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A long range Hybrid Tesla, thinking outside of the box...

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
So I had an idea that sounds like it would work, but I don't have all of the technical expertise that some in here have, so perhaps someone here may know how viable this concept would work...

So we have a great, efficient motor, but we still have limited range without taking a lot of time at a charge station. My thoughts were a way to make the vehicle lighter, give you 600+ miles of range, and be able to fill up the fuel tank for $20 or less.

To date, the only Hybrid concepts I've seen are gas engines with electrical motor assist. I think we have it all wrong though. The electric motor seems far more efficient, and has the added advantage of insane torque! So what if we took the concept of the Tesla, but made the battery pack MUCH smaller (say 10kw). We put an ICE in the vehicle, but a small, light weight one (we don't need a ton of power). Last, we put a 6 gallon fuel tank in the vehicle. Now we've just reduced the weight of this vehicle dramatically (battery pack would weight somewhere around 200 lbs instead of 1200).

How would it work? Everything would be exactly as it is in Tesla now. Everything is 100% electric with one exception. The power source for the electricity is shared between the battery pack and the ICE turning a powerful alternator. There are currently 4kw generators on the market that weight 150lbs or less and use very little fuel to generate that amount of power. Granted, they are putting out 120v/240v, but I'd imagine a custom built alternator with more windings wouldn't be too difficult to produce, and there are actually alternators out already that put out 3 phase AC.

For efficiency, the ICE would be running variable speeds. When you needed that burst of power, power would be drawn from both, the alternator and the battery, with the battery putting out less power as the ICE spools up and can compensate for the needed power draw. When you are cruising, the ICE is running at slower speeds, supplying enough power to keep your motors running and to recharge anything you've drawn from the batteries. In addition, you could have a plug in mode, for when you only use your car to drive to the grocery store and back etc (the battery pack should be able to last 40 miles or so on a charge). This way, you only use fuel when you want to go on a long trip, and you turn the ICE on.

Looking at the Honda EG4000cl, with a 6.3 gallon fuel tank, it can run at half power for 15.7 hours at 240v. If you're cruising at 65mph, that's over 1000miles on 6 gallons of gas, or nearly 162 miles per gallon. This particular generator weights 148lbs with the steel frame and everything else, which would not be needed. So in the end, you have a car that's nearly 1000lbs lighter weight (also making it more fuel efficient), gives you the peace of mind of not running out of power, and unheard of range on what is equivalent of a cruiser motorcycle fuel tank.

Thoughts?
 

Uncle Paul

Well-Known Member
Nov 1, 2013
6,299
7,598
Canyon Lake,CA
This is already an option in the BMW i3 and i8.

Smaller batteries and the i3 uses a scooter motor to gin up some juice when the tiny battery gives out. Really gets the weight down and the range up. Fuel tank only holds a few gallons.

Combines all the weaknesses of a small battery hybrid with all the misery of a tiny motor trying to drive a car.

Totally different driving experience compared to Tesla. Not in the same league.
 

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
This same above concept could also potentially be used in propeller based airplanes, keeping the airplane light weight, but giving it a ton more power. The only difference is you don't need the instant burst of power, so you'd eliminate the battery pack, and instead, just run the electric motor powered prop off the alternator from the ICE. The Lycoming engines used in Cessna's weight over 300lbs, and burn 8-10 gallons of fuel per hour. What if you could eliminate those 40+ gallon fuel tanks, replace it with a 6 gallon fuel tank, be able to fly twice as long on that fuel tank, AND have a lot more available weight to the passengers?

Most Cessna's have a usable weight of between 800-1000lbs... not including fuel. Once you add fuel in, you are down to 500-600 usable lbs of weight.. a 4 seater Cesna isn't really a 4 seater at that point, unless everyone weight 125 lbs. Make this change, and you've freed up an additional 400 lbs or so of usable weight capacity, and have more performance to boot! Of course, the air frame would have to be redesigned to handle the extra performance, or there would have to be a limiter put in to prevent the engine from pulling too hard.
 

