Gen2 weird HVB current consumption...

Hi guys,

I drive Priuses more than 7 years and now i have 2008 Gen2 prius.
Also I have good knowlegde how Prius operates and have Torque app on my tablet PC with custom PIDs.
During years I has studied all Torque parameters, which value parameter could have, etc.
But couple weeks ago my car had confound me. Please look at screenshots.
Car is fully warmed, idle check done. Car is stay in parking mode, climate system fully off.

At this time HVB gives about 1.1Amp for DC-DC converter, lights, ECUs etc. AFAIK, it's normal current.
When I press accelerator pedal, ICE starts up and goes to consume the gas. It obvious because injection time increases to 1.8msec,
and temperature of O2 sensor increases as well.
But whatever HVB gives 4.4Amp of current. I'm talking not about start-up time then MG1 spin-up the ICE. ICE is already rotates using gas burning energy.
3.3Amp current increasing means that HVB gives about 800 watts of energy. But who "eats" this energy??
As I can calculate, the ICE electrical consumption about 250Watts (throttle body, injectors, spark plugs, gas pump, sensors, ECUs, etc.). But 500-600Watts goes to nowhere.

Maybe you have some ideas where 600watts goes? Maybe there is the thread with similar topic but i can't find it through searching.

Thanks!

 

dorunron, thanks for your reply.

Zero MG2 rpm means that car is stay on the place.
When ECU want to rotate any MG, it could apply current to the windings and we can see non-zero torque value in the application. But both MG's torques equals zero. So I doubt that ECU want to rotate MG1 using HV battery.

 

Sorry guys, I forgot to say that ICE torque PID is wrong. System gives calculated ICE torque, but it don't match with reality. As I remember, at full acceleration it can show up to 200Nm, but it impossible, because max torque of ICE about 115Nm.
In my calculations I always use simple equation: Torque(ICE)=3.6*Torque(MG1). It always true due to HSD construction.
The Torque application also has wrong PIDs, for exaple, MG1&MG2 inverter temperature never shows less than 15 degrees, even in -30 C outside. I think it either car ECU bug or Torque app bug.

 

Refresh rate about 2-3 times per second.
Of course, Prius can warm ICE, but in shots ICE temperature is 88 C. ICE is fully warmed. Shots was made after 1 hour suburban trip, so catalytic converter was heated enough.

 

Of course, ICE can be spinned by MG1. But in this case application must show torque of MG1. When MG1 spin up the ICE, it torque can be over 20Nm short time. But after start it goes to zero in this case. If you doubt in my words, later I can prepare graph picture with 10-20 second time period instead one shot.
From my point of view zero torque means that neither MG1 applies torque to ICE, nor ICE applies torque to MG1.
Also, when ICE spins, injection time increases, ignition timing advance increases, O2 sensor temperature increases as well. From my point of view this parameters tells me that ICE spins using burned fuel energy. As for me, it's illogical to use both electricity and gas for ICE rotating. Maybe you have info regarding this special mode but I haven't.

 

Thanks a lot, uart,

due to your great idea power "eater" has been catched.
The only difference is the purpose: I'm sure that the main reason not rapid torque response (because the speed of electrical signals much more faster than mechanical moving), but eliminating high back-EMF voltage for good HSD operating.

Why this guess? Firstly, the typical 3-phase inverter looks like this:

Each IGBT has diode for voltage spikes clamping. Spikes usually generates by inductive load (motor windings has noticable inductance). You could notice that if even all IGBTs are closed,6 diodes operates like 3-phase rectifier. This means if motor rotates fast enough, it becomes a powerful generator if even we don't like it.

According to ORNL report, MG1 has significant back-EMF and 5344 rpm MG1 means about 265V of DC link voltage. But if you'll check first post attachment, boosted voltage has only 237V. Why?

I'm sure that HV ECU controls IGBT gates and creates opposite magnetic field to decrease back-EMF voltage to ensure for good HSD control. According to uart idea the offset between rotor magnet field and stator coil field is zero, so no torque produced by MG1.

One more screenshot:

If we need charge the battery, MG1 generates voltage strongly according to ORNL data graph. In this mode ECU stops generate anti-back EMF field and uses all generated voltage.