Featured Toyota Announces New Powertrain Units Based on TNGA

Toyota gives us marketing speak: "By adopting a new control system that optimally distributes torque to the rear wheels based on the driving conditions, the E-Four system offers high off-road performance, handling, and stability.

Moreover, both the Dynamic Torque Vectoring AWD system and the new E-Four system feature AWD Integrated Management (AIM), which harmonizes engine, transmission, braking, and 4WD systems to offer superb handling and stability regardless of road surface conditions."

If this means that rather than cut engine power, it brakes the wheels that are spinning, then it will do what you want to some degree. The front brakes could provide the resistance so MG/1 could be used to provide electrical power to the rear wheels.

I have no sure knowledge that that marketing fluff means that or not. Even if it does, can MGR provide enough power to get you unstuck? I have no idea, 1.3 times more is not very definitive. The first one out the door should go to Bob Wilson so we have measured tests.

 

MG1 does not drive the front wheels. MG2 does. MG1 starts the engine & charges the HV battery.
The exception to this is the one-way clutch on the Prime that uses MG1 to aid acceleration from a stop,

 

Electricity generated by M/G1 also goes directly to M/G2. That is where the series hybrid part of this power-split system comes from.

 

I thought it was
Gasoline ->ICE engine -> MG1 -> HV Battery -> MG2

 

M/G1 can power M/G2 just via the inverter, the battery is optional. (there is not a wire from MG1 to the battery then a wire from the battery to M/G2. Just one set from the inverter to charge or drain the battery as needed)

In some scenarios, (heretical mode) M/G1 can be the motor and M/G2 be the generator. The software is very versatile.

 

Be skeptical of any new engine, witness the troubles the new Honda 1.5 is having with cold weather and short trips leading to massive gas in the oil. I'm really interested in the next gen for my next car but I have to remind myself to let the real world early adopters do the testing for me.

 

I imagine this announcement relates to the upcoming Prius V and RAV hybrid. These are significant improvements over the current hybrid powertrains..

 

+1

Yep, marketing speak for e-four. The torque vectoring for non-hybrids they give details about how power is split left and right and front to back that technically should be better than the current system that does poorly compared to say an audi or subaru let alone a heavy duty system.

I watched a youtube on the MGR system in current use. Power flows from mgr through a universal reduction gear then powers an open rear differential. Torque to the wheels is about 690 ft-lbs through the gearing which means the new unit will provide up a peak of around 900 ft-lbs. I can post a link if anyone is interested in the disassembly ;-) That is plenty of torque but not nearly what is going on in the front axle. I take youtube with a grain of salt, but it said that it is powered from 0-3 mph then gets no power until the system detects a front wheel slip. Its easy to understand that with the fairly aggressive toyota hybrid traction control system, this is non-optimal.

Definitely the new motor and engine hardware looks to be there to have a good system, although battery energy is probably low. The question is really has the software improved and is there proper control electronics. As you say braking the wheel that slips can work to provide good power to 3 wheels. Tesla does this in their excellent awd system. If done properly traction control needs to be modified to allow more slippage as well as more power to the rear wheels in many conditions compared to the current system. That may be less efficient, so perhaps a button could put it in a more safe awd mode, or this awd added traction is disabled in eco mode.

 

By April, we should be able to get SAE papers on the new engine and drivetrain.

Bob Wilson

 

We have been early adopters for almost 18 years now. Personally, I'm getting used to do all the testing, but with Toyota only.

 

First months of introduction cars I've owned...

'70s:
Plymouth Horizon - transmission bolts to engine let loose fortunately at 20MPH (weird looking through your rear view mirror and seeing parts of your car bouncing along the ground)
Porsche 914 - perhaps 10 trips to the dealer to try and get a mechanical side window fixed, rust showing within two years

'80s-90s
Nissan Stanza - rust inside trunk and hood lids within 2 years.
Honda Civic - 5 brake cylinders replaced within 4 months
Acura - transmission subject to recall, inspected and said to not need fix. failed at 70k miles

'10s
Avalon - nothing
Prius v - inverter recall, plock actuator

 

I don't think we need to wonder about the new engine, it uses the same stuff as the Atkinson 2.5L in the camry 13:1 expansion in the non-hybrid and Camry 14:1 in the version for hybrids with PI and DI. This engine family represents about as far as is possible in terms of efficiency and power in a normally aspirated engine that can run on US regular E10 in a low polluting manner.
2.0-liter Dynamic Force Engine, a New 2.0-liter Direct-injection, Inline 4-cylinder Gasoline Engine | TOYOTA Global Newsroom

