Stresses of a Plug-In Hybrid

[jtay2024]

So, this is something I thought about on the way to work the other day.

I was driving on the motorway when I saw a car pull into the faster lane to overtake a lorry. As he floored it to accelerate quickly, a huge plume of white steam came from the exhaust.

What I noticed was that the car was a plug-in hybrid!

The driver had probably been cruising using just the batter and motors. Then, when they needed power just stamped on the accelerator. The engine must have fired up and revved up high as the car took off like a rocket.

Bearing in mind this was on a cold winter morning and this was probably the first time that the engine had started that morning and it was straight into a high rev and high load situation.

Does anyone know if car makers do anything to mitigate this? Is there a way of pre-heating the block maybe or the oils are super thin and ready to lubricate anyway.
It sounds like a recipe for a broken engine to me.

What are you guys thoughts?

 

[OVERKILL]

So, this is something I thought about on the way to work the other day.

I was driving on the motorway when I saw a car pull into the faster lane to overtake a lorry. As he floored it to accelerate quickly, a huge plume of white steam came from the exhaust.

What I noticed was that the car was a plug-in hybrid!

The driver had probably been cruising using just the batter and motors. Then, when they needed power just stamped on the accelerator. The engine must have fired up and revved up high as the car took off like a rocket.

Bearing in mind this was on a cold winter morning and this was probably the first time that the engine had started that morning and it was straight into a high rev and high load situation.

Does anyone know if car makers do anything to mitigate this? Is there a way of pre-heating the block maybe or the oils are super thin and ready to lubricate anyway.
It sounds like a recipe for a broken engine to me.

What are you guys thoughts?

One of the X5 xDrive45e reviews remarked on this and actually checked to see if BMW did anything to pre-heat the engine. They do not, it's stone cold. Apparently this is planned for in how the engine is designed, but yeah, that's gotta be hard on things you'd think? Though that may be our "mechanical compassion" weighing in at making it seem more important than it actually is in application.

 

[jtay2024]

One of the X5 xDrive45e reviews remarked on this and actually checked to see if BMW did anything to pre-heat the engine. They do not, it's stone cold. Apparently this is planned for in how the engine is designed, but yeah, that's gotta be hard on things you'd think? Though that may be our "mechanical compassion" weighing in at making it seem more important than it actually is in application.

You are probably right. I did some more reading about it. One of the other things I've seen that sounds interesting is the wear on the bearings while the engine isn't even running (Due to vibration while oil pressure is 0). I've seen machinery that's sat idle next to other running machines, they can then be hard to get working correctly after due to worn roller bearings as they have sat in the same position and worn on just that one spot. (I doubt this would be an issue in an engine though!)

 

[TumblrDucks]

On Youtube I once saw a video about 3-years-old plug in hybrid (Ioniq) has milkshake as oil because of repeated short trip on gasoline engine and no warm up. Neglecting gas engine in PHEV is a problem as owner tend to treat it as BEV.

 

[supton]

Should know before long, good number of PHEV here on the roads.

I suspect it is a non issue. Super thin oil. Plus the ecu could keep engine loading low for the first few seconds, right? it might not be 100% loaded for a bit of time.

 

[brianl703]

Depends on the plug-in hybrid. The Volt doesn't do that. It warms the engine up before it allows full power from the engine. But the Volt can run 100% from batteries, and it knows about when the batteries are going depleted so it fires the engine up before that happens, allowing for the warm-up.

 

[OVERKILL]

Depends on the plug-in hybrid. The Volt doesn't do that. It warms the engine up before it allows full power from the engine. But the Volt can run 100% from batteries, and it knows about when the batteries are going depleted so it fires the engine up before that happens, allowing for the warm-up.

Doesn't the Volt use electric drive for the wheels though and the petrol engine is more just a generator?

In the X5 for example, the electric motor is 111HP. You can drive the vehicle around on it, but if you command full power from the vehicle via the pedal, the 286HP gas engine fires up and they run in series; that is, the petrol engine is coupled to the electric motor (which replaces the torque converter in the ZF8) and their output is compounded to give you just shy of 400HP.

I believe this is also how the Ford system in the Corsair and Aviator work, as well as the system in the Jeep 4xe (that also uses the ZF8), as well as the Audi PHEV's. It's a more performance-oriented setup than what you have in the Volt.

