Abstract: In a free-wheeling vehicle drive system in which the free-wheeling function is cut in and cut out entirely in response to normal driving operation of acceleration and deceleration, at least the signal corresponding to engine acceleration, which may be provided by the accelerator pedal, is subjected to delay before it may set a flipflop establishing the free-wheeling function. The braking signal, which may conveniently be derived from the brake-light switch, can likewise be advantageously delayed in its resetting of the flipflop in order that brief touching of the brakes should not disable free-wheeling. A more refined system which cuts in free-wheeling only after acceleration of the engine followed by the establishment of an idling condition of the engine can be used without the necessity of providing an overrunning clutch, since the control of a normal clutch connecting or separating engine and drive train can provide free-wheeling.

Abstract: To provide an indication of the presence of a trailer connected to a vehicle, operating as a tractor, without any additional terminal or contact elements on a plug-socket connector between the electrical system of the tractor and the trailer connected thereto, a logic gate (11), preferably a NAND-element, is connected to the output line of the direction flasher circuit, or other suitable connecting line, to a low-resistance load on the trailer, for example the brake light (19a), position lights or the like, the resistance circuit element including a connection from the positive power supply through a resistor (12) having a value which is high with respect to that of the lamps on the trailer (19, 19a) so that, with the trailer disconnected, an effectively 1-signal will be applied to the logic circuit but, upon connection of a low-resistance lamp, that is, upon connection of a trailer socket, the signal at the logic gate will drop to a O-signal although the current through the lamp is insufficient to cause ligh

Abstract: The heat exchanger of the temperature control system for a vehicle passenger compartment exchanges heat with air entering the passenger compartment. The flow of heat-exchange medium through the heat exchanger is controllable for controlling passenger-compartment temperature. A servo comparator receives and compares a temperature command signal and a feedback signal and produces an error signal which operates an actuator which in turn actuates an adjuster for fluid flow through the heat exchanger. The command signal is derived from a command transducer whose setting is adjustable by a passenger. The feedback signal is derived from a passenger-compartment temperature sensor but additionally, in order to avoid system instability, is furthermore derived from a heat-exchanger temperature sensor. In particular, the feedback signal includes a component whose value is determined by the rate of change with respect to time of the temperature sensed by the heat-exchanger temperature sensor.

Abstract: A valve arrangement, especially for controlling flow of hot water through a heating device of a motor vehicle, mainly comprises a closed housing provided with an inlet chamber and an outlet chamber communicating with each other through an opening forming a valve seat, and a valve member movable relative to the valve seat for opening and closing the opening. The arrangement includes further a flexible membrane which is clamped at its outer periphery to the housing and which forms a control chamber at the side of the inlet chamber facing away from the valve seat. The valve member is operated by an electromagnet which acts also on an auxiliary valve member in the control chamber to create during movement of the valve member toward the valve seat a higher pressure in the control chamber than in the outlet chamber and during movement of the valve member away from the valve seat a lower pressure in the control chamber than in the inlet chamber.

Abstract: A fluid control valve, controlling flow of hot water through a heating arrangement for motor vehicles, comprises a pot-shaped guide sleeve in which the armature of an electromagnet is movable in axial direction, and to which a valve member is connected by a push rod, which extends through an axial bore of a magnet core fixed in the guide sleeve. The facing ends of armature and core are spaced a small distance when the valve member engages a valve seat in the valve housing between an inlet and an outlet socket. The guide sleeve is flowed through by water passing through the valve. The magnet core is clamped in the guide sleeve with a clamping force greater than the axial force acting on the core. The magnet core is positioned in the guide sleeve by first moving the core closer to the armature and then imparting to the latter a predetermined axial force in closing direction of the valve.

Abstract: An apparatus to regulate the temperature of the interior of a motor vehicle, including a room air temperature sensor and a heating air temperature sensor, with the room air temperature sensor providing a substantially higher controlled variable change per unit of temperature change and wherein the sensor signals are summed by a controller. The heating air temperature sensor consists of two series-connected temperature sensors of which one is thermally insulated. The sensor control signal is taken from the junction between these two temperature sensors so as to provide dynamic coupling of the heating air temperature sensor to the room air temperature sensor. In this manner, the room air temperature is sensed precisely and relatively more rapidly so that an excessively large fluctuation of the actual temperature is avoided if the heating output of the heat exchanger varies between a high and a low value.

Abstract: A motor vehicle is equipped with a heater assembly in which hot coolant from the engine is circulated through a first heat exchanger, normally called heater. The vehicle is also equipped with a refrigerating unit, i.e., an air conditioner, which has a second heat exchanger, or cooler, located in front of or behind the heater. Two separate temperature sensors are provided. One of these senses the compartment temperature while the other is located directly adjacent to the heater and senses the temperature of the air leaving the heater. The responsivity of this latter sensor is made substantially lower than that of the compartment sensor, i.e., its signal change per unit temperature change is lower, resulting in differential weighting. A control unit is so constructed that when the compartment temperature rises, the heater, which is normally cycled on and off in a quasi-continuous fashion, is shut off. If the temperature rises further, the controller activates the refrigerator unit and the air is cooled.

Abstract: A heating system for a motor vehicle has temperature sensors for gauging the compartment temperature as well as for gauging the temperature of the effluent hot air. These sensors are connected in series, with the compartment sensor generating the more significant control signal. The flow of heating medium, for example engine water, is regulated by a valve under the control of a regulator which compares the sensors signals with a set-point value. The valve may be cyclically actuated by pulses of fixed frequency but having a width which depends on the results of the signal comparison.