[FKHeath]

This post is in response to comments by meeder, Primestraw and wscan. I am trying to understand comments about MG1 and its relation to the eCVT. I appreciate all comments on this thread. As I mentioned at the start, I am still in the learning stages and there is a lot I don’t know.

From the Toyota tech manual: “Electric Generator, MG1, which is driven by the engine, generates high voltage electricity in order to operate MG2 (not sure why it is not mentioning MGR here) and charge the HV battery. Also, it functions as a starter to start the engine.”

The part I don’t understand is multiple statements in this thread that MG1 “controls the eCVT”. That implies this MG1 650V AC Motor/Generator has some kinds of smarts (control system) that adjusts the transmission gear ratios. I would expect the Electronic Control Unit (ECU) controls eCVT operations. Is the eCVT even used in EV only operations? (I thought the eCVT was only used to adjust gearing for the Internal Combustion Engine (ICE).) Would appreciate any additional comments explaining how the eCVT is used in the Prime and how it relates to EV only operations.

On a different subject, the mention of MG1 “as a starter to start the engine.” is very interesting. I had wondered if there was a standard “starter” for this car’s ICE like the ones we grew up with. Over the years I’ve replaced two starters which of course are just 12V DC motors. The MG1 Electric Generator is first and for most a 650V AC generator driven by the ICE to charge the Hybrid Vehicle Battery Pack during Hybrid operations. During electric only EV operations it is idle (disengaged from ICE). When the car’s operational computer (ECU) determines the ICE needs to turn on, it orders MG1 to turn on as a motor which starts the ICE. So this means the ICE is physically started by the car’s 355V DC ecosystem. This also means you don’t need heavy thick low gauge jump cables to do a high DC current “jump start” the ICE. Worst case if the 12 DC battery were to totally fail, hooking up to another 12V battery using jump cables can then power up the car’s 12 DC ecosystem where the smarts are to power up the EV systems and get the ICE going if necessary. (I took a look at the owner’s manual. On page 539, it covers “If the 12 volt battery is discharged”. It uses the term “jump start”. Which technically it is. It is just not the conventional high current jump start we know from past ICE engines. It does mention the purpose of this jump start is to “recharge” the battery.)

Please correct any comments I made about MG1 as the ICE starter that I made above. Thanks.

This video gives a good description of the two motor/ generators in the RAV4 hybrid transaxle and how they are used to move the car, start the ICE, and regenerated power for the battery:
Understanding the Toyota RAV4 Hybrid - YouTube

 

[meeder]

Are we sure that MG1 never adds power? I would think that in EV mode MG1 and 2 could both be putting energy into the wheel. It wouldn’t make sense for MG1 to not be involved. I don’t have time to go back through the Weber videos to study though. I get it that it has to be a generator in HV mode but it would just be a spinning lump of rotational mass in EV mode- why wouldn’t it be working?

It can do that if they have the sprag clutch fitted which some versions like the Prius Prime have.
The RAV4 Prime supposedly doesn't have that and instead uses the rear motor to add additional force to the wheels.

Without the sprag clutch MG1 would when adding torque cause the ICE to spin (that's how a planetary gearset works).

Here is a good explanation:

 

[SoNic67]

To power the car in EV mode, the 355 DC battery voltage goes to an inverter/converter to be converted to 650 volts DC. Then this 650v DC inverted to 3-phase 650 volt AC to power the motors.

I didn't don't see any DC-DC converter. Just from 355 Vdc to 650 Vac three phase.

 

[meeder]

There is a boost converter which converts the battery voltage to a maximum of 650V DC which is then fed into the, in effect, VFD to drive the motor.

It's a buck/boost converter which also steps down the generated voltage to the battery voltage.

It's shown here from the 33:40 mark:

 

[wscan]

This video gives a good description of the two motor/ generators in the RAV4 hybrid transaxle and how they are used to move the car, start the ICE, and regenerated power for the battery:
Understanding the Toyota RAV4 Hybrid - YouTube

The only difference between the transaxle described here and the prime transaxle (p810) is the prime transaxle is slightly larger. The prime transaxle is also shared with the Sienna Hybrid.

 

[dkaplan]

In case you get bored thinking about the hybrid drive system in the RAV4 Prime, here’s some information about the heat pump system which manages both cabin and battery temperatures: RAV4 Prime HVAC Explained

 

[RAV4_ON]

I’ve owned a RAV4 Prime now for nine months and I thought I had a pretty good understanding of how it works (I was wrong). I was doing some on line research trying to understand AC to DC conversion efficiencies. I was trying to find out what kind of Power Factor Converter (PFC) is used in the RAV4 Prime EV Charger Assembly. I actually have not been able to find out. But as I have been looking, I ran across this Toyota Service Manual titled RAV4 Prime Hybrid Vehicle Dismantling Manual. The purpose of this manual is to provide guidance “to educate and assist dismantlers in the safe handling of Toyota RAV4 PRIME”. In other words, if a RAV4 Prime is totaled in a crash, this manual provides guidance to technicians to safely dismantle handle high voltage components.

