[PANDA]

here's the thing. I found an old gauge meter that I used to connect to the OBDII port in my older cars to measure ECT, RPM, Oil pressure, BATT, and some other things. so I decided to plug it in to my '17 Volt an IT WORKS.

the thing that I notice is that the oil pressure is obiuosly cero when I drive in normal or sport mode. But, When the car is on hold or mountain mode ther is Oil Pressure, but EVEN WHEN THE I.C.E. IS NOT RUNING!!!!!

It seems like te electric unit engage the crank shaft even if there is no combustion in this modes, that makes me think a lot of thigs about how this sistem works, and this may be related to the back fire in some cases? honestly I dont know but I'll keep nosing my car

 

[Guest]

When the car is in Hold or Mountain Mode, the ICE is running.

 

[PANDA]

When the car is in Hold or Mountain Mode, the ICE is running.

I may be misunderstood, In hold mode when the car starts to move from stop or when I release the throttle the power flow display shows that the ICE is off, but in this mode there is oil pressure, even when I can clearly notice that the ICE is completly off.

 

[Guest]

When you are stopped in Hold etc. mode the ICE is off but it takes a while for oil pressure to bleed off. There are few engines where this might not true like motorcycle engines and some cars that use motorcycle technology (like the early Honda sports car) specifically where they use roller bearings in the connecting rods. Even when these are running they don't have much if any oil pressure as oil circulation is not restricted by bearing clearances.

 

[obermd]

When in hold mode the car starts the ICE immediately. In Mountain Mode the ICE will only be running if the car needs to charge the battery to the target level or maintain the charge at that level. The ICE won't start when you enable Mountain Mode prior to the battery SOC reaching the Mountain Mode point.

As for the oil pressure, anytime the car starts the ICE it will maintain oil pressure, even if you're coming down a long descent regenerating the battery above the Mountain or Hold Mode set point. The main engine coolant will also continue circulating but the radiator fan will only run if needed. The engine is still turning as well via direct link to the transmission. The car does this so it can feed gas to the injectors as soon as the battery SOC drops again. If it didn't do this it would take 50-60 seconds to restart the ICE.

 

[Guest]

When in hold mode the car starts the ICE immediately. In Mountain Mode the ICE will only be running if the car needs to charge the battery to the target level or maintain the charge at that level. The ICE won't start when you enable Mountain Mode prior to the battery SOC reaching the Mountain Mode point.

As for the oil pressure, anytime the car starts the ICE it will maintain oil pressure, even if you're coming down a long descent regenerating the battery above the Mountain or Hold Mode set point. The main engine coolant will also continue circulating but the radiator fan will only run if needed. The engine is still turning as well via direct link to the transmission. The car does this so it can feed gas to the injectors as soon as the battery SOC drops again. If it didn't do this it would take 50-60 seconds to restart the ICE.

I didn't know about full charge with Mountain Mode, When I put mine in Mountain mode the battery was near empty and I wanted battery for when I turned off the highway so it started right away. The battery charged up to 40% but the ICE kept running for another half hour until I later turned off and switched it to normal to complete the last part of the journey (36mph) on battery.

The motor doesn't have to keep running to keep gas at the injectors as there is always gas at the injectors and why the motor starts immediately and will come into effect in 3 seconds even if the car has been standing. Even my 1980 FI TR7 Spider will start in a couple of seconds after standing for a couple of weeks.

 

[obermd]

I didn't know about full charge with Mountain Mode, When I put mine in Mountain mode the battery was near empty and I wanted battery for when I turned off the highway so it started right away. The battery charged up to 40% but the ICE kept running for another half hour until I later turned off and switched it to normal to complete the last part of the journey (36mph) on battery.

In Mountain Mode the car operates as is if in hold mode once the battery SOC reaches the Mountain Mode target. The ICE engine will continue running.

​

The motor doesn't have to keep running to keep gas at the injectors as there is always gas at the injectors and why the motor starts immediately and will come into effect in 3 seconds even if the car has been standing. Even my 1980 FI TR7 Spider will start in a couple of seconds after standing for a couple of weeks.

