailer's leading edge is, well, a large, flat, un-aerodynamic rectangle. Lots of potential for aero improvements there. I sometimes see boat-tails etc attached to trailers, but my understanding is that they are usually attached (an unattached at destination) by tractor owner, as trailer owner doesn't pay for fuel costs. Could be wrong on that though.