Featured Mazda competes for thermal efficiency against Toyota with Skyactiv-Z

Nothing against diesels? How would I get that idea. Oh yeah, maybe it was post #7?

As for a dying technology? Maybe talk to Toyota about that, Ah la their hydrogen mobile the Mirai
The typical grocery getter consumer get to work car is only 10% of national Transportation whereas diesel trucks are doing the heavy lifting of the other 90% of transportation. But I realize you've already ignored that glaring issue when mentioned above.
So yea right - the diesel is on its sunset Death March.

 

My place is work has gasoline pickups, CNG pickups, hybrid pickups, BEV pickups, and a whole lot of diesel trucks and machinery. 90% of the time I'm driving a diesel truck if some sort. The ones used the least are the BEV pickups since we have a lot of driving to do on a regular basis and they don't go very far and then need lengthy charging.

 

You can talk to Toyota about a lot more than the Mirai
ex:
Toyota develops high-efficiency 'free piston' no-crankshaft combustion engine... to power an EV | Extremetech

Toyota's Free-Piston Engine: A Revolutionary EV Range Extender - Ourmechanicalworld.com

Come to think of it while you are at it you might want to talk to Toyota about this new family of engines also
Toyota’s New Engine Family: Here's Why Rivals Should Worry

Also kudos for Toyota for keeping their strategy of exploring all technologies and not giving up on them - the key to success is to not limit yourself or foolishly dive off the deep end into only one approach to moving people around.

 

Their numbers are probably comparable to the pre EPA change numbers of the gen2 Prius. Which is besides my main point that your complaint on diesel hybrid fuel economy is really a complaint on power hybrids fuel economy.

Heavier? These are V8 blocks. On the 1.6L that was once available in the Cruze and Equinox, "The engine only weighs 33 pounds more than the base 1.4-liter(gas) turbo, so no serious suspension recalibration was needed." Tech Deep Dive: GM 1.6-Liter LH7 Turbodiesel

I am unfamiliar with start stop issues in diesel, but we are talking hybrids. Even mild hybrids have a more powerful starter and battery than what the ICE model is using for auto stop/start.

Don't see how I was throwing emissions under the rug when I entered the discussion discussing their emission controls, and saying multiple times that a lean burning gasoline engine might need to use the additional controls that diesels need.

VW was cheating. The BMW tested along side them when they were caught was not. One of VW's crimes from that was in making it harder for honest manufacturers to bring diesels to market in the US. We almost got a diesel Accord after Honda cancelled the first hybrid, but they gave up when they couldn't figure out how VW 'passed' emissions.

The electric motor and battery in your hybrids were free? Diesel cars in the US had an inflated price because there were limited options, and those that offered one only had it in higher trims.

Perhaps, they haven't given us any actual numbers.

I'm just going to add that the lean ratio produces less heat by simply burning less fuel per cycle.

 

Exactly!

 

I kind of had to laugh at this part

does it blow away engines used in cars today?

I agree its good to explore new technologies, but that linear piston thing isn't really much of an advantage even if they get it right compared to the current hybrid engines. Toyota has turbo charged engines in the lab that do much better than 42%.

 

Well, my question is if a free poison engine can maintain that 42% over a larger range of loads.

The problem with a lot of engines today is they are quite efficient at x amount of load at x amount of RPM. Once you get out of that their efficiency drops as their displacement and stroke remain the same. So even if your engine is advertised as "52% efficient" or whatever, that is only peak efficiency, whereas your actual efficiency might be 20% or 25% on average, depending on how you drive.

Engines have had variable ignition timing for years. In more recent years, variable valve timing has helped improve efficiency even more over a wider range of engine loads. Getting rid of the connecting rod now makes variable compression ratios and piston stokes possible, widening up the efficiency band over an even larger range.

 

That linear engine can only be used as a generator. In a series hybrid, how it performs under variable load isn't a concern. It just runs at one speed, and shuts off when the battery reaches full. The question is how does its efficiency and emissions compare to a piston engine generator? Even then its size could trump those for use as a range extender.

