I never said performance couldn't be improved, especially in a supercar, but at the cost of increased input power.
Adding a hybrid solution to a low power engine will improve overall efficiency but will create a reduction in engine performance due to the higher percentage of additional load during charging.
Adding the same solution to a high power engine will generate a reduced percentage of engine performance losses due to the high HP engine to begin with.
This whole discussion started about adding an option to our cars by marsrock7 and has evolved, or been side-tracked, into a super car and ALL possibilities of hybrid technology into increased performance...
Hybrids are interesting and work fairly well for economy, or short bursts of performance, but not very well for performance only.
The energy losses created when converting from the combustion to electrical storage, coupled with the mechanical losses used for the vehicle's motion, means the engine's output power must be split during the drive charge cycles.
Just some things to think about.
I will just quote from this again which is what started it all. Hybrid power is used very well for performance only applications as in racing, supercars and formula 1.
Of course they are not perfect by any means for its efficiency, cost and weight to make that power but it has an overall net advantage when used correctly which can combine its power where it counts in a performance only application.
I never said performance couldn't be improved, especially in a supercar, but at the cost of increased input power.
Adding a hybrid solution to a low power engine will improve overall efficiency but will create a reduction in engine performance due to the higher percentage of additional load during charging.
Adding the same solution to a high power engine will generate a reduced percentage of engine performance losses due to the high HP engine to begin with.
This whole discussion started about adding an option to our cars by marsrock7 and has evolved, or been side-tracked, into a super car and ALL possibilities of hybrid technology into increased performance...
😛
Thats the thing we are not adding the same solution to the high power engine. We are adding combined power for a power only advantage. Although these super cars can claim a little more efficiency it is not what the hybrid system was designed for in a performance only application.
As far as overall performance in other aspects such as handling since it was brought up there is a very good argument to be made here as well.
The Porsche 918 Spyder takes advantage of the hybrid system for both power and handling by being able to utilize the lowest center of gravity for the battery placement. This gives them a weight distribution advantage that they claim is another reason for going with a hybrid solution.
I get your argument of no free lunch but that is not the case when applied even if the losses of the conversion are enormous but the same argument can be used for using fossil fuel but this is not the point of it all. The point is it can be and has been used in performance only applications with a successful advantage.
I never said performance couldn't be improved, especially in a supercar, but at the cost of increased input power.
Adding a hybrid solution to a low power engine will improve overall efficiency but will create a reduction in engine performance due to the higher percentage of additional load during charging.
Adding the same solution to a high power engine will generate a reduced percentage of engine performance losses due to the high HP engine to begin with.
This whole discussion started about adding an option to our cars by marsrock7 and has evolved, or been side-tracked, into a super car and ALL possibilities of hybrid technology into increased performance...
😛
it doesn't really matter the input power requirements if the net output power is higher with the same amount of energy into the system. See: Superchargers. takes power to make power.
Even if it requires the gas engine to output more power, the net effect of the whole arrangement is that a larger percentage of the energy stored in each gallon of gasoline can be turned into physical work. a gallon of gasoline contains approximately 120,000,000 joules of energy.
When an engine uses that energy, it creates power. 1 watt is 1 joule per second of energy output, or expelled from the system (in this case the engine)
Modern gasoline engines have a maximum thermal efficiency of about 20% to 35% with a theoretical limit of ~46% efficiency at a steady state load. This means that in this optimal state, when a pure gasoline engine car burns through 1,000,000 joules of energy (1/120th of a gallon) the amount of energy that can be made into useful work is only 350,000 Joules. Power is determined by how fast the car burns through this amount of energy.
Hybrid systems are able to recover around a net amount of around 10-15% of the energy that the gasoline engine cannot turn into useful work. this is a sum of the amount of energy recovered by the hybrid system minus the amount of energy that it takes away from the gasoline engine. The gains to be had with a hybrid are most relevant where an engine is idling, coasting, or decelerating, because now the engine goes into negative efficiency. the engine isn't doing any work, but the engine is still generating power and using energy. Without a hybrid energy recovery system, this energy is wasted as dissipated heat. With a hybrid system, it keeps the efficiency from going negative during these scenarios because now the engine is still doing useful work, which is running the generator which pushes some of the energy back into the battery.
