Means For Controlling The Course Of Operation Of An Auxiliary Heating System In Motor Vehicles Or Ships

Abstract

The control means controls, in particular, the safety period, the restarting delay and the retardation time of an auxiliary heating system operable during interruption, or at low outputs, of a main heating system. A permanent magnet on the drive shaft of the drive motor of the vehicle or ship cooperates with a stationary inductance coil or a stationary magnetically controlled resistor to provide output pulses which are supplied to a counter having an associated decoder connected to a control device controlling the operation of the auxiliary heating system, particularly, the shutting down of the auxiliary heating system. The pulse counter transmits a pulse to the control device only after the counter has received a preselected number of pulses from the pulse transmitter.

Description

FIELD AND BACKGROUND OF THE INVENTION

This invention is directed to means for controlling the course of operation of an auxiliary heating system, in motor vehicles or ships, and particularly for controlling the safety time, the restarting delay and the retardation time of the auxiliary heating system.

Such auxiliary heating systems are installed in motor vehicles or ships, and serve to heat the interior of the vehicle or ship adequately when the motor of the vehicle or ship stops or when there is a low output of the heating plant of the vehicle (motor heating plant).

The operation of such an auxiliary heating system must meet special safety requirements. Thus, it must be assured that no fuel, or only a very small amount of fuel, can flow into the combustion chamber of the auxiliary heating system when the auxiliary heating system is shutoff, or in case of troubles or irregularities in the auxiliary heating system. Otherwise, the fuel that has entered the combustion chamber will burn off during the ignition when the auxiliary heating system is started again, and this would result in smoking of the auxiliary heating system. If the combustion chamber is still hot enough to ignite the fuel, an explosion also may occur.

In addition, it must be assured that "cold blowing" occurs when the heat is shut off. By "cold blowing" is meant the blowing out of any ignitable fuel-air mixtures by restarting the combustion air blower and the heating air blower of the heating system. This also serves directly to cool the hot combustion chamber walls.

The retardation time also acts in the sense of these safety measures, with the result that the spark plugs or glow plugs of the heating system are shut off only a certain time after ignition of the auxiliary heating system. This has the effect that the ignition of the ignitable fuel-air mixture is effected positively, and that no explosion occurs during start-up.

Furthermore, it is necessary to supervise the combustion in the combustion chamber of the auxiliary heating system. For this purpose, it is known, in certain cases, to use a device with a photocell, and which shuts off or opens the safety switch after a certain time by electrical bridging, so that the photocell device does not shut off the heat when the temperature drops during operation.

These various safety devices are controlled by a control device. In known auxiliary heating systems, the safety period, the restarting delay and the retardation time are controlled, in the electronic devices, by an electrical discharge, which provides the switching signal. Discharge is effected by the series connection of an electrolytic capacitor and an ohmic resistor, which together form a time constant and which start an operation, for example, shutting off of the system, when a certain voltage level is attained.

This known safety device has proved disadvantageous, however, since the tolerances of the various parts are temperature-dependent, each part having a different coefficient and not always showing the desired constancy due to storage. Additionally, large electrolytic capacitors are required, where a new forming process takes place, as known, whenever a new voltage is applied, so that the entire capacity always varies in time. This has the result that the setting of the devices and their response, or the control operation initiated by them, are not always accurate, despite careful selection and checking.

SUMMARY OF THE INVENTION

The invention is directed to providing means by which the control durations for the safety time, the restarting delay and the retardation time, to be maintained for the safety of operation of an auxiliary heating system, can be easily and safely set independently of the temperature and of the voltage over wide ranges, and can also be maintained in operation.

In accordance with the invention, this problem is solved by a single pulse transmitter whose output pulses are fed to a pulse counter with an attached decoder and to a control device. Advantageously, the pulse transmitter is formed by a permanent magnet arranged on the drive shaft of the vehicle motor or ship motor and cooperating with a stationary inductance coil or a stationary magnetically controlled resistance.

With the means provided by the invention, it is possible to count the pulses originating from the interrupter contact of the combustion air motor of the vehicle or ship, and to provide, at various points, logical outputs which initiate operations in the auxiliary heating system. This has the advantage that the duration of the safety time need no longer be indicated in minutes or in any other units of time, but rather is indicated in pump strokes and thus in a measure which enters directly into the behavior of the pump. This has the additional advantage that the amount of fuel, for example, which is injected into the heater, is accurately defined by the number of pump strokes independently of the voltage. Thus, it can no longer happen that a heater running with 15 volts battery voltage injects slightly more fuel than when operating with 12 volts or even with 9 volts.

