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Discussion Starter · #1 ·
I was under the impression that the GTE‘s ICE doesn’t have a starter motor. I assumed that the engine would only fire up when on the move relying on the electric drive motor driving the car to spin up the ICE through it’s drive clutch. Twice now the engine has fired up unexpectedly when stationary when I first get in the car in the morning.
 

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The electric motor is the starter motor, it’s sandwiched between the engine and the gearbox.

It doesn’t have a traditional starter motor/flywheel, but yes it can fire up from stationary.
 

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Is it firing up (ie burning petrol) or just turning the engine over?

On mine it will say 'engine starting' but it is just turning the engine over with no petrol / ignition to keep everything lubricated.
 

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The GTE will start the engine when the battery is very low, whether you are moving or not. This is because the only power for auxillaries, like heating, air conditioning or the 12V system, comes from the hybrid battery. If the hybrid battery is at low state of charge, the car starts the engine as a generator to supply this. It also charges the battery up at around 3kW, so roughly the same as a mains charger.

To accomplish this it just declutches the gearbox and starts the engine with the hybrid motor. Then running with the engine declutched from the gearbox the hybrid motor acts as a generator supplying power to the hybrid battery. The battery pack is then simultaneously discharged by the DC-DC converter and other accessories.

Note that if you put high heat demand on when the battery is very low you can see the car's computer will increase the engine speed so as not to have any net discharge from the battery. It seems the car can work up to about 6kW from the engine while stationary, although the heat from the engine will eventually become sufficient enough to replace the electrical heating supply.
 

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I use the same principle to get heat into the car in winter if I'm not using the departure timer. The engine being on gets heat into the cabin much more quickly than relying the resistive heater in e-mode.
 

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Discussion Starter · #6 ·
Many thanks for the information. I didn’t think the GTE had a conventional starter motor but I thought the car had to be moving to get the ICE to start. Several times recently the engine has fired up unexpectedly when stationary (full HV battery and set on EV mode - think). Haven’t put any petrol in the car for ages, perhaps the car is sensing that the petrol is getting stale and firing up the engine to burn it off. Probably not, but I gather there is a function that does this but I gather the engine will run until the tank is nearly empty.

Obviously I could be talking total pants?
 

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I use the same principle to get heat into the car in winter if I'm not using the departure timer. The engine being on gets heat into the cabin much more quickly than relying the resistive heater in e-mode.
Which mark GTE do you drive? There is no difference in Mk7, and I imagine Mk7.5. The electric heater is 6.5kW, and supplies heat for the first few minutes, before the engine is warm. The only benefit to starting with engine earlier, is less drain on the battery if you intend to use that later for e.g. city portions.

I've been unable to confirm this, but I suspect due to the electric heating system in the GTE, it's less effective at using the engine for heating, until the engine is at full operating temperature, which takes a few more minutes. The electric coolant heating system normally operates around 50C, compared to the 90C or so of the engine. There is a heat exchanger which transfers heat between the 90C engine loop and the hybrid system loop, but since this hybrid system loop is also responsible for cooling some hybrid components, they don't want it getting too hot.
 

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2017 Passat so identical to the Mk7 I guess?
Are you sure these don't have a wet heater core too? Definitely on a frosty morning the electric heater is a mere suggestion of warm air compared to when the engine is on (in the first five minutes anyway)
 

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2017 Passat so identical to the Mk7 I guess?
Are you sure these don't have a wet heater core too? Definitely on a frosty morning the electric heater is a mere suggestion of warm air compared to when the engine is on (in the first five minutes anyway)
As far as I know it has a single cabin heater core, as the cabin heating system is similar to the standard Golf, just with some software differences.
 

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You might find this interesting if you want to learn what's going on and how it works. "Heat exchanger" on the schematic is the cabin heater
 
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