Some vehicles are equipped with an automatic stop/start controller which automatically stops and starts the vehicle engine, without operation of an ignition key, in order to improve fuel economy. Some of these vehicles are provided with an air conditioner, and the coolant of the engine is employed as a heat source for heating the vehicle, while the driving force of the engine is employed to drive an air conditioner compressor for cooling the vehicle interior. However, stopping of the engine by the automatic stop/start controller results in degradation of the heating or cooling performance.
One traditional automatic stop/start controller to address these problems includes an engine for drive, a motor, an air conditioner which employs a coolant or driving force of the engine, an engine controller to start/stop the engine according to the driving state, and an air conditioner controller to start/stop the air conditioner. A target temperature of output air that is sent to the driver's compartment of the vehicle is determined, and the engine is operated to permit air conditioning when this target temperature is at such a temperature that the driver's compartment needs air conditioning (see JP No. 3323097).
Another conventional automatic stop/start controller includes an engine, a motor, and an air conditioner to control the temperature by a refrigerating cycle created by a compressor and an evaporator in the vehicle. When the vehicle is stopped, if it is determined that the temperature of the air is below a predetermined temperature after evaporation, then the engine is required to start to maintain the cooling performance (see JP No. 3305974).
Further, another conventional automatic stop/start controller includes an air conditioner in a vehicle in which an engine is automatically stopped or started based on the driving state. The engine is prevented from automatic stopping so as to maintain air conditioning performance when a blower fan of the air conditioner is activated and the operational switch for the air conditioning is activated and the temperature of the outer air is below a predetermined temperature (see JP Laid-Open No. 2001-341515).
The conventional air conditioner on the vehicle having an automatic stop/start controller is a so-called automatic air conditioner system in that the system automatically controls the air in the driver's compartment to be at a set temperature. This automatic air conditioner cannot be applied to a so-called manual type air conditioner that manually controls the quantity of air, an air mix damper, and an outlet.
Although some of the conventional vehicle air conditioners having an automatic stop/start controller may be applied to the manual-type air conditioner, the heating performance cannot be maintained, since it is designed to keep the cooling performance by stopping the engine when the air temperature after the evaporation is below a predetermined temperature, thereby saving fuel.