WO1982004126A1

WO1982004126A1 - Circuit and switch responsive to engine running condition

Info

Publication number: WO1982004126A1
Application number: PCT/US1981/000659
Authority: WO
Inventors: Tractor Co Caterpillar
Original assignee: Fuzzell Joe E; Hansen Brent A
Priority date: 1981-05-11
Filing date: 1981-05-11
Publication date: 1982-11-25

Abstract

The invention activates and deactivates components in a vehicle using an engine in which the ignition switch is left in the "on" position even when the engine is shut down. An engine running sensor (10) is provided for activating and deactivating components (78, 80) of a vehicle in response to the vehicle being in a running condition. The sensor (10) includes an electrical signal generator (24, 26, 36) responsive to vibrations of the vehicle, a switch (70) responsive to the generator (24, 26, 36), and the components (78, 80) being activated in response to the switch (70). The generator (24, 26, 36) is mounted on a portion of the vehicle, preferably proximate the engine, to vibrate as the engine runs. The generator (24, 26, 36) need not be exposed to any of the pressurized systems of the vehicle. The described embodiment is useful for ensuring deactivation of the hourmeter (80) and electrical monitoring system (78) of a vehicle when the engine is shut down.

Description

Circuit and Switch Responsive To Engine Running Condition

Technical Field

The present invention relates to apparatus control systems and more particularly to systems for activating and deactivating components of an engine or vehicle in response to the engine or vehicle being in a running condition.

Background Art

. Many engines and vehicles include peripheral components which it is desirable to activate or deactivate in response to the engine or vehicle being in a running condition. For example, the hourmeter and electrical monitoring system of an engine should be activated only during the period when the engine is ^■ running.

In gasoline engines, activation and deactivation of these peripheral systems is typically accomplished by placing the ignition switch in series with the power supply to these systems. This is not sufficient, however, in the case of diesel engines because in many instances the ignition switch of a diesel engine is left in the "on" position even when the engine is shut down.

To avoid this difficulty, an oil pressure sensor-switch has been employed to activate and deactivate these peripheral systems. When the engine is running the sensor detects a pressurized condition and responds by closing a circuit providing power to the hourmeter and monitoring systems. When the engine -2-

is cut-off the oil becomes depressurized and the sensor-switch responds by opening the power circuit to the peripheral systems.

This use of an oil pressure sensor requires, of course, access to the pressurized oil system of the engine. In. many instances, the sensor-switch has permitted the loss of oil pressure which on occasion has resulted in damage to the engine.

There is a need for an extremely reliable low cost switch whose function it is to maintain an electrical component of an engine in an armed state while the engine is running. This switch should be of a design not requiring that it be introduced into any pressurized system of the vehicle. The present invention is directed to overcoming one or more of the problems as set forth above.

Disclosure of the Invention In one aspect of the present invention, a motion responsive switching circuit includes means for detecting vibration, means for generating a signal in response to the detected vibration, a switch controlled by said generating means. The switch has an open and a closed condition and is adapted to be in one of said conditions in response to receiving said signal. A component has an activated and a deactivated state and is controllably maintained at a preselected one of said states in response to the condition of said swi^'tch. Engines and vehicles often include peripheral electrical equipment which it is desired be turned off or on in response to the engine or vehicle being in a running condition. For example, it is required that the hourmeter of a vehicle be activated only when the engine of that vehicle is running. This has been accomplished by including a switch controlled by a sensor which detects when the engine is running. • In the present embodiment, this sensor is a knock detector or accelero eter utilizing vibration as an indication that the engine is running. The sensor can be attached to any of a. great number of locations on the vehicle. Existing machines can easily be retrofitted to include the motion responsive switching circuit.

Brief Description of the Drawing

The drawing details an embodiment of the present invention. It should be understood that this drawing is not intended as a definition of the invention, but is provided only for the purpose of illustration.

Best Mode for Carrying Out the Invention

A circuit and switch system responsive to the running condition of an engine is generally indicated in the drawing by the reference numeral 10. A voltage +B is provided by the engine battery (not shown) . As will subsequently become apparent, the circuit and switch system 10 may be powered by engine batteries of any of the common output voltages, from 18 to 36 volts, with no changes needing be made to the system 10. Between the high and low terminals +B, -B of the voltage supply are in series connection, a 270k current limiting resistor 12, a reverse biased zener diode 14, and a forward biased diode 16. The diode 16 provides reverse voltage protection to the system 10 and prevents damage should, for example, the engine be incorrectly jump-started. The zener diode 14 establishes a constant potential of approximately 10V for the system 10. preferably this zener diode 14 is a 1N5347 . A high and a low rail 18,20 for the system 10 are connected, respectively, to the cathode and anode of the zener diode 14. A noise suppression circuit 19 is connected between the high and low rails 18,20. This noise suppression circuit 19 includes first and second capacitors 21,22 and serves to prevent spurious voltage changes from activating the circuit and switch system 10.

