Featured Digital Valvetrain

First, I like it but I also realize it is unlikely to be coming to any manufacturer soon ... 'not invented here.'

When I step back to a systems view, my vision is:

• high-power motor-battery - primary power to drive wheels sized for ~2,000 ft elevation change at 75-80 mph.
• high-efficiency, low pollution engine - sized for sustained speed at 75-80 mph

By letting the motor-battery handle peak power, the cars become much more nimble and compatible with automatic driving aids. Disconnected from the wheels, the engines become quieter, significantly more efficient, and easier to control emissions.

Personally, I like opposed piston engines and/or fix speed, Wankel. With modern fuel injection, problem solved. The opposed piston engine expands the combustion gasses about 2x faster than single piston engines which reduces the high temperature, dwell time that leads to the worst nasties. The Wankel because I love small power plants.

Bob Wilson

 

That is how my BMW i3-REx works. The two-cylinder, 640 cc, motorcycle engine only drives the generator.

If the waste heat of the turbine could be used for another cycle or pre-heat the compressed air before the combustion chamber, OK. The key metric is the exhaust gas temperature. The lower it is, the more efficient the engine.

Bob Wilson

 

The original Audi A1 E-tron program was a series PHEV like the i3 REx that used a 250cc Wankel for the genset. That genset was small enough to sit between the rear wheels. Initially, it ran at one speed, but they switched to three set speeds after user feedback showed some people were disconcerted by hearing a constant speed engine hum that had no relation to road speed. They might have had as many as twenty cars running for testing, but the program got shelved during the Recession. Even if it continued, there was a good chance the Wankel would have been replaced by some small piston engine Audi was already producing.

As for turbines, Wrightspeed is offering series hybrid conversions for commercial trucks that uses one.
Technology | Wrightspeed Powertrains

 

Electronic valves are in a chinese partnership car, the Qoros with Freevalve.
https://www.motortrend.com/news/is-the-era-of-the-camless-valvetrain-finally-upon-us-technologue/

The problem today for both are costs. With some breakthroughs in engineering electronic valving, at least for intake valves

Therodynamically wankels have some severe problems and then there are problems with seals. You can build them at low cost, but that comes at the expense of efficiency. A 3 cyclinder 1.2L turbo charged engine with an iron block and aluminum heads is quite small and can be built to be less than 200lbs, not really a big advantage getting much smaller or lighter. Toyota has had trouble getting their most efficient cylinders bellow half a liter, so maybe a 3 cylinder 1.5L which is also quite small. See this 1.5L 88lb engine. Nissan 1.5L, 3-cylinder 400 hp engine to complement electric Le Mans ZEOD RC powerplant - Green Car Congress

Mazda seems to be furthest on track for efficiency with skyactiv-X again using half liter cylinders for their prototype. 2019 Mazda 3 with Skyactiv-X Compression-Ignition Gas Engine Prototype Drive | Review | Car and Driver
The beuty of camless is on something like this engine it could stay in the efficient range longer, and use an electronic turbo mostly as a regen to charge the battery from exhaust pressure after acceleration. Camless would also drop the weight and size of the engine like it did on the quoros. Skip cylinder also is easier with camless. Camless will happen when fuel prices get higher and electronic costs go lower. It does need a big battery, but if its a hybrid or phev its got one already ;-)

 

Why would you want to preheat the charge air? That's kind of just asking for pre-detonation.

Anyone who has ever owned a turbo RX-7 will commiserate when you mention apex seals. A few people with high-power ones have seen the (parts of) seals flying out of the exhaust.

 

It was reference to a turbine engine. You take the turbine exhaust and run it through an intercooler. The intercooler is between the compressor and combustion chamber so part of the waste heat is captured.

Bob Wilson

 

Turbo and super chargers today already have intercoolers. To cool the compressed air down. The act of compression generates heat. Without cooling it, the hot air limits the efficiency of the charger. For designs going for better vehicle efficiency, that is a limit on the downsizing of the engine. The hot compressed air also isn't good for reliability and longevity.

Warmed intake air for a natural aspirated engine could help efficiency; it is a common ecomod. A factory car would simply use a smaller engine.

 

"Cyclone power" sounds like something advertised in an infomercial at 2am.