Visteon Corporation, a leading supplier of a full range of cockpit electronics products for vehicles, has developed a second-generation pulse count system for automotive heating, ventilation and air conditioning (HVAC) controls. The new system provides a significant reduction in wiring complexity and weight, achieving up to a 25 percent system cost savings (based on system control only) compared with conventional HVAC control solutions.

In Visteon’s system, the position of the actuator in the HVAC system is determined by reading pulses from the motor. The system uses Visteon’s patented climate control algorithms to control the direct current (DC) motor actuators via the power and ground wires only, eliminating the traditional feedback wire harness and position sensors.

The pulse count control system enables vehicle manufacturers to use simpler, lower cost non-feedback DC motor actuators. System reliability is improved by using fewer connections and deleting the position sensors in the HVAC actuators.

Visteon used its system expertise to develop an Application Specific Integrated Chip (ASIC) with an embedded inductor-based sense element. The microprocessor, with Visteon proprietary software, monitors and filters the current/voltage fluctuations inherent within permanent magnet DC motors to determine the position of the motor and then employs pulse counts to control the position of HVAC doors.

The accurate sensing, filtering and adjustments of the pulses provide robust overall HVAC system performance. The system is self-calibrating and monitors key operating parameters to maintain optimal performance during its life. It is compatible with a range of actuator solutions and hardware configurations for a cost-efficient solution.

Visteon’s technical centers in China and in India worked on implementing this first program application of the second generation of Visteon’s pulse count technology, which is scheduled for commercialization in mid-2010. Visteon launched its first-generation pulse count HVAC control system on the Chrysler Pacifica in 2006.

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