Modern GM ICE (both gas and diesel) cars implement a mode call Deceleration Fuel Cut Off (DFCO). In this mode the fuel injectors are turned off while descending slopes as small as 1 to 2%. The engine continues to turn via the transmission's connection to the drive wheels. While in DFCO the water and oil pumps continue to operate to keep the engine cool and lubricated.

Your 1980 Spider, like all ICE engines, starts immediately. The engine is turning at low speed and this provides the power, either mechanical via the accessory belt, or electrically via the alternator feeding the 12V battery, to operate the water and oil pumps. But what you don't normally do as a driver is rev the engine while under heavy load, giving the fluids a chance to circulate completely.

On the other hand, the Volt may start the ICE engine at any time, either via the driver asking for SOC hold or battery exhaustion. By any time I mean any time and at any speed, up to the roughly 100 MPH top speed for the car. The absolute worst thing you can do to an ICE engine is put it under heavy load before all the components are lubricated and the cooling system is fully operational. To avoid excessive wear on the ICE engine the Volt fires up the oil and water pumps and runs them for a short period of time before transferring the power from the electric motors to the ICE engine.

 

[hellsop]

The absolute worst thing you can do to an ICE engine is put it under heavy load before all the components are lubricated and the cooling system is fully operational. To avoid excessive wear on the ICE engine the Volt fires up the oil and water pumps and runs them for a short period of time before transferring the power from the electric motors to the ICE engine.

To add to this a little bit (and I've heard that that this applies to Gen 2 as well as the Gen 1 I personally experience): the startup sequence for the Volt ICE from cold is 1) Volt uses MGA (one of the electric drive motors) to spin the ICE up to about 1400 (like a very fast idle) in half a second or so. Most pumps start at this time. 2) after the speed is settled at 1400 RPM, the ignition system turns on and the fuel injectors start applying fuel, and MGA stops turning the engine, letting it resettle at the same speed under fuel-burning condition. The engine warms for about 30 seconds in this state. 3) At this point, MGA rengages as a generator, the ICE switches to a lean burn, the throttle opens all the way and RPM is being balanced by rate of fuel being supplied and the load pulled by the generator. USUALLY the RPMs go up to about 2200-2400 because there's some battery deficit* to make up. At stable driving speeds, the ICE will normally turn at 1400 to 1800 RPM, with or without MGA being clutched into the planetary gearset, and MGB will adjust its speed to make the wheels turn at the desired rate.

Warm start (which is most of them) just shortens step 2 down to almost nothing. Spin up, apply ignition and fuel, start drawing power from MGA, all done in about a second, then the RPMs may change to meet demand.

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* Big battery deficits may rev up rather further, but Gen 1 never spins any faster than 4800 RPM. I think Gen 2 gets a little higher than that, but there is still nothing YOU as a driver can do to over-rev the thing.

 

[PANDA]

To add to this a little bit (and I've heard that that this applies to Gen 2 as well as the Gen 1 I personally experience): the startup sequence for the Volt ICE from cold is 1) Volt uses MGA (one of the electric drive motors) to spin the ICE up to about 1400 (like a very fast idle) in half a second or so. Most pumps start at this time. 2) after the speed is settled at 1400 RPM, the ignition system turns on and the fuel injectors start applying fuel, and MGA stops turning the engine, letting it resettle at the same speed under fuel-burning condition. The engine warms for about 30 seconds in this state. 3) At this point, MGA rengages as a generator, the ICE switches to a lean burn, the throttle opens all the way and RPM is being balanced by rate of fuel being supplied and the load pulled by the generator. USUALLY the RPMs go up to about 2200-2400 because there's some battery deficit* to make up. At stable driving speeds, the ICE will normally turn at 1400 to 1800 RPM, with or without MGA being clutched into the planetary gearset, and MGB will adjust its speed to make the wheels turn at the desired rate.

Warm start (which is most of them) just shortens step 2 down to almost nothing. Spin up, apply ignition and fuel, start drawing power from MGA, all done in about a second, then the RPMs may change to meet demand.

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* Big battery deficits may rev up rather further, but Gen 1 never spins any faster than 4800 RPM. I think Gen 2 gets a little higher than that, but there is still nothing YOU as a driver can do to over-rev the thing.

so this means there is no regular starter at all... that leads me to use my sunday to check under the hood hehehe.