New ICE engine for extended range EV's

Detroit has a long and sad history of being approached with novel ideas and either rejecting them or failing to turn the idea into a profitable product.

Hybrids follow that pattern exactly.

 

True, but this design was always better at electrical output vs mechanical output, and now with demand for range extenders, it seems as if there is finally a use for all the unique engine designs we've heard of in recent years that are efficient, but lack power or the RPM band or some other characteristic necessary for direct-drive. As a ReX of course, its no problem.

Here is a design that is similar, but uses springs which also sounds promising in the ReX role :


This is a good article on some others:
5 Alternative Engine Architectures - How to Replace the Internal Combustion Engine - Popular Mechanics

 

In one word: cost.
A towable range extender made for the Leaf uses a Capstone turbine. Its price is in the $30k to $60k range.

I'm sure the production levels needed for mass car use will bring costs down. The tolerances and materials needed for long service life will keep a microturbine's price higher than a comparable piston or rotary engine.

The opposed piston layout is also an old idea, and has seen use in diesel locomotives. Maybe even some experimental plane engines. It requires a bit more to direct the mechanical energy to the wheels, prop, or a single generator, but it saves weight in not needing a cylinder head. Toyota even considered it before deciding on the single cylinder for this engine. The papers should have the details on why, but I think part is that the single cylinder's shorter length allows more packaging options.

 

The problem with single piston is vibration. It is not a balance design. Wonder why Toyota choose this.
The opposite pistons are balanced.

 

The vibrations can be improved by simply using two single cylinders. The Yaris/Corolla example uses two units.

 

A couple of problems with the opossed piston layout can be reduced with di and turbo charging. My guess at why toyota its design and not opposed pistons is that ecomotors may have the patents. All of these are long shots so why compete with a fleshed out operation.
opoc® Overview | EcoMotors

OK well the NA mazda skyactiv 2L generates 155 hp, so its really not that big of a difference. Toyota will use a 1.3L version of the skyactiv in the north american yaris replacement ;-) This engine may be cheaper to make though or more efficient, or it may wait longer for more technology.
EcoMotors' Opposed-Piston Engine To Be Built In China
We should see a version soon in china. Definitely will be cheaper than an engine here, since its likely they won't make it fit epa emissions. It does have bill gates's deep pockets to help push through any resistance that auto companies might try to use to legislate against it.
Bill Gates Buys Stake in EcoMotors, Producer of Potentially Revolutionary Engine - AutoObserver

 

Creating electricity directly via pressure changes caused by internal combustion via using the Hall Effect. The challenge being that the combustion would exposed the electric coils to very high temperature and thus change the output of the coils. High temperatures of an ICE might effect the lifespan of the magnets or electro magnets and coil insulation. Reliablity would be my primary concern. If the pressurize gas that moved the electric coil pistons were kept cool or was thermally isolated from the ICE pressurized gas this would work very nicely.

 

You can have 2 cylinders in either the opposed-piston design or the one in this article; the benefit that the Toyota concept is that you can put the pistons side-by-side, which can help with packaging depending on how the engine bay is configured.

 

One of the reasons why I think Toyota choose the single cylinder to study further. Another is in the flexibility of adding more units for larger applications. The single cylinder layout might also be cheaper to adopt to current manufacturing than the opposed cylinder.

The W shape of the cylinder might be the real advancement here. The coil cylinders are removed from the combustion cylinder. The 2-stroke design is going to dictate greater cooling capacity to begin with. So a production design should have a larger cooling system than a comparable sized 4-cycle engine.

 

Well we have 2 main variations on free piston - opposed piston and single piston. Both remove the crankshaft (fewer moving parts, lower friction) and the posibility of variable compression. Another advantage of the design is that modules can be stacked with clutches in between, allowing say timing to balance nvh for the number of modules being called on.

the single piston has the advantage of easier control laws, and figuring optimum stoke and valve timing is not easy. The biggy is that others have patents on opposed pistons and are doing lots of research. That means if they do build a better ice, toyota can license it, and would not be out much, but if toyota makes the single piston work, they can keep competitive advantage on other automakers.

The big disadvantage is free pistons have to be 2 stroke beasts. This normally means more pollution and less efficiency. Di and better valve timing along with agressive cooled egr may be able to tame the two stroke beast, but I would not bet on that. Ecomotors seems to be leading the charge with oposed pistons, but there is a german company also racking up patents. Ecomotors will start in China where the additional pollution may not matter to regulators, in the US or Europe they likely would need more expensive pollution control equipment hurting the lower costs of removing the crank shaft.

They maybe able to reduce cooling needs by using a low compression cycle (leaving both iexhaust valves open for a larger part of compession) and alternative a lean buring hcci high compress cycle, cooling in a otto cycle with aggressive cooled egr.