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I dont think there is any way an alternator running off of the engine can keep up with a 160 hp electric motor going up a ten mile long hill in snow. Is there???
First you only get 2 miles at 45 mph max in Stealth Mode using the full battery storage. You thought that the 160 hp can operate for 10 miles is far off!
Second a 5 to 10 hp alternator at best could operate a n electric Moyer maybe max 7 of 8 hp! That is a simple energy balance at high efficiency. For what describe need a Jeep or GM electric power Jeep type EV
I dont think there is any way an alternator running off of the engine can keep up with a 160 hp electric motor going up a ten mile long hill in snow. Is there???
If that is your true need, then it does appear that the E-Ray is not the car for you.
Question - what angle slope / speed requires 160 hp at the front wheels while being pushed by 495 hp at the rear? My point is NOT sarcasm, but ... do you really need 160 hp in the situation you are envisioning?
The maximum peak power output rate of the eRay is 655hp (495hp LT2 engine + 160hp electric motor).
The maximum sustained power output rate of the eRay is 495hp (LT2 engine only). The battery is just a small energy reservoir. All the energy in the battery must have originally come from the LT2 engine. The battery in the eRay is only ever charged when the motor/inverter converts kinetic energy into electrical potential energy. All kinetic energy of the car (1/2*mv^2 + 1/2*Iω^2) must have originally come from the LT2 engine.
The law of conservation of energy always applies. The battery is an energy storage reservoir, not a source of energy. (Horse)power is energy per unit time.
From what has been posted sounds like it charges when braking, coasting and by the alternator. In fact in a post a few weeks ago it said it was only by alternator. Probably wrong but have to believe as everything else in the car a computer and many algorithms it picks what’s needed
IMO Performance boosted by electric motors NOT economy All the GM talk is about performance!. Low end acceleration feel. 0 to 60m and 1/4 mile times.
Now the question is how do "the computer and the algorithms" work to accomplish that performance boost? and have the power available when wanted? Economy dos not play in the game.
" The battery is charged via regenerative energy from coasting and braking, as well as during normal driving."
Also a careful reread of the GM announcement makes it seem that all charging is done by running the front motor in reverse. Therefore you actually charge by driving the front wheels in the system with the 6.2 lt engine, not with an alternator. So you're cruising on a road and the system decides to charge the batteries. Unbeknown to you, the system activates the charge mode in the emotor increasing the drag of the front wheels slightly and boosting the power output of the IC engine slightly. to compensate. That's one busy computer.
Will you be able to sense any of this?
Last edited by Kodiak Bear; 01-19-2023 at 06:02 PM.
Assuming the reports are true, one thing I don't like about it is why such a small battery, it seems the battery will be depleted after 3 or 4 miles but most importantly it looks it will be cycling often.
Meaning it could be subjected to way too many charge/discharge cycles while driving normally, batteries degrade quickly this way. The NSX forums claim the cost to replace one is around $5K to 8K, which is not bad.
Of course, just a guess.
Where is a larger battery going to go? The tunnel is already full with batteries, high and low voltage wiring and connectors, inverter, cooling / heating circuits (and the pre-existing coolant and A/C lines).
Was an AP article in our town paper that clearly said what many are missing. Unlike most hybrids the E-Ray will not increase mpg! In the EPA City Test is will increase mpg slightly. In the EPA Highway test it's less than a standard C8 because of the added weight!
And once again, extra weight has virtually no impact on highway mpg. Once you accelerate up to highway speed, aero and tire drag and the primary impacts on mileage. Weight affects acceleration, but not steady state speed. Physics 101.
The maximum peak power output rate of the eRay is 655hp (495hp LT2 engine + 160hp electric motor).
The battery in the eRay is only ever charged when the motor/inverter converts kinetic energy into electrical potential energy. All kinetic energy of the car (1/2*mv^2 + 1/2*Iω^2) must have originally come from the LT2 engine.
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Incorrect. You're ignoring the role of regenerative braking, which in typical urban / suburban driving will largely provide the charging needs of the battery.
" The battery is charged via regenerative energy from coasting and braking, as well as during normal driving."
Also a careful reread of the GM announcement makes it seem that all charging is done by running the front motor in reverse. Therefore you actually charge by driving the front wheels in the system with the 6.2 lt engine, not with an alternator.