Uncle Paul

Well-Known Member
Nov 1, 2013
6,299
7,598
Canyon Lake,CA
True dat.

When the juice runs low, the scooter motor kicks on and provides just enough juice to keep your speed up.

Gets poor mileage when running on the ICE motor...sounds funny too.

You get to a gas station with an empty tank and an empty battery.

Will run forever on just the motor, but it will not go fast up hills or offer much performance.

Need to stop every 50 miles or so until you can get a place to plug in.
 
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maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
@Uncle Paul That's the model everyone is using.. Not the model I'm talking about. I just looked up all of the options on the I8. It has a 6 speed transmission on the gas motor (in my design, you wouldn't need a transmission on the gas motor), an 11.8 gallon fuel tank, and it's hp reported is combining the ICE with the Electric. It's doing Electric assist...

My concept, its not possible for the ICE to physically move the car. It's not in any way, shape, or form, connected to the drive shaft. It's mounted with a belt to a large alternator, and that's it. 3 power cables running from that alternator into the car, and then everything else is electric from that point forward. You'd derive 100% of the drive from the electric motor and 0% from the ICE.
 

Uncle Paul

Well-Known Member
Nov 1, 2013
6,299
7,598
Canyon Lake,CA
That is how it is on the i3.

BMW sells hardly any i8. Market failure. Good looking but overpriced and way to complicated. Just opening the hood takes two people that have been trained on the opening proceedure.
 

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
@Uncle Paul

Just looked up the details on the i3. It's closer to my concept, but still not there. It has a 42.2kwh battery pack, and the 2 cylinder engine doesn't kick on until you are 5% battery life. It's being used as a battery backup, rather than the main power source. Have that engine kick on when the battery is at 100% power, and the battery pack is only a 10kwh battery pack. Use the engine as a power source for electricity, with the battery being a backup, and now you have my concept. When the motor is running at low RPM, not kicking out a ton of power, and you hit the accelerator, needing instant power, any excess power the engine hasn't yet been generating as it starts to spool up, is subsidized by pulling from the battery pack. Once the engine has spooled up, it pulled the power from the engine instead, which can now maintain that pedal to the floor.
 

maverick3n1

Member
Apr 30, 2019
44
27
Oceanside
I admit, this design would sound odd while driving, but realistically, with such a small engine, piped properly, it could be a whisper quiet engine, and you really wouldn't notice it.
 

ewoodrick

Well-Known Member
Apr 13, 2018
5,285
4,270
Buford, GA
You are describing basically a hybrid.

Biggest issue is that charging isn't that big of a deal. It's a normal interval for a stretch break. 3 hours in a car is a long time.
 
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swaltner

Active Member
Oct 13, 2012
1,631
1,678
Kansas, USA
Looking at the Honda EG4000cl, with a 6.3 gallon fuel tank, it can run at half power for 15.7 hours at 240v. If you're cruising at 65mph, that's over 1000miles on 6 gallons of gas, or nearly 162 miles per gallon. This particular generator weights 148lbs with the steel frame and everything else, which would not be needed. So in the end, you have a car that's nearly 1000lbs lighter weight (also making it more fuel efficient), gives you the peace of mind of not running out of power, and unheard of range on what is equivalent of a cruiser motorcycle fuel tank.

You're confusing electrical potential (Volts) with power (Watts). Volts means nothing when you ignore amperage (and thus total power). A little 9 Volt battery in a stun gun can be ramped to 30,000 Volts to even into the millions of Volts, but that doesn't mean it can run your house or the whole neighborhood off that 9 Volt battery.

The EG4000cl generator is a 4,000 Watt (peak) generator that can maintain 3,500 Watts continuous. Translating that into horsepower, that's 4.7 horsepower. Most EVs require somewhere around 15 kW (15,000 Watts or 20.1 hp) to maintain 55 mph on a level highway. You're 6.3 gallon tank is only going to run the engine for 9.7 hours at rated power (not the 15.7 hours you quote, which is when it's generating 1,750 Watts). It's also only able to supply 23% of the power demands of the vehicle (3.5 kW vs 15 kW).