Toyota had presented this several years ago though. What was presented here doesn't have any new info.

 

The free piston engine which toyota announced its "breakthrough" over a decade ago produces electricity. Then you need an electric motor to use it and likely a battery to buffer, so we are talking a hybrid or more likely a phev. In a phev the most efficient regions could be banked in the battery. The 42% is for a two stroke toyota engine, which needs more pollution control unless they are using compression ignition. I would expect friction to reduce the efficiency of a 4 stroke.

These things I don't know. They seem to work well to compress gasses or hydrolyc fluid. I think they have a lot more to work out to make them as efficient in moving a hybrid as toyota's current engine. The main advantages are size and weight and probably lower cost. Mazda was touting these for its wankel but the efficiency never got high enough to sell in large numbers except in the rx.

 

Tuners Are Going To Love Toyota's Latest Overengineered Turbo Engine
"Toyota has long been claiming that there is no single path to carbon neutrality, arguing that cleaner combustion engines and hybrids need to bridge the gap to electric cars powered by renewable energy. With a back catalog of brilliant engines like the overengineered 2JZ, which is still revered 35 years after its 1JZ foundation was built, Toyota knows what it takes to beat the world's best, and its upcoming 1.5- (black top) and 2.0-liter (red top) four-cylinder engines appear poised to handle the weight of expectation with ease. According to Toyota engineers who spoke with German publication Auto Motor und Sport, the G20E (that's the 2.0-liter) is easily capable of exceeding the 400-450-horsepower figure of the mid-engine GR Yaris M concept: "With a larger turbocharger, more than 600 hp is easily possible.""

 

The new Toyota engines have a short piston stroke to reduce the overall engine size. That reduces torque. Which isn't an issue for Toyota as they are going to use them in hybrids, but how many tuners work on hybrids?

 

Some articles complain about excess vibration that Seriously offsets possible efficiency gains

 

Yes, ideally such an engine would power the wheels as directly as possible and use it's advantages to vary it's load efficiently and not vary it's load by using a battery as a buffer.

IMO, the weight, volume and friction savings would likely not be enough to amount to anything if what we want is a constant speed engine to fill batteries.

 

It has no motive force output; no crankshaft. It makes electricity in the same way as those shaking flashlights.

I don't see it working as the primary source of moving a car. The packaging could allow it to work as a range extender to an EV though.

 

While I understand that it produces only electricity, I was hoping it could transfer that electricity directly to the motors as efficiently as possible varying load at the engine, not in a storage system, kind of like the BMW i3 RExes sold in the USA that waited until the battery was nearly depleted and then switched over to an underpowered engine, which kind of gave the i3 REx a bad reputation in the USA.A free piston engine could potentially be a small, powerful, efficient engine that could work similarly, simply supplying all needed electric power to the drive motors without any need storing anything in the battery, but rather leaving that to when you actually make it to a charging station.

But storing the energy in a battery and then releasing it incurs more energy loss and kind of reduces or eliminates any benefit of the potential variability of compression and stroke in a free piston engine. A small, constant-speed crankshaft engine would likely be even more efficient and not take up that much more weight or space.

 

Wasn't the absence of a crank and rods and bearings supposed to contribute to the free piston engine's efficiency?

 

Yes.

From Toyota's current perspective the free piston engine is meant for charging up batteries and extending range without having to run out of charge- it is not meant to propel the car.

"The piston is called "free" because there is no crankshaft. On its power stroke, the piston dumps its kinetic energy into the fixed windings which surround it, generating a shot of three-phase AC electricity"

Right now, it is just another tool that may or may not be adopted - part of a multi-faceted approach to keep all avenues open to help move people around and keep pace in the ever-changing Automobile Industry.

 

<GRUMBLE> <GRUMBLE> <AHEM>

-- Wiki

Bob Wilson