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I'm seriously waiting for auto-makers to pull their heads out of their asses and start putting kinetic energy capture systems into every car, economy to perform

by iaw 10y ago

I'm seriously waiting for auto-makers to pull their heads out of their asses and start putting kinetic energy capture systems into every car, economy to performance. The absurdly priced Porsche 918 is the only car to date that takes advantage of this technique in an ideal fashion (small batteries, small electric motors augment the engine and brakes). After that, what about ICE's that run at optimal load/RPM for the highest possible efficiency to charge a smallish electrical system? Batteries are still a long way off from gasoline in their energy density. Gasoline will never be "clean" but the way we burn it in our existing automotive fleet is horribly inefficient. There's this beautiful middle ground in the technology that no one is exploring and it's such a shame.

thomas11 10y ago
Isn't the Chevrolet Volt what you describe in your third paragraph?
- joezydeco 10y ago
  Or Mazda's i-ELOOP?
  - iaw 10y ago
    Nope, the Mazda i-ELOOP system scavenges waste kinetic energy to run only the electrical system as opposed to augmenting propulsion. It's a step in the right direction but is a 5% efficiency gain opposed to a 50% gain.
- beamso 10y ago
  BMW i3 REX as well.
  - iaw 10y ago
    Close, except for they lobbed a motorcycle engine into an electric car and called it a "range-extender" but the engine can't generate power to meet maximum demand of the car's electrical system. So, instead of putting the motorcycle engine in as an afterthought take a 1.5l turbo as the primary source of electricity generation.
    - luca_ing 10y ago
      > So, instead of putting the motorcycle engine in as an afterthought take a 1.5l turbo as the primary source of electricity generation. This is kinda what they did on my new 225xe. 7(?)kWh battery, decent electrical drive, and said 1.5l turbo for if the car needs more power or range. Under real-world conditions, the battery seems to be good for about 40km of electrical driving in my current temperate climate (where I don't really need cooling or heating). So far, it's a fun car.
      - iaw 10y ago
        I hadn't heard of the 225xe, that's a much more intelligent build out.
      - masklinn 10y ago
        The 225xe looks like a completely different system, it's not a series hybrid where the ICE feeds into the electric engine, it's a parallel hybrid with completely separate drivetrains, the electric engine in propulsion and the ICE in traction (which can be used at the same time for 4WD).
    - URSpider94 10y ago
      Why put a bigger motor in? You really don't need to meet the max power consumption of the electric motors, that's what the battery is there for. However, I will point out that the i3 REX gets relatively poor fuel economy when running on gas -- only about 40 mpg, nowhere near what a parallel-hybrid Prius can get.
- iaw 10y ago
  Edit: corrected a mistaken assessment here. Yes, Volt is closest on the market but it's a horrible car. My point is that every single car produced from VW to Ferrari can get 50% better fuel efficiency if the auto manufacturers changed their approach to the problem.
  - rdtsc 10y ago
    > Yes, Volt is closest on the market but it's a horrible car. Ok, I am curious why. Is it one specific thing? Is it something fixable (like needs newer generation batteries)?
  - Tempest1981 10y ago
    Horrible for you, or for everyone?
  - Tagbert 10y ago
    I'm curious why you think its horrible. Have you had a bad experience driving one? It seems well matched to a lot of real world use cases.
  - URSpider94 10y ago
    One word: customers. People wouldn't buy them. The cost to add a motor/generator and storage battery to a car is substantial, and for most buyers, they'll never recover the cost in fuel savings over their ownership.
  - bluGill 10y ago
    50%? That is only in the worst case of stop and go traffic. The volt and pirus are a small aerodynamic cars. They would get in the upper 30mpg range with a traditional power train. On the highway they could get better mpg with the right traditional power train (0-60 times would be in the 20 second range - there are obvious reason nobody does this). That hybrid system is just extra weight once the battery is exhausted so you need a slightly bigger engine to haul it around on pure highway driving. Don't get me wrong, hybrid makes sense for most people. However it isn't that the system is more efficient for everything, it is that for the way most people [want to] drive it pulls in enough advantages to be worth the negatives.
ZeroGravitas 10y ago
Aren't you describing the very popular Prius? And PHEV cars (and buses) seem to be a major new segment generally.
lucaspiller 10y ago
