US3119991A

US3119991A - System for indicating the pressure of the lubricant circulating in an internal combustion engine

Info

Publication number: US3119991A
Application number: US60191A
Authority: US
Inventors: Friedrich K H Nallinger
Original assignee: Daimler Benz AG
Current assignee: Daimler Benz AG
Priority date: 1959-10-02
Filing date: 1960-10-03
Publication date: 1964-01-28
Anticipated expiration: 1981-01-28

Description

F. K. H. NALLINGER SYSTEM FOR INDICATING THE PRESSURE OF THE LUBRICANT CIRCULATING IN AN INTERNAL COMBUSTION ENGINE Filed Oct. 5, 1960 Jan. 28, 1964 .722 ven for FRIED /c/1 K H MALL/Na! 1 5) M l 9 A fro/ens 15 United States Patent 3,119,991 SYSTEM FOR INDICATING TI IE PRESSURE OF THE LUBRHCANT CIRCULATING IN AN INTER- NAL CQMBUSTEQN ENGHNE Friedrich K. H. Nailinger, tuttgart, Germany, assignor to Daimler-Benz Alrtiengeseilsehatt, Starttgart lUnterturkheim, Germany Filed Oct. 3, 1966, Bar. No. 69,121 Claims priority, application Germany Oct. 2, 1959 5 Claims. (Cl. 340-270) My invention relates to a system for indicating the pressure of the lubricant circulating in an internal combustion engine, more particularly in the engine of a motor vehicle, said system including a signaling lamp for giving a signal indicative of insufiiciency of the lubricant pressure.

Prior systems of this type include switching means which is adjustable to a single definite minimum pressure and energizes the signaling lamp as long as the pressure of the lubricant is lower than said minimum pressure. If this switching means is so adjusted that the minimum pressure is rather high, the lamp keeps burning, whenever the engine is idling or is operating within a lower range of its speed of operation, such lower range being of considerable extent. When the switching means is so adjusted that the minimum pressure to which it responds is lower, the lamp will be turned off when a comparative low speed of operation has been reached but will give no assurance that the lubricant pressure prevailing at a higher speed of operation is really sufiicient.

It is the object of my invention to provide an improved system of the type described hereinabove which gives a reliable indication whenever the lubricant pressure is lower than a minimum limit which increases with rising speed of operation. More particularly, it is an object of my invention to provide an improved system for indicating insufiiciency of the lubricant pressure where a low pressure sufiices for a slow operation whereas a higher lubricant pressure is required for a faster operation of the engine.

More especially, it is an object of my invention to provide a system of this character which is simple and includes but a single indicating lamp which will indicate insufficiency of the lubricant pressure over the entire range of speed of the engine in steps of smaller or larger extent.

Further objects of my invention will appear from a detailed description of a preferred embodiment thereof illustrated in the accompanying drawing. It is to be understood, however, that my invention is in no way restricted to such details but is capable of numerous modifications within the scope of the appended claims and that the terms and phrases used in such detailed description have been chosen for the purpose of illustrating rather than that of restricting or limiting my invention.

In the accompanying drawing an electrical circuit dia gram of a preferred example of my novel indicating system is shown in which the signaling lamp burns whenever the lubricant pressure is below a low minimum during idling and at low speeds of operation and below a higher minimum during higher speeds of operation of the engine.

The system shown for indicating insufficiency of the pressure of the lubricant circulating in an internal combustion engine includes a signaling lamp 11 suitably disposed on the instrument panel of a motor vehicle, a plurality of contacts 12 and 13 selectively connectable to the lamp 11, a current distributor 14 responsive to the speed of operation of the internal combustion engine 10 and connected to the contacts 12 and 13 for selectively supplying current to at least one of said contacts selected in dependence on the speed of operation and switching means 15 which is connected to the lubricant circulating system and responds to diiferent minimum pressures of the lubricant for selecting one of the contacts 12 and 13 in dependence on the pressure and for connecting it to the signaling lamp 11 for operating same.

In the embodiment shown the switching means 15 comprises a pair of actuators 16 and 17 which respond to different minimum pressures and are individually c0- ordinated to the contacts 12 and 13 for electrically con meeting the same to the signaling lamp 11. As the two actuators are similar, it will suffice to describe one of them, to wit the actuator 16. It comprises a cylinder connected by communicating

pipes

18 and 19 to the lubricant circulating system of the engine 10, a piston 20 movable in the cylinder and a spring 21 inserted between one face of the piston 20 and the end wall of the cylinder, whereas the other face of the piston 20 is subjected to the lubricant pressure. The chamber including the spring 21 is vented and the piston is provided with a piston rod 22 extending through the vented chamber and out of the cylinder and connected to a switch arm 23 which cooperates with the contact 12 for connecting same with the lamp 11 through

leads

24 and 25 as long as the spring 21 keeps the switch arm 23 in engagement with the contact 12 contrary to the pressure exerted upon the piston 20 by the lubricant. The spring is so adjusted by suitable means not shown that it will keep the switch arm 23 in closed condition whenever the lubricant pressure is lower than a minimum pressure of e.g. 43 p.s.i. The actuator 17 is so constructed and adjusted that it will keep its contact arm 26 in closed condition as long as the lubricant pressure is below a minimum of 7 p.s.i.

