[Guest]

Hi All:

___After reading a bit more about Lean Burn, it apparently is one hellish environment for a piston and heads. From my understanding, some racing engines running lean burn mixtures use ceramic coated pistons. Does the Insight use or need such an exotic material on the pistons/heads to keep from self destructing or is its HP/Liter detuned enough to where this is a non issue?

___Given the Insight has logged millions of miles and it isn’t falling apart by the thousands, I have to give the benefit of the doubt to those Honda engine designer magicians but I thought I would ask …

___Thanks in advance.

___Wayne R. Gerdes
___Hunt Club Farms Landscaping Ltd.
___[email:184pxzu6][email protected][/email:184pxzu6]

 

[Insightful Trekker]

Hi All:

<snip>

Does the Insight use or need such an exotic material on the pistons/heads to keep from self destructing or is its HP/Liter detuned enough to where this is a non issue?

<snip>

None that I am aware. However, I remember reading somewhere (but can no longer find the source) that the pistons have a special texture (shot peened?) that encourages oil hang-up to provide additional lubrication because of the auto-stop feature's consequence of frequent restarting.

The Insight's "lean-burn" mode is an evolutionary step from wayyy back with Honda and their CVCC engine of the early 80's. The Insight's closest predecessor the CRX HF (91 was the last production year) had a lean burn mode very similar to the Insight.

The lean burn mode is specifically a stratified charge whereby the mixture in the combustion chamber is ideally rich at the tip of the spark plug but progressively leaner throughout the remainder of the chamber. The mixture is also very turbulent which prevents excessively lean pockets in the chamber that would cause incomplete combustion. This approach allows normal initial combustion without potential misfires, engine knock and pre-ignition thermal runaway while preserving the higher MPG benefit of simply providing less fuel to the engine.

Lean-burn won't be sustainable during anything but very light loads. Eliminating one of the detrimental factors of a racing lean burn engine.

Hope you are enjoying your new(?) Insight.

John K. Bullock
aka. Insightful Trekker

 

[Tim Maddux]

Trekker, here is your reference:

http://www.insightcentral.net/encyclope ... ction.html

"In the interest of friction reduction, Honda engineers specified a new lightweight aluminum-alloy piston design for the IMA engine. The pistons have a minimal skirt area and the surface of the skirt has been shot-peened. Shot-peening is a process in which a metal part, such as a piston or connecting rod, is blasted with shot-like particles, creating uniform, microscopic dimples on the surface. This dimpled surface is better able to retain a lubricating oil film. Shot-peening the IMA engine's pistons accounts for another 1.5- to 2.0-percent reduction in internal friction."

To the original poster, the encyclopedia on this site is very thorough:

http://www.insightcentral.net/encyclopedia/index.html

and I find no mention of ceramic piston heads in it. Of course that doesn't prove that they are not there. I just can't find confirmation that they are.