No thrust when towing in steep hill

[emil1982]

A couple of month ago I was going to drag my parants caravan (~900kg) up from a building plot they have. This plot is quite steep and the caravan had rusted one of the tires stuck. I was trying tu pull with my PHEV and first off the tires was spinning but when they evetually got hold the car just died.

Nothing happened and the engine just "bzzzzd". I tried to set the car in charge mode to apply seriel mode but still nothing happened. It was like if it was missing a couple of kW but the strange thing was that the petrol engine did not helped at all, did not even start. One more strange thing wast that when I disconnected the caravan and was going to drive the car up, same thing happened again, but without caravan. The front weels was standing on gravel and the back wheels in mud. 4wd lock on.

Any Ideas why no power was generated and why the petrol engine did not helped the front wheels that had grip?

 

[maby]

So, how did you eventually get moving? I don't think anyone has reported exactly the same issue, but there does seem to be a mechanism that the car can invoke to protect the hybrid systems from a perceived risk of damage - transients on rapid chargers, for example. I guess that it could decide that you are overloading the motors and shut them down to protect them?

 

[emil1982]

I will add, ASC was turned off.

I got helped by my father and my brother in law. I managed to reverse some meter and got some speed and then they whare able to push. The problem was from still standing, so with the extra speed from reversing (the backwheels was standing in a pot from spinning in the mud).

That was my idea as well, if there where som protection for the shaft. But quite bad then if the shaft cant handle the torque from the engine.

/Emil

 

[PolishPilot]

.... why the petrol engine did not helped the front wheels that had grip?

Very simple, there is no slip clutch or torque converter on the petrol engine.
It can be only synchronized and connected with the wheels at certain speed, ca. over 40mph.

Your speed was 0 mph, no way petrol engine could connect.

It could only "help", if desired, by running the generator and delivering more power to
the electric engines. Obviously the computer algorithm decided that the power from
the battery is enough, or more than enough.

 

[anko]

As a matter of fact, the engine can help, but indeed not in parallel mode.

Although one might expect that a (charged) battery would provide plenty kW to satisfy both e-motors at very low speed (max torque * RPM * some factor yields max kW) , this does not apply when getting away from 0 RPM. The amount of power needed to get the motors to start spinning is much more than what you need once they are spinning (I think it is called Lock Torque or something like that). I had a situation where the engine engaged and provided extra electric power when taking off from stand still. I had to pull my 1500 kg caravan out of a ditch at that time. Took me by surprise. But yet, it managed.

I think that because of the fact that TS had the issue even after detaching the caravan, the title of this topic is not correct. And because the engine did not start at all, the issue seems to have been more traction related than thrust related.

 

[jaapv]

My guess? The OP forgot to disengage the Stabilty Control and the system locked the spinning wheels.
That is the reason the manual recommends switching Stability Control off in these conditions. All cars with Stability Control behave this way.
It took me ages to figure out why my previous car ground to a halt when driving up a slippery hill.

 

[emil1982]

My guess? The OP forgot to disengage the Stabilty Control and the system locked the spinning wheels.
That is the reason the manual recommends switching Stability Control off in these conditions. All cars with Stability Control behave this way.
It took me ages to figure out why my previous car ground to a halt when driving up a slippery hill.

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Nope, definitly sure that I turned off ESP. In fact I tried: ESP ON/OFF, 4wd ON/OFF, save mode on/off, charge on/off. There where definitly no traction problem on the front wheels but definitly on back wheels. Strange thing that none of the wheels did even spin at all.

 

[emil1982]

My guess? The OP forgot to disengage the Stabilty Control and the system locked the spinning wheels.
That is the reason the manual recommends switching Stability Control off in these conditions. All cars with Stability Control behave this way.
It took me ages to figure out why my previous car ground to a halt when driving up a slippery hill.

You might be right, the towing was not the issue. But still the torque was missing. We pulled the caravan easily up with a L200 in low gear but without the diffrencials diffed.

/Emil

 

[jaapv]

In that case the ICE should have come in to supply the missing power whatever setting of charge etc.Considering Anko's post, did you let the car roll backwards slightly before applying power? Or rock the combo by switching between R and D?

My guess? The OP forgot to disengage the Stabilty Control and the system locked the spinning wheels.
That is the reason the manual recommends switching Stability Control off in these conditions. All cars with Stability Control behave this way.
It took me ages to figure out why my previous car ground to a halt when driving up a slippery hill.

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Nope, definitly sure that I turned off ESP. In fact I tried: ESP ON/OFF, 4wd ON/OFF, save mode on/off, charge on/off. There where definitly no traction problem on the front wheels but definitly on back wheels. Strange thing that none of the wheels did even spin at all.

 

[Grigou]

Nope, definitly sure that I turned off ESP. In fact I tried: ESP ON/OFF, 4wd ON/OFF, save mode on/off, charge on/off. There where definitly no traction problem on the front wheels but definitly on back wheels. Strange thing that none of the wheels did even spin at all.

Was it on ECO or Normal mode ?

 

[emil1982]

emil1982 wrote:
Nope, definitly sure that I turned off ESP. In fact I tried: ESP ON/OFF, 4wd ON/OFF, save mode on/off, charge on/off. There where definitly no traction problem on the front wheels but definitly on back wheels. Strange thing that none of the wheels did even spin at all.



Was it on ECO or Normal mode ?

Normal

 

[emil1982]

In that case the ICE should have come in to supply the missing power whatever setting of charge etc.Considering Anko's post, did you let the car roll backwards slightly before applying power? Or rock the combo by switching between R and D?
emil1982 wrote:
Quote:
My guess? The OP forgot to disengage the Stabilty Control and the system locked the spinning wheels.
That is the reason the manual recommends switching Stability Control off in these conditions. All cars with Stability Control behave this way.
It took me ages to figure out why my previous car ground to a halt when driving up a slippery hill.

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Nope, definitly sure that I turned off ESP. In fact I tried: ESP ON/OFF, 4wd ON/OFF, save mode on/off, charge on/off. There where definitly no traction problem on the front wheels but definitly on back wheels. Strange thing that none of the wheels did even spin at all.

When having the caravan I was not able to roll backwards more due to much angle between car and caravan. When I detached the caravan I was able to slightly roll back and take some speed.

 

[anko]

When having the caravan I was not able to roll backwards more due to much angle between car and caravan.

Typically, this is advised as a strategy for getting away on a steep hill without burning your clutch or smoking up your tires. Due to the angle, the car does not have to pull the caravan on the first few feet, just rotate. The more surprising your car couldn't cope.