The manual is found at the following link https://www.toyota-tech.eu/HYBRID/HVDM/EN/hvdm RAV PHV.pdf

I found the first 13 pages (the “educate” section) to be a fascinating summary of how the RAV4 Prime works. Main points I learned are:

• The HV battery pack consists of 96 low voltage (3.7 Volts) Li-ion battery cells connected in series to produce approximately 355.2 Volts DC.
• To power the car in EV mode, the 355 DC battery voltage goes to an inverter/converter to be converted to 650 volts DC. Then this 650v DC inverted to 3-phase 650 volt AC to power the motors.
• The two electric motor/generators (one front and one rear) power the car with 650V 3-phase AC power. (The "generator" part is the Regenerative Braking. When you take your foot off the accelerator, the car coasting still turns the motor which allows it to be a generator which recharges the battery. This generator mode provides resistance which slows the car down.)
• The cars electric generator is a 650v three phase AC generator. This generator powers the electric motors or charges the battery through the Inverter/Converter.
• There is a 350v DC to 14v DC converter to drive the drive the cars 12v DC electrical systems and change rear 12v battery.
• The cars Air Conditioning runs using a 355V DC compressor.

I attached a picture of the main drawing that shows the RAV4 Prime High Voltage System. The “Inverter/Converter” in the blue box is the focal point of what makes the EV part of this car work.
View attachment 185088

You learn something new every day.

Great find! Thanks for sharing. Read some of the text - sure are a good deal of warnings!
Reading through and seeing the diagrams - let us pray we never need a major service of any significant kind. Unlikely the local service shop, dealer or otherwise, is qualified to service this complex machine. No disrespect to our mechanics yet the inner workings of this masterpiece of engineering is not going to be well understood after a 2 day training seminar. The other thought I had reading through the 30+ pages is there are quite a few electrified components under us.
Thankfully the Flux Capacitor is onboard.

Again, thanks for sharing.

 

[TZX4]

So MG1 was only ever used in the Prius Prime to drive the vehicle.

I believe MG2 is the larger motor generator and it is the only motor in the vehicle that is directly mechanically geared to the drive wheels. (the rear motor is direct drive too on AWD RAV4h and Prius AWD)
I don't know about the RAV4prime system but I do know that the Prius prime combines both MG1 and MG2 to drive the wheels due to an additional part that allows MG1 to mechanically lock in someway I can't recall exactly.

Edit . . I was scrolling down the thread and somebody wrote up the sprag clutch, that's it !

 

[Chrisa741]

I’ve owned a RAV4 Prime now for nine months and I thought I had a pretty good understanding of how it works (I was wrong). I was doing some on line research trying to understand AC to DC conversion efficiencies. I was trying to find out what kind of Power Factor Converter (PFC) is used in the RAV4 Prime EV Charger Assembly. I actually have not been able to find out. But as I have been looking, I ran across this Toyota Service Manual titled RAV4 Prime Hybrid Vehicle Dismantling Manual. The purpose of this manual is to provide guidance “to educate and assist dismantlers in the safe handling of Toyota RAV4 PRIME”. In other words, if a RAV4 Prime is totaled in a crash, this manual provides guidance to technicians to safely dismantle handle high voltage components.

The manual is found at the following link https://www.toyota-tech.eu/HYBRID/HVDM/EN/hvdm RAV PHV.pdf

I found the first 13 pages (the “educate” section) to be a fascinating summary of how the RAV4 Prime works. Main points I learned are:

• The HV battery pack consists of 96 low voltage (3.7 Volts) Li-ion battery cells connected in series to produce approximately 355.2 Volts DC.
• To power the car in EV mode, the 355 DC battery voltage goes to an inverter/converter to be converted to 650 volts DC. Then this 650v DC inverted to 3-phase 650 volt AC to power the motors.
• The two electric motor/generators (one front and one rear) power the car with 650V 3-phase AC power. (The "generator" part is the Regenerative Braking. When you take your foot off the accelerator, the car coasting still turns the motor which allows it to be a generator which recharges the battery. This generator mode provides resistance which slows the car down.)
• The cars electric generator is a 650v three phase AC generator. This generator powers the electric motors or charges the battery through the Inverter/Converter.
• There is a 350v DC to 14v DC converter to drive the drive the cars 12v DC electrical systems and change rear 12v battery.
• The cars Air Conditioning runs using a 355V DC compressor.

