SALISBURY — As Joe Givens listened to the diesel engine revving, he was really following the numbers.
The temperature inside the exhaust filter would reach just shy of 1,200 degrees. The number of particles coming out the exhaust stack: 0.
Givens is a technical trainer for James River Equipment, which sells John Deere equipment in Virginia and North Carolina.
He was in Salisbury on Thursday demonstrating the technology in the tractor-maker’s line of machinery that will meet the latest tier of emission limits for industrial machinery.
The engine in the tractor is what’s different about the 8310R model sitting on the lot at the James River Equipment dealer on Klumac Road. Heat generated by the engine is used to burn nearly all pollution from the engine and keep the emissions filter clean.
Computers monitor the tractor while it operates to maximize fuel use.
“You’ll never see black smoke coming out of the stack,” because sensors regulate the engine performance so closely, he explained.
All manufacturers are preparing for the implementation of tighter emission rules, known as “Tier 4.”
The Environmental Protection Agency (EPA) rules  apply to new diesel engines used in off-road  equipment. Essentially it requires manufacturers to reduce the levels of particulate matter and oxides of nitrogen (NOx) 50 percent to 96 percent.
Givens said that John Deere’s technology is almost at the point where it will meet the new regulations. 
Other manufacturers are employing similar technologies. The new systems can be confusing for buyers, so here’s an online guide from the Farm Industry News website that offers a rundown of the low-emission models for 2012.