Yes, yes and yes. 100% of the E-Ray's battery energy comes from fossil fuels.
While they could use an alternator, it doesn't really make sense as they'd need an extra dc-dc converter, and the amount of current pumped into the batteries would barely even offset the motor's parasitic frictional losses, and certainly wouldn't provide charge gain during the hypothetical 100% uphill in snow for 10 miles. To do this would require a very, very large alternator, and I don't think they did this, as they were very focused on weight/cost and there's already a perfectly good generator in the drive unit that covers 99.99% of the use cases.
You can always come up with a scenario in which the battery becomes depleted .... 20-30 minutes at VIR also comes into mind as a potential battery drainer. That's part of the tradeoff here, for performance/weight and cost.
Incorrect. You're ignoring the role of regenerative braking, which in typical urban / suburban driving will largely provide the charging needs of the battery.
Regenerative braking captures energy from the motion of the vehicle (rotational and translational kinetic energy) and stores it in the battery. The energy of motion of the vehicle was originally generated by the LT2 ICE.
The only exceptions would be: A) a never-ending downhill road, B) a never-ending tailwind.
.....The energy of motion of the vehicle was originally generated by the LT2 ICE.
....
But if you consider the data, cars of an "average drive" most ICEs only ~19% of the energy in gasoline gets to he rear wheels (EPA data.) Of that ~19% "on average ~20%" is turned into heat when braking. It's some of that otherwise "wasted braking energy" is what is used to generate battery charging.
So yes it was energy was originally generated by the ICE but it was used to recharge the battery was going into heat when braking.
The E-Ray will have a bit better than the standardC8 EPA ratings of 19 City, 24 highway mpg. An equally powerful C8 Z06 only gets 12 City, 21 Highway on the EPA test cycles.
But if you consider the data, cars of an "average drive" most ICEs only ~19% of the energy in gasoline gets to he rear wheels (EPA data.) Of that ~19% "on average ~20%" is turned into heat when braking. It's some of that otherwise "wasted braking energy" is what is used to generate battery charging.
So yes it was energy was originally generated by the ICE but it was used to recharge the battery was going into heat when braking.
The E-Ray will have a bit better than the standardC8 EPA ratings of 19 City, 24 highway mpg. An equally powerful C8 Z06 only gets 12 City, 21 Highway on the EPA test cycles.
So when you say a "bit better", what is your prediction? The Stingray is 16 City, 24 Highway and 19 combined.
So when you say a "bit better", what is your prediction? The Stingray is 16 City, 24 Highway and 19 combined.
On the EPA Tests I'd guess perhaps a 0.5 mpg better City and 0.2 worse highway (from what a writer posted after the revel who was talking with GM folks.) City could be significantly better in some drive mode IF GM programed it to get better mpg. Didn't see a optimum mpg mode listed.
The reason from my PDF is the EPA test cycles shown below. Have a fixed mount of idle, probably not using more than 50 hp. Real world will be dependent on how you drive. If like the Mobil economy Run where you were not allowed to use a vacuum gauge they drove like having a raw egg between floor and gas pedal!
SIDEBAR
Remined of ~1980 when waiting for the new corporate office to be finished in Danbury CT. I and some of my newly formed group drove from CT to Tarrytown NY in a car pool. I had purchased a subcompact Dodge Colt (twin stick, 8 speed- later bought the Turbo version which was called a pocket rocket and installed Plus 1 Pirelli P7s etc.) Made a bet that I could get 50 mpg on the way down. Had installed a JC Whitney MPG meter that used a ball bearing moving in a race that measured fuel flow. Properly calibrated it was pretty accurate.
Recall keeping a fixed throttle best I could and letting it slow going up hill. Can still hear the horns behind on hills going to the Saw Mill River Parkway. It was a twisty two lane highway with lots of downhill on the trip to Tarrytown. Shut the motor off and coasted, hitting some pretty fast speeds! As we were creeping into the parking lot just hit the 50 mpg! Typically was getting 35 to 40 mpg with that ~70 hp, 1700 lb car. The later turbo model had 105 hp and really was the pocket rocket as described.
That was thru a period where you could only buy gas every other day based on out license plant number. I could not make it from CT to LaGuardia Airport and back on one tank of my V8 C&5 Jeep with big offroad tires, headers etc. . Traveled almost every week and a few times had to stay overnight and come home the next day when I could buy gas to get back to CT. Sold the Jeep and bought the subcompact!
