The dirty cost of one man's hypermiling?

[SentraSE-R]

I'm checking in after a couple of days at my mom's w/o Internet access. I've driven a lot of highway miles, Bay Area to SoCal to ABQ. I'm going to start a new mileage log for my car, and will post the results. There's a slight mileage penalty, but it's mostly due to the cold weather and elevation gain driving to 7000' elevation, rather than ending EOC P&G. My highway technique remains unchanged since my smog testing education.

I do run a grill block (and smaller F-1 side mirrors). This morning's ~20F temperature in Flagstaff would have justified a block heater. I don't use them in coastal CA. I'm not sure there's a net gain from the electricity used to warm the coolant v. the miniscule gas savings from warming the engine up sooner.


My grill block has split upper and lower portions. I had both fully blocked this morning. About 2/3 of the way from Flagstaff to ABQ, my coolant temps rose over 204F on uphills and steady state driving, so I removed the entire upper grill block.

Driving from the Bay Area to SoCal, I noticed temps >204F 15 miles from home, so I removed 1/3 of the upper grill block. The coolant temps topped 204F climbing the Grapevine, so I pulled over and removed the remaining portion of the upper grill block.

I don't do much DFCO, but will do it soon to observe its effects on cat temps.

I appreciate the suggestions for efficiency. Assuming I implement them, I'm still left with my personal conclusion that EOC P&G is a gross polluter.

p.s. The Magnaflow cat isn't legal in CA unless it has California Air Resources Board certification. Unless I'm missing something, Magnaflow doesn't mention CARB certification for its cats.

[cfg83]

SentraSE-R -

Originally Posted by SentraSE-R

...

p.s. The Magnaflow cat isn't legal in CA unless it has California Air Resources Board certification. Unless I'm missing something, Magnaflow doesn't mention CARB certification for its cats.

I wasn't advocating the Magnaflow cat. I was just using the good cutaway view for asking Old-Mech where to install the temp-probe.

CarloSW2

[SentraSE-R]

Originally Posted by dcb

Sentra, can you summarize the events a bit more (without foregone conclusion bias if possible)? I cannot confirm or deny your assertion of HC returning to normal, I don't know why they are so different in test 3 and test 2.


What happened before test 1?

What happened after test 1?

What happened after test 2?

Thx!

Before test 1. I drove 800 miles RT to/from SoCal Oct 2011, got a CEL because my kill switch wires disconnected and I reverted to key-off-on EOCing. I cleared the TCs. Drove the car 800 miles in local driving after clearing the TCs. Hadn't driven the car at all in December 2011.

Before test 2. After failing the first smog test, I learned the cat converter drive cycle on my xB is 15 minutes at speeds between 60 and 100 kph, the O2 sensor drive cycle is taking the car >40 mph, and the evap purge drive cycle starts 5 hours after the key is switched off after completing the cat drive cycle. So I drove up the highway between 50 and 60 mph for 15 minutes, drove back, and parked the car overnight. The next morning before the test, I drove around to take the miles driven since the failed smog test to >100 miles.

After test 2. I drove 900 miles RT to/from SoCal looking for a Gyrfalcon (missed seeing it), with no EOC, keeping the cat lit the whole time.

[user removed]

Sentra, I appreciate this thread, and understand your convictions. I have only used engine off coasting for one tank in the last 70k miles. On my Insight which had idle stop, the guts of the cat came loose in the shell and started rattling like crazy. It was replaced under warranty, or it would have cost me $2k for the front cat. I always wondered if the heat-cool cycles of the idle stop caused the problem.

Now I wonder if the idle stop introduction in the near future will not create similar problems, and this may be one of the reasons why the manufacturers seem to be reluctant to adopt what seems to be a no brainer to me, unless there are consequences we may not yet understand.

Your situation also supports my belief that the best emissions system is the one that works in the combustion chamber itself. The factories have been trying for 40 years to stick on this or that device to clean up what should be clean when it exits the combustion chamber. When the feedback systems with O2 sensors became common in the early 1980's, performance returned.

Now we face another point where the pretreatment of ultra high pressure injection with multiple injection points and super critical very hot fuel shows a potential to reach a goal that has eluded us for 40 years. The inherently clean engine.

cfg83, I was posting about using a hand held thermometer for checking cat temps, which would have required stopping and opening the hood, considering the CAL emission test would reject anything permanent regardless of it's effectiveness.

It reminds me of the problems with the Civic VX and lean burn which produced emissions very close to today's hybrids, with the single exception of NOX which caused their demise. It's OK to drive a 10 MPG fuel sucking pig but if your NOX barely goes over a bureaucrats imposed limits you are doomed. I prefer a system that allowed for some leeway when the sum total of emissions is considered in it's totality.

To me it's much the same reason we can not get the highly efficient cars sold in Europe. Not to start an off topic heated debate, but absolute legislated limits, without overall total consideration seems to me to be shortsighted. Kind of the tail wagging the dog.

regards
Mech

[dcb]

This link describes well to tank ghg emissions as 20% of the total
http://www.netl.doe.gov/energy-analy..._Feb%2025a.pdf

I can't say how many hydrocarbons get released before it gets in your tank, but stuff like Kuwait and deep water horizon and Exxon Valdez make me think a lot. Saving gas is worth the effort, oil itself is a gross polluter.