I've just bought a new-to-me Prius and I think the way it works is the way forward until the issues with electric-only cars are resolved (i.e. how to refill it in 2 minutes as opposed to 2+ hours): The ICE is connected to the drive shaft via the 'hybrid synergy drive' which is a gear box and electric drive in one. It can drive the vehicle either under electric mode with the ICE off, with both electric and ICE, or in electric mode while the ICE charges the battery. When you brake it cuts power to the ICE (either just cutting the fuel, or stopping it completely) and charges the battery. There are also normal brake disks if you push the peddle extra hard. I like it because it's relatively mechanically simple, which means less things can break. The ECU does a lot of work, but try and find a car that doesn't nowadays. Also it only needs electric motors in one place - the rest of the axle and drive system is exactly the same as a normal car. The only thing really letting it down is the low capacity battery pack, but I guess that's for cost savings. There is also a plug-in version which can do 26 miles on electricity alone. Toyota offer this as an option in most of their cars, even the Rav4 SUV, so I expect in the next 10 years it will become standard across their range.
- 2sk21 10y ago
  Good points - I should also note that one of the motor generators actually doubles in functionality as the starter motor for the internal combustion engine. The Prius transmission system is truly a work of wonder and deserves more recognition by the wider community.
  - lucaspiller 10y ago
    Oh I forgot about that one. It basically replaces the automatic transmission, starter motor/alternator, clutch and braking system with one simple unit. It has a total of six fixed gears in a planetary arrangement. Unlike a normal automatic transmission (which quite often fails in older vehicles) it doesn't change gears, so should last a lot longer. Here are some good articles explaining how it works with diagrams: http://prius.ecrostech.com/original/Understanding/PowerSplitDevice.htm http://prius.ecrostech.com/original/Understanding/PowerSplit... http://prius.ecrostech.com/original/Understanding/WhatsGoingOnAsIDrive.htm http://prius.ecrostech.com/original/Understanding/WhatsGoing...
masklinn 10y ago
> After that, what about ICE's that run at optimal load/RPM for the highest possible efficiency to charge a smallish electrical system? I've long wondered about that given so many trains and ships run that way using electrical transmission from the prime mover ("that's what "diesel-electric" is), I know little about the concerns so I must be missing some significant drawback on the scheme given so few hybrids are "series" and most manufacturers go for either parallel or split topologies. Of note, an other potential advantage of a series hybrid is you can run alternative ICE topologies e.g. with high but very short efficiency bands.
- bluGill 10y ago
  A mechanical gear transmission is more efficient than a generator and motor. Can you make up that difference? For trains nobody has the ability to make the required parts of that size (this might be in part that you can't fit them in the space required - I think you could build the machine to make them if you wanted it) It is only with the most recent emissions standards that the losses from non-optimal RPM is a significant factor and the generator/motor is better.
- detaro 10y ago
  The big issue with trains is starting to move: that requires a slipping clutch, which is inefficient and maintenance-intensive. Also you tend to loose power while switching gears. Lower-power trains (e.g. around 300 kW per motor) are still available with mechanical coupling. In ships, gears are used up into the multi-Megawatt range, but there you don't need a clutch and have a lot of space and mass available.
Grishnakh 10y ago
They are exploring it, it's just slow. Lots of cars now come with "mild hybrid" systems which capture kinetic energy and store it in a supercapacitor, using it to charge the battery and power electrical loads (which are significant these days, with things like electric power steering). Mazda's i-eLoop is one such system (available only on high-end vehicles at additional cost), and Volvo has a similar system, and I imagine some other automakers do too. The reason you don't see this kind of system everywhere is most likely cost; these systems cost extra. I have the Mazda system on my car; there's a pricey supercapacitor for storing power, plus a pricey DC-to-DC converter under the driver's seat, plus a special high-voltage alternator, plus a special battery. It improves fuel economy by 1-2mpg, which is the other reason you probably don't see them that much: an extra $500 or more in the new price of a car is a lot for an extra 1-2mpg when gas is $2/gallon and everyone's buying SUVs. Such systems could be done better, but that's likely going to cost even more; to get a more significant improvement you really need to go full-hybrid with a large traction motor, which of course is going to make the vehicle cost even more. Take a look at the Chevy Volt for a good example of what you can achieve here: it's a serial hybrid with a small gas engine with generator plus a traction motor that actually moves the car. It can go 50+ miles without using any gas, which is pretty cool, but when the gas engine comes on (like for long trips) it can only get fuel economy in the low 40s because of the lossiness in the system. On top of that, having all that hardware in the car (engine, generator, motor, battery pack) limits the useful space, and the cost of the vehicle is rather high. Or you can get a Toyota Prius which is a parallel hybrid (engine drives wheels) and gets much better highway economy, but it can't go very far without burning gas and it's pretty expensive for an economy car with very anemic performance.

