Comments by "John Burns" (@johnburns4017) on "Rotary Engines - Why YOU Should Love Them, Even Though They SUCK | WheelHouse" video.

  1. Mazda have done promising research on HCCI ignition for its SkyActiv-R rotary engine project using research from its SkyActive 2 program. They have removed the need to locate the spark plug outside the combustion chamber to allow the rotor to sweep past. Mazda solved this in the SkyActiv-R rotary project. Rotaries generally have high compression ratios giving the design easy adoption of homogeneous charge compression ignition (HCCI). It looks like the next Mazda rotary will not have a spark plug and be HCCI ignition. Fuel consumption will match piston engines and when used at a constant speed genny as in a hybrid, outperform piston engines with all the advantages of low weight, small size, super-smooth, simplicity, etc. The expectation will be that the engine will be introduced in 2020, the 100th anniversary of Mazda. Looking good. Rotaries are better suited to constant speed, high efficiency genset applications rather than direct drive via gearboxes. In that application piston engines cannot compete. Rotaries are better suited for series-hybrid cars being much superior than piston engines. Direct fuel injection and laser ignition will improve the Wankel considerably when introduced. The problem of unburnt fuel in the exhaust will be eliminated improving emissions and fuel consumption. The engine performs very, very well in fuel consumption and emissions running at a 'constant speed' turning a generator - its most efficient "sweet spot". Wankels lose efficiency dramatically when they are revved up and down as when directly driving a car. The engine has a vastly superior power-weight ratio than piston/crank engines and is about one third of the size and weight of a piston engine for a similar power output. All these positive attributes combine to make a superb range extender, when the wheels are turned by electric motors. If a car is plugged in each night and uses grid power to run most of the time, then wear on these units will be negligible. As the engine is only periodically used, the life of the engine is greatly extended. Also newer metallurgic techniques are being used to make the engines. Even when batteries are depleted, the Wankel can provide enough electricity to power the car and still be economical. It takes only 25 to 30hp to propel a large American car down the highway at 70mph. Yet they put engines in them that can output 150 to 200hp. Most of that output is for acceleration and heavy loads. Highly inefficient. The great thing about a series-hybrid is that the generating engine works totally independent of the demands of the electric driving motor, enabling maximum efficiency when running. This means the generating engines can be greatly downsized. The battery acts as an energy buffer to give acceleration boosts. Mazda announced a rotary in a hybrid will be available in 12-18 months.
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  2. Millions of them were made.
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