The details that are missing are really involved with MGR and the new control laws in a 3 mg setup. Toyota claims 30% more torque, which I take to mean about 900 ft-lb at the wheels. The current MGR is 50 kw, 30% more torque doesn't mean that it needs to grow in power at all, but IMHO it should be able to provide 40% of the power up to X mph to the rear wheels to be a good awd system and the 2L engine can supply 107 kw, the 2.5L 131 kw. I'd make sure MGR is at least 55 KW and it could even be lower torque than the current mgr for these engines as long as the gear ratio increased the torque to the rear wheels. With toyota's newer motor tech this should be less expensive to produce than the current mgr. The question of how well toyota's electronics and software works can't be answered until cars are shipped to the US with the new system and tested. The video does show the old system failing on what should be an easy test for an awd system but the new system passing.

 

Although I appreciate a good press release as anyone, I prefer the technical detail of a good SAE paper if I don’t have one in my hands.

Bob Wilson

 

The announced new PSU is likely the production introduction of the 2014 breakthrough silicon carbide power devices. The original release stated results in up to 10% better MPG. Less power losses allows the smaller packaging, less cooling required.

My guess is the Prius will get a mid-cycle refresh with the new powertrain and the upcoming Corolla the non hybrid verion to compete with the Civic 1.5 turbo.

 

The 2.0 L engines are D4S toyota's version of Atkinson port and direct injection. On a cold start port injection is preferred as there is no need to cool the cylinder, and direct injection causes higher pollution in cold engines. The real reason for port injection is fuel mixing deep in the Atkinson cycle, my guess is ranges goes down to about 6:1 compression which because of late valve closing doesn't have time to evenly mix direct injection, and does not need the cylinder cooling benefits. Later valve closing will be either all port injection or a combination of direct and port. My guess from the design it can go up to 12:1 compression with direct injection, allowing for lower rpm and friction when more power is called for. Torque is 133 lb-ft @4400 rpm for the 2L hybrid engine versus 105 lb-ft @3600 rpm for the current 1.8L prius engine. That gives the 2L 111 hp @4400 versus the current prius 1.8 of 95 hp @ 5200 rpm and the new engine goes to 11 (hp builds to 143@6000 rpm allowing more power if you are willing to get in less efficient range of the engine). The only downside is more expense the place where the 2L is less efficient than the 1.8 is at very low power levels that can simply be eliminated by storing excess power in the battery.

2.0-liter Dynamic Force Engine, a New 2.0-liter Direct-injection, Inline 4-cylinder Gasoline Engine | TOYOTA Global Newsroom

IMHO when the new 2.5 and mgr gets in the rav4 hybrid the prius v will be forgotten in north america.

 

I suspect the Prius v will maintain a >10 mpg advantage over RAV4 hybrid, improved crossover styling, made in Japan, and possibly plugin option. Certainly the RAV4 hybrid will sell better in US given current preferences. I would be interested if it can approach 40 mpg avg..

 

Prius v has been discontinued in the US for the 2018 model year. The prius v is being sold in Canada, and the prius alpha is being sold in Japan. There are rumors that something more CUV than prius wagon may be coming in the 2019 model year. I have no idea what this thing will be called or if it will be sold in the US. Rav4 and Rav4 hybrid will be redesigned for the 2019 model Year.

 

I assumed this discussion was about upcoming models using said new powertrains. These models are testing in camouflage and Toyota typically keeps models names, but who knows the bigger Prius could change to a new letter.

 

Oh yeah sorry, you are quite right. Some people want to keep the v as it is, a very efficient prius wagon, but neither I nor toyota think that is what the market wants. I'd say there is only a 60% chance that those test mules will make it to a car sold in america, but they are quite different than the v. If they build it I hope its a phev/hv only with no traditional transmission available. The success of the prime should point to a plug-in option. Just for a little crazy talk, a 3 cylinder 1.5L version might be the right thing for a plug-in ;-) Toyota stated going smaller in capacity per cylinder makes the di portion not work as well, so that would be a way to downsize this technology in terms of cost and weight but not hurt efficiency or power. Chevy and honda both have 1.5L in there phevs, and its probably the right size, but a 3 cylinder version of this engine would be more efficient and less expensive to produce.

I hope it comes here and is a cool car no matter what it is called.

 

New Auris:

2.0 Hybrid is rated at 180 HP, NiMH battery, there will also be steering wheel-mounted paddles.

Lexus UX 250h:
World Debut of the Lexus UX, a New Genre of Crossover | LEXUS | TOYOTA Global Newsroom

2.0 Hybrid with 178 DIN hp/131kW, NiMH battery, E-Four up to 70 kmh, Predictive State of Charge Control, Lexus Safety System + with Lane Tracing Assist.