An vibration detecting means, such as a knock detector 24, is positioned adjacent or on the engine (not shown) to sense the vibration thereof. Preferably, this knock detector 24 is of the pi zo-electric accelero eter type. Its purpose is to generate an electrical output in response to changes in the velocity it experiences. As all engines vibrate during operation, the knock detector 24 will provide an output in response to the engine being in a running condition. Typically, this, output includes -a number of cyclical wavetrains, the major component of which varies between 50 and 500 Hz.

An amplifier 26 is provided for the output of the knock detector 24. The amplifier 26 includes a single ended first operational amplifier 28 with feedback through a first resistor 30 to the inverting input. This first resistor 30 is preferably rated at 500 k . The non-inverting input of the operational amplifier 28 is connected to the output of the knock detector 24 through a 50 k second resistor 32. This first operational amplifier 28 and those others described subsequently are all located on a single chip, preferably a LM124J.

The output of the amplifier 26 is connected through a 15 k third resistor 34* to a zero-crossing detector 36. The zero-crossing detector 36 and the amplifier 26 together form means 37 for detecting vibration induced output from the knock detector 24. This zero-crossing detector 36 includes a second single-ended operational amplifier 38. The third resistor 34 is connected in series with both the output of the first operational amplifier 28 and the inverting input of the second single-ended operational amplifier 38. A 10 k fourth resistor 40 and a 220 k fifth resistor 42 are series connected from the output to the inverting input of the second operational amplifier 38. A 220 k sixth resistor 44 is connected from the junction of the fourth and fifth resistors 40,42 to the non-inverting input of the second operational amplifier 38. A 15 k seventh resistor 46 is connected between the non-inverting input of the second operational amplifier 38 and the low rail 20. A 1.0 M eighth resistor 48 is connected between the non-inverting input and the output of the second operational amplifier 38.

A parallel connected second diode 50 and 150 k bleeder resistor 52 are connected to the output of the second operational amplifier 38 with the second diode 50 being connected by its anode to this output. Preferably, the diode 50 is a 1N4454. A 10 uF third capacitor 54 is connected between the cathode of the second diode 50 and the low rail 20.

A third voltage following operational amplifier 58 is connected by its inverting input to the cathode of the second diode 50. A fourth voltage following operational amplifier 60 is connected by its non-inverting input to the cathode of the second diode 50. Tenth and eleventh 50 k resistors 62,64 are, respectively, series connected intermediate the second diode 50 and the third and fourth operational amplifiers 58,60. Each of the third and fourth voltage following operational amplifiers 58,60 receive feedback

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to its non-inverting and inverting input, respectively, through twelfth and thirteenth 500 k resistors 66,68. The output of the third and fourth operational amplifiers 58,60 is connected to a respective one of a fourteenth and a fifteenth 470 k resistor 67,69.

The base of a first and a second switching transistor 70,72 is connected to the output of the respective one of the third and fourth operational amplifiers 58,60. The emitter of each of the switching transistors 70,72 is connected to the low rail 20.

These transistors 70,72 are respectively defined as a 2N6474 and a T1P47.

The collector of each of the switching transistors 70,72 is connected through a current limiting thermistor 74,76 to a component of the engine such that switching of the respective transistor 70,72 effects activation and deactivation of that component. For example, the second transistor 72 is connected in series with a power supply circuit 75 and the hourmeter 80. Hence, switching on of the second transistor 72 effects a closing of the circuit bringing about activation of the hourmeter 80. Those skilled in the art will recognize that a circuit could be provided such that switching off of the transistor effects activation of the corresponding component. This is the case for the first transistor 70 and the corresponding electrical monitoring system 78 of the present invention.

Industrial Applicability

The circuit and switch system 10 is best suited for activating or deactivating a component, such as a sensor, of a vehicle or engine in response to the engine or vehicle being in a running condition. The present system 10 may be utilized, for example, to

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prevent continued operation of certain functions when the engine or vehicle is not operating, but the key is left^' in the ignition and at the "on" position.

Operation of the engine or vehicle serves to cause vibration of the knock detector 24. We have found that .in response to vibration the knock detector 24 establishes a varying output which includes voltage spikes. These voltage spikes are amplified by the amplifier 26 and establish saturated positive and negative output from the zero crossing detector 36. This output serves to switch on and off both of the switching transistors 70,72.

