i'm baffled by this conclusion. need more input.
Steve Jones
If memory serves, Saab also had a design for a variable-compression engine which did so by somehow tilting the whole engine block away from the crank. Interesting stuff. I was under the impression there is also a use for it in non-turbo engines, by varying the compression ratio through the rev range, but that's just a vague recollection.
Mel Tisdale
Surely a lighter solution is to have a fly-by-wire throttle on the inlet manifold to the combustion chambers and on the exhaust feed to the turbo charger. All that is then required is monitor the resultant cylinder pressure at t.d.c. and adjust the pressure of the charge to suit the performance required at any particular moment.
Since there is more energy in a gallon of diesel than a gallon of gasoline, I wouldn't count the diesel out yet. I would imagine a diesel-electric hybrid being the car of the future.
Yes, ICE is on the way out, but the lack of battery technology is sort of a red herring. The vast majority of trips are less than 30 miles and batteries could be swapped out on long road trips with proper battery standardization. That simple small step would eliminate most, if not all of the technological hurdles.
Expanded Viewpoint
It looks to me like way more complexity being built into a system than is needed to accomplish the goal. Just look at all of that extra machine work to make those parts alone!! And then when you factor in the original assembly time of each engine, the cost of the additional parts when they break and wear out and such, who would really want one of these things except the tech junkies who are always looking for their next "fix"? Just how much more will be added to the bottom line of the cost of the car when all is said and done? And right now, as gasoline prices are plummeting (2.19 a gallon yesterday at ARCO) how can this boondoggle be justified? Yes, Diesel fuel has more BTU in it than gasoline, but what is the most efficient way to extract it? Is external or internal combustion better?
Bob....dieselgate. Wow. It is almost a shame that the age of the ICE is coming to an end. They are truly powerful and amazing works of engineering today. And efficient and clean compared to just a decade ago even. But they are peaking so it's time to roll in the next better technology. We won't marvel over these engines for too long. In 10 years hardly any automobile manufacturer will be making ICEs anymore.
"But until batteries can offer all-day driving range or quick enough charging to make recharge stops practical..."
If you are willing to pay, you can swap batteries in the same time as it takes to fill gas - at least that's what Elon's video claims.
Better yet, on all-day drives plan your charging with lunch / snack time. Teslas take between 20 - 40 minutes. It's free.
Just don't use the auto-pilot!
The internal combustion engine was developed in the late 19th century. By the end of the 1st. World most on the mechanical developments has been made. Then after WW2 , the final configuration we use even today were finished. After that, electronics have been the drivers of advances. Electric cars have been around since the first decade of the 20th Century , and range + recharging time was the big problem. One hundred six years the same problems exist. The exotic metal batteries of today suffer from losing recharge capacity loss, expense to manufacture , environmental damage from mining, making them difficult to be competitive in the open market. Hopefully we'll see a solution to the problems soon, it would be exciting to see success and the resulting competition between electric and internal combustion engines.
Martin Hone
I'm with Mel. Who needs the extra complication. And how much better is the fuel efficiency at the higher compression ratio anyway ?