Nissan has created a strange new backwards working hybrid powerplant that includes an internal combustion engine but doesn’t use it to drive the wheels at all.
It’s called e-Power, it’s going to be in the Japanese-market Note first, and it’s essentially a Nissan Leaf that you don’t ever plug in. It also keeps the oil companies somewhat happy. Allow me to explain…
Traditional hybrids have an internal combustion engine supported by an electric motor that draws power from a battery. During braking the electric motor switches roles to charge the power source. However, some hybrids do offer forward momentum provided by both the ICE and electric motor — either by working together or trading on and off.
However, Nissan’s e-Powered cars don’t use the combustion engine for direct propulsion at all. Instead, the gas-powered 1.2-liter three-cylinder works as a generator to charge a battery used to power the electric motor. The electric motor provides all of the forward locomotion.
The end result delivers the better characteristics of an electric vehicle without some of the drawbacks.
The lithium-ion battery in the e-powered Note is only one-twentieth of the size of the battery on the all-electric Leaf. It’s so small that Nissan has managed to wedge it under the front seats without sacrificing much meaningful cabin space.
A vehicle equipped with e-Power doesn’t require plug-in charging. Instead, the gas motor hums along at an optimized 2,500 rpm, powering a generator that continuously charges the battery.
Conspicuously missing from this series hybrid is the fully-electric capability seen on similar vehicles like the Chevrolet Volt. Even though the battery is relatively small, you’d still expect an electrical port and the ability to do away with gasoline for limited distances. The upcoming Toyota Prius Prime offers one and, when taken advantage of, offers some all-electric driving. Of course, a smaller battery means less cost, which is key for an entry-level model like the Note.
Or, maybe Renault-Nissan just hasn’t had enough time to benefit from its Mitsubishi takeover and that company’s plug-in hybrid technology.
Regardless, Nissan suggests fuel economy ratings of the Note e-Power will remain similar the conventional hybrids currently on the market. It also promises the Note to be more of a laugh to drive. With the instantly accessible torque of an EV, Nissan is making a big deal of the system’s driving enjoyment. The Japanese marketing slogan for the e-Power is, “You’ll love it with your foot on the pedal.”
I assume they are referring to the throttle.
The Note e-Power X is listed in Japan at 1,959,120 Yen, which equates to around $19,000 U.S. — less than a base model Toyota Prius.
[Images: Nissan]
Wasn’t this the original plan for the Volt? My understanding is that they dropped it when they just couldn’t coax enough power out of the engine (taking the efficiency loss of going into and out of electricity) when the battery was depleted.
It was the original plan. In the end, they decided that the engine had to drive the car as well and put in a prius-like transmission to allow it to do so. I have no idea if this is why GM botched the range-extender efficiency, or if they really needed to remove the conversion losses of going mechanical-electrical-mechanical through the drivetrain.
But no, this is what they claimed the Volt would be. Not what it was.
If you look at GM patents for the Volt, the fact that the combustion engine provided motive power at some times was part of the technology from the beginning. Also, while both the Volt and Prius use planetary gearsets to connect things, the Volt’s setup is different from the Prius. Ford uses a similar hybrid setup as Toyota.
An oversimplification (enough to illustrate my point) is basically this:
The Gen 1 Volt has an engine attached to a generator, and a second motor attached to the wheels. It also has, for use in a certain speed versus power demand range where it’s efficient to do so, a clutch to also connect the engine (and generator) to the wheels. When that happens, conversion losses are minimized (not necessarily eliminated, as it may be more efficient depending on vehicle load to engage that clutch, but then pull excess power off the engine and charge the battery, or conversely, it may be more efficient to supplement the engine power with battery power).
This Nissan system removes that clutch.
(The oversimplification comes in, because the GM system actually has more clutches, so that it can use the (smaller) generator to propel the vehicle, instead of the (larger) main motor, for higher efficiency operation. But, when the engine’s running, that isn’t happening.)
The Volt connects the gas engine to the wheels at highway speed, to improve the mpg when the battery is run down. I pure series hybrid, like this E-Power will be a gas hog, relatively speaking, in highway driving, since it combines the inefficiencies of an electric motor and generator.
they didn’t “drop” anything. they included the capability for the engine to link mechanically to the motor/generator when it is more efficient to do so. Because there are cases where mechanical drive is more efficient than mechanical-electrical-mechanical.
it is not a “Prius-like” transaxle as claimed below, nevermind how much the nerds lost their minds when GM brutally shattered their dreams.
that didn’t change the fact that GM’s marketing apparatus tried desperately to deny the mechanical link existed at all, despite car magazines explaining it repeatedly.