Can ignore my words but the graphs are the EPA required drive cycles. Probably never need more than 50/60 hp.
And once again, extra weight has virtually no impact on highway mpg. Once you accelerate up to highway speed, aero and tire drag and the primary impacts on mileage. Weight affects acceleration, but not steady state speed. Physics 101.
Yep, perhaps if it were straight highway driving BUT the EPA Highway Cycle is not that simple. I was just quoting Tom Krisher from Associated Press who was talking with GM folks at the Reveal. Those GM folks know a lot more than your or my guesses!
QUOTE: Unlike most hybrids, it’s not really made for efficiency, although will get a little better city mileage than a standard Stingray at 16 mpg. But because of higher mass and air drag, it will do worse than the standard Corvette’s 24 mpg on the highway."
Hmm yep that dam air drag! No E-Ray Cd's (drag Coefficients) yet but that wide body will made it worse! Did the C7 Grand Sport versus the standard C7. Tadge forum posted Cd #s for that were: Base C7 = 0.30
Grand Sport = 0.35
Grand Sport Stage 2 Aero = 0.40 (which I had)
Grand Sport Stage 3 Aero = 0.50 (How could the Stage 3 Aero be that bad? Easy, both Stage 2 and 3 had height extensions on the real spoiler ends. Stage 3 added a clear plastic piece between the two that GM called a wickerbill. At 50 mph it would be like sticking a 6-inch wide 4-foot-long board out the window. Lots of drag force!)
Could be GM is purposely leaking low numbers so that can publish higher when the E-Ray is available. Things like that known to happen! We'll see.
Graph is EPA Highway Test. My comments are from my PDF if a full Prius type hybrid. But would have to be a GM program designed for higher mpg. Have not seen that mentioned. Doesn't appear to be Stealth mode which is only electric drive until the battery runs out of energy in what was also quoted as ~2 miles at 45 mph reported by folks at the Reveal. BTW Not sure what the EPA rules are for having a special program just designed for their tests. Remember the VW Execs that went to Jail for having a trick program to fool the EPA test? In fact, waiting now for payment for our early Porsche Cayenne were some Porsche models were fined by the EPA for inaccurate mpg reported. Our Cayenne VIN is one. Been advised our refund is the works. We'll see how much the lawyers are allowed to take!
........... Remember the VW Execs that went to Jail for having a trick program to fool the EPA test? ..........
I would not call "Stealth" mode a trick program - it is not hidden. I do not know why GM would not be allowed to start out in stealth mode for their test. If so, having a couple free miles should make a big improvement in city mpg. And apparently the electric motor allows more frequent cutting off all 8 cylinders. Start/stop is suppose to be worth 4-5% on its own. I am hoping right now GM doesn't want to talk about mileage: A. they are waiting for official numbers. and B. because too many of their base are anti anything electric or perceived as "green" - even if it is the quickest Corvette ever. The biggest tip so far is in their ERAY only instrument cluster you can check out a bunch of new stats including a data point for "Fuel Saved". Why would they have that in their if it could not show a significant number?
^^
All I have seen is Stealth Mode is so you don't disturb your neighbors in the morning, and you can go 2 miles at 45 mph. I agree, IF Stealth works that way, i.e. runs on electric power only then turns on the LT2 when it gets to 20%.
In a E-Ray Cutaway walk around, Aaron Link, Chevy Performance Car Manger said they don't let the battery go under 20%. So if Tracking, as example, and you're expecting front wheel help coming out of an apex it will be there. He also said in Track Plus charging only takes 1/2 mile to recharge the battery. Assume when say going down a straight the motor is turned generator and you are "steeling" some the LT2 power to charge the battery.
As I said above, I'm just quoting the AP reporter: Tom Krisher from Associated Press who was talking with GM folks at the Reveal. QUOTE: Unlike most hybrids, it’s not really made for efficiency, although will get a little better city mileage than a standard Stingray at 16 mpg. But because of higher mass and air drag, it will do worse than the standard Corvette’s 24 mpg on the highway."
Yep as you say they have a digital readout of fuel savings. We'll need more info to see just how it operates on a highway. Perhaps GM is purposely leaking low mpg #'s so when it's available they can look like heroes.
01-19-2023, 02:19 PM
