Hybrid vs EV mode

Yes, the "target" in regular hybrid mode is something like 60% charge. But even once it's there, you'll see energy flowing to the battery in the display the entire time you are at a steady speed on level ground despite the fact that the battery state of charge never increases beyond the target.

 

Oh so you're specifying beyond maximum (60%) charge. Prior to that point the ICE does charge the battery, and I think that was the question Pizza driver was asking.

 

In the Prime, that point will be below where Ev mode will work. It will be at 15% or something - 15% of a far larger battery, but still once Ev mode is depleted. The only ways to get back into Ev mode will be CHG mode, descending a big hill or plugging in. Driving an unlimited distance in normal conditions in Hv mode won't get you back to Ev mode levels of charge.

 

The LB first priority (engine warm) is to stay in EV if conditions allow (stop and go is an example) but when Battery SOC drops to the minimum allowed the engine starts to charge it partially.
The second priority (EV is not possible) is that the SOC will stay at ~60-65% any drop from this level (like in acceleration) will be followed by charging the battery back to this level. Any increase from this (like in driving downhill) will follow by using the extra charge by the motor back to this level.
This is all for protecting the battery.
PiP, in HV mode, once EV is depleted, behaves the same, only in a SOC window of about 16-26% of the bigger battery. You cannot go back to EV miles unless you have a very long regeneration opportunity.

 

If CHG mode runs the engine even when decelerating when ICE should be at 0 rpm then IMO that's just stupid engineering.

 

Do you mean that you only have a 1-car garage currently? Or no garage at all? In the former case, why not give this car the highest priority?

 

Deja vu Remember this thread? Prius PHV: Optimization strategy with lessons learned from the prototypes | PriusChat

Still looking for my posts back then about wanting a "charge button" or was it forced regen or ?

 

Maybe because he has a Leaf in the garage

 

I have no doubt that high priority of best use for the gas engine continued. Prius isn't going to sacrifice overall efficiency simply for the sake of offering more EV... unlike what others have done.

The approach is to seek out a balance, despite the wide variety of uses it must fulfill.

The expectation is that we'll see outstanding performance from charge-mode in some cases (like highway cruising), where we'll promote the use. In others, we'll discourage. But even when it's not as good of a return, it will still be clearly better than what a traditional vehicle offers.

It is interesting reading those old posts. That serves as a great remember of what market expectations were and how they've changed since.

 

Fair enough. I've heard enough about HOAs to avoid them for any of my homes.

Or just the wife's, whatever it maybe.

 

No, that would be getting something for nothing. If you are charging the Ev battery, that energy is coming from the engine and being ultimately converted from the thermal energy in the gasoline. As Danny said, switching to charge mode reduces current measured mileage obviously by increasing the power output of the engine (and thus its fuel consumption) with the extra power being converted to electricity by the generator (MG1) and sent to the battery.

 

Gave some more thought to this.

There is 33.4kWh of energy in a gallon of gasoline. For 20 miles on EV, the Prime needs 5.01kWH. That's based from the 133mpge figure, which includes charging losses from the wall.

At 40% thermal efficiency, the engine needs to burn 12.525kWh of gas, or 37.5% of a gallon, which means it is a little worse than just burning the gas in hybrid mode.

This is a YMMV number since when Charge mode is entered may put the ICE at its most efficient, or knock it out of it. Then the charging loss is assumed to be the same as for charging from the wall, and MPGe does not account for production losses, so I think the chances that the loss between the ICE and battery is worse than wall charging is greater. Finally, this ignores the negative impact Charge mode has on hybrid efficiency.

The energy monitor isn't showing you everything, and what it does show is an approximation.
You don't see the energy taken to run accessories like the lights, radio, and air conditioner. The arrows from the MG1 don't show how much energy is coming from it; modulating that is how the system varies the gear ratios.

Then the battery monitor is just a percent charge reading for an @1.5kWh amount. The Primes usable capacity is at least 5 times this. Some slow steady growth of the SOC seen on your display would barely budge the Prime's display.

A portion of the ICE's torque is always going to MG1. Ideally, any electricity it makes will go directly to MG2. The power demand of highway cruising is too low for this, and losses of storing this electricity in the battery is acceptable. Up to a up point. When possible, the system takes energy out of the battery to run MG2, and cut fuel to the ICE. This is a counter to the gasoline energy lost charging the battery, and keeps overall efficiency high.

To charge up a battery in the Prime while cruising requires skipping those ICE off, MG2 operation periods, and thus reduced overall efficiency.

 

The arrows on the monitor are "binary icons" in the sense that they are either on or off, when an arrow is on - you cannot tell if it is 10mA that initiate it or 10A... you cannot make a magnitude decisions out of them.

 

And that generated electricity is going to the other motor - MG2 - to help propel the car.

 

And in that "mostly" mode, once the battery is at the target level, that flow is only there as make-up current to cover the electricity being drawn by the accessories. If the battery state of charge isn't changing, then no net electricity is flowing to the battery.

 

From memory:
the route: MG1 - MG2 - Wheels (without occasional battery "help") is not shown on the monitor at all, correct me if I am wrong.