And then AutoWeek came out with their Volt article, which denied the existence of the mechanical link in terms and phrases that looked and sounded JUST like the ones from GM marketing. In other words, AutoWeek proved itself in one shot that they weren’t a magazine so much as a shill for the advertisers.
The big issue is if you are climbing a mountain. The battery is depleted quickly, and the generator can’t keep up.
I would hope that the nav system could interface with the battery computer and carry a higher state of charge if the route ahead had long climbs. That isn’t too much of an issue over most of the US though. For the very occasional event it isn’t the end of the world either. People forget how common it was to see VW vans and other underpowered vehicles chugging up mountain highways at 35mph but it was not unusual “in the day”. Still is the case with heavily laden trucks too.
The Volt has a Mountain Mode that you can engage before an ascent manually, but the navigation doesn’t do it automatically.
Would it be good to also have a bank or two of Super Caps in that circuit? And is it possible that the battery could be smaller than the ICE in the production version? Maybe the lead picture is just diagrammatic.
Here’s the future, guys.
In other news, Nissan pulled all the stops out for high-efficiency/high power gas-only engines. An absolute miracle of engineering and it barely gets a few miles better than the competition.
https://www.thetruthaboutcars.com/2016/10/infinitis-variable-compression-turbo-holy-grail-power-efficiency/
Or you could power a Tesla motor with a Prius engine. Get your 50mpg, lose 95% of the battery weight, and keep the Tesla power. The only thing I have to question is the Li-ion battery: will it last? Wouldn’t you want a FeLiPO4 (fast charge/discharge) instead? Is there some sort of capacitor storage as well? As always, the battery is the make or break tech for this type of thing (powerful electric motors aren’t cheap either, unlike displacement which is merely missing space inside an engine*).
And anything you can do to increase the efficiency of all-gas engines you can do for the “range extender” engine, but not vice-versa. Don’t pretend tricks like HCCI will be easy to do at wildly changing engine loads, while the “range extender” engine will happily stay at a single rpm and load for quite some time. This car will be in the dead center of the BSFC island for most of its life (I should hope, but somehow GM utterly failed at this), and that will be almost unbeatable. The only weak point should be the battery.
* tongue only partly in cheek. Part of “the truth about cars” is that displacement is pretty cheap to manufacture.
Tesla motor with Prius range extender = Prius range extender power minus charging inefficiencies if the battery is ever depleted
Plus this has the weight of both a gas tank and battery pack
I’m starting to wonder how this is any different from a Volt
it’s evidently a pure series hybrid (like the Volt operates *most* of the time) but without the battery capacity to run in EV-only mode for more than a short distance.
Hmm…It’s probably cheaper? It doesn’t seem to have any notable capability advantage over the Volt.
The Nissan would be much cheaper than a Volt to make, because it has a tiny battery. It might not be much, or any cheaper to make than a Toyota/Ford hybrid, because it has a biggish electric motor, and a fairly big generator. The Toyota/Ford gearbox is more complex, but not terribly so.
Maybe, sometime, we will get real world fuel efficiency data on the Note E-power, but I would expect it to be bad, under most conditions. You combine the inefficiencies of a motor, a generator, and battery charge/discharge under nearly all driving conditions. I hope real world information will eventually become available, because I am curious.
That gas motor better be quiet. A steady 62.5 Hz drone will get old very quickly.
Also unless this thing is turbocharged within an inch of its life, it will be seriously down on power once the charge is depleted this thing will be gutless. Even a turbo 1.2L can’t be making more than like 60-70 HP at 2500 RPM. Interesting concept though.
Note the big liquid cooled inverter with the orange cable running to the traction motor and a separate orange cable running to the battery. In normal operation when the ICE is active the power currently demanded by the driver will flow right through that inverter as AC. If the engine is producing more power than currently needed then it will convert that excess to DC and use it to charge the battery. Once the battery reaches the max SOC the engine will shut down and the battery will be the sole source of motivation. The battery gets down to the min SOC and the process will repeat. The limiting factor will be the generator’s max power output, if it matches the output of the battery then there will be zero loss of power at the wheels. Just because the engine’s target operating RPM is 2500 does not in any way mean that they won’t operate it at higher RPM if needed.