[SentraSE-R]

Trying to answer older questions.

Mech, in answer to the bigger trip/maintain clean emissions issue, I have to maintain clean emissions. Longer trips 2-3X/year clean the cat, but that's putting a band-aid on a gaping wound. The gaping wound is the 75X higher than average hydrocarbon emissions when the cat's not lit. What's needed to maintain the emissions reduction found after my 900 mile SoCal trip? Keeping the cat lit.

Will I be able to come close to my previous fuel economy without EOC? No. I was getting 176% of EPA. I can expect 135-140% of EPA keeping the engine on. That's a drop from my 49.4 mpg combined average to an expected 39 mpg combined average. Considering the xB's 2008 EPA estimates are 26/30/28 city/hwy/combined, 39 mpg still looks good.

Since I started keeping the engine on, I've driven 1505 miles, and am averaging 46.3 mpg. However, ony 215 of those miles are city miles. So, if I can use the xB as a long trip car, its FE will barely suffer.

On this trip, I'm only using the kill switch on long (>1 mile) downhills, and approaching/at long stoplights. I figure restarting a hot engine barely emits pollutants, v. perpetually keeping the engine cool w/P&G.

I have two cat temp functions, Bank 1 sensor 1, and bank 1 sensor 2. When I looked at them uncritically, they looked to read the same, within 5 degrees of each other. Now I'll set them up side-by-side, to compare them while the cat is cooling/heating, and under DFCO

[euromodder]

Originally Posted by Arragonis

When it was being replaced the guy insisted on disconnecting the battery - "health and safety" - no idea why.

If it has a passenger airbag, this could inflate and blow out the windshield while they're working on it.

[euromodder]

Originally Posted by rmay635703

If you don't like nitric which turns into fertalizer when it hits soil, you could have a driveway saltwater mist into the exhaust post cat, then you end up with again more fertalizer.

Our farmers have to cut down on fertilizers to reduce NO2 and NO3 in the soil - which then end up in the surface waters.

For example my folks dumped acid on their garden for years and had some nice blueberries and rhubarb.

That's not to say they were really healthy.
You can't judge the poisons in fruits or vegetables by looking at their external appearance.

Some pretty bad stuff can accumulate in plants without readily apparent ill consequences for the plant, but with severe long term consequences for those eating them.

To really reduce NOx we really need to reduce the number of gas guzzlers, since all cars make NOx regardless of lean or not.

That would surely help - with high fuel consumption comes high air intake and more NOx .

[SentraSE-R]

I drove into the Sandias chasing (successfully) two life birds (Black Rosy-Finch and Brown-Capped Rosy-Finch) today. Didn't have time to set up both front and rear cat temp sensors, but I did observe the temps on a long DFCO. Cat temp dropped from ~1200F to 630F during the DFCO.

p.s. the coolant temps topped 204F climbing the Sandias @~8000' elevation with 3 people in the car, with the upper grill block removed, and ambient temp ~+20F.

[Piwoslaw]

Originally Posted by SentraSE-R

I drove the car 900 miles RT to/from SoCal last week, and the cat stayed lit, between 1101-1185 degrees F. When I do my normal low speed P&G, cat temps are 285-550 degrees F, too low to light the cat.

As mechman600 mentioned, new turbodiesels have a exhaust temperature sensor to monitor DPF regeneration. I found a site which shows how to tap into that signal to monitor the temps yourself (for PSA HDi - FAP Sensor Regeneration & Turbo temperature - exhaust gas temperature monitoring). From the data there it appears that diesel exhaust is quite cool compared to a gasser (maybe because turbodiesels are more efficient?). The main temperatures of interest are:

• Below ~200°C (400°F) - idle,
• 200°-400°C (400°-750°F) - normal driving temp,
• >450°C (840°F) - natural DPF regeneration,
• 500°-600°C (930°-1110°F) - forced DPF regeneration.

The bottom line is that for the diesel's egt to be close to what lights up Sentra's cat the ECU must force the regeneration of the DPF (preheating intake air, increasing EGR, dumping extra fuel, increasing engine load by turning on rear window heater, etc.), in normal driving the exhaust temps wouldn't light Sentra's cat. In fact, "forced" exhaust temps can't be kept for long since they could damage the DPF. But new diesels still have to pass European emissions standards, so their cats must work at lower temps.

So my questions are:

1. Do diesel catalytic converters differ from their gasser counterparts?
2. If so, ie if they light at a lower temp, then could a gasser's cat be replaced by a diesel cat for cleaner emissions while hypermiling?
3. Could a "universal" cat be constructed with elements from both gasser and diesel cats, so that it works in a broader temperature range?

Slightly OT, but still in emissions, I there was an article in Popular Science (October 1995, page 40) about coating car radiators with catalytic materials, thereby turning your car into a "pollution eater". I know this thread is about reducing emissions, not emitting them then cleaning someone else's, but I thought this is interesting. Of course, it probably wouldn't work well while hypermiling (cool, partially/fully blocked radiator). On the other hand, if there are materials which work on a radiator with temperatures below 100°C/212°F, then why not use them in a low-temp exhaust cat?