Featured Nissan claims it's made a more thermally efficient gas engine, but there's a catch

I heard of this earlier and owner of the BMW i3-REx, the Nissan approach makes sense. Now if they can bring it to market ???

Bob Wilson

 

Apparently they've had an small E-Power serial hybrid car out for about 2 years, though not in the US. This announcement is because they've made it even more efficient, and it looks like they are planning on a plug-in-hybrid version.

They have a graph in the video showing value vs time (whatever they heck they mean by 'value'--a true marketing graph) with a line going up to the right. Above the serial hybrid E-Power is a regular plug-in hybrid, and above that is the supposedly upcoming E-Power plug-in-hybrid.

Above that they list a FCEV. At the risk of inviting some comment spamming, I'll say that, like many fuel-cell fans, maybe they are counting on some amazing breakthroughs in hydrogen or fuel cell science. Or maybe they need to put that on there for some Japanese political reasons.

 

The e-Power Note came out in 2017. Nissan went series hybrid so they could make use of their BEV experience; a series hybrid is a lot easier to do than others when you have a working EV drive train. This also means making a plug in version will be simple. The down side is high speed efficiency, which doesn't show up in the Japanese test cycle. A more efficient engine will help all around though.

Unless there has been a radical change at Nissan, their FCEVs where using a small solid oxide fuel cell with big battery. Again this lets them make use of their existing EV parts. Didn't use hydrogen, but was fueled by 55% ethanol.

 

I wonder how this design compares to similar ones by BMW and others?

Had they come up with this 25 years ago this website would of been called NissanChat rather than PriusChat...

But they're a little bit behind schedule when it comes to transitioning away from fossil fools.

 

I skimmed through that presentation. Did it mention emissions?

 

LOL. A serial hybrid using a constant speed Atkinson cycle engine is not that new. I think the distinction that made Prius so popular was that it worked without any coddling of any kind. Mountain ranges were no problem. Neither was extended stop and go. Or all day at freeway speeds. And all that with some of the lowest emissions and highest mileage available.

Nissan's been using this design for a couple years. You'd think that they would have been evaluated for USA use by now.

Dan

 

How many series hybrids with a constant speed Atkinson engine are on the market? According to @bwilson4web, the i3 REx doesn't operate that way. The Prius's series operation was limited. The idea isn't new, but it really hasn't been done commercially.

It isn't coddling. For best efficiency, the constant engine speed is going to be under 70% to 80% load.

The US may get a performance version, but Nissan is focusing this for Japan, China, and Europe; they're seen as better markets for fuel efficiency. Battery and motor supply will be a factor. The US has cheap gas, and it seems to be only in the Note right now. Not a top seller here to begin with. Perhaps more importantly, the EPA test is also the hardest.

Nissan e-Power hybrids for the US will aim for performance, not just mpg

 

That's not really a catch, if you think about it. All new ICE cars should be hybrids anyway.

 

At the very least governments need to require that... And if they did, it might well be what saves Toyota and their anti-BEV business plan...

 

I think they're more pro-profits than they are anti-BEVs. Every company decides their own strategy based on expectation of future profits.

 

First 50% efficiency in a gasoline engine- Mercedes did it in their F1 car in 2017. All the winning formula one cars are hybrids with electric recovery systems. The way they recover energy from the exhaust is through an expensive electronic turbo charger. This year Mercedes and their supplier Garrett are bringing the F1 tech to some of their cars.

Mercedes, AMG, and Garrett Bringing E-Turbos to Production

Simply adding a turbo charger allows for exhaust energy recovery, but it is often sized to bring power not efficiency, and drivers push these turbocharged engines into inefficient zones. It is my guess that Nissan is going this less expensive route and forcing the engine to the proper mode by restricting the engine to efficient rpm and power levels then using the battery to buffer this when not needed, or provide extra power when its needed. Mercedes likely are trying to build a better e-turbo 4 cyclinder that is high powered (2L - 400+ hp) which is difficult to design to be the most efficient. Still this stuff could trickle down as costs are reduced. Add bypasses and a 2L 4 cylinder with 10:1 native compression could run an atkinson cycle with the turbo bypassed, or a miller cycle with up to 20:1 boosted compression with everything in between.

The prius prime though shows that having a fairly high power range but direct connection to the wheels is going to be more efficient. Without turbocharging the atkinson version of toyota's dynamic force engines are most efficient at 41%. This seems like the best type of engine for a 200 hp or less phev.

 

Damn. I knew that I should have patented that e-turbo design in 1975. My dad did not want to boost my allowance to the levels needed to pay the fees. I have a high school notebook around here somewhere that has a sketch of the basic design. Oh well.

 

Invest in alternative energy companies to make up for it. Seems like a sure bet!

 

You'd be in good company with not just new and improved battery makers, but also new and improved mouse trap makers.

 

And if you did patent it back then, it would have expired long ago. Before the turn of this century.

 

Yeah, but I could have sold the patent to Garret and would have had a nice nest egg.

 

I haven’t read the article yet, but I will. Nevertheless, regarding 40% efficiency, remember that that’s peak efficiency. In a pure-gasoline drive train, an engine is hardly ever able to operate at peak efficiency. That’s a big part of how hybrid drive trains improve MPG: by keeping the engine off as much as possible except when it can be operated at close to peak-efficiency conditions.