NGV Driver

We have been driving the Nissan on CNG for some time now.  I can’t seem to tell enough people how cool it is to pump 10 Gallons of Gas and only pay $8.  However, the Nissan has only undergone a portion of the conversion.  The final step is to integrate the CNG Computer into Nissan’s Computer.

A little background, cars are run by an Electronic Control Unit (ECU).  The ECU takes data sets from a number of different sensors throughout the car and processes the information to optimize performance.  A couple of posts back we talked about Aspirated vs. Injected, a key differentiation is that most modern aspirated kits will tap the ECU to help moderate and control the fuel to oxygen mix on the fly.  Mixing the fuel on the fly is important to optimize performance, an automobiles needs are drastically different for idling as compared to merging on the freeway in a snow storm.

A critical data source to the ECU on the fuel demands is the Manifold Pressure Sensor (MAP Sensor).  Integration with the MAP Sensor a necessary component of any modern kit, and one a step that many conversion kit manufacturers and installers are overlooking (Natruell has not).  Before Fuel injection most cars relied on a vacuum pressurized system to handle the mix of fuel to oxygen.  A pressurized system is functional but is not accurate.  In more extreme conditions (anything that causes your cars RPM’s to fluctuate) you need more than precise - you have to be accurate.

The picture of us filing up with CNG in Park City Utah that I used to open the post is a great example of why integration with the MAP Sensor is important.  Air Mass can be effected by things like temprature, elevation, or humidity.  A vacuumed system struggles to account for these variables in situations.  MAP Sensor’s take into consideration the mass of the air (adjusting for environmental variances) that needs to mixed with fuel.

This is where Nissan and most auto manufactures stumble, factory MAP Sensor’s do not allow for outside devices to connect and read the data that is being generated.  Brandon, my mechanic, has had to order an aftermarket MAP Sensor that he is going to install.  This will allow the Natruell Computer to read the exact same data that ECU is getting - mixing fuel and oxygen on the fly.  In theory this will better the performance of the Nissan, I will keep you posted.

Finally, a couple of news items: Toyota is releasing two bi-fuel (CNG & Gasoline) vehichles in the coming year - Camry and Yaris.  The Yaris only a concept at this point but, it is great to see the automakers taking these solutions and integrating them into the product lines.

I thought I would get one more post up before the weekend was up. I was using CNGPrices to plan a vacation trip (once again I wish there was an application that I could use on my Windows mobile phone in conjunction with the phones GPS to map stations) driving the X-Terra to Ouray Colorado for the Ice Festival (ice climbing).

There are a couple of great feature on the CNGPrices website. First you can use it to plan your local commute, find the stations closest to you local travels. The new feature will help you plan your vacations so that you can stop by some new stations that you may not have known about. Unfortunately for my trip I run out of station for the last 160 miles of my trip. If you know of a station in the south western part of Colorado I would love to fill the Nissan with CNG (help to keep costs down so that I can afford more trips to Ouray).

I did use the CNGPrices mobile application to find and try out a new station in Murray Utah today. If you have a mobile browser give it a try, I added it to my favorites.

One last item, in preparation for my vacation I made a bet with some cohorts to get down to my wedding weight before we head down in January. The second hurdle in the bet is to be able to do100 pull ups in under an hour. I need your help, if you see me or we eat out together don’t let me eat that second serving, honestly I will thank you. I will update my twitter feed regulary with the progress.

I have always liked windows mobile, it is what I cut my teeth on when I got my first smart phone. I upgraded the ROM and lost my email functionality. I could recieve but not send, until today. I found a great .cab file over at Tracy and Matt - thanks guys.

Now I just need to find a plugin or a mapping application that will use my phones GPS and a map to help me find fueling stations.

Well I finally got our projector mounted and working. The audio components are not connected yet but I could not resist I had to try it out. Here is the temporary audio set up:

Heather also pointed out that I should have given a little more explanation on my table:

GGE - Gallon to Gallon Equivalent because CNG is a pressurized gas it more difficult to measure a liquid gallon. So somebody created GGE.

$/Mile - This is how much it cost me to drive a mile.

$/GGE - This the cost per gallon of CNG.

Pressure - I am sure I should be factoring the pressure into my equation in order to truly get an accurate mileage. I just have had time to really try and figure out how to work it in. For now I just kind of not that my fill volume and resulted calculations could be affected if the pressure is low.

I am excited to try and tow something with the CNG to see how the X-Terra does. I can feel a little difference between CNG and Gasoline. However, my wife says that she can’t tell a difference in acceleration between CNG and Gasoline. We will see.

The conversion is done and I have been driving it around. I can’t tell you how exciting it is to fill up for only a few bucks!

Looking at the chart makes it look like I have very little range. Actually, I can drive 160 - 190 miles when the tanks are full. Even with the non-arrow dynamic rack on top the Nissan still gets 20+ MPG on CNG. There are a couple of things to remember about CNG, it might be obvious to some but thought I would share it anyways.