If you ran for 10 hours at 55 mph with this setup, while you would travel 550 miles, you would FULLY DEPLETE a 115 kWh battery (11.5 kW shortfall for 10 hours is 115 kWh shortfall that needs to be made up by batteries). Your proposed 10 kWh battery wouldn't even allow this vehicle to drive a full hour at highway speeds. The little 3,500 Watt generator would help in this situation. With the same battery and not having the generator, so only the 115 kWh battery, you would only be able to travel 422 miles (115 kWh / 15 kW = 7.67 hours --- 7.67 hours at 55 mph = 422 miles). Yes, the little generator would help, but not near as much as I think you are claiming.
 
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PCP1701

Member
Sep 8, 2019
7
0
Norwood
So I had an idea that sounds like it would work, but I don't have all of the technical expertise that some in here have, so perhaps someone here may know how viable this concept would work...

So we have a great, efficient motor, but we still have limited range without taking a lot of time at a charge station. My thoughts were a way to make the vehicle lighter, give you 600+ miles of range, and be able to fill up the fuel tank for $20 or less.

To date, the only Hybrid concepts I've seen are gas engines with electrical motor assist. I think we have it all wrong though. The electric motor seems far more efficient, and has the added advantage of insane torque! So what if we took the concept of the Tesla, but made the battery pack MUCH smaller (say 10kw). We put an ICE in the vehicle, but a small, light weight one (we don't need a ton of power). Last, we put a 6 gallon fuel tank in the vehicle. Now we've just reduced the weight of this vehicle dramatically (battery pack would weight somewhere around 200 lbs instead of 1200).

How would it work? Everything would be exactly as it is in Tesla now. Everything is 100% electric with one exception. The power source for the electricity is shared between the battery pack and the ICE turning a powerful alternator. There are currently 4kw generators on the market that weight 150lbs or less and use very little fuel to generate that amount of power. Granted, they are putting out 120v/240v, but I'd imagine a custom built alternator with more windings wouldn't be too difficult to produce, and there are actually alternators out already that put out 3 phase AC.

For efficiency, the ICE would be running variable speeds. When you needed that burst of power, power would be drawn from both, the alternator and the battery, with the battery putting out less power as the ICE spools up and can compensate for the needed power draw. When you are cruising, the ICE is running at slower speeds, supplying enough power to keep your motors running and to recharge anything you've drawn from the batteries. In addition, you could have a plug in mode, for when you only use your car to drive to the grocery store and back etc (the battery pack should be able to last 40 miles or so on a charge). This way, you only use fuel when you want to go on a long trip, and you turn the ICE on.

Looking at the Honda EG4000cl, with a 6.3 gallon fuel tank, it can run at half power for 15.7 hours at 240v. If you're cruising at 65mph, that's over 1000miles on 6 gallons of gas, or nearly 162 miles per gallon. This particular generator weights 148lbs with the steel frame and everything else, which would not be needed. So in the end, you have a car that's nearly 1000lbs lighter weight (also making it more fuel efficient), gives you the peace of mind of not running out of power, and unheard of range on what is equivalent of a cruiser motorcycle fuel tank.

Thoughts?
I've really gotta say -- let's ditch the ICE for anything, and this is a concession, absolute emergency situations. For instance, I can see tolerating ICE engines in those huge arctic vehicles that have the tank style treads, and even then the ICE would only be for situations in which some unforeseen circumstances stranded someone with dead batteries. Or, perhaps an arctic research with and emergency diesel generator in case their solar energy system went down (not the panels but the energy transfer apparatus). Things like that.
 

303JeffB

Member
May 9, 2017
62
47
Colorado
You're confusing electrical potential (Volts) with power (Watts). Volts means nothing when you ignore amperage (and thus total power). A little 9 Volt battery in a stun gun can be ramped to 30,000 Volts to even into the millions of Volts, but that doesn't mean it can run your house or the whole neighborhood off that 9 Volt battery.