The new Mazda that was recently discussed on here, also uses the same system, with an electric motor replacing the torque converter.

Now, on the bimmer (not sure on the others) if you put it in Sport, the gas engine runs all the time and the two just work together.

 

[brianl703]

Doesn't the Volt use electric drive for the wheels though and the petrol engine is more just a generator?

The Volt can drive the wheels directly with the gas engine under the same conditions that a regular vehicle would shift into overdrive.

 

[OVERKILL]

The Volt can drive the wheels directly with the gas engine under the same conditions that a regular vehicle would shift into overdrive.

Interesting.

So, if you've got full charge in the Volt, and you stuff it, does the gas engine kick on to give you full power? Or is full power limited to whatever the electric drive can churn out and so petrol engine isn't fired up in this scenario?

 

[brianl703]

Interesting.

So, if you've got full charge in the Volt, and you stuff it, does the gas engine kick on to give you full power? Or is full power limited to whatever the electric drive can churn out and so petrol engine isn't fired up in this scenario?

No, if you have full charge the gas engine won't kick on to give you full power. It's limited to what the electric drive can put out.

However, if the battery is depleted, and the gas engine is running, it seems that it might accelerate ever so slightly quicker than when it's running only on battery. I don't know if anyone has ever actually tested this and find it to be true.

 

[OVERKILL]

No, if you have full charge the gas engine won't kick on to give you full power. It's limited to what the electric drive can put out.

However, if the battery is depleted, and the gas engine is running, it seems that it might accelerate ever so slightly quicker than when it's running only on battery. I don't know if anyone has ever actually tested this and find it to be true.

Ahhh, thanks for the clarification, so different system for sure.

I'm really surprised there isn't some pre-heating that happens on the vehicles I mentioned, it seems wild to just fire up an engine and send it WOT from stone cold.

 

[brianl703]

I'm really surprised there isn't some pre-heating that happens on the vehicles I mentioned, it seems wild to just fire up an engine and send it WOT from stone cold.

I've heard of people who drive their cars that way. Fire it up, floor it while it's still cold. One guy I heard about who drove that way managed to total the car before he killed the engine.

 

[eljefino]

My Prius Prime goes easy on the gas engine revs, but only for about 10-20 seconds. I'll hold a steady accelerator position then the thing goes "Vroooom" all on its own when it's ready.

Since I have some control over when I use the 26 miles of battery, I try to engage the ICE long enough before heavy loading so it's not an issue.

 

[ATex7239]

Toyota’s cooling/heating system works somewhat similar to a heat pump. It’s warms up the engine and hybrid system when it’s cold and visa versa. It’s uses directional control valves to direct fluid where needed.

Batteries do not like extreme heat or extreme cold and there is an optimal range for efficiency.

 

[justalubetech]

Ahhh, thanks for the clarification, so different system for sure.

I'm really surprised there isn't some pre-heating that happens on the vehicles I mentioned, it seems wild to just fire up an engine and send it WOT from stone cold.

I don't think it's as bad as we think it is, I have some early 80's water cooled lawn tractors that go full-tilt as soon as fires off and it's never needed to be opened up internally

 

[tcp71]

Generators, except inverter types, go from 0 to full speed right away. Not sure that it causes any real issues.

 

[wolfox03SS]

I would wager that there would be more issues with fueling and lubrication. I have a neighbor that says he's got his Prius pretty much set up from infotainment screen buttons to behave more like a PEV. He's got stage 1 charging (Fancy adapter plug to car, standard 120V wall plug on the other) so it takes time to top up if the battery is truly depleted.

He says it can go miles and miles on battery alone, the engine only kicking over if the trip is either over 80-some miles and you're not in the driveway with an extension cord in hand. He claims it is the perfect short tripper for fetching groceries, church, hardware store runs, etc. But what alarmed me the most:

"Oh, I maybe have to put gas in it every 4 months...."

I get antsy using fuel 4 weeks old in a sealed, approved container...(!) if it wasn't stabilized. And all of that cold-sat, mostly never run engine is a candidate for sludge in my mind's eye if it's ever spooled up long enough for water vapor burnoff. That's just me and overthinking mostly. I hope. MOSTLY I just do what the voices in my head say to do. ;>