Belt-driven engine accessories have long been a challenge for engineers. Maximizing performance, reducing noise, dealing effectively with limited space in the engine compartment – not to mention reducing energy consumption of the accessories – have long been an engineer’s “Holy Grail.”
This challenge is now solved as you can reduce energy consumption of belt-driven engine accessories with a crankshaft-mounted accessory drive incorporating NuVinci® CVP technology, and still have the accessory power you need on demand for modern electronics-intensive vehicles.
- Increased fuel economy during cruising and acceleration by reducing belt speeds
- Additional power at idle: higher accessory output on an as-needed basis
- Smooth, responsive accommodation of engine/load transients
- Opportunities to add “smart” controls for accessory drives
- Opportunity to optimize both accessories and their associated heat exchangers to reduce overall vehicle packaging
- Faster acceleration “underdrive pulleys on demand”
The NuVinci technology enables a practical accessory drive that measurably improves fuel economy by separating accessory speed from engine speed.
During a typical drive cycle, engine speeds operate between idle and highway cruise depending upon conditions. For vehicles with belt-driven accessories, accessory speeds follow these transients, wasting power when the engine is accelerating or cruising. With the NuVinci-equipped accessory drive mounted on the crankshaft, belt speeds may be varied independent of engine speed, reducing accessory speeds and power consumption.
By maintaining steady accessory speed, both performance and economy improve. At higher engine RPM, decreasing accessory speeds decreases power use, thus saving energy. Additional energy savings can be gained by optimizing the accessories for a narrow speed range operation. Conversely, at low engine RPM, the accessory belt speed can be increased to provide additional battery-charging power or to increase the water pump speed.