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Outlander B3-5 Engine Spin-Up Protocol - Mike Mas

465 Views 11 Replies 3 Participants Last post by  LowOnCash
Hey Guys - I just got back from a test ride of my 23 Outlander this morning to evaluate what happens when we select higher than B2 mode while in EV mode which causes the engine to start. (Depending on HV battery SOC)

As the car travels in EV mode in “D” (drive) the processor defaults regen level to a B2 setting.

As we move “B” mode to either 3, 4, or 5, the gas engine will immediately start and begin a warm-up sequence running at 1500 rpm raising temperature to roughly 100 degrees and to circulate oil thru the engine. Once the engine warms, it then decreases speed to around 1300 rpm in a readiness state.

During the mode change, the main processor calls up a protocol allowing the drive motors two continue to generate regen power to slow the car, however instead of using the regen to charge the battery, it instead must dissipate the regen energy in another form.

Therefore, rather than charge the battery, current is instead diverted to the engine starter / generator motor which I nick-named “High Speed Spin-Up Sequence”

Therefore, as the accelerator is let off, the regen power created by the drive motors is sent to the engine starter motor, which then accelerates the engine from 1300 rpm high-idle, to well over 3000 rpm, depending on the cars speed. The higher the speed the faster the engine is turned to dissipate regen energy. I witnessed 4000+ rpm at 65 mph.

Considering this is the state in higher B Modes, there is little to no regen advantages using higher than B2 while in EV mode. The Outlander is equipped with large disks and calipers to easily handle slowing the car during high SOC.

I included some images below captured at the OBD port. The first image shows the engine in a warm up state running at 1500 rpm to reach around 100 degrees.

The second image shows the engine warmed in a B mode “ready state” and lowered to 1300 rpm waiting for regen or speed-up.

The third image shows after releasing the accelerator at 45 mph, the starter motor has now spun the engine to over 3000 rpm to dissipate regen energy.

The next two images show the regen levels from the drive motors as the accelerator is let up at the speed of 45 mph. I noted that regardless if the B mode was in 3-4 or 5 regen level did not change and remained constant.

Regards - Mike


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That's great stuff, thanks for looking into that and sharing! The unrelated-regen photo at the end is a nice touch haha!

I wish that Mitsu provides this info in the manual and used a different colour for the engine icon when this protocol is engaged, such as blue. Right now people associate the orange engine with using fuel and then get confused when they are doing their best to not use fuel. Using a different colour here would help reduce that confusion.
I was thinking about what you uncovered in your post, which was great, but wonder what happens to the regen energy from B2 when the battery is at a high charge? It's not "high" enough to start the ICE and the high-speed spin-up sequence even though when apply the brakes you can still get the full 40 kw back. But B3+ the energy has to go to the generator and not the drive battery.

I don't understand the programming logic: B2 continue expected operation and feed the drive battery; B3+ surprise everyone and direct regen to the ICE generator instead of the drive battery.
Thanks for the reply - Regen at full charge still goes to the battery.
Right, so why don't they program this to also happen when using B3+?
Hmmm, the above holds true if regen from pedal braking in B1 and B2 is throttled back, even with max pressure. Do you know if this is the case? I will try to remember to keep my eye on what happens in this condition.
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