My posting/spiel on the Million Dollar Way blog.

REDRANT:  AH! THE STORY OF MY LIFE!  "INVENTING THINGS THAT HAVE ALREADY BEEN INVENTED.  ACTUALLY IT IS CALLED "REVERSE ENGINEERING".  BASICALLY IF YOU MIX NATURAL GAS WITH INTAKE AIR IN A DIESEL ENGINE YOU WILL NEED TO KEEP IT LOW ENOUGH SO YOU DON'T GET "KNOCK" OR PRE-IGNITION.  YOU CAN THEN SUPPLEMENT WITH

DIESEL BUT WOULD WILL NEED LESS BECAUSE HYDROCARBONS ARE HYDROCARBONS.  I WOULD GUESS THAT DIESEL FUEL CONSUMPTION WOULD DECREASE BY ONE QUARTER TO ONE THIRD.   IF YOU RAN OUT OF NATURAL GAS YOU COULD RUN ON STRAIGHT DIESEL.  GREG LANG

http://milliondollarway.blogspot.com/2011/10/encana-expands-compressed-natural-gas.html#comments

Greg Lang said...

Two ideas here: First off, if the government wants to promote vehicle natural gas they should focus on give a subsidy for public natural gas filling stations where they don't have them now.
(A couple of weeks back I checked and the Twin Cities,MN has only one nat gas public filling station at a nat gas equipment yard four miles south of downtown Minneapolis.This was installed in the mid 1970's. If we subsidize vehicles too much we can get a "cargo cult" mentality where people and companies wait for a bigger subsidy.
Utah is the only state with something of a network. A natural gas car only has half the range of a regular gasoline car.

The second "muse" is a posting here a couple of days back about using natural gas in oil rig diesel engines. Older oil fields have long used "gasoline type" engines running on natural gas.

With the far higher compression of diesel engines running them on natural gas, or better yet "convertible" seems problematic. A full nat-gas air mix would through the intake would have a horrible "knock" to it since diesels get compression through ignition.

A couple of theories: The first is a very lean nat-gas mixture to use as a "diesel fuel extender". Keep it lean enough to prevent "knock" and use a diesel "spritz". Same as the current injection but lower amounts. This would not require much modification of the modern computer controlled diesels. Basically knock sensors that adjusted the nat-gas to air ration.

The second method would involve direct injection of the nat-gas. Diesel injection involves hydraulics while nat-gas injection would involve pneumatics. With heat a diesel engine can compress to almost 1,000 PSI so you need to work against that. This is complicated, especially with the injection speed needed.

That said, I have not worked on diesels since the early 1970 when they were pre electronics and pre-EPA.