Diesel engines have been around for 130 years. Any improvements that could be made were made decades ago.
I don't think you need a tractor for fruit farming.
I don't think you need a tractor for fruit farming.
The power output of an engine that achieves 30mpg today is easily double that of just 15 years ago.
Turbos are a good example. Before, they were very expensive to add to a car, and altered the driving experience such that they weren't very practical for the average driver. Now, essentially every new combustion engine has them because you can lower displacement and actively manage power output to a greater degree, pushing up efficiency.
Some cool things are on the horizon as well, like camless engines and opposed piston diesel engines.
>The power output of an engine that achieves 30mpg today is easily double that of just 15 years ago.
That's a complete lie.
And you're completely wrong. And this can be trivially easily confirmed by looking up the power outputs of vehicles that get any given fuel economy today vs the power outputs of vehicles of like fuel economy from decades past.
With respect to small diesels specifically, ever since diesels went from naturally aspirated indirect injection to direct injection and turbos power output has skyrocketed while fuel economy has mostly flat-lined.
Fuel economy is mostly dependent on the displacement of the engine and the load to do work (like cruise the highway or plow a field at part throttle) so it doesn't vary much unless the efficiency of converting fuel to force improves (hard) or the demands of the task decrease (hard for cars, even harder for industrial applications).
Edit: Also, you're confusing theoretical and practical efficiency. For instance, a V8 engine can be 30% efficient in absolute terms, but if you can use an I4 for the same application because you now have a Turbo, your real world efficiency is way higher. This is exactly what we see happening in performance cars an large trucks: big displacement being replaced with turbos and hybrid systems.
Diesel's engine used 317g/kWh.
So the amount of fuel used has not even halved in more than a century.
In Europe, yes, due to extremely stringent fuel consumption regulations — essentially, the engine needs to have very small displacement, so you need to add turbo to get at least some power out of it. A typical new car in Europe has turbocharged 1.2L engine or something in this neighborhood. In the US, however, naturally aspirated 2.0L engines are still king.
This is true. In fact, some manufacturers (Volvo ?) have new models that are both super and turbo charged.
But this isn't cost-free - these are tremendously complicated engines running at very close tolerances. These will have higher failure rates and will be more expensive to maintain and fix.
Remember, kids: There's no replacement for displacement.
Engines aren't really a problem as long as you don't let Washington bureaucrats tell you what to put on them (emissions components are a long term consumable on modern diesel engines).
There's all sorts of incremental improvements to things that just make the machines easier to operate and faster at what they do. More and more equipment (or functions on said equipment) has been going hydraulic over time and machines have been adding more and more auxiliary circuits to support that. If you're moving a lot of stuff not on pallets a pair of forks that has hydraulic width adjustment is a huge upgrade over manual. Joystick style controls are a lot smoother and faster to operate than lever style controls. New mostly glass cabs have amazing visibility compared to the mostly sheet metal cabs of old. Having a cab at all greatly improves your ability to work in the elements. A 10yr difference in equipment isn't much but for a given HP you'll start seeing a big difference in productivity at 20-30yr as all the little stuff adds up.