Wednesday, November 27, 2013

Pulse and Glide in Honda Accord Automatic

After achieving 39 mpg in our 2007 Honda Accord automatic without doing anything special, aside from using Marvel Mystery Oil in gas, watching the speed and doing a couple of things from my post on maximizing fuel efficiency, I decided to try "Pulse and Glide", a.k.a. "Burn and Coast".

The idea behind P&G is simple: the engine is more efficient at moderate throttle openings at moderate RPMs. There are so-called brake-specific efficiency maps for every engine, and the ones I saw show that the maximum efficiency was reached at RPMs close to the torque peak at throttle openings of 40-80%.

Pulse and Glide involves accelerating at moderate-to-high throttle in highest gear possible (to keep the engine in the most efficient range, close to its torque peak) and then, ideally, shifting into neutral. Then coasting for a while and repeating the process. So instead of driving, say 50 mph, accelerate to 55, coast to 45, repeat.

Some people even switch off the engine during coasting, but this is unsafe as the power assist in steering and brakes is lost.

The easiest application of the P&G is in a car equipped with manual transmission. Since the driver has a full control over the gear selection, you can push on the gas pedal almost all the way to get maximum efficiency at a high gear without the transmission downshifting. In the automatic transmission equipped cars, one has to be careful to just enough pressure on the gas pedal so that the transmission does not downshift.

Also, I have reservations about shifting into neutral in an auto-equipped Honda Accord. While some cars are purportedly safe to do so, the others aren't. Furthermore, I am not willing to conduct experiments that might result in a failure of a part that costs thousands to fix and would result in hassle and time lost.

As a result, here is my experiment: apply P&G for one tank of gas as follows:

  1. Accelerate moderately
  2. Coast with the transmisision in "Drive"
  3. After the speed decreases 5-10 mph, repeat.
While not the most efficient P&G method there is, I suspect I might be able to finally get over 40 mpg. Stay tuned.

Update #1: I was unable to mostly drive in the manner described above for the first tank of gas and as a result got 34.7 mpg. I will try again with the next tank.

Update #2: Not really getting good results with this approach. Switched to mild drafting behind trucks instead :)

Friday, November 15, 2013

Another record - 39 MPG in 2007 Honda Accord

I am using the Marvel Mystery Oil again, in our 2007 Honda Accord. A while ago I got 38.5 MPG in out 2006 Accord, and a similar MPG number in the 2007 Accord. But now I deflated the tires back to factory-recommended 30-32 psi. Conditions: mostly long trips and about 10% A/C use. I would say about 90% highway at 55-65 mph.

I drove using techniques I outlined in my post on maximizing fuel economy, but with no tire overinflation. I added about 4 oz MMO to fuel (per 15 gallons).

I added the Marvel Mystery Oil (MMO) to the tank and filled it up with regular 87-octane gas. This time I drove 546 miles before refueling and refueled with 14 gallons of gas, averaging 39 MPG. This MMO test included a couple of short trips and about 10% of time I also used A/C. Without those, I probably would be able to get to 40 MPG. And I expect MMO to keep the fuel system clean, even when using semi-questionable (not "top-tier") gas. I will give MMO another try in my 2004 Infniti G35. The previous attempts did not achieve much.

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Wednesday, November 6, 2013

TP-LINK TL-WR841N Wireless N300 WiFi Router

I have recently replaced a 802.11g WiFi router with the TP-LINK TL-WR841N Wireless N300 Router . The reason was the fact that my old WiFi router didn't have enough range to reach through several concrete walls into our other bedroom. More importantly, its WiFi connection was somewhat unstable, resulting in pauses when using Skype over WiFi.

I decided to upgrade the router and get better range, more stable connection and not spend a lot of money. As a result, I got the TP-LINK TL-WR841N for $20 or so, shipping included. Not only was it super-easy to install and use, it comes with a 2-year warranty.

The router supports 802.11b/g/n standards, has the latest security features, including WPA2 encryption that I use. It has 4 wired Ethernet 10/100 ports and dual antennas.

I am happy with this router's stability, range, ease of use and unobtrusive design. The periodic connection dropouts in the WiFi are no longer happening. Ditto the Internet connection resets. Highly recommended.