Sign in to follow this  
FROSTYBALLS

New Yaris hybrid powertrain

Recommended Posts

Nice work by Toyota, more compact CVT gear train with higher speed EV mode, the latest Atkinson motor and over 30% more power from the electric motor which should give excellent performance from standstill. From the pictures the Battery looks like it is around 0.75kWh with probably 48 3.7 volt cells. Check out the Lithium Battery used in a non-plugin US Prius as a comparison:

https://voltaplex.com/learn/prius-2017-lithium-ion-battery-teardown/

If the car is able to do more miles in EV mode, the lithium Battery is probably used harder and deeper as the old Battery had more kWh, (0.9 but seemed to use just the 'middle' 25%) and only did around 1 mile.

Also, the cat position looks unsteal-able!

  • Like 1

Share this post


Link to post
Share on other sites

Im intrested how will E fours rear motor work is it motor/generator like forward MG1 and MG2 or is it just a motor. If former it will be awsome becouse it will charge Battery faster during braking so more EV time😁  

Share this post


Link to post
Share on other sites

Atkinson cycle?

The hybrid system features Toyota’s new 1.5-litre three-cylinder Atkinson cycle petrol engine

Is that what they're saying?

As far as I'm aware, the AC needs a strange hinged crankshaft.  Toyota don't make an Atkinson engine but use an Otto system that SIMULATES an Atkinson engine.
.......... or am I wrong?

Mick.

 

 

Share this post


Link to post
Share on other sites

you are right Toyota does not have Atkinson engine.

About Toyotas Atkinson cycle:

Quote

the Atkinson cycle engine itself was also designed specifically to minimize engine drag via an offset crankshaft to minimize piston drag during the power stroke, and a unique intake system to prevent drag caused by manifold vacuum ("pumping losses") versus the normal Otto cycle in most engines. Furthermore, the Atkinson cycle recovers more energy per cycle than the Otto because of its longer power stroke. The downside of the Atkinson cycle is much reduced torque, particularly at low speed; but the HSD has enormous low-speed torque available from MG2.

 

Share this post


Link to post
Share on other sites

So they are stretching the truth in their statement?

How can they say that they have a new Atkinson engine ............................. when they patently do not?

Yes, it might be a new 3cyl engine, but not Atkinson.

Mick.

Share this post


Link to post
Share on other sites
31 minutes ago, Mick F said:

So they are stretching the truth in their statement?

How can they say that they have a new Atkinson engine ............................. when they patently do not?

Yes, it might be a new 3cyl engine, but not Atkinson.

Mick.

not really they call them Atkison cycle petrol engine but new Yaris will have new engine for Hybrid version

Share this post


Link to post
Share on other sites

This is what I found with a search..... first hit is this video from Toyota.

Share this post


Link to post
Share on other sites

So ...................

I still maintain they're stretching the truth.

The Toyota system is a Simulated Atkinson Cycle.  You cannot switch from Atkinson to Otto because Otto is on a fixed-throw crank shaft.  The mere fact that they can change the valve timing doesn't make it an Atkinson Cycle engine .......... it's still Otto Cycle engine.  Other manufacturers call it VVT ........ variable valve timing?

Atkinson Cycle engines have a hinged multi-piece crankshaft, so the stokes have different lengths - unlike Otto Cycle engines which have a fixed one-piece crankshaft.

https://en.wikipedia.org/wiki/Atkinson_cycle#/media/File:Atkinson_Engine_with_Intake.gif

Maybe I'm being pedantic?

Mick.

  • Like 1

Share this post


Link to post
Share on other sites

I quote  ...........................now feature engines with variable valve timing, which can run in the Atkinson cycle as a part-time operating regimen, giving good economy while running in Atkinson cycle, and conventional power density when running as a conventional, Otto cycle engine.

Can't do Atkinson, but Simulated Atkinson using variable valve timing.

 

Mick.

Share this post


Link to post
Share on other sites
Quote

What has been confirmed is that the Yaris hybrid can switch to electric-only mode at speeds of up to 80mph – far higher than previously.