It is a very sound process that will work great with the proper implementation or could be crappy with poor implementation.
So it’s a BMW i3 REX with more ICE power. Should be interesting.
If the engine was diesel, we’d note that it’s been commonplace on trains for a long time.
Two points:
1) No plug
2) I’d always thought that diesel locomotives use diesel-electric drives more for torque conversion than for efficiency. How else do you take 3000HP at 800RPM and convert it down to 1 RPM with a gazillion foot-pounds of torque, and deliver that torque for the minutes it takes to get a freight train up to speed? It seems to me that diesel-electric locomotives need the control that comes with the electric drivetrain in order to work at all.
locomotives are diesel-electric to take the place of a mechanical transmission, which would be enormous and failure prone.
The i3 REX is basically an electric car, with a big(ish) battery, but carries along a scooter engine powered generator to get some extra range, though not too efficiently. This Nissan is similar, but with a tiny battery providing essentially no electric-only range, but a bigger ICE.
I think there is a possibility that there may be an optional charging port in the future models with the powertrain but it will be similar to the original PIP with a very very limited range.
Here is how it will operate in various scenario in which we will assume that there is no HVAC demanded.
Coasting to a stop or sitting at a stop engine off as long as the battery SOC is above Min.
Accelerating from a stop with Min SOC the ICE will power the car and power generated that exceeds that need will be used to charge the battery.
Accelerating from a stop with Max SOC the ICE will stay off and the vehicle will run in EV mode.
Steady state cruise the ICE will cycle on and off. When the ICE is on the power needed to drive the vehicle will come from the ICE and excess if any will be used to charge the battery. When the battery reaches the max SOC the ICE will shut off and the vehicle run in pure EV mode until Min SOC is reached and then the process will start over.
If a situation exists where the power need is greater that what the ICE can deliver at 2500 rpm the battery will make up the deficient if it has a high enough SOC. If the battery doesn’t have a high enough SOC then the ICE will operate at the RPM required to make the needed power.
Pretty much any time the ICE is on it will be powering the car directly, just with an electrical connection instead of a mechanical one.
Now if you add the HVAC into the equation then you will see instances of the ICE operating while the vehicle is stationary. The ICE will power the compressor and again excess energy will be used to charge the battery, the ICE will shut down once the SOC target is met and then the process will repeat.
Now this is interesting. Drive a strong hybrid long enough and it just makes you want an EV, because the MooOOOOOOO of the gas engine winding up is no fun at all after a mile or so of urgent, silent shove from the electric motor. But if the gas engine could run at a constant speed and be thoroughly soundproofed for that very narrow RPM range, then you could get much of what you like about an EV without the range anxiety, and at lower initial cost. Plus it’s easier to control emissions within a narrower RPM range, so it might be cleaner at the tailpipe than a standard hybrid. It still would make more sense with a little bigger battery and a plug, but I like it.
@hotpotato: “Drive a strong hybrid long enough and it just makes you want an EV”
That’s exactly what happened to me. I suspect that’s the real reason most EVs are sold. Nothing to do with saving the environment or money. They’re just awesome to drive. Wait until we get more quad motor driven EVs. Torque precisely delivered to each wheel individually. The ultimate in all-wheel drive technology. Rimac has it now, but eventually it will trickle down to lower end vehicles.
Why not have the ICE ‘interface’ directly with the electric motor, like Aquarius Motors from Israel and Toyota has been working on? No need for batteries, and an efficiency, reportedly, that’s at least twice that with a conventional ICE propulsion. Or leave a battery big enough for 10 miles of inner city driving. That should cover most errand runs, in case the owner is too lazy to take the bicycle.
Sorry but no way is a ICE-generator-motor-wheels set up going to double the efficiency of a conventional system particularly if there isn’t a battery involved. What you describe is pretty much what the current Accord Hybrid uses with a clutch to connect the generator and motor at higher speeds. W/o the clutch engaged the system works more or less as a CVT replacing the frictional losses with the conversion losses and then eliminating most of the losses once that clutch is engaged.
This is just the same thing the Karma did years ago, right?