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This would be easily solved if car manufacturers cared at all… simply cover the bottom of the car with panels. A side benefit would be the increased fuel econom

This would be easily solved if car manufacturers cared at all… simply cover the bottom of the car with panels. A side benefit would be the increased fuel economy from the cleaner airflow and reduction in drag (this is an inherit benefit of electric vehicles—-especially trucks). It’s not done because no one looks under their cars and it’s easier/cheaper to manufacture and design for cooling. I should add that installing a simple piece of metal cut to fit over the bottom of your vehicle isn’t a great idea if it doesn’t properly account for the changes in ventilation and cooling that it causes.

connor4312 5y ago
I recently bought a new Prius. Toyota even has bolt holes to allow easy installation of a "cat shield", and could install a nice steel plate there with minimal additional cost, but instead it was on me to buy and install an aftermarket product. Maybe it's a question of liability?
- avalys 5y ago
  This isn't a problem for about 90% of the population in the US. At best, Toyota would offer it as an option.
- renewiltord 5y ago
  My hypothesis is that when you’re selling a product to a price-sensitive customer you have to strip down things.
- imglorp 5y ago
  The shield would affect price, weight and mileage.
Someone1234 5y ago
We're starting to see changes in vehicle design to address this but typically it is only during a major model redesign rather than between model years. The popular solution, that is almost free, is simply moving the catalytic converter from mid-tailpipe to directly connected to the engine block. Essentially the CC is surrounded by the engine block itself on all sides, and you have to disassemble the entire engine from above to get to it. But you're talking about 4~ years between redesigns and that doesn't address any of the vehicles already sold/tens of years of old designs.
- d0gsg0w00f 5y ago
  I believe that the increased heat level closer to the engine would alter the CC's performance characteristics. [1] - https://www.open.edu/openlearn/science-maths-technology/science/chemistry/the-three-way-catalytic-converter/content-section-1.5.2 https://www.open.edu/openlearn/science-maths-technology/scie...
  - dotancohen 5y ago
    Alter: Improve. Catalytic converters must be hot to operate effectively.
    - CarVac 5y ago
      Improve the performance but reduce the lifespan.
- hbwo40 5y ago
  > The popular solution, that is almost free, is simply moving the catalytic converter from mid-tailpipe to directly connected to the engine block. Essentially the CC is surrounded by the engine block itself on all sides, and you have to disassemble the entire engine from above to get to it. You are aware a catalytic converter is a wear part that is a component of the exhaust system, right? You want a block disassembly to replace a part so understood to be a wear part it’s covered by US federal warranty to 80,000 miles? You just added at least eight hours of labor — which in major metros can reach $300/hr — and risk to a one hour job. There are absolutely zero reasons to open a block unless the engine itself is imperiled or under inspection. Blocks are notoriously difficult to reassemble to spec and the idea is to avoid opening them as long as possible. I’m aware manufacturers are burying cats closer to the block but that’s universally thought to be a bad idea for owners and a great idea for mechanics. Now you want to put it inside the block? Please, please, please don’t design cars, and let me know which manufacturer came up with that genius solution so I can avoid driving one of their vehicles for the rest of my life. The rest of you should as well because all that “fix” does is octuple your repair bill for fixing a bad cat and risk your engine for doing the same. No disrespect, truly, but after over a decade of being a tech, that might be the stupidest idea I’ve ever heard in vehicle design. And all of that for what, to avoid theft? What makes you think they won’t just steal the car instead if the cat is buried in some Fort Knox inside? We all know where the stolen cats go. Why not start with those places rather than lobby for some John Deere type screwing over on self repair?
bradlys 5y ago
People buy at a price point. Adding those panels adds cost. You’d have to give something up to get those panels. Luxury cars have had these panels for a long time because they’re built to a higher price point.
- RNCTX 5y ago
  Yep. Just keeping dirt and water out goes a long way for parts longevity, too.
  - greedo 5y ago
    And helps dramatically with soundproofing.
trollied 5y ago
The problem will go away over time as we migrate to electric cars.
- powerbroker 5y ago
  Perhaps a new problem -- that of stealing the more valuable batteries, might emerge?
  - jccooper 5y ago
    That's approximately the same sort of operation as stealing the engine of a car. Not something you can do in a couple minutes with a battery powered angle grinder.
    - leecb 5y ago
      Tesla has demonstrated that their batteries can be removed and replaced in a matter of a minute or two, given the right equipment. https://www.tesla.com/videos/battery-swap-event https://www.tesla.com/videos/battery-swap-event Since the batteries cost an order of magnitude more than a catalytic converter, this could justify criminals developing more sophisticated equipment to pull it off.
      - skunkworker 5y ago
        This used to be more true, but with their new battery packs becoming an integral part of the frame, this is no longer going to be possible. https://electrek.co/2021/01/19/tesla-structural-battery-pack-first-picture/ https://electrek.co/2021/01/19/tesla-structural-battery-pack...
      - johnnywasagood 5y ago
        Four bricks and a jack I guess.
      - SilasX 5y ago
        Interesting, I’ve always thought it would make more sense to optimize for hot-swappable batteries rather than try to improve supercharger tech.
deleted 5y ago
[deleted]
dotancohen 5y ago
Then where would the catalytic converter dump the heat? Those things are dangerously hot and need cooling.
- erik_seaberg 5y ago
  The engine dumps heat to the radiator and the exhaust. I think the catalyst does enable exothermic reactions, but it’s not using power, so it can’t get hotter than the outgoing exhaust (although that is pretty toasty). A computer adjusts the fuel/air ratio and timing to keep the incoming temperature and oxygen level in the catalyst’s effective range. Some models even have a heater to get the catalyst working quickly after a cold start.
kube-system 5y ago
Manufacturers have been slowly adding plastic panels for aerodynamics under cars over the past couple of decades. Many new cars have just about everything covered other than areas that get too hot, like the exhaust.
giarc 5y ago
Automakers resisted putting backup cameras in cars and they provide the driver utility. A panel under the car adds no immediate utility to the buyer and therefore the extra $200 or whatever it would cost would detract buyers.