The EG4000cl generator is a 4,000 Watt (peak) generator that can maintain 3,500 Watts continuous. Translating that into horsepower, that's 4.7 horsepower. Most EVs require somewhere around 15 kW (15,000 Watts or 20.1 hp) to maintain 55 mph on a level highway. You're 6.3 gallon tank is only going to run the engine for 9.7 hours at rated power (not the 15.7 hours you quote, which is when it's generating 1,750 Watts). It's also only able to supply 23% of the power demands of the vehicle (3.5 kW vs 15 kW).

If you ran for 10 hours at 55 mph with this setup, while you would travel 550 miles, you would FULLY DEPLETE a 115 kWh battery (11.5 kW shortfall for 10 hours is 115 kWh shortfall that needs to be made up by batteries). Your proposed 10 kWh battery wouldn't even allow this vehicle to drive a full hour at highway speeds. The little 3,500 Watt generator would help in this situation. With the same battery and not having the generator, so only the 115 kWh battery, you would only be able to travel 422 miles (115 kWh / 15 kW = 7.67 hours --- 7.67 hours at 55 mph = 422 miles). Yes, the little generator would help, but not near as much as I think you are claiming.


swaltner's logic is right on point - here's a slightly different approach to the same logic

The concept is interesting, unfortunately the OP's physics won't work.

If your car consumes 300 wh/mi at 60 mph steady speed, that is equivalent to 18 kW power consumption. Your "alternator" (let's call it a generator) will be required to produce at least 18 kW just to keep the battery charged when you're driving at this speed. This power level will not allow recovery of the charge level of the battery. Once you do anything that pulls more power than the generator can produce, like trying to accelerate, the charge level will drop and not be made up until you stop using power to drive the car.

The 4 kW generator in your example along with a 10 kWh battery at the same 300 wh/mi and 60 mph would result in drive time of about 45 minutes before the battery depleted, given that the generator would be replacing power at 4kW during the drive (full load). Once the battery is depleted, you have to stop for 2.5 hours to let the generator recharge the battery.

I think the closest thing to what you are suggesting is the Chevy Volt - the propulsion for the car is all through the electric motors, the ICE is only used to drive a generator to recharge the 18 kWh battery when it depletes. In this case, the ICE is 100 hp (about 75 kW) or more than 20 times larger than the Honda generator - this allows for a usable performance envelope with about 50 miles of EV range before the ICE has to operate. This accomplishes at least 2 important things - the car can operate in most commuting uses without running the ICE, and when the ICE is necessary, it can charge the battery while driving.
 
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Vannex

Member
Sep 11, 2019
19
11
California
This idea goes completely against Elon Musk's vision and the reason for Tesla's existence. Fossil fuels are not sustainable. I am pretty disgusted that this was even suggested.
 

wdolson

Supporting Member
Supporting Member
Jul 24, 2015
7,823
10,948
Clark Co, WA
This same above concept could also potentially be used in propeller based airplanes, keeping the airplane light weight, but giving it a ton more power. The only difference is you don't need the instant burst of power, so you'd eliminate the battery pack, and instead, just run the electric motor powered prop off the alternator from the ICE. The Lycoming engines used in Cessna's weight over 300lbs, and burn 8-10 gallons of fuel per hour. What if you could eliminate those 40+ gallon fuel tanks, replace it with a 6 gallon fuel tank, be able to fly twice as long on that fuel tank, AND have a lot more available weight to the passengers?

Most Cessna's have a usable weight of between 800-1000lbs... not including fuel. Once you add fuel in, you are down to 500-600 usable lbs of weight.. a 4 seater Cesna isn't really a 4 seater at that point, unless everyone weight 125 lbs. Make this change, and you've freed up an additional 400 lbs or so of usable weight capacity, and have more performance to boot! Of course, the air frame would have to be redesigned to handle the extra performance, or there would have to be a limiter put in to prevent the engine from pulling too hard.

It won't work because you need a gas engine the same size you have now to drive the alternator and then an electric motor. It would be less efficient because it would be heavier. Hybrids only work efficiently when the ICE is running at peak efficiency 100% of the time it's running. That means when you aren't using all the power the motor is putting out, it's charging the battery. But there are all sorts of trade offs that keep you from running the motors 100% efficient or off because there are times the battery gets full, or you need to add power directly from the ICE. If you don't have any batteries, then the ICE needs to run at whatever the demand of the electric motor and that probably isn't it's most efficient setting.

