Here's a close up look at the CNG controller

Or maybe it should be titled "Here's a look inside a Chinese controller". Actually it's not too bad, it hasn't been on the car yet so I can't tell how well it performs in a working situation but from an evaluation standpoint it seems good enough - At this point I would give it 2.5 out of 5 stars; 5 being the best.

The CNG controller case has a two piece case made of cast aluminum containing the PC board

 Although the case isn't all that good, it's sealed with clear silicone in the molded two piece inter-locking U channel and screwed together with four machine screws. Looking at the case, it's obvious that case is good enough but not very high quality. A General Manager I used to work for in product development had a saying "Don't let the perfect be the enemy of the good enough" - This is certainly the case here - That is, the casting is good enough.

 Rear of the case - The mediocre casting quality

 is evident on the lower case seam shown

Back cover of the controller 

and attachment screws

A close up view of casting quality

It's obvious from this picture that the plastic on the shells for the interconnects have shrunken during cooling due to lack of attention paid to plastic thicknesses - Also note that this also means that there is a marked absence of  glass filling used in most automotive connectors to stabilize the plastic and ensure that it functions well in the automotive temperatures under the hood.

Here is a view of inside the CNG control module - This module uses a Freescale micro-controller. In closer inspection it was reveled that the micro controller is rated to Industrial temperature range (-40 to 105 C) rather than Automotive Temperature (-40 to 125 C) as most under the hood control modules are - Clearly implementing the "good enough" principal. On the right, the "U" channel is visible. This channel is loaded with silicone sealer before placing the inter-locking back plate in place. Although the casting for this unit is mediocre, the application of sealer seems to make a pretty good water-tight seal.

Installation of the Exon CNG kit

DMC / Exon CNG kit installation

Exon CNG kit - Not including the CNG tank

Main Features:
Easy to install and calibrate
Excellent performance & high quality
Waterproof connector
Euro III/IV emission & OBD compatible
ECE Certified ---R67,R110

This kit will be installed and evaluated on a 1992 Honda hatchback to check the installation and the functionality of the kit.

The Components

First some evaluation of the task at hand - Shown below is the car with the spare tire removed, ISO listed / tested CNG tank (more on the tank later).

After a few considerations and some measurements of the tank and the location in the back of the Honda to ensure that the tank would fit, the tank was test fitted by just sitting the tank inside on a metal spacer to check to see where the tank would fit best.

Once that it was certain that the tank would fit in the approximate location in the back, some measurements were taken as a preliminary exercise to get an idea as to how high / low the tank should be mounted. Obviously, the tank should be mounted as low as possible but because the time to install the kit is short, it was decided to install the tank inside as apposed to inverting the spare tire metal and mounting the CNG tank outside. Outside would be better, just not enough time to make it work.

Here are the height measurements sitting on top of a piece of scrap metal.

Test Fitting the CNG Tank

Spare tire and cargo compartment

Measurement between strut towers

Now that some basic measurements have been taken, a rough draft plan is created on engineering paper for reference and to save the measurement numbers.

This is an important step to ensure that the fabrication stays on track with the design idea. Nothing is worse than starting off with a general idea and not staying with idea and / or changing plans part way through.

Rough draft of plans for mounting CNG tank