Combustion’s Last Stand Could Come In The Form Of A Solid-State Engine

One very common mistake people make when thinking about EV energy usage is to compare it to ICE vehicles. On the surface, this seems like a fair comparison, because it takes a certain amount of energy to go down the road, right? But, it’s never that simple. Combustion engines have a nasty habit of producing crazy amounts of waste heat, or heat energy that doesn’t contribute to moving the vehicle down the road.

Managing all that wasted energy is an important part of ICE vehicle engineering. The extra heat has to be sent away somehow, or the motor will damage itself or even melt down. Radiators, exhaust systems, and even brakes all have to be designed with enough capacity to shed all of that heat off into the air, even when driving in extreme conditions. The one benefit to having all of that extra heat around is that you can use it to help heat up the cabin of the vehicle in the winter!

Because around 75% of burnt fuel becomes worthless waste heat, ICE vehicles are very difficult to make more efficient. EVs, on the other hand, produce very little waste heat, so they are even cleaner when powered by a coal power plant (the engine at the coal plant is far more efficient than a car or truck’s piston engine).

Add in other things, like the cost of maintenance for a machine with dozens of fast moving parts, oil changes, tune-ups, transmission flush-fills, and changing out everything from water pumps to alternators to timing belts, and ICE engines are put at an even bigger disadvantage compared to EVs.

For ICE technology to stay economically and environmentally competitive in the coming years, a miracle would have to occur. Not only would the ICE engine have to become a lot easier to maintain, but it would have to become a LOT more efficient. Basically, you’d have to make a cheap vehicle-borne engine that can compete with the multi-million dollar combined cycle turbines down at the power plant!

But, never say never, because this might actually be happening.

Unlike basically all automotive engines, the Lightcell design has no moving parts. It’s a solid-state engine. Its designers also claim that it’s between 70% and 80% efficient at converting fuel to electrical energy, which would still make it less efficient than EVs, but could make it more efficient than EVs plus your local methane gas power plant.

In other words, if the claims pan out (more on that in a bit), the only way an EV would be cleaner than this engine would be when charged with renewable energy (wind, solar, etc.) or nuclear power.

How does it work? Instead of trying to use the pressure of combustion to move the parts that move the car, the Lightcell is designed to generate electricity by turning fuel into light and then converting that bright light into power to charge batteries or directly power an electric motor in much the same way as a diesel-electric locomotive. But, it seems likely that there’d at least be some buffer capacity to allow for a smaller but more continuously operating efficient burn.

To turn the burning fuel into intense light (3000x brighter than the average sunlight on the Earth’s surface), the engine heats up sodium. Then, specialized photovoltaic cells (kind of like solar panels) are used to collect the energy from the sodium’s light emissions. Because the light from the sodium is consistent and concentrated at certain wavelengths, it’s possible to use germanium carbide or gallium arsenide (likely alloyed with aluminum for tuning), to optimize the cells for that specific color of light.

But these are only claims made on paper, and there’s plenty of reason to be skeptical.

One big problem will be dealing with the energy without burning up the sodium or the tube holding it. The company says it will be using quartz for testing, but will eventually move to sapphire, which is obviously expensive. The engineers will need to make sure that the assembly is durable enough to run for a long, long time without needing refitting or the engine will not be economical. If the sodium gets consumed or depleted, you’re basically talking about making sodium one of the fuels the engine uses.

Another thing to be concerned about is conversion losses. At every step, some energy will be lost. Going from fuel to heat, and then going from heat to light, and then going from light to electricity will mean wasted energy. If conversion losses mount, the company could end up with a combustion engine that doesn’t achieve targeted efficiency levels, which then makes it no better than running a piston engine to turn a generator.

Another challenge is that other companies are working on similar approaches. Mesodyne has its own LightCell technology that claims to achieve only 13%, but in a much more compact design. Fuel cells are another approach that could work better in the long run, too.

My educated guess on this technology is that it probably won’t save ICE cars and light trucks. Even if it works, it could prove to be more expensive and less effective than simply charging batteries, which is exactly what the engine would do in a car anyway. There is no direct motion energy coming out of this engine, so unless you want to build a truly massive one, you’d need to pair it with a large battery that stores at least a few dozen miles’ worth of energy. This would basically be an EV that is on Level 2 charging all the time, even when moving.

Where this technology could prove very useful is in areas currently thought to be the domain of hydrogen fuel cells. Aviation, large land vehicles, and larger ocean-going vessels could all be well-served by a highly efficient engine that can burn multiple types of fuel to heat the sodium up. For example, container ships could be a lot more efficient burning natural gas or kerosene instead of burning nasty bunker fuel in a giant piston engine.

Featured image from Lightcell.