In response to there being either no output or a positive output from the knock detector 24, the inverting input of the second operational amplifier 38 will be positive with respect to the non-inverting input, thereby establishing a negative output from the zero crossing detector 36. This permits the positive charge on the third capacitor 54 to be bled through the bleeder resistor 52 and establish, after a period of time, a condition in which the third and fourth operational amplifiers 66,68 apply a voltage to the base of the switching transistors 70,72 that is insufficient to maintain the first transistor 70 in non-conduction and the second transistor 72 in conduction. As a consequence, the power supply circuit 75 to the hourmeter 80 is opened and that to the electronic monitoring system 78 is closed, resulting in these components being shut off. The charge on the third capacitor 54 dissipates through the bleeder resistor 52 with a time constant of 1.5 seconds. As a consequence, it is an appreciable time, several seconds, from the time of the last voltage spike produced by the knock sensor 24 before the hourmeter 80 and electronic monitoring system 78 are shut off. As long as the knock sensor 24 vibrates at least sufficiently often to send the amplifier 26 negative about once each second, the hourmeter and electrical monitoring systems will remain in an activated condition. We have found that the continued operation of an engine provides vibration sufficient to maintain the switching transistors 70,72of the present embodiment in the state requisite for continued operation of the components they respectively control.

It will by now be apparent that there are numerous other means for utilizing an element providing an electrical output in response to vibration to activate and deactivate sensors, hour eters and the like. Those skilled in the art will recognize that in the described embodiment circuit components of values other than those listed could be utilized with satisfactory results.

Other aspects, objects, advantages and uses of this invention can be obtained from a study of the drawings, the disclosure and the appended claims.

Claims

1. A movement responsive switching circuit (10) , comprising: means (24) for detecting vibration; me-ans (11,26,36,54,66) for generating an electrical signal in response to detected vibration; a switch (70) connected to said generating means (26,36) , said switch (70) having an open and a closed condition and being adapted to be at one of said conditions in response to receiving said .electrical signal; a component (78) having an activated state and a deactivated state, said component (78) being controllably maintained at a preselected one of said states in response to the condition of said switch (70) .

2. The movement responsive switching circuit (10) , as set forth in claim 1, wherein said component (78-.) is maintained in said activated state in response to said switch (70) being in said closed condition.

3. The movement responsive switching circuit (10) , as set forth in claim 1, wherein said vibration detecting means (24) has a first electrical output.

4. The movement responsive switching circuit (10), as set forth in claim 3, wherein said vibration detecting means (24) includes a piezo-electric element.

5. The movement responsive switching circuit (10), as set forth in claim 3, wherein said generating means (26,36) includes means (37) for detecting the presence of said first electrical output, said generating means (26,36) establishing an amplified output in r-esponse to detection of said first electrical output.

6. The movement responsive switching circuit (10), as set forth in claim 5, wherein said switch (70) is a semiconductor controlled by said amplified output.

7. The movement responsive switching circuit (10), as set forth in claim 6, wherein said component (78) has a power supply circuit (75) in series with said switch (70) , said component (78) being activated in response to said switch being in said closed condition.

8. The movement responsive switching circuit

(10), as set forth in claim 6, wherein said component (78) has a power supply circuit (75) , said switch (70) being adapted to establish power flow to said component in response to said switch being in said open condition.

9. A vehicle, comprising: means (24,26,36) for generating an electrical signal in response to vibration of a preselected portion of said vehicle; a switch (70) having a conducting and a non-conducting condition and being connected to said generating means (24,26,36) and of a configuration sufficient for entering one of said conducting and non-conducting conditions in response to receiving said electrical signal; and a component (78) having activated and deactivated states and being connected to the switch (70) , said component (78) being maintained in said deactivated state in response to said switch (70) being in one of said conducting and non-conducting conditions.

10. The vehicle, as set forth in claim 9, wherein said generating means (24,26,36) includes an acceleration responsive device (24) .

11. The vehicle, as set forth in claim 9, wherein said vehicle includes an engine, said generating means (24,26,36) being connected and responsive to vibration of said engine.

12. The vehicle, as set forth in claim 9, wherein said switch (70) is adapted for deactivating said component (78) in response to said switch (70) receiving said electrical signal,

13. The vehicle, as set forth in claim 9, wherein said switch (70) is adapted for activating said component (78) in response to said switch (70) receiving said electrical signal.

14. The vehicle, as set forth in claim 9, including a power supply circuit (75) connected to said component (78) , said switch (70) being connected in series with said power supply circuit (75) .

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