by iaw 10y ago

thomas11 10y ago

Isn't the Chevrolet Volt what you describe in your third paragraph?

joezydeco 10y ago
Or Mazda's i-ELOOP?
- iaw 10y ago
  Nope, the Mazda i-ELOOP system scavenges waste kinetic energy to run only the electrical system as opposed to augmenting propulsion. It's a step in the right direction but is a 5% efficiency gain opposed to a 50% gain.
beamso 10y ago
BMW i3 REX as well.
- iaw 10y ago
  Close, except for they lobbed a motorcycle engine into an electric car and called it a "range-extender" but the engine can't generate power to meet maximum demand of the car's electrical system. So, instead of putting the motorcycle engine in as an afterthought take a 1.5l turbo as the primary source of electricity generation.
  - luca_ing 10y ago
    > So, instead of putting the motorcycle engine in as an afterthought take a 1.5l turbo as the primary source of electricity generation. This is kinda what they did on my new 225xe. 7(?)kWh battery, decent electrical drive, and said 1.5l turbo for if the car needs more power or range. Under real-world conditions, the battery seems to be good for about 40km of electrical driving in my current temperate climate (where I don't really need cooling or heating). So far, it's a fun car.
    - iaw 10y ago
      I hadn't heard of the 225xe, that's a much more intelligent build out.
    - masklinn 10y ago
      The 225xe looks like a completely different system, it's not a series hybrid where the ICE feeds into the electric engine, it's a parallel hybrid with completely separate drivetrains, the electric engine in propulsion and the ICE in traction (which can be used at the same time for 4WD).
  - URSpider94 10y ago
    Why put a bigger motor in? You really don't need to meet the max power consumption of the electric motors, that's what the battery is there for. However, I will point out that the i3 REX gets relatively poor fuel economy when running on gas -- only about 40 mpg, nowhere near what a parallel-hybrid Prius can get.
iaw 10y ago
Edit: corrected a mistaken assessment here. Yes, Volt is closest on the market but it's a horrible car. My point is that every single car produced from VW to Ferrari can get 50% better fuel efficiency if the auto manufacturers changed their approach to the problem.
- rdtsc 10y ago
  > Yes, Volt is closest on the market but it's a horrible car. Ok, I am curious why. Is it one specific thing? Is it something fixable (like needs newer generation batteries)?
- Tempest1981 10y ago
  Horrible for you, or for everyone?
- Tagbert 10y ago
  I'm curious why you think its horrible. Have you had a bad experience driving one? It seems well matched to a lot of real world use cases.
- URSpider94 10y ago
  One word: customers. People wouldn't buy them. The cost to add a motor/generator and storage battery to a car is substantial, and for most buyers, they'll never recover the cost in fuel savings over their ownership.
- bluGill 10y ago
  50%? That is only in the worst case of stop and go traffic. The volt and pirus are a small aerodynamic cars. They would get in the upper 30mpg range with a traditional power train. On the highway they could get better mpg with the right traditional power train (0-60 times would be in the 20 second range - there are obvious reason nobody does this). That hybrid system is just extra weight once the battery is exhausted so you need a slightly bigger engine to haul it around on pure highway driving. Don't get me wrong, hybrid makes sense for most people. However it isn't that the system is more efficient for everything, it is that for the way most people [want to] drive it pulls in enough advantages to be worth the negatives.

ZeroGravitas 10y ago

Aren't you describing the very popular Prius? And PHEV cars (and buses) seem to be a major new segment generally.

lucaspiller 10y ago

I've just bought a new-to-me Prius and I think the way it works is the way forward until the issues with electric-only cars are resolved (i.e. how to refill it in 2 minutes as opposed to 2+ hours): The ICE is connected to the drive shaft via the 'hybrid synergy drive' which is a gear box and electric drive in one. It can drive the vehicle either under electric mode with the ICE off, with both electric and ICE, or in electric mode while the ICE charges the battery. When you brake it cuts power to the ICE (either just cutting the fuel, or stopping it completely) and charges the battery. There are also normal brake disks if you push the peddle extra hard. I like it because it's relatively mechanically simple, which means less things can break. The ECU does a lot of work, but try and find a car that doesn't nowadays. Also it only needs electric motors in one place - the rest of the axle and drive system is exactly the same as a normal car. The only thing really letting it down is the low capacity battery pack, but I guess that's for cost savings. There is also a plug-in version which can do 26 miles on electricity alone. Toyota offer this as an option in most of their cars, even the Rav4 SUV, so I expect in the next 10 years it will become standard across their range.

