John Deere Power Systems’s (JDPS) complete lineup of Interim Tier IV/Stage III B off-highway and gen-set diesel engines 75 hp (56 kW) and above will be available with a new factory-installed variable-speed fan drive.
John Deere’s variable-speed fan technology enables original equipment manufacturers to meet new not-to-exceed (NTE) emissions regulations associated with Interim Tier IV while improving fuel economy and engine performance. Not-to-exceed limits, which began Jan. 1, 2011, for 174 hp (130 kW) and above power ratings, require engines to stay within the emissions standard across the normal operating range of an engine. The NTE regulation effective date for 75 hp (56 kW) to 174 hp (130 kW) engines is Jan. 1, 2012.
Factory-integrated, uniquely tuned to engine/fan size and controlled by the engine control unit, the new variable-speed fan requires no additional OEM installation or operator intervention. With the need for a separate controller/control valve, wiring harness and mounting hardware eliminated, the variable speed fan drive’s factory integration will benefit OEMs through engineering expense savings, shorter product development schedules and lower total installed costs, according to the manufacturer.
“This component further enhances the line of simple, fuel-efficient and field-proven technologies we’re using to meet the more stringent Interim Tier IV/Stage III B emissions requirements,” said Doug Laudick, manager of product planning at John Deere Power Systems. “The variable-speed fan optimizes performance and minimizes operating costs, making it valuable for most mobile and stationary applications.”
In contrast to a fixed-speed fan, the variable-speed fan adjusts to engine speed, load and ambient conditions and operates at the slowest speed required to provide proper cooling. By operating at slower fan speeds, the new variable-speed fan drive:
• Allows the engine to remain within the new not-to-exceed emissions zones across the operating range of the engine in variable-speed and load applications
• Improves engine performance by increasing available flywheel power, improving transient response in variable-speed applications and block loading in gen-set applications
• Improves engine/vehicle warm-up and cold-weather performance by reducing the amount of cold air circulated across the different cooling system components in lower ambient temperatures
• Extends the life of fan-drive components such as the fan belt, pulleys and bearings
• Decreases fan noise
• Allows owner/operator to achieve greater fuel efficiency
“In fact, our research shows that the payback period for variable-speed fan technology is short,” Laudick said. “Based on a fuel cost of $3 per gallon, the payback period is approximately 400 hours on a 9.0L engine operating at a 60 percent load factor in OEM applications. That is a significant return on an investment that already benefits emissions, performance and durability.” Typical payback periods on the 6.8L and 13.5L engine platforms are less than one year based on a typical annual average usage of 500 hours per year.