I attached a picture of the main drawing that shows the RAV4 Prime High Voltage System. The “Inverter/Converter” in the blue box is the focal point of what makes the EV part of this car work.
View attachment 185088

You learn something new every day.

So to the layman, does this mean that to achieve full power for acceleration and efficiency, would I want to have the AC -OFF -, as in, if I wanted to sprint or race?

 

[Chazz8]

I don’t think you will/can notice the missing 2 kW (usually less) to power AC, but it is energy that could be used for locomotion. So turn off your AC when you are drag racing your R4P and every 1/1000 of a second counts.

 

[jdob28]

This post is in response to comments by meeder, Primestraw and wscan. I am trying to understand comments about MG1 and its relation to the eCVT. I appreciate all comments on this thread. As I mentioned at the start, I am still in the learning stages and there is a lot I don’t know.

From the Toyota tech manual: “Electric Generator, MG1, which is driven by the engine, generates high voltage electricity in order to operate MG2 (not sure why it is not mentioning MGR here) and charge the HV battery. Also, it functions as a starter to start the engine.”

The part I don’t understand is multiple statements in this thread that MG1 “controls the eCVT”. That implies this MG1 650V AC Motor/Generator has some kinds of smarts (control system) that adjusts the transmission gear ratios. I would expect the Electronic Control Unit (ECU) controls eCVT operations. Is the eCVT even used in EV only operations? (I thought the eCVT was only used to adjust gearing for the Internal Combustion Engine (ICE).) Would appreciate any additional comments explaining how the eCVT is used in the Prime and how it relates to EV only operations.

On a different subject, the mention of MG1 “as a starter to start the engine.” is very interesting. I had wondered if there was a standard “starter” for this car’s ICE like the ones we grew up with. Over the years I’ve replaced two starters which of course are just 12V DC motors. The MG1 Electric Generator is first and for most a 650V AC generator driven by the ICE to charge the Hybrid Vehicle Battery Pack during Hybrid operations. During electric only EV operations it is idle (disengaged from ICE). When the car’s operational computer (ECU) determines the ICE needs to turn on, it orders MG1 to turn on as a motor which starts the ICE. So this means the ICE is physically started by the car’s 355V DC ecosystem. This also means you don’t need heavy thick low gauge jump cables to do a high DC current “jump start” the ICE. Worst case if the 12 DC battery were to totally fail, hooking up to another 12V battery using jump cables can then power up the car’s 12 DC ecosystem where the smarts are to power up the EV systems and get the ICE going if necessary. (I took a look at the owner’s manual. On page 539, it covers “If the 12 volt battery is discharged”. It uses the term “jump start”. Which technically it is. It is just not the conventional high current jump start we know from past ICE engines. It does mention the purpose of this jump start is to “recharge” the battery.)

Please correct any comments I made about MG1 as the ICE starter that I made above. Thanks.

Here is a good video explaining how the transmission works:

 

[RAV4Primer]

This is a very timely thread because we've been discussing EV/HV hp in this thread. I'd greatly appreciate your expert insights on two topics:
1. Where does the Prime's 302 hp come from presuming the following info is accurate on this webpage?
"First is a 2.5-liter Dynamic Force four-cylinder engine with Sport, ECO, Normal, EV, HV, Auto EV/HV, Charge, and Trail modes. This engine produces up to 177 horsepower and 165 lb-ft of torque. Next, we have the electric motor which produces 179 horsepower and 199 lb-ft of torque in the front and 53 horsepower and 89 lb-ft in the rear. Together, the engine and electric motor have a horsepower of 302 hp."
2. What is the Prime's hp when EV has been exhausted (0 miles)?

Thanks!

 

[Widgets]

This is a very timely thread because we've been discussing EV/HV hp in this thread. I'd greatly appreciate your expert insights on two topics:
1. Where does the Prime's 302 hp come from presuming the following info is accurate on this webpage?
"First is a 2.5-liter Dynamic Force four-cylinder engine with Sport, ECO, Normal, EV, HV, Auto EV/HV, Charge, and Trail modes. This engine produces up to 177 horsepower and 165 lb-ft of torque. Next, we have the electric motor which produces 179 horsepower and 199 lb-ft of torque in the front and 53 horsepower and 89 lb-ft in the rear. Together, the engine and electric motor have a horsepower of 302 hp."
2. What is the Prime's hp when EV has been exhausted (0 miles)?

Thanks!

1. Torque is a curve that varies over the RPM range. The industry often quotes the maximum value. When you combine two motors, the curves are added. The max torque does not get added unless they both happen to be at the same RPM. It is best to combine something with max torque at low RPM and something with max torque at high RPM.

