Systems for climate control for an interior of a motor vehicle may comprise heating, ventilation and/or air conditioning and/or cooling of the interior. An increasing number of passenger cars and other motor vehicles are equipped with systems that involve automatic temperature control. In most such systems, control inputs of the driver and data supplied by sensors are used to introduce appropriately temperature-controlled and/or air-conditioned air into the interior, in particular the passenger cabin of the motor vehicle, in order to achieve a pleasant temperature control for the occupants.
Automatic temperature control systems in general comprise one or more sensors for acquiring control variables of the interior that are relevant to climate control (such as air temperature in the interior), a control element for selecting a desired temperature, and a device for controlling an air stream flowing to the interior. The quantity, direction and/or temperature of the air stream may be controlled. If, for example, the measured temperature of the interior air is below the desired temperature, then the air stream supplied to the cabin is heated more strongly or cooled to a lesser degree, and/or the intensity (rate of flow) of the heated or cooled air stream is correspondingly changed. In this case, use is made of control algorithms which are preferably optimized to reach a desired temperature quickly and to avoid control oscillations. With such systems, the quantity, the temperature and the distribution of the temperature controlled and/or air-conditioned air introduced into the interior is generally adequately adapted to the comfort requirements of the occupants for a stationary vehicle and given ambient conditions.
If conditions are variable, though, for example when the vehicle interior is to be heated up to comfortable temperatures in the event of a start in cold surroundings, the known algorithms are frequently not efficient. A substantial outlay is required to adapt the control algorithm to the characteristics of a specific vehicle that is, for example, dependent on the size, shape and equipment of the cabin and likewise on the type of engine and other drive components. Even if the control algorithm is optimized for a multiplicity of climatic conditions, the existing controls are frequently not optimal under other climatic conditions.
Many variables and considerations may also have an effect on the interior climate, for example, if there is a change in the thermodynamic properties of the interior as a function of the number of persons in the vehicle, opening of a door, the presence/absence of a cargo space cover, and the presence/absence and/or temperature of a load. Other pertinent factors may include different equipment or different chassis variants of a particular base vehicle.
An additional problem may be posed by engines that operate at a high efficiency and therefore do not produce sufficient heat to heat up the interior in cold ambient conditions. The heat generated by the engine, which is not constant all the time, must therefore be stored and used as effectively as possible. Thus, for example, it is necessary to avoid a drop in the ventilation temperature through an excessive cooling of the engine because of the HVAC system, but on the other hand the interior is to be heated up to the desired temperature as quickly as possible, particularly in the case of a cold start at low ambient temperatures.
EP 1 159 520 B1 discloses a method for controlling and/or regulating thermal flows in the motor vehicle, in which a forecast is made for future load states of the engine cooling system on the basis of a model, and the thermal flows of the engine cooling system and of the climate control system are controlled and/or regulated in a fashion taking account of said load states. The model used takes account in this case of the variables relevant to the driving state and the thermal inertia of the engine cooling system, but is optimal in each case only for a specific vehicle with a specific drive system as well as specific thermal properties of the vehicle, in particular of the vehicle interior.