a.moore wrote:
This may be a dumb question but what exactly is "lean burn"? Do they just lean out the mixture in areas of low load where it won't destroy the engine?
There's no dumb questions. Only dumb answers.
The Insight has a specially designed 3 cylinder, 1 Liter engine with Vtec. The combustion chamber etc was designed so the engine can still run and produce acceptable power on very lean mixtures. My CRX was a stepping stone in that direction and I've measured 17:1 F/A ratio when cruising along keeping up with city traffic.
The Insight has the capability when running along at low power demands to go into a distinctive mode ("lean burn") where the mixture is leaned out up to 24+:1 ratio.
Running that lean does produce more NOx than is acceptable for emissions but the Insight has a 2nd cat converter that absorbs the NOx. When the O2 sensors detect that it is time, the computer commands a "purge" to be done for 5 to 15 seconds by making the F/A ratio richer. After the purge the car re enters lean burn and the cycle repeats every once in awhile. For the short time you are out of lean burn you will still be getting 60 or more mpg. You can definitely feel a slight lurch as the car enters and leaves lean burn. But your butt dyno has to be tuned to notice it.
To force the lean burn condition you go a few mph over the speed you want to maintain and hold the throttle steady. At that point you will probably be seeing 55 to 65 mpg on the instantaneous mileage gauge. Then you let off the gas pedal very slightly and the fuel gauge will go up over 100 mpg (and even up to 150 mpg, the top of the gauge). At that point you feed in just a little throttle to maintain your speed and the mileage will go down to "only" 80 to 100 mpg and stay at that mileage. With the correct tires, high tire pressure, level road, no wind etc 120+ mpg numbers are obtainable without drafting.
People that don't know the trick of forcing the car into lean burn still get the advantages because they go through the steps of entering lean burn in the course of driving along without realizing it. By just driving carefully they could stay in lean burn for an extended time and even double their mileage. It's really weird to be driving at 20-30 mph and seeing over 85 mpg.
This is the technology that is out there that could be used as a donor car. But only 17,000 first generation Insights were sold worldwide in the 2000-2006 time period they were made. Luckily the largest percentage were sold in the USA. And wrecked or damaged ones can be found on eBay etc. Parts for the cars are quite expensive if bought from Honda though. I bought mine through craigslist.
Typically the cars will have weak high voltage batteries but they can many times be brought back to working condition by trickle charging (the term used is "grid charging") the batteries and going through several charge/discharge cycles. Just like the RC guys do with their Ni-MH batteries.
By the way I do NOT work for Honda (I'm just an over enthusiastic owner).
Lot's of info and maybe ideas can be found at the Insight forums.
http://www.insightcentral.net/forums/This is a review page of the car,
http://www.insightcentral.net/KB/index.htmlJack: I'm sorry if I'm hijacking your thread but this might be a good source for the engine etc for a fuel sipper. But topping a stock Insight is going to be a challenge for sure. I'll go to the back of the room now.
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