U.S. Provisional Application No. 60/757,638 filed Jan. 10, 2006 is incorporated herein in its entirety by reference.
Environmental conditions, such as, but not limited to, temperature, humidity and/or air pressure, within an enclosed operator platform or cabin of a self-propelled work machine are typically controlled or regulated using a climate control system, also commonly referred to as a heating, ventilating and air-conditioning (HVAC) system. The climate control or HVAC system of a work machine typically includes several operator operable controls located within the cabin including, but not limited to, a mode selector, a temperature selector, and a fan speed selector. The mode selector will typically allow selecting a heat mode, an air conditioning mode, a window defrost defog mode, an air recirculation mode, and a fresh air mode. Additionally, some systems may be operable in an automatic temperature control (ATC) mode wherein the system controls the cabin air temperature to or within a range of an operator selectable value. Reference in this regard, Panoushek et al., U.S. Pat. No. 5,993,312, which illustrates a representative HVAC system for a work machine including this latter feature. Still further, some systems may be operable in a mode which automatically controls the fan speed and other elements of the system to maintain the cabin air pressure at a level above that of outside air, to limit infiltration into the cabin of outside air, dust and other contaminants from the outside environment. This feature has particular utility in work machines used in off-road applications such as construction, mining and agricultural applications, and, more particularly, such as agricultural tractors and harvesting machines, which are sometimes operated in very dusty environments, for instance, wherein the dust is so dense as to significantly limit visibility. A cabin pressure sensor may be provided for use in regulating cabin air pressure.
Operation in such intense dust can cause problems, including for instance, the partial or full clogging of the air intake filter or filters for the cabin, as well as of radiators and heat exchangers, including the air conditioning condenser, which is typically cooled using external air. As a consequence, in the instance of the air-conditioning system, the system may be required to operate for longer periods, and/or more frequently, to achieve or maintain a selected climate setting for the operator cabin. Such dust problems may be sufficiently severe so as to make it impossible for the air-conditioning system to achieve the climate setting. Such conditions, if allowed to exist, can result in increased power usage, system and component degradation and shut-down or failure, downtime for cleaning and/or repair, and operator and/or machine owner dissatisfaction.
Other conditions that can lead to or result in system, operation and component degradation and failure include, but are not limited to, operation of high electrical current using items such as the cabin air fan when the engine is not operating or is operating at less than an adequate level, drive belt slippage and failure, air-conditioning system refrigerant and oil leakage and internal blockages, coolant leakage in the lines and heat exchanger of the heating system, fan motor failure, sensor failure, cabin seal failure, and control failure.
Still further, the operation of the climate control system, and, in particular, the compressor of the air-conditioning component thereof driven by the engine of the work machine, can have power requirements which can be significant for a smaller engine, and/or an engine under heavy load, such as when the engine is being started, the work machine is accelerating, going uphill, and/or the engine is powering components such as harvesting and crop processing equipment, load bearing fluid lift cylinders and the like, such that if the air-conditioning compressor is operated, or is allowed to initiate operation, when the engine is under heavy load, the performance of the air-conditioning system, engine, and/or other components powered by the engine, and/or the engine itself, may be degraded.
It is well known to provide devices in connection with the air-conditioning system operable for sensing a condition or conditions representative of engine load and/or operating conditions, such as the engine intake vacuum and temperature, and devices for automatically controlling the engagement of the air-conditioning compressor clutch and/or the compressor, for avoiding or minimizing overloading the engine and/or degrading operation of the air-conditioning system and other systems of a vehicle. It is also well known to provide sensors, such as thermal sensors and the like, in association with various of the components of the climate control system, and operable for sensing problem conditions and outputting a signal and/or shutting down the system or component when a problem is indicated, for instance, when a component of the system such as the compressor or the condenser is clogged or obstructed, beginning to overheat, or the evaporator is freezing. Such sensors are typically connected to an air-conditioning electronic control unit (ECU), which may be operable for storing information representative of a problem condition in a memory for retrieval for use in diagnosing the problem. The ability to rapidly diagnose problems with work machines is a particularly sought after capability, as downtime for such machines can be costly.
Presently, the known climate control or HVAC systems in work machines used for off-road applications are stand-alone units having dedicated ECUs. These controllers operate in isolation and do not communicate or interface effectively with other controllers in the vehicle. This isolation has been found to restrict the ability of the HVAC system to optimally use available resources and hence ends up making the HVAC system a higher cost system.
More recently, it has been observed that work machines commonly utilize controller area networks (CANs) connecting multiple system controllers and operable for sharing both raw and processed data and information, in real-time, relating to a variety of machine systems and components, including information relating to the engine, via the engine controller, to function in a coordinated and integrated fashion. It is also observed that some CANs have a controller including software capable of automatically troubleshooting and diagnosing problems with a system or component on the CAN. It has also been found that, often, a variety of controllers on work machines have under-utilized processing capacity.
Accordingly, what is sought is a climate control system, and a method of operation of the same, which advantageously and economically integrates into and utilizes the resources and capabilities of a CAN of a work machine, including, but not limited to, shared data from other systems of the machine, particularly engine control data from an engine controller, for controlling climate control system operation, as well as for troubleshooting and diagnosing problems.