In a net effect, the 1,000,000 joules of stored energy gets 500,000 joules instead of 350,000 joules becoming actually useful for moving the car. Controlling the rate at which this energy is output is down to other factors, which will dictate how much power you are producing at a given moment in time, but having a larger pool of energy means that if you want to output all of this power in 5 seconds at a constant rate, you can produce 5 seconds of 100kW (134hp) of power instead of 5 seconds of 70 kW (94 hp). (consider that this is 1/120th of a gallon of gasoline we're talking about here)
if you are not defining the performance of an engine by the HP it makes, idk what to tell you.
First things first, I found no mention of Audi's 12v system providing torque back to the crank. From what I'm reading it only used for start/stop and reducing engine load from accessories.
Short bursts of performance is what I had in mind, depending on how much battery would be necessary to say... Run an AutoX course a few times or something. My mental abomination of MHEV strips out all the economy stuff including increasing engine idle load and cruise load, puts power out above 50% throttle and regens only when engine is decelerating. I would fully expect to juice this at home, rather than it being self-sustaining.
I agree a hard (geared?) connection to the transmission would likely be more reliable in the long run but I'm having trouble envisioning how it would be any easier to develop. These are already developed to be belt driven and assume the role of an alternator, so my initial thoughts are to use it as such even if it needs its own secondary belt drive. Maybe a cogged belt system could nix the concern of belt slippage without having to use something ridiculously wide.
Weight is a concern, but assuming a 2200lb Spyder with a 180hp NA 2ZZ gained 10 peak hp from this, at the cost of adding (stab in the dark, see pic) 100lbs, there would still be a small gain in power/weight.
Also area under the curve should be taken into account... This system would greatly enhance throttle response and low end torque, which the 2ZZ lacks before lift. Area under the curve should greatly improved.
I have thought of and done some reading on wheel mounted motors as well. They are out there, and not terribly expensive. There are quite a few folks who use them to build electric motorcycles with great results. My concerns are:
1. The fact that even though car wheel sized kits are available, I have found nothing about anybody actually retrofitting them to a normal ICE car successfully. Nothing with detail anyway.
2. Adding these to the wheels would drastically increase the unsprung weight of said wheels, which is sure to affect handling. Installing them in front would likely necessitate a complete redesign of the front suspension both due to increase in wheel weight and finding a way for them to fit in general. I would also be concerned they could increase load on our precious power steering system.
I also earlier came across a PDF (too large to upload here) that I can no longer seem to dig up the source link to. A certain section discussed performance differences between an alternator generator providing power to the crank vs an electric supercharger. The supercharger is touted to be 5x as effective.
The other day an article popped up in my feed about Garrett beginning to produce "electric turbochargers" in which an electric motor will sense power demand from operator and immediately spool the turbo up, producing a baseline boost and eliminating lag, until the exhaust gases overcame it. This would allow the use of smaller displacement engines and/or much bigger turbos.
You missed my whole original point, a low HP output engine with an added MHEV system (added to our Spyder) would have to divert some of the engine's output mechanical power when recharging the batteries and it may be significant depending on the additional weight added for the system. This would therefore reduce performance during this recharge period even though it would have short bursts of improved performance. Just some thoughts, not an argument for or against Hybrid technology or its uses. I know electric motors have the benefit of adding improved efficiency and can easily add power when needed, just not sure it fits in a retrofitted Spyder...
You're theoretical Joule discussion is just that. A motor/generator has a rated HP at a certain speed. At that speed, the motor/generator action generates a CEMF voltage internal to the motor that is measured across the armature at a certain current. These values determine output power which is a real world Joule/second concept and this value is limited or the motor/generator is destroyed. You cannot get an instantaneous energy much greater than the rated device for any period of time without damaging the motor/generator winding insulation, rectifier diodes, etc... BTW, power in a motor is defined as Power (J/S) = Torque (N-m) x Angular Velocity (r/s) or rotational force times its angular velocity.
Oh, and there is no such thing as negative efficiency... Efficiency is the ratio of input and output powers, or energy, and is defined as output power/(output power + all of the system power losses) and its values lives between 0 -> 1.