In the embodiment shown the current distributor 14 is formed by a relay provided with a winding 27, with an armature 28 and with a pair of armature contacts 29 and 31) for alternative engagement by the armature 28 and a generator 31 coupled with the engine 10 and connected to the winding 27 to supply current thereto. The

members

28, 29 and 31 thus form a plurality of pairs of contacts comprised respectively by

members

28 and 29 and

members

28 and 30. More particularly, the generator is provided with a regulator element 32 which is grounded when the generator rests or operates at a low speed and at higher speeds of operation is supplied with a DC. voltage. The armature 28 engages the contact 29 when the winding 27 is deenergized, and engages the contact 13, when the winding 27 is energized. The contacts 12 and 13 wihch are selectively connectable to the lamp 11 by the switching means 15 are connected to the

armature contacts

29 and 30 by leads 33, and 34 respectively. The system further comprises a source of current diagrammatically represented as a battery 35 which is connected to the armature 28 through a switch 36 which preferably is the ignition switch of the engine 10 and a lead 37. The winding 27 has its upper terminal connected to the lead 37 and its lower terminal connected by a lead 38 to the regulator element 32 of the generator 31.

From the above it will appear that the armature contact 29 engaged by the armature 28, when the winding 27 is deenergized, is connected with the contact 12 which is connectable to the lamp 11 by the actuator which is responsive to the higher minimum pressure of 43 p.s.i. of the lubricant.

It will be apparent from the foregoing description that the device comprises a first switch means comprising

members

28, 29, 39, and a second switch means comprising

members

12, 23 and 13, 26.

The operation is as follows:

When the ignition switch 36 is opened, the engine 1 being at rest, the elements assume the position illustrated. When the ignition switch 36 is closed, it closes a circuit including the

elements

35, 36, 37, 2'7, 38 and 32 and ground. The relay winding 27 included in this circuit is energized and withdraws the armature 23 from the position shown into engagement with the contact 39 which, in its turn, closes a circuit including the

elements

35, 36, 37, 28, 30, 34, 13, 26, 24, and 11 and ground. The indicating lamp 11 included in this circuit will burn thus indicating insufficiency of the lubricant pressure prevailing in the engine 10 which is still at rest.

As soon as the engine 10 has been started causing its lubricant pump to feed lubricant to the lubrication points, the pressure produced by the pump will be conveyed through the

pipes

18 and 19 to the actuators 16 and 17. As long as the engine is idling, this pressure will be higher than 7 psi. but lower than 43 psi. Therefore, the actuator 17 only will respond to such pressure opening the switch arm 26 thereby interrupting the circuit described hereinabove and turning off lamp 11.

When the speed of operation of the engine 10 increases above the idling speed, the generator 31 will produce a positive voltage counteracting the flow of current through the relay winding 27 thus causing the armature 28 to drop into engagement with contact 29. This establishes a circuit including the

elements

35, 36, 37, 28, 29, 33, 12, 23, 24, 25 and 11 and ground. In this circuit the lamp 11 will burn. As soon, however, as the lubricant pressure exceeds 43 psi. which is the minimum pressure required for a median range of speeds of operation of the engine 10, the actuator 16 will open switch arm 23 and thus turn olf the lamp 11 again.

From the above it will appear that in my novel system current will be supplied to the lamp in dependence on the speed of operation first by one of the actuators and then by the other actuator, the relay being deenergized, when the difference of potential between the battery and the generator 31 decreases with increasing speed of operation of the generator causing the relay to be deenergized and to put the other actuator in control of the signal lamp.

The embodiment described hereinabove is capable of numerous modifications. Thus, the number of actuators need not be limited to two. Moreover, the switch arms 23 and 26 may be mounted for actuation by a single actuator in response to different lubricant pressures. In most cases, however, it will suffice to check the lubricant pressure prevailing in the lubricant system of the internal combustion engine in two different ranges of speeds, for instance in an idling speed to ascertain whether the lubricant system functions at all and in a higher speed of operation to ascertain that the lubricant pressure is high enough for such higher speeds.

From the foregoing it will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth, together with other advantages which are obvious and which are inherent to the system.

While the invention has been described in connection with a preferred embodiment thereof, it will be understood that it is capable of further modification, and this application is intended to cover any variations, uses, or adaptations of the invention following, in general, the principles of the invention and including such departures from the present disclosure as come within known or cus tomary practice in the art to which the invention pertains, and as fall within the scope of the invention or the limits of the appended claims.