2. There is a lower charge limit for EV mode that allows for HV operation. In HV mode, the full power of the electric motors is available to assist when needed.

I believe both these points have already been discussed in the HP thread.

 

[greenginger56]

Can you tell me when i select the Charge option while driving does the power to recharge the batteries come from the onboard charger ...just like when you plug it in to a external source? Thank you for your insight! Kevin Smith 480 930 0355

 

[wscan]

Can you tell me when i select the Charge option while driving does the power to recharge the batteries come from the onboard charger ...just like when you plug it in to a external source? Thank you for your insight! Kevin Smith 480 930 0355

No. The power to charge the battery comes from MG1. This is the same as when the car is running normally in HV mode and excess energy from the ICE is directed to the battery. Charge mode just increases ICE rpm a bit to provide more energy to the battery and also keeps the ICE running all the time with energy directed to the battery when not needed for propulsion.

 

[greenginger56]

No. The power to charge the battery comes from MG1. This is the same as when the car is running normally in HV mode and excess energy from the ICE is directed to the battery. Charge mode just increases ICE rpm a bit to provide more energy to the battery and also keeps the ICE running all the time with energy directed to the battery when not needed for propulsion.

No. The power to charge the battery comes from MG1. This is the same as when the car is running normally in HV mode and excess energy from the ICE is directed to the battery. Charge mode just increases ICE rpm a bit to provide more energy to the battery and also keeps the ICE running all the time with energy directed to the battery when not needed for propulsion.

Thanks When i plug it in the the green light on the power cord flashing on and off. The green light on the plug in port remains steady on. I can hear the charger fan and charger starting up. Then it cycles on and off. Repeatedly. The tech is not skilled and has to report his finding to Toyota Canada for further investigation. After 4 appts and delays they are suggesting i replace the Charger sub assembly (4300$). The problem is if it doesn't fix the problem i still have to pay for the part!!! Any suggestions ? BTW out of warranty

 

[chuckles70]

Thanks When i plug it in the the green light on the power cord flashing on and off. The green light on the plug in port remains steady on. I can hear the charger fan and charger starting up. Then it cycles on and off. Repeatedly. The tech is not skilled and has to report his finding to Toyota Canada for further investigation. After 4 appts and delays they are suggesting i replace the Charger sub assembly (4300$). The problem is if it doesn't fix the problem i still have to pay for the part!!! Any suggestions ? BTW out of warranty

My understanding was Toyota Canada has an 8yr / 160k km warranty on the hybrid system which would likely include the onboard charger.
And have you eliminated the EVSE as the issue by trying to use an alternate EVSE (or public one)?

 

[greenginger56]

My understanding was Toyota Canada has an 8yr / 160k km warranty on the hybrid system which would likely include the onboard charger.
And have you eliminated the EVSE as the issue by trying to use an alternate EVSE (or public one)?

My auto has 161000 km! Nevertheless the charger is covered under the 5 yrs 100k not the considered hybrid related !!! ......I agree that was a surprise for me too. EVSE~Yes 3 different public one same issue.

 

[wscan]

Thanks When i plug it in the the green light on the power cord flashing on and off. The green light on the plug in port remains steady on. I can hear the charger fan and charger starting up. Then it cycles on and off. Repeatedly. The tech is not skilled and has to report his finding to Toyota Canada for further investigation. After 4 appts and delays they are suggesting i replace the Charger sub assembly (4300$). The problem is if it doesn't fix the problem i still have to pay for the part!!! Any suggestions ? BTW out of warranty

One thing I would do is look at the connector pins on the car where the EVSE plugs in. Has any dirt accumulated on the pins? If so, try cleaning with a Q-tip with alcohol.

Also, in the US, they have a support group at Toyota that is intended to help dealers diagnose difficult problems such as this. I imagine they have the same in Canada. Make sure that the dealer is working with them to figure out the problem. Sometimes it takes a bit for the dealer to contact their support because they do not want to appear like they do not know what to do.

 

[greenginger56]

One thing I would do is look at the connector pins on the car where the EVSE plugs in. Has any dirt accumulated on the pins? If so, try cleaning with a Q-tip with alcohol.

Also, in the US, they have a support group at Toyota that is intended to help dealers diagnose difficult problems such as this. I imagine they have the same in Canada. Make sure that the dealer is working with them to figure out the problem. Sometimes it takes a bit for the dealer to contact their support because they do not want to appear like they do not know what to do.

Thanks for this i just did this cleaning for the second time. No improvement. BTW The techs are working with Toyota Canada tech experts. It their recommendation to replace the charger! Gosh i wish that the qtip would have worked!