I wonder if this is even worth it at such speed Battery will be drained fast

  • Like 1

Share this post


Link to post
Share on other sites

Maybe for downhill segments?

I was in Cornwall recently on holiday and more than a couple of times maxed out the Battery, but too fast for it to stop using the engine.

Share this post


Link to post
Share on other sites
On 10/31/2019 at 1:06 AM, YarisHybrid2016 said:

I was in Cornwall recently on holiday and more than a couple of times maxed out the battery, but too fast for it to stop using the engine.

We come down the Cornish hills and usually max out the Battery.  I must check on the screen to see if the engine is running, or maybe check if the EV light is out.

Coming down from Devon to cross over to Cornwall s few miles of constant downhill.  I'll check next time.

Mick.

  • Like 1

Share this post


Link to post
Share on other sites

Just remembered about this.

Coming down the long hill near here, the car does just over 50mph (indicated) with your foot completely off the throttle.

From about 30mph at the top of the hill, it slowly increases speed.  I had the screen on showing the engine/battery power flows and kept an eye on the EV light.

Just over 40mph, the EV light went out, but the engine wasn't running.  The power flow was green (charging) all the time and no pink showing at all.

Seems strange that when you're in EV mode, the EV light isn't lit at much above 40mph.  Why is it like that?

Mick.

Share this post


Link to post
Share on other sites

The engine has to rotate when the electric motor (MG1) reaches a certain rpm - this is a characteristic of the hybrid's CVT design. More info here: Power Split Device animation but you need Adobe Flash to view the animation. As mentioned on the website "Rotation speeds of MG1, MG2, and ICE are inter-dependent, and the speed of MG1 will always change when you vary the speed of either of the other 2. MG1 has a maximum rate of 10,000rpm in either direction (positive or negative) with a software limit of 6500 RPM if ICE is off. Using the model below, you can see for yourself why this software limit means the ICE will always spin if you're travelling above 42mph. And in case you were curious, yes MG1 can and often does change spin directions under normal driving conditions".

Note that newer generations of PSD have differing rpm limits and speeds, but the theory is similar.

 

  • Like 1

Share this post


Link to post
Share on other sites

Thanks.

Hence the EV light off but no pink power flow to the wheels.  Still in EV though the engine is turning but not powering the car ................ sort of like in B mode?

Mick.

Share this post


Link to post
Share on other sites

I would imagine that it is powered so appropriate rpms are reached, but no real power added to the system.

Share this post


Link to post
Share on other sites

I think the engine is spun by MG1 (the car knows it's generating power from coasting so this cost is "free"). AFAIK no fuel is injected (FF meter reads 99.9).

Share this post


Link to post
Share on other sites

That's right, a benefit of fuel injection is that on overrun (off throttle) no fuel can be pumped into the engine.  It's different to B mode in that the valve timing will be varied to minimise pumping to the benefit of regen braking, wheres in B mode pumping action in active to assist in controlling speed.  This mean less energy is available for regeneration, which is why B mode is good for control but not economy, except on rare occasions when the HV Battery is truly maxed out.

I've heard it said that 3rd Gen Hybrids (2009 onwards) automatically select B mode when off throttle once the HV is maxed, but I've not seen definitive confirmation of this.

Share this post


Link to post
Share on other sites
1 hour ago, YarisHybrid2016 said:

I think the engine is spun by MG1 (the car knows it's generating power from coasting so this cost is "free"). AFAIK no fuel is injected (FF meter reads 99.9).

No, I think the engine is powered by petrol to get to certain revs. as this allows the MG1 rotation to be kept below the limits set by Toyota (6500 rpm software limit) - there would be little power used and so mpg is easily over 100.

Share this post


Link to post
Share on other sites

The new Yaris Hybrid petrol engine will be M15A-FXE that 14.0:1 compression ratio is achieving 41% combustion efficiency. 90HP and 120Nm torque. 

Electric motor will be 79HP and 141Nm instant torque.

WLTC consumption is 2.8L/100km.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this