connor4312 5y ago

I recently bought a new Prius. Toyota even has bolt holes to allow easy installation of a "cat shield", and could install a nice steel plate there with minimal additional cost, but instead it was on me to buy and install an aftermarket product. Maybe it's a question of liability?

avalys 5y ago
This isn't a problem for about 90% of the population in the US. At best, Toyota would offer it as an option.
renewiltord 5y ago
My hypothesis is that when you’re selling a product to a price-sensitive customer you have to strip down things.
imglorp 5y ago
The shield would affect price, weight and mileage.

Someone1234 5y ago

We're starting to see changes in vehicle design to address this but typically it is only during a major model redesign rather than between model years. The popular solution, that is almost free, is simply moving the catalytic converter from mid-tailpipe to directly connected to the engine block. Essentially the CC is surrounded by the engine block itself on all sides, and you have to disassemble the entire engine from above to get to it. But you're talking about 4~ years between redesigns and that doesn't address any of the vehicles already sold/tens of years of old designs.

d0gsg0w00f 5y ago
I believe that the increased heat level closer to the engine would alter the CC's performance characteristics. [1] - https://www.open.edu/openlearn/science-maths-technology/science/chemistry/the-three-way-catalytic-converter/content-section-1.5.2 https://www.open.edu/openlearn/science-maths-technology/scie...
- dotancohen 5y ago
  Alter: Improve. Catalytic converters must be hot to operate effectively.
  - CarVac 5y ago
    Improve the performance but reduce the lifespan.
hbwo40 5y ago
> The popular solution, that is almost free, is simply moving the catalytic converter from mid-tailpipe to directly connected to the engine block. Essentially the CC is surrounded by the engine block itself on all sides, and you have to disassemble the entire engine from above to get to it. You are aware a catalytic converter is a wear part that is a component of the exhaust system, right? You want a block disassembly to replace a part so understood to be a wear part it’s covered by US federal warranty to 80,000 miles? You just added at least eight hours of labor — which in major metros can reach $300/hr — and risk to a one hour job. There are absolutely zero reasons to open a block unless the engine itself is imperiled or under inspection. Blocks are notoriously difficult to reassemble to spec and the idea is to avoid opening them as long as possible. I’m aware manufacturers are burying cats closer to the block but that’s universally thought to be a bad idea for owners and a great idea for mechanics. Now you want to put it inside the block? Please, please, please don’t design cars, and let me know which manufacturer came up with that genius solution so I can avoid driving one of their vehicles for the rest of my life. The rest of you should as well because all that “fix” does is octuple your repair bill for fixing a bad cat and risk your engine for doing the same. No disrespect, truly, but after over a decade of being a tech, that might be the stupidest idea I’ve ever heard in vehicle design. And all of that for what, to avoid theft? What makes you think they won’t just steal the car instead if the cat is buried in some Fort Knox inside? We all know where the stolen cats go. Why not start with those places rather than lobby for some John Deere type screwing over on self repair?

bradlys 5y ago

People buy at a price point. Adding those panels adds cost. You’d have to give something up to get those panels. Luxury cars have had these panels for a long time because they’re built to a higher price point.

RNCTX 5y ago
Yep. Just keeping dirt and water out goes a long way for parts longevity, too.
- greedo 5y ago
  And helps dramatically with soundproofing.

trollied 5y ago

The problem will go away over time as we migrate to electric cars.

powerbroker 5y ago
Perhaps a new problem -- that of stealing the more valuable batteries, might emerge?
- jccooper 5y ago
  That's approximately the same sort of operation as stealing the engine of a car. Not something you can do in a couple minutes with a battery powered angle grinder.
  - leecb 5y ago
    Tesla has demonstrated that their batteries can be removed and replaced in a matter of a minute or two, given the right equipment. https://www.tesla.com/videos/battery-swap-event https://www.tesla.com/videos/battery-swap-event Since the batteries cost an order of magnitude more than a catalytic converter, this could justify criminals developing more sophisticated equipment to pull it off.
    - skunkworker 5y ago
      This used to be more true, but with their new battery packs becoming an integral part of the frame, this is no longer going to be possible. https://electrek.co/2021/01/19/tesla-structural-battery-pack-first-picture/ https://electrek.co/2021/01/19/tesla-structural-battery-pack...
    - johnnywasagood 5y ago
      Four bricks and a jack I guess.
    - SilasX 5y ago
      Interesting, I’ve always thought it would make more sense to optimize for hot-swappable batteries rather than try to improve supercharger tech.

deleted 5y ago

[deleted]

dotancohen 5y ago

Then where would the catalytic converter dump the heat? Those things are dangerously hot and need cooling.

erik_seaberg 5y ago
The engine dumps heat to the radiator and the exhaust. I think the catalyst does enable exothermic reactions, but it’s not using power, so it can’t get hotter than the outgoing exhaust (although that is pretty toasty). A computer adjusts the fuel/air ratio and timing to keep the incoming temperature and oxygen level in the catalyst’s effective range. Some models even have a heater to get the catalyst working quickly after a cold start.

kube-system 5y ago

Manufacturers have been slowly adding plastic panels for aerodynamics under cars over the past couple of decades. Many new cars have just about everything covered other than areas that get too hot, like the exhaust.

giarc 5y ago

Automakers resisted putting backup cameras in cars and they provide the driver utility. A panel under the car adds no immediate utility to the buyer and therefore the extra $200 or whatever it would cost would detract buyers.