As another feature of the invention, the pulse counter feeds a pulse to the control device only after the pulse counter has received a preselected number of pulses transmitted by the pulse transmitter. The effect of this is that an operation controlled by the control device is started only when a very definite number of pulses has been counted. With the invention means, the individual control times or durations can be selected freely.

In accordance with a further development of the invention, it has been found that, for each of the outputs of the counter, the number of the pulses to be received from the pulse transmitter before releasing a pulse to the respective output of a control device, may be selected separately. With this arrangement, respective control times thus can be set for each of the individual units to be controlled.

In accordance with a further feature of the invention, the pulse transmitter, as well as the pulse counter, the decoder and the control device can be combined to form a unit. This has the advantage of extreme compactness, and it is also suitable for the subsequent installation in existing auxiliary heating systems.

An object of the invention is to provide improved means for controlling the course of operation of an auxiliary heating system in motor vehicles or in motor-driven ships.

Another object of the invention is to provide such a means by which the control times for the safety period, the restarting delay and the retardation time of an auxiliary heater can be easily and safely set independent of temperature and voltage over wide ranges.

A further object of the invention is to provide such a means utilizing a single pulse transmitter in association with a pulse counter, a decoder and a control device.

For an understanding of the principles of the invention, reference is made to the following description of a typical embodiment thereof as illustrated in the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

In the Drawing:

The single FIGURE is a simplified schematic diagram of a control means embodying the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawing, a permanent magnet 3 is arranged on the shaft 2 of a motor 1, and forms, with stationary inductance coil 5, a pulse transmitter 4. The pulses 6, originating from pulse transmitter 4, have a certain pulse sequence. In the case of the illustrated example, the pulse sequence depends on the speed of motor 1. However, in the case of an electronic pulse transmitter which is independent of the motor 1, the pulse sequence of the output pulses 6 can be preset.

Pulses 6 are fed to a pulse counter 8 with an attached decoder 9 and to a control device 11. Pulse counter 8 counts the number of pulses independently of the pulse frequency and, after a given number of pulses has been counted, selected pulses 10 are supplied to control device 11.

Control device 11 controls, by means of output pulses 12, pump 13, heating air blower 14, ignition device 15 and the safety switch 16 of the auxiliary heating system. Pump 13 is a fuel dosing pump, which is driven electromagnetically by current pulses 12, and which feeds the fuel in pulses to the combustion chamber of the auxiliary heating system.

With the means of the invention, the control durations or periods or times can be set very accurately over wide ranges independently of the voltage.

While a specific embodiment of the invention has been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

What is claimed is:

1. In an auxiliary heating system, for supplementing or augmenting a main heating system, of a motor-driven vehicle, and including a main motor having a drive shaft, and of the type including, as components, a heat exchanger independent of the main system, a fuel pump, a heating air blower, an igniter for a fuel burner, and a safety switch, and further including a control device for its components: means for controlling the safety period, restarting delay, igniter operating time and safety switch of the auxiliary heating system, said means comprising, in combination, pulse generating means including a single pulse transmitter, constituted by a permanent magnet on said drive shaft and a stationary magnetic field responsive element operatively associated with said permanent magnet providing output pulses for controlling the operation of said auxiliary heating system; a pulse counter connected to said transmitter to receive and count such output pulses; a decoder connected to the output of said pulse counter to receive counted output pulses therefrom; and a pulse responsive control device, controlling the operation of said auxiliary heating system components, connected to said decoder to receive such output pulses therefrom; said pulse responsive control device having respective outputs connected to said heating air blower, said igniter, said safety switch and said fuel pump; said pulse-responsive control device providing control signals at each of its outputs only responsive to respective preselected numbers of counted pulses.

2. Means for controlling the course of operation of an auxiliary heating system, as claimed in claim 1, in which said single pulse transmitter provides a presettable output pulse sequence.

3. Means for controlling operation of an auxiliary heating system, as claimed in claim 1, in which said pulse transmitter comprises a permanent magnet on the shaft of a drive motor; and a stationary inductance coil cooperable with said permanent magnet.

4. Means for controlling operation of an auxiliary heating system, as claimed in claim 1, in which said pulse transmitter comprises a permanent magnet on the shaft of a drive motor; and a stationary magnetically controlled resistor cooperating with said permanent magnet.

5. Means for controlling operation of an auxiliary heating system, as claimed in claim 1, in which said pulse counter transmits an output pulse to said control device only after said pulse counter has received a preselected number of output pulses from said pulse transmitter.

6. Means for controlling operation of an auxiliary heating system, as claimed in claim 1, in which said pulse transmitter, said pulse counter, said decoder and said control device conjointly form a unit.