Use engine block heater to warm Catalyc converter ?

[Piwoslaw]

There pad type heaters. I have one on my oilpan to supplement the coolant heater, but I've seen users here with a heating pad on the engine block or transaxle. You could use a low power pad wrapped around the cat to slowly bring it partially up to temp, giving it a head start. If well insulated from the outside then maybe you might get it 60-80°C above ambient. Not sure if the pads are made to handle temperatures that high? I think it's doable, just need to get the parameters right.

Some of the pads are for 12V DC, so you could prewarm the cat 1-2 minutes before starting the engine, or keep it warm when coasting (SentraSE had a thread about that not too long ago).

PS: Why is this in the Unicorn Corral?

EDIT: You know, they make heating pads especially for cats. Meow cats

[Cd]

Originally Posted by Ryland

Most 4 wire o2 sensors are heated, as far as I know the only non heated o2 sensor is the single wire o2 sensor.

Funny you should mention that. I decided to perform some testing on my emissions equipment on my car to make sure everything was performing as it should.
According to the Hanes manual, the '94 and newer CIvics had an O2 sensor.

Mine is a '93 and doesn't have one.

I replaced the O2 sensor a couple of years ago with a Bosch unit because it supposedly reduces emissions better than a stock part.

I wonder if I can install an O2 heater without buying one for a ' 94.

[WD40]

Newer Toyotas use a block heater that is simply installed into a hole in the block so it actually warms the metal first.
I doubt it's as efficient, but it must work or Toyota would have used the traditional frost plug method.

[Cd]

Originally Posted by Piwoslaw

PS: Why is this in the Unicorn Corral?

EDIT: You know, they make heating pads especially for cats. Meow cats

I had seen mention on this forum of using a heating pad on the " cat " a while back. I think the response was that it wouldn't work because any sort of heating pad would not get hot enough.

I thought I'd ask if you could use a engine block plug type heater, but it seemed too easy to work.
If it could really work, I assumed others would have already tried it.
Therefore, I put it here just to find out why it doesn't work.

Heating pads for cats ? Spoiled !

[Grant-53]

The circulating block heater may reach 150 F; a catalytic converter operates at 1,000+ F. The block heater may save fuel by allowing a leaner mixture sooner and the cat will have less fuel to burn to reduce HC emissions.

[t vago]

Not sure about heating pads. They're not really supposed to go much above 100 C. Catalytic converters, on the other hand, have an operating temperature of around 450 C. I'm tending to think that any sort of heating pad would burn off in a relatively short period of time.

Now, there are cats out there that have built-in heating coils - I think BMW uses them.

[Piwoslaw]

Originally Posted by t vago

Now, there are cats out there that have built-in heating coils - I think BMW uses them.

That wouldn't easily retrofitable (something about tampering with emissions control devices?), but fitting a heating coil between the exhaust manifold and catalyst might work. Not sure how long it would hold up in that kind of environment.

[old jupiter]

Frank is right that getting the cat lit off sooner doesn't effect fuel economy, just emissions (though that is desirable, too). If you want to get the cat hotter, sooner, you could try using a thermal wrap around the exhaust system upstream from the cat. You could test the effect before and after (with the engine completely cooled off between tests) using a stopwatch and one of those infre-red temperature "guns". The exhaust thermo-wrap might give your engine a small improvement in fuel efficiency and power, too, and a lot of racers use it. There are some limits to its use, though; you don't want to use it where it can get wet and rust out your exhaust pipe or headers.

Cd, if you are asking if one of the stick-on or magnetically-affixed heating pads could be applied directly to a cat, my guess is that none of them would survive the very high heat generated by the cat when it has lit-off.

[some_other_dave]

Originally Posted by Cd

According to the Hanes manual, the '94 and newer CIvics had an O2 sensor.

Mine is a '93 and doesn't have one.

That's curious. My 1990 CRX had one, and AFAIK all fuel-injected Civic derivatives from 1988 and later (and even some carbureted earlier Civics!) had O2 sensors.

-soD

[Piwoslaw]

Originally Posted by Cd

I did not know that engine block heaters were immersed in coolant - but then since I live in scorching hot Texas, I had never seen one.

That's still no reason not to have an engine preheater. It's definately worth more in cold-country, but hot places can benefit from them, too. For example, the effects of engine preheating on emissions and fuel consumption caught the attention of the Univerisity in Amman, Jordan*.

*) I found a link to this article here at EM a long time ago, but can't find it at the moment. I have it on my disk, but it's large to attatch, so I can e-mail it if you PM me. But maybe it can be found elsewhere. Here's the info:
American Journal of Applied Sciences 4 (3): 106-111, 2007
Evaluation of Fuel Consumption and Exhaust Emissions During Engine Warm-up
M. Al-Hasan
Department of Mechanical Engineering, Faculty of Engineering Technology, Al-Balqa' Applied University, Jordan, Amman, Marka