I agree a hard (geared?) connection to the transmission would likely be more reliable in the long run but I'm having trouble envisioning how it would be any easier to develop. These are already developed to be belt driven and assume the role of an alternator, so my initial thoughts are to use it as such even if it needs its own secondary belt drive. Maybe a cogged belt system could nix the concern of belt slippage without having to use something ridiculously wide.
Weight is a concern, but assuming a 2200lb Spyder with a 180hp NA 2ZZ gained 10 peak hp from this, at the cost of adding (stab in the dark, see pic) 100lbs, there would still be a small gain in power/weight.
Also area under the curve should be taken into account... This system would greatly enhance throttle response and low end torque, which the 2ZZ lacks before lift. Area under the curve should greatly improved.
I was thinking of a more engineered approach from a company conversion for our transmissions where they can split part of the case and modify what needs to be done. As far as belts go I just don't see it being able to handle the torque especially on a side where the crank is just spinning accessories with very little load. Maybe a chain but I dont know what the forces might do in terms of bearing stresses.
When the manufactures of these supercars write about combined horsepower they seldom mention the actual purpose of these motors which is more or less torque gap filling. Engines by nature are not perfect in terms of flat torque delivery and one of the many reasons why V12 are chosen over V8s apart from the power but the packaging is often the problem. They are finding that they can get the same kind of V12 performance using electric motors to fill in the gaps. For the 2ZZ as you have illustrated in your graph it would be beneficial but unfortunately I think the 2AR trumps this solution by just being a better motor where it counts, costs and the least complex. I have also heard of the electric supercharger and turbo charger and I think that would be a great solution but it comes at a cost of engine longevity for any boost option. Maybe a very small supercharger system that can be added inline with very low boost where it can work within the fueling limits of the stock ECU or just a small change in injector size.
There is another highly under-utilized waste product from ICE engines: heat.
This isn't low-grade heat either. When you have 20 feet of piping that is sitting at temperatures high enough to vaporize alcohol, or even water, its a shame to just vent it. Better refrigerants vaporize at much lower temps.
Heat can be stored in thermal sinks and used for constant boost. Yes, losses, sure. But right now, it is 100% waste. It is the enemy of turbo/superchargers, friend of cat converters. Route it correctly, and collect it on the intake (I'm looking at you, Mr. Intercooler) and the exhaust side, give the cat what it needs, then use tge rest to supplement the ICE with a small steam-style engine.
Why nobody do this? Complexity? No, a VGT is pretty complex. Weight? Maybe. Cost? Maybe, but obviously we would need improved efficiency to do it in the first place. Maybe its just poor ROI? But... the heat is *free*.
Yep, the energy created in the combustion chamber has two basic effects; push the piston downward for mechanical energy transfer and generate waste heat. Current technology engines are designed to be emission friendly, which costs efficiency and increases fuel consumption which actually counteracts the whole emissions design. If efficiency was the primary design factor, less fuel would be needed, but with an increase in emissions. Seems we struggle to find an appropriate balance.
Thermocouples, while having pretty meager efficencies, are just about the least complex conversion mechanism we have. Straight from heat to elecricity, but I am not sure what the volume/weight:power ratio is. Assuming it is tolerable, one could charge a battery at least? Obviously all of this assumes proper sizing of components.
But, why am I sitting here asking all this? Haven't actual eggheads (that's a compliment) like neomr2, dblotii, and about 20 others just in this small community already thought of this? Nobody at Toyota or Honda ever gave all that heat any thought?
So there must be some fruit that hangs lower, but honestly, I just cannot imagine that these ridiculous start-on-demand engines are lower-hanging fruit than looking at large quantities of 600F exhaust gas. Obviously, I haven't looked at actual numbers, nor have the engineering background that many others here have.
You make a good point, neo, that emissions are taking top priority when we once again face the fact that we can't have it all. Still, a thermocouple and electric motor doesn't create much pollution, we just get more power from the original pollution. You really only need the juice nearly on demand (ie, capacitors). There is a bit of lag moving the heat around, though. Again, there are low tech, inexpensive, simple solutions for that.
I bet the numbers just don't agree. Frickin' engineers and their reality checks, harshin' my pipedreams...