2sk21 10y ago
Good points - I should also note that one of the motor generators actually doubles in functionality as the starter motor for the internal combustion engine. The Prius transmission system is truly a work of wonder and deserves more recognition by the wider community.
- lucaspiller 10y ago
  Oh I forgot about that one. It basically replaces the automatic transmission, starter motor/alternator, clutch and braking system with one simple unit. It has a total of six fixed gears in a planetary arrangement. Unlike a normal automatic transmission (which quite often fails in older vehicles) it doesn't change gears, so should last a lot longer. Here are some good articles explaining how it works with diagrams: http://prius.ecrostech.com/original/Understanding/PowerSplitDevice.htm http://prius.ecrostech.com/original/Understanding/PowerSplit... http://prius.ecrostech.com/original/Understanding/WhatsGoingOnAsIDrive.htm http://prius.ecrostech.com/original/Understanding/WhatsGoing...

masklinn 10y ago

> After that, what about ICE's that run at optimal load/RPM for the highest possible efficiency to charge a smallish electrical system? I've long wondered about that given so many trains and ships run that way using electrical transmission from the prime mover ("that's what "diesel-electric" is), I know little about the concerns so I must be missing some significant drawback on the scheme given so few hybrids are "series" and most manufacturers go for either parallel or split topologies. Of note, an other potential advantage of a series hybrid is you can run alternative ICE topologies e.g. with high but very short efficiency bands.

bluGill 10y ago
A mechanical gear transmission is more efficient than a generator and motor. Can you make up that difference? For trains nobody has the ability to make the required parts of that size (this might be in part that you can't fit them in the space required - I think you could build the machine to make them if you wanted it) It is only with the most recent emissions standards that the losses from non-optimal RPM is a significant factor and the generator/motor is better.
detaro 10y ago
The big issue with trains is starting to move: that requires a slipping clutch, which is inefficient and maintenance-intensive. Also you tend to loose power while switching gears. Lower-power trains (e.g. around 300 kW per motor) are still available with mechanical coupling. In ships, gears are used up into the multi-Megawatt range, but there you don't need a clutch and have a lot of space and mass available.

Grishnakh 10y ago

They are exploring it, it's just slow. Lots of cars now come with "mild hybrid" systems which capture kinetic energy and store it in a supercapacitor, using it to charge the battery and power electrical loads (which are significant these days, with things like electric power steering). Mazda's i-eLoop is one such system (available only on high-end vehicles at additional cost), and Volvo has a similar system, and I imagine some other automakers do too. The reason you don't see this kind of system everywhere is most likely cost; these systems cost extra. I have the Mazda system on my car; there's a pricey supercapacitor for storing power, plus a pricey DC-to-DC converter under the driver's seat, plus a special high-voltage alternator, plus a special battery. It improves fuel economy by 1-2mpg, which is the other reason you probably don't see them that much: an extra $500 or more in the new price of a car is a lot for an extra 1-2mpg when gas is $2/gallon and everyone's buying SUVs. Such systems could be done better, but that's likely going to cost even more; to get a more significant improvement you really need to go full-hybrid with a large traction motor, which of course is going to make the vehicle cost even more. Take a look at the Chevy Volt for a good example of what you can achieve here: it's a serial hybrid with a small gas engine with generator plus a traction motor that actually moves the car. It can go 50+ miles without using any gas, which is pretty cool, but when the gas engine comes on (like for long trips) it can only get fuel economy in the low 40s because of the lossiness in the system. On top of that, having all that hardware in the car (engine, generator, motor, battery pack) limits the useful space, and the cost of the vehicle is rather high. Or you can get a Toyota Prius which is a parallel hybrid (engine drives wheels) and gets much better highway economy, but it can't go very far without burning gas and it's pretty expensive for an economy car with very anemic performance.