HWH Active Air

[davidbrady]

Six and a half years ago I posted this to the yahoo:groups:wanderlodgeForum; I wonder if there have been any recent developments in HWH's Active Air program:


I spoke with an HWH engineer today regarding their Active Air suspension. For the uninitiated, Active Air provides dynamic suspension height adjustment. Enter a turn or change a lane and the outboard airbags are inflated and the inboard bags deflated to maintain a level chassis attitude. HWH uses their own technology: high flow air valves, electronic height control sensors, and computer mother boards. They link it all together with a CAN, J1939, bus known as RV-CAN, and have been active in the standards committees to formalize the RV protocol. The system consists of three height control sensors, pressure sensors for each air bag, high flow air manifolds with solenoids, a transmission speed sensor, an accelerometer, and a steering wheel angle sensor, along with associated wiring and plumbing. Integrated within the Active Air is an Air Leveling System. Control is also provided to the operator to allow raising the coach at each end to clear obstacles and to allow lowering the coach to clear obstacles. While en route the operator can raise or lower sides or ends of the coach to low, medium, or high to suit his needs; i.e, crowned roads, side wind, or front wind, etc. Air bag inflation takes time. While on a cloverleaf HWH instrumentation can show an increase in outboard air bag pressure of 20 to 30 psi and a reduction of inboard air pressure of 30 to 40 psi. The high flow valves use orifices of .25 inch and hoses can range from 1/2 inch to 5/8 inch. The required pressure changes may require 0.5s or more to attain. To help eliminate delays, HWH uses the accelerometer, vehicle speed, and steering wheel angle to "anticipate" changes in direction and to get a head start on inducing bag pressure changes. When pressed, I was unable to pin HWH down on actual air bag response rates, but the engineer did cite and improvement in ride and handling of from 30 to 50%. The test mule at HWH is an 1988 BB PT40 and is available for test drives. The system comes with monitoring and diagnostics tools and air bag pressure displays. There are 2 modes of operation plus disabled. Below 15 mph the air in an axle's air bags are pressure equalized and the system is disabled, above 15 mph the system can be in "economy" mode or "active" mode. In economy mode the bus is leveled and the system is basically put in standby, this eliminates load on the air compressor and is said to improve fuel mileage. In "active" mode, the system is sensing air bag pressure, accelerometer, steering, and speed inputs, and is poised to dynamically pulse air into airbags as needed. The overall goal in "active" mode is to keep the coach level. This is done by anticipating roll and acting quickly to circumvent it. A perfectly level coach under all circumstances is the goal of the "active" mode.