My New N/A Del Sol Project

[GasSavers_Erik]

pfg- I'd love to see some pics of your pre-combustion chamber mod. Or at least a description if you intend to keep your specific design a secret.

[pgfpro]

Originally Posted by Erik

pfg- I'd love to see some pics of your pre-combustion chamber mod. Or at least a description if you intend to keep your specific design a secret.

I can't show pics at this time. Lets just say I have a lot on the line.

My design is not like most "torch-ignition three valve stratified-charge engines".

Its very unique with a centered spark plug configuration that generates a torch-ignition without a third valve. It does share a rich near stoichiometric condition near the spark plug so it can produce a nice strong flame kernel to light off the leaner stratified-charge.

Because its design, its very finicky to fuel temperature and intake-stroke pressure differential. This is where the turbo helps a ton. Plus its also has some Nox issues. Working on this part...still

A couple other things I would like to bring up. There has been a ton of talk... not so much here but on the other _ _ _modder forum that lean-burn engines have poor BSFC numbers with anything leaner then 14.7:1 A/F. This is not the whole truth. When looking at BSFC numbers you need to know the load of the engine or the BMEP. IMO I think at light load... that's being throttled you can better the BSFC numbers with a lean burn engine.

Good example:http://www.gassavers.org/showthread....448#post157448

Thanks tjts1 for this link!!!!

Also the torch-ignition helps with flame speed. It burns a larger part of the leaner air/fuel stratified charge in the main combustion chamber. This accelerates the total flame speed so you can run less timing advance. Thus making more cylinder pressure at a better crank angle.

The second part that I would like to share is when an engine is running at these very lean conditions it will have less fuel to protect the boundary areas.

Fuel tends to be attracted to the cylinder walls and top of the piston and especially around the valve relief area on the pistons. The fuel creates a protective film on these areas. This is a good thing because it absorbs heat that normally could start using the pistons as fuel.

You do loose a lot of this protection in a lean burn engine. This is where a turbo charger helps again. It provides a simple thermal management system by using air to help cool these areas. Once cooled the "Heavy Fractions" of fuel can attach themselves easier to these areas. Its kinda along the same lines as how fuel is used for thermal management when running a high boosted race engine. Example 11.8 A/F at high boost. A lot of the fuel is not being burnt, but just used to cool temps down before the next cycle.

Well there is a ton more to it but that about enough for one night.

[GasSavers_Erik]

Very interesting- so how do you get a rich mixture near the spark plug? With the swirl principle that the Civic VX uses? Or something with separate rich mix intake runners like the old Honda CVCC?

I am also intrigued about how the turbo can cool the pistons while running lean- is this cooling effect present only under vacuum conditions or only under boost? I would think that intake air that went through a turbo would be warmer than air that came through a NA stock air intake, even if an intercooler was present.

I'm also a fan of lean burn. I had been tinkering with my CVCC civic engine leaning it out as much as the factory feedback system would let me. I was definitely improving my mileage until I had to swap in an auto trans.

[pgfpro]

Originally Posted by Erik

Very interesting- so how do you get a rich mixture near the spark plug? With the swirl principle that the Civic VX uses? Or something with separate rich mix intake runners like the old Honda CVCC?

I am also intrigued about how the turbo can cool the pistons while running lean- is this cooling effect present only under vacuum conditions or only under boost? I would think that intake air that went through a turbo would be warmer than air that came through a NA stock air intake, even if an intercooler was present.

I'm also a fan of lean burn. I had been tinkering with my CVCC civic engine leaning it out as much as the factory feedback system would let me. I was definitely improving my mileage until I had to swap in an auto trans.

It would be more like the VX. But a whole lot better. In my case both intake valves are open not just one.

Piston cooling happens under light boost. The turbo is not creating any heat at these light loads due to a very low turbine/compressor wheel speed.

Plus in N/A form a engine can only flow one atm of pressure. With the turbo it is above one atm so more air is flowing per engine cycle. I can have the same injector pulse width as I would with a N/A version but increase the air flow and run leaner with the turbo. This also helps a ton with pumping losses.

Its great that there are so many lean burn fans on this site. How were you changing the factory CVCC system?

[GasSavers_Erik]

Originally Posted by pgfpro

How were you changing the factory CVCC system?

The factory feedback system used a 1 wire oxygen sensor output to judge when the mix was rich, if so, it basically used an EGR type vacuum signal (low at idle, low at WOT) to open a diaphragm that opened a "vent" in the intake manifold to allow extra filtered air to bypass the carb- leaning it out when it was too rich. Once I figured out how it worked, I just bypassed the electronic controls and had the vent diaphragm get the vacuum signal all the time- just as if the computer thought it needed to run leaner. This gave an estimated 8-10% boost in summer highway mpg (from 42mpg to 46 mpg) I did it on 7/10/2008 if you want to reference my gaslog.

[pgfpro]

Originally Posted by Erik

The factory feedback system used a 1 wire oxygen sensor output to judge when the mix was rich, if so, it basically used an EGR type vacuum signal (low at idle, low at WOT) to open a diaphragm that opened a "vent" in the intake manifold to allow extra filtered air to bypass the carb- leaning it out when it was too rich. Once I figured out how it worked, I just bypassed the electronic controls and had the vent diaphragm get the vacuum signal all the time- just as if the computer thought it needed to run leaner. This gave an estimated 8-10% boost in summer highway mpg (from 42mpg to 46 mpg) I did it on 7/10/2008 if you want to reference my gaslog.

Wow!!! that's a cool idea. Nice work!!!

I would love to get my hands on one of those cars.

[Tygen1]

Originally Posted by pgfpro

Thanks.

I'm leaning more towards the building of an extreme aero car. It will have custom built roof quarters and rear section. I'm looking at a CRX body or a 91 Civic. It will be powered by my extra VX engine with a 13b turbo.

Go for the Aero! Why not start with a Orginal Insight Shell, that's the best starting point. They can be had affordably and are quite light.

So the 13B and TD04 are about the same size So this would be a good choice for a high mpg car. Would give enough boost at 1500 rpm to see the difference you see....I drive slower than you

[pgfpro]

Originally Posted by Tygen1

Go for the Aero! Why not start with a Orginal Insight Shell, that's the best starting point. They can be had affordably and are quite light.

So the 13B and TD04 are about the same size So this would be a good choice for a high mpg car. Would give enough boost at 1500 rpm to see the difference you see....I drive slower than you

I was looking into the Honda Insight but I'm worried that I will have to meet the Insights emissions? Plus I'm not to sure what they would think with a engine transplant? I'm trying to see what my local laws are for such a build.

The 13b TDO4 is from a auto DSM. You can find them really cheap. Most guys don't want them. They work great for a small sized engine.

[Tygen1]

Why not just work your magic with an Insight motor? It already goes 25:1

[pgfpro]

Originally Posted by Tygen1

Why not just work your magic with an Insight motor? It already goes 25:1

To be honest I just don't know enough about the engine and the CVT drive train. Plus it would require a big dollar full time management system. A lot more parameters to control.