PRESSURE - CNG is a pressurized gas. It’s not like you can take pour it from the pump into a bucket. How much gas you can get into your tanks depends on how much pressure the fueling station is capable of pumping. When Heather and I filled up at a Clean Energy Station in Seattle (it is out by SETAC if you are wondering), you had an option what pressure you wanted to fill up with. The short and simple of it is, the more pressure -> the more fuel you are going to get into the tanks.

SLOW FILL VS. FAST FILL - There are getting to be more and more home filling station kits out there these are usually what is known as a slow fill. I need to learn more about it but, for purposes of this discussion all you need to understand is that a slow fill takes hours to pump. Where as a gas station that can fill your tanks in seconds is known as a fast fill.

EXCITED MOLECULES - Where am I going with this… A slow fill eases the pressurized gas into the tank allowing the molecules to settle gently into place. However when you fast fill the molecules get all excited and start bouncing all over, making harder to get the same amount of fuel in the same amount of space.

I know of one way to settle the molecules down during fast fill - chill the tanks. A cold tank will force the excited molecules to settle faster allowing you get more fuel into the tanks. For me, I have another theory as well, that more frequent smaller fills will allow me to get more fuel into the tank. It is a little early to tell if my experiment is going to pay off I will keep you posted.

The Kit

Alan, a reader helped me realize that I had not talked about my kit or the mechanic that I had found to do the conversion on the X. I was apprehensive at the start to have somebody cutting up a brand new car (make no mistake, this was a huge commitment for me) so I spent a long time meeting and talking with different mechanics and shops.

I settled on a little shop in Centerville, Utah – CNG Technologies of Utah. They came with some great recommendations from others that I have known who have done the conversions. Brandon and his crew are true mechanics in every sense of the word. The first time I was up to his shop he was demoing one of his drift cars that he was in the process of selling. The more I talked with Brandon the more I realized just how much he enjoyed doing these conversions and working on cars. Working on cars was not just a 9-5 job for him, it made life worth living. Who else would you want to work on your car?

The kit that CNG Technologies is installing is the Natruell kit. An aspirated kit out of the Netherlands, I will talk more about this kit next time.

NGV Driver Store

Well I created some shirts and added them to the blog. I have three different styles, click on the link and check out the NGV Driver Store.

The big news is that Nissan has released a factory CNG vehichle. I am not sure this is very practicle for the average consumer but it is great news. Nissan says that one of the unique things about it system is the ability for the car to automatically switch from diesel to CNG. Initially that souds really neat but, the Natruell system that will be installed on the X does the same thing.

Other news, a guy at work told me that Goldman Sachs oil analyst predict crude going below $50 a barrel. He commented that the oil industry is going to use the reduced prices to stifle alternative fuel adoption and development. I think the tactic will work in the short run but alternative fuels have too much momentum now. Besides with crude closing around $70 I am still paying about $3.50 per gallon, I would think I should be paying around $2.50? I could not find the Goldman article but, here is another link talking about oil futures.

Finally Heather and I are planning  a trip to Settle then down the Oregon coast when we get the X-Terra back from it’s conversion. I got curious and was disappointed to find out that there are no fueling stations on the drive through Idaho and only two stations in the Seattle and none on the coast of Oregon. What a let down.

I thought I would share some learned knowledge on conversion kits. There are two basic types aspirated (aspirated, fumigated, pneumatic, or carbureted) and injected. I thought I would give a breif and unsophisticated overview of the two systems.

Aspirated were the first kind of kits to gain real traction. The system is a very ‘mechanical’ system. If I understand it correctly CNG lines interupt the gas line prior to the carburetor. I think the carburetor creates a vacuum that pulls necessary fuel into the carburetor. There are some more details than that (like a two stage piston that controls the amount of fuel) that can be added to the system but the simple explanation is the car ‘takes’ the fuel.

Injected systems come in post carburetor, usually at this type of system will replace the injectors. This system sort of T’s the two gas lines at the injector a switch (usually in the cab) will dictate which fuel is allowed to flow into the injectors some kits allow for a mixed fuel system 60% fuel and 40% CNG. Injected kits also have a computer that calculates the necessary amount of fuel the engine will require per the RPM’s. The onboard computer tells the system to push the necessary amount of fuel through the injector and into cylinder.

Feel free to add insight and detail to this rough description in the comments.

"Fitted" Mounting System

The first big step was getting to the steel supplier. I had to get into work extra early so that I could make it to the Wasatch before 4:30 PM (they aren’t open on Saturday). I made with 5 minutes to spare loaded up on twon inch angle iron and one and a quarter inch steel strap. The shop guy tried to help by loading it up for me in the process he scraped the hell out of the new rack.

One Tank Loaded

The second step was to figure out the best way to mount tanks. We stripped all of the trim material and flooring out the back to figure out the best method. We, my dad and I, settled on removing the false floor and an internal mounting track to mount our system. Leveraging a lot of the existing mounting points on our system. This made it so that I only had to drill 6 new holes to mount the system.

Back of the Bracket

I put the brackets I bought earlier back-to-back them mounted them on a grid of angle iron and steel strap. I am not much of a welder but, my dad was able to help me out - tell me which welds were bad, and fix my bad welds. Finally, we painted it and got it all loaded up.