What I claim is:

1. System for indicating the pressure of the lubricant circulating in an internal combustion engine in which the minimum pressure required increases with rising speed of operation, said system comprising a signaling lamp, said signaling lamp being in an unenergized condition when the pressure of said lubricant is sufficient and in an cner gized condition when said pressure is insufiicient, a current distributor responsive to the speed of operation of said internal combustion engine, said distributor comprising a plurality of pairs of contacts selectively connectable to said lamp and means for selectively supplying current to at least one of said pairs of contacts in dependence on said speed, and switching means comprising a plurality of actuators connected to the lubricant circulating system and being respectively responsive to dilferent minimum pressures of said lubricant for selecting at least one of said pairs of contacts in dependence on said pressure and for connecting it to said signaling lamp for energizing same when at least one of said minimum pressures is insufficient.

2. System as claimed in claim 1, in which said current distributor comprises a relay provided with a winding, :1 first contact, a second contact and a conductive armature alternatively engageable with said first contact and said second contact, said pairs of contacts comprising, firstly, said armature and said first contact, and secondly, said armature and second contact, and a generator coupled With said engine and connected to said winding for supplying current thereto, said system further comprising a source of current connected to said armature.

3. System for indicating the pressure of the lubricant circulating in an internal combustion engine in which the minimum pressure required increases with rising speed of operation, said system comprising a signalling lamp, said signalling lamp being in an unenergized condition when the pressure of said lubricant is suflicient and being energized when said pressure is insuificient, a pair of switch means connected to said lamp, a pair of actuators for said switch means connected to the lubricant circulating system of said engine and responsive to different minimum pressure of said lubricant, a pair of contacts selectively contacted by said switch means, a current distributor relay provided with a winding, with an armature and with two armature contacts for selective alternative engagement by said armature, one contact of said pair of contacts being connected respectively to one of said arm ture contacts, a generator coupled to said engine for producing a voltage depending upon said speed of operation, electrical means operatively connecting said voltage produced by said generator to said relay, a source of current and circuit means including an ignition switch for connecting said source of current and said relay.

4. System as claimed in claim 3, in which that one of said two armature contacts engaged by said armature when said winding is deenergized is connected with that contact of said pair of contacts which is connectable to said lamp by that one of said actuators which is responsive to the higher minimum pressure of said lubricant.

5. A means for indicating the pressure of the lubricant circulating in the lubrication system of an internal combustion engine in which the minimum pressure required increases with the rising speed of operation, said means comprising a signalling lamp, circuit means connected to said lamp, said circuit means including a generator driven by said engine and having an output proportional to the speed of operation of said engine, said circuit means further including switch means including two switches, control means for said switches opcratively connected to said lubrication system, said control means including means for closing said switches, each of said switches being rc spectively closed by said last-named means in response to a lubricant pressure which is different for each of said switches, each said dilferent lubricant pressure being below a difierent one of two respective selected minimum lubricant pressures, said circuit means further including e1ectrical means for controlling current supplied to said two switches, said electrical means comprising relay means including a pair of switch means responsive to energization of said relay for closing a current circuit to one of said two switches and a further pair of switch means responsive to de-energization of said relay for closing a current circuit to the other of said two switches, a source of current selectively connectable to energize said relay for closing said first-named pair of switch means, and means connecting said generator output to said relay for de-energizing said relay at a predetermined engine speed.

References Cited in the file of this patent UNITED STATES PATENTS

Claims

1. SYSTEM FOR INDICATING THE PRESSURE OF THE LUBRICANT CIRCULATING IN AN INTERNAL COMBUSTION ENGINE IN WHICH THE MINIMUM PRESSURE REQUIRED INCREASES WITH RISING SPEED OF OPERATION, SAID SYSTEM COMPRISING A SIGNALING LAMP, SAID SIGNALING LAMP BEING IN AN UNENERGIZED CONDITION WHEN THE PRESSURE OF SAID LUBRICANT IS SUFFICIENT AND IN AN ENERGIZED CONDITION WHEN SAID PRESSURE IS INSUFFICIENT, A CURRENT DISTRIBUTOR RESPONSIVE TO THE SPEED OF OPERATION OF SAID INTERNAL COMBUSTION ENGINE, SAID DISTRIBUTOR COMPRISING A PLURALITY OF PAIRS OF CONTACTS SELECTIVELY CONNECTABLE TO SAID LAMP AND MEANS FOR SELECTIVELY SUPPLYING CURRENT TO AT LEAST ONE OF SAID PAIRS OF CONTACTS IN DEPENDENCE ON SAID SPEED, AND SWITCHING MEANS COMPRISING A PLURALITY OF ACTUATORS CONNECTED TO THE LUBRICANT CIRCULATING SYSTEM AND BEING RESPECTIVELY RESPONSIVE TO DIFFERENT MINIMUM PRESSURES OF SAID LUBRICANT FOR SELECTING AT LEAST ONE OF SAID PAIRS OF CONTACTS IN DEPENDENCE ON SAID PRESSURE AND FOR CONNECTING IT TO SAID SIGNALING LAMP FOR ENERGIZING SAME WHEN AT LEAST ONE OF SAID MINIMUM PRESSURES IS INSUFFICIENT.