Robert Heinlein used the phrase a lot and it comes up in engineering whenever discussing efficiency: There Ain't No Such Thing As A Free Lunch. Hybrids are a bridge technology. They allowed car makers to make battery powered cars when batteries were lower capacity and very expensive. It also allowed people who were unsure about the new power trains to have something familiar to fall back on, but they really are the worst of both worlds, you lugging around a big lump of iron and all the extra hardware to support an ICE and a gas tank, plus all the equipment of an electric drive train. They can squeeze out a little more efficiency than a pure ICE by running the engine at it's peak efficiency, but you're still running a motor that is, at best about 25% efficient burning a fuel that takes 8-16 KWH of electricity to refine as well as all the other losses getting it out of the ground and refined. Honda has announced a new ICE that can achieve 39% efficiency, but it isn't in production yet.

Pure electric drive trains peak at about 90-95% efficiency and can run in the real world over 70%. There is a graph out on the net comparing hydrogen to an EV and it estimates the efficiency from power generation station to turning the wheels on an EV is 65%. That includes transmission losses, charging losses, and the losses getting the wheels turning from the battery. Just the 8 KWH needed to refine a gallon of gas will propel a Model X around 25 miles (about 3 miles per KWH). That's half the MPG of the best hybrids with the electricity wasted refining the gallon of gas to go 50 miles in the hybrid.

People worry about the extra charge time for batteries with an EV, but in practice it really isn't a problem. When running around town the ~300 mile range of most of Tesla's fleet is more than enough for whatever you need to do in a day. You then come home and plug it in and leave it overnight.

On the road, supercharging is actually a boon to a body. I'm one of those people who will drive until I drop if given a chance, but I end up paying for it the next day (or week sometimes). But being forced to stop a couple of times in a day of driving and walk around forces me to stretch my legs and keeps me from getting stove up. I drove 600 miles in a day and while it took a couple hours longer than driving straight through, I wasn't wiped out when I got to my destination (tired but not sore and stiff) and the next day I felt just fine.

Most people don't take frequent road trips and those that do are usually retired and would prefer to take things at a leisurely pace anyway.

My Model S 90D has slightly less than 300 miles range and it's fine for a road trip. The current 370 range Model S would only require one stop in an average road trip day (500 miles or a bit more). So you sit down for lunch rather than grabbing fast food and eating it on the road? It's probably a bit healthier and safer to eat at a table anyway.

Pure EVs are vastly superior tech to hybrids. They are simpler machines (less to break and maintain), have better cargo space, better performance possible (though some EVs are deliberately made sluggish to prevent them being too popular), and the bulk of the time they are vastly easier to fuel and keep fueled. With batteries getting cheaper and networks like the supercharger network when you travel, the arguments against EVs get weaker and weaker every day.

ICE will be required for a while. There is no good alternative for air travel beyond some relatively short ranged experimental projects. For ocean going ships the only workable alternative is sails and that's much slower. Though computerized sails could make semi-automated sailing ships happen much cheaper than old sailing ships.

For ground transport ICE are dead tech walking, but they will be around for some time because it's going to take a very long time to replace all the existing ICE. There are over 1 billion ICE vehicles to replace and worldwide car and light truck production is about 100 million a year. Current battery production allows for about 1 million long range EVs to be built. It's going to take about 99 more GigaFactory equivalents to be able to build 100 million cars a year. Then after reaching 100 million a year it's going to take another decade to replace the 1 billion ICE (possibly less than that because of the ramp time to 100 million will be replacing some ICE, but the overall time between now and all ICE gone is more than 10 years, 20 years might be possible with a crash program starting tomorrow, but it will likely be longer than 20 years).

I believe hybrid sales have started to drop as hybrid owners switch to electric now there are enough 200 mile+ EVs out there. The hybrid is a dying tech like CD players. You can still get them in some cars, but they are being phased out in favor of newer formats.
 
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