MPG in Hybrid Mode

Yap, that sums up the perceived differences you see on battery charge level when you have EV SOC vs 0%. And I have shown with a little tweak by using more gas, you can regain the deficit when you drive HV with EV SOC remaining.

 

I'm glad to hear that we both came to similar conclusion. I really didn't think model year difference would change the underlying ECU control over something like battery use management. Still, losing 7% of SOC is somewhat more than I usually see on my trips, but that could be attributed to the use of AC.

 

"EV drive mode" in this case is not the same thing as EV MODE you switch between EV/HV. When you see the "EV icon" lit in HSI, all the energy for the traction is coming from the battery, and ICE is off. This is true either you are in EV MODE or HV MODE. However, there may be some instances when the battery is providing 100% of traction and ICE stays on, in which case "EV icon" in the HSI is unlit. One instance I don't remember about the "EV icon" in the HSI being lit or unlit is when the temp outside is below 14F and ICE is forced on for use in heating. I think for this instance even though you have plenty of SOC left and you are on EV MODE, the ICE stays on and "EV icon" in the HSI is unlit, IIRC. As long as the ambient temp is above 14F, the traction battery SOC provides energy for the heat pump, this is true either you are on HV MODE with or without "EV icon" in HSI lit, or you are on EV MODE.

 

I look at it this way, and I think @Salamander_King does, too. The EV light on the HSI tells you if the ICE is running. If it's off, ICE is running, no matter why it's running. If it's on, ICE is not running, no matter why it's not running.

The EV light on the main display tells you what driving mode you have selected. If it's off, it's reminding you that you have chosen HV mode. The ICE may or may not be running depending on the car's decision at the moment as to which is more efficient. If the EV light on the main display is on, it just means you have chosen EV. The ICE might need to run for heat if it's too cold for the heat pump or you turned on the defroster. At least that's what I expect; I've not yet been in weather that cold.

I won't say much about EV auto since I never use it, but it should work the same as EV I would think.

 

Again, if the EV light on the HSI is not lit, the engine is running. Period. Always.

Right. If you are in HV mode, whether you chose it with a button or lack of remaining EV range forced it, he HSI indicator light tells you if the ICE is running or not.

HSI EV light is an ICE on/off indicator. Main display EV light is an operating mode indicator. It's just that simple.

 

Jerry's statement is ALMOST always true. If you keep the HSI on the MID and Energy Info on the large screen simultaneously, you will see whenever the ICE is fired up with "orange" glow, the "EV icon" in HSI is unlit. However, I have seen from time to time there is a short period of lag for this icon changing. During this lag period, you might see engine ON but EV light lit, or engine OFF but EV light unlit. I could not take a picture today, but I will try tomorrow again to show you what I mean. And, yes, you can have both ICE and Moter working at the same time. This happens all the time when you are on HV.

 

True! There's sometimes about a second or so of lag in the HSI EV indicator. That lag is also detectable if the main display is showing the current mpg indicator. But then, any of the indicators might be sluggish in updating, so it's hard or impossible to know which, is any, is exactly correct at any given instant. But it's close enough.

And, as SK said, when in HV mode, the MGs are constantly fluctuating in speed and torque.

 

Here is a pic I took this morning. ICE is OFF, I am in EV mode running 100% from battery. The battery is in regen charging. However, EV icon is not lit. You can have similar instance in HV mode as well. I did not have an opportunity to take a pic, but you can also see EV icon ON and ICE ON moment briefly too.

 

I had a pic of HV MODE, EV OFF, ICE OFF instance. Out of focus, but you can see my points.

 

The flow of the "light" between the traction battery and the motor can occur in both directions. Yellow light is energy going out from the battery to the motor (traction). Green light is energy going into the battery from the motor (regeneration).

 

Reverse the polarity and current flows in the opposite direction while the device continues to spin in the same direction. Power flow to the battery can originate at the ICE or the front wheels.

 

"MG" stands for "motor/generator." The Prius transaxle has two of them.

Have you watched Professor John Kelly's videos on the Prius? Here's a quick look at the Prime's transaxle. Totally amazing!

 

I am no expert in Prius mechanics, but as explained above, my understanding is motor/generator (MG1 and MG2) are dual purpose. Please don't ask me how they work! I just drive the car and I know they work. I will leave the technical discussion to someone more knowledgeable.

 

None more so than Professor Kelly.

Let’s see if we can get another 160 posts on the topic .