Kia Niro Forum banner

1 - 9 of 9 Posts

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #1 (Edited)
I'm a recent owner of the Niro PHEV and would like to understand how all drivetrain components work together. I came across a very nice explanation for the Optima Hybrid:

Does anyone know of a similar reference to the Niro? One thing that surprised me is that the ICE seems to power the wheels through the motor. Wonder if this is true for the Niro? I have graphed speed and RPM for motor, engine, and HSG and yes, there are periods during which motor and engine RPMs ovrlap.
EV-Hybrid.PNG
 

·
Registered
Joined
·
2,842 Posts
Engine>engine clutch>motor>DCT>wheels is how the drivetrain is connected. You can look at the energy flow diagram on your dash or infotainment screen to see what is working in real time. The motor and engine can work in parallel to create torque and forward momentum, or on their own (but the motor is always turning - not necessarily adding torque or charging the battery).
 

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #3
Engine>engine clutch>motor>DCT>wheels is how the drivetrain is connected. You can look at the energy flow diagram on your dash or infotainment screen to see what is working in real time. The motor and engine can work in parallel to create torque and forward momentum, or on their own (but the motor is always turning - not necessarily adding torque or charging the battery).
Thanks. Yes, it's evident that when engine is running and clutch is engaged the motor is turning at the same speed. Very interesting! I guess at least that part matches the schematic of the article I referenced. For additional, information I've added state of charge (SOC) to the graph. One can see that once it transitions from EV to Hybrid, the SOC varies from around 17-20%. I would still be very interested in a similar article for the Niro esp if it included the plug-in option.
EV-Hybrid2.PNG
 

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #4 (Edited)
I analyzed another trip which took place entirely in Hybrid mode. I graphed the portion of the trip while in cruise control at 70 mph. One can see that for the majority of time the car was powered by the engine with relatively short periods in which the engine turned off and the car ran on EV only. During engine operation, the SOC increased (due to charging by HSG) and while in EV only, the SOC dropped. During the course of the trip, the SOC varied from 16.5% to 20.5%.
HybridRPM.PNG
 

·
Registered
Joined
·
2,842 Posts
One can see that for the majority of time the car was powered by the engine with relatively short periods in which the engine turned off and the car ran on EV only.
You know of course this is not an either/or scenario. Much of the time the engine is on, the motor is adding torque. Easily visible on the flow schematic on your dash or large screen. When the motor is not adding torque, the HSG is charging the traction battery.

In fact, here is a small puzzle that you may be able to see in your OBD info: Is the HSG charging at all times while the engine is on? My bet is that it is. Obviously, there needs to be the ability to stop the HSG charging in the case the traction battery is saturated but it seems simpler otherwise just to have it charging at all times. Kind of doubt your info covers the HSG, but seems like there would be a PID for it.
 

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #6 (Edited)
You know of course this is not an either/or scenario. Much of the time the engine is on, the motor is adding torque. Easily visible on the flow schematic on your dash or large screen. When the motor is not adding torque, the HSG is charging the traction battery.

In fact, here is a small puzzle that you may be able to see in your OBD info: Is the HSG charging at all times while the engine is on? My bet is that it is. Obviously, there needs to be the ability to stop the HSG charging in the case the traction battery is saturated but it seems simpler otherwise just to have it charging at all times. Kind of doubt your info covers the HSG, but seems like there would be a PID for it.
Thanks for the response. As you can see in the graph, I also display HSG RPM. So does that show charging or can the HSG be turning without charging? I've now added motor current to the graph which does, indeed, show motor torque in combination with engine operation.
HybridRPM2.PNG
 

·
Registered
Joined
·
2,842 Posts
HSG is turning whenever the engine is on, but not necessarily charging.
 

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #8 (Edited)
HSG is turning whenever the engine is on, but not necessarily charging.
Thanks. Actually in the previous graph there was an error. The variable displayed as motor current was actually battery current. Also I need to allow graph to display negative values which indicate battery charging. Now as shown in the corrected graph you can see that when the engine is off, battery current goes positive indicating a discharge which I assume indicates motor torque, but while the engine is on, the current is often negative indicating a charge. There are also positive spikes while engine is running which indicate discharge which might also indicate motor torque. Things are confused by the fact that we also have auxiliary power requirements such as the draw by AC. Unfortunately I cannot find any variable which indicates motor torque directly.
HybridRPM3.PNG
 

·
Registered
2020 Niro PHEV LXS
Joined
·
75 Posts
Discussion Starter #9
Anyone know of article describing the Niro's drivetrain? The best I could find is one describing Optima Hybrid drivetrain as referenced above.
 
1 - 9 of 9 Posts
Top