초록 ▼

An environmental control system for an enclosed cab of an off-the-road vehicle such as a tractor includes a pressurization blower for pressurizing the cab to a positive pressure with respect to atmospheric pressure outside the cab, and a recirculation blower for recirculating air within the cab. The

An environmental control system for an enclosed cab of an off-the-road vehicle such as a tractor includes a pressurization blower for pressurizing the cab to a positive pressure with respect to atmospheric pressure outside the cab, and a recirculation blower for recirculating air within the cab. The system includes a fresh air intake for taking in air from outside the cab, a recirculation air intake for taking in air from within the cab, and outlets through which the air from the blowers enters the cab. An air precleaner and a fresh air filter are provided between the pressurization blower and the fresh air intake. A control circuit automatically provides a speed control signal to the pressurization blower, and a manually selected speed control signal is provided to the recirculation blower. A speed sensor senses the speed of the pressurization blower, which varies for a given speed control signal as a function of air pressure within the cab and the condition of the fresh air filter. The control circuit varies the speed control signal to the pressurization blower as a function of the pressurization blower speed to provide essentially constant air flow from the pressurization blower despite changes in cab pressure and filter condition.

대표청구항 ▼

In an off-the-road land vehicle of the type having prime mover means for providing motive power and ground engaging means driven by the prime mover means, and having an enclosed cab in which a human operator resides when operating the vehicle, an environmental control system for the enclosed cab, th

In an off-the-road land vehicle of the type having prime mover means for providing motive power and ground engaging means driven by the prime mover means, and having an enclosed cab in which a human operator resides when operating the vehicle, an environmental control system for the enclosed cab, the environmental control system comprising: a plenum having fresh air intake means through which fresh air is drawn into the plenum, recirculation air intake means through which air is drawn from the cab into the plenum, and outlet means through which air is exhausted into the cab; pressurization blower means between the fresh air intake means and the outlet means for causing air flow from the fresh air intake means to the outlet means; first motor means for driving the pressurization blower means as a function of a first motor control signal; recirculation blower means between the recirculation air intake means and the outlet means for causing air flow from the recirculation air intake means to the outlet means; second motor means for driving the recirculation blower as a function of a second motor control signal; speed select means for providing a speed select signal; fresh air filter means for filtering air flowing from the fresh air intake means to the pressurization blower means; pressurization blower speed sensor means for providing a speed sensor signal indicative of speed of the pressurization blower means, wherein the speed of the pressurization blower means varies as a function of air flow from the pressurization blower means; and control means for producing the first and second control signals to drive independently the pressurization blower means and the recirculation blower means, the first motor control signal being a function of the speed sensor signal to maintain an essentially constant air flow from the pressurization blower means to the outlet means despite changes in cab pressure and condition of the fresh air filter means and the second control signal being a function of the speed select signal.