U.S. patent number 3,708,683 [Application Number 05/142,582] was granted by the patent office on 1973-01-02 for diesel engine starting switch and circuit.
This patent grant is currently assigned to Thermo King Corporation. Invention is credited to Leland L. Howland.
United States Patent |
3,708,683 |
Howland |
January 2, 1973 |
DIESEL ENGINE STARTING SWITCH AND CIRCUIT
Abstract
A diesel engine pre-heating, starting and running switch and
circuit is comprised of a three pole, three position switch
connecting the battery source to the engine starter, the electric
fuel actuator and auxiliary equipment, the pre-heating glow plugs
and a safety circuit that can be energized only when the engine is
running, the fuel actuator can be energized only in the run and
start positions of the switch, the starter can be energized only in
the start position of the switch, and the glow plugs can be
energized only in the pre-heat and starting positions of the
switch.
Inventors: |
Howland; Leland L. (Rosemont,
MN) |
Assignee: |
Thermo King Corporation
(Minneapolis, MN)
|
Family
ID: |
22500422 |
Appl.
No.: |
05/142,582 |
Filed: |
May 12, 1971 |
Current U.S.
Class: |
290/37R;
123/179.21; 290/38R |
Current CPC
Class: |
F02P
19/02 (20130101); F02B 3/06 (20130101) |
Current International
Class: |
F02P
19/00 (20060101); F02P 19/02 (20060101); F02B
3/00 (20060101); F02B 3/06 (20060101); F02n
011/00 () |
Field of
Search: |
;290/37,38 ;123/179 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Simmons; G. R.
Claims
I claim as my invention:
1. A diesel engine pre-heating, starting and running switch and
circuit comprising, a three position switch having first, second
and third poles, a source of current, a starter solenoid, an
electrically operated engine fuel actuator, at least one engine
pre-heating glow plug, a safety circuit having a normally closed
contact to be connected to be energized only when the engine is
running, means connecting said fuel actuator in series with said
normally closed contact and the contacts of a main control switch
to one terminal of said source, at least one alarm safety switch
having normally open contacts, means electrically connecting
together the first and second poles of said three position switch,
means connecting said third pole to said one terminal of said
source, means connecting the second and third switch positions of
said first pole in series with said normally closed contact and
said main switch to said one terminal of said source, means
connecting the second position of said second pole in series with
the said safety circuit and said at least one safety switch
normally open contacts to the other terminal of said source, means
connecting the third position of said second pole in series with
said starter solenoid and the other terminal of said source, and
means connecting the first and third positions of the second pole
of said switch in series with said at least one glow plug to the
other terminal of said source whereby said starting solenoid is
connected to be energized only when the three position switch is in
the third position, said at least one glow plug is connected to be
energized to pre-heat the engine only when said switch is in the
first or third positions, and said safety circuit is connected to
said at least one safety switch only when said switch is in the
second position.
2. The invention of claim 1 in which the three position switch is
spring biased to the second position for normal running of the
engine.
3. The invention of claim 1 in which said at least one safety
switch includes a thermally operated engine high temperature
switch.
4. The invention of claim 1 in which said at least one safety
switch includes a low oil pressure switch whose contacts are closed
when engine oil pressure is lower than desired.
5. The invention of claim 2 in which said at least one safety
switch includes a thermally operated engine high temperature
switch.
6. The invention of claim 2 in which said at least one safety
switch includes a low oil pressure switch whose contacts are closed
when engine oil pressure is lower than desired.
Description
CROSS-REFERENCE TO RELATED APPLICATION
So far as it is known, this invention is not related to any pending
patent applications.
BACKGROUND OF THE INVENTION
Truck and railroad car refrigeration systems are often powered by
auxiliary diesel engines that are self-contained with the system.
These engines are designed to run unattended for relatively long
periods of time and therefore are provided with safety switch
circuits to shut-off the engine in the event of a system
malfunction such as low engine oil pressure, high engine
temperature, or some other failure of the system including the
refrigerant gas pressure conditions or the like. As is well known,
a diesel is comparatively difficult to start and is usually
pre-heated with one more glow plugs or the like before attempting
to start the engine. During the pre-heating and the starting of the
diesel engine, the safety circuits should be disabled since there
would normally be little or no engine oil pressure at that time. A
simple starting switch and circuit to provide the aforementioned
starting functions in the desired and correct sequence is therefore
needed and the arrangement should be such as to inactivate any
safety circuits during the pre-heating and starting of the
engine.
PRIOR ART
Applicant is not aware of any prior patents disclosing the starting
switch and circuit of this invention.
SUMMARY
A three position, three pole starting switch that may, if desired,
be spring biased to the second position designated as the running
position, with the first position designated as a pre-heat position
and the third position designated as a start position is provided.
In the first or pre-heat position of the switch, only the
pre-heating glow plugs are connected to the battery source and the
safety switch circuits are not energized or connected to the
battery source in any manner. In the second or running position of
the switch, the electric fuel actuator is connected through
normally closed safety relay contacts and a main running control
switch to be energized by the battery source. Also, the operating
coil of the safety relay is then connected through normally open
safety switch contacts in a manner to be energized by the source if
any one of the safety switches is closed by a system fault during
normal running of the engine such as low engine oil pressure and
the like. Thus while the engine is running and the start and
running switch is in the running position, the safety relay coil
may be energized whenever any of the normally open safety switches
are operated to close their contacts. Therefore, when the safety
relay is thus operated, the electric fuel actuator will be
deenergized to stop the engine since the normally closed safety
relay contacts will then be open. When the starting and running
switch is in the third position, only the flow plugs together with
the engine starter solenoid and the electrical fuel actuator will
be connected to be energized through the normally closed contact of
the safety relay, and the safety relay coil is not connected in a
manner to be possibly energized by any one of the alarm switches as
previously described.
Further objects, features and the attendant advantages of the
invention will be apparent with reference to the following
specification and drawings in which the sole FIGURE is a schematic
wiring diagram partly in block outline showing the three position,
three pole, starting and running switch and the circuit of the
invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The three position starting and running switch of the invention is
shown at 10 and is provided with three poles 11, 12 and 13. Pole 11
has three positions 11A, 11B and 11C. Similar poles 12 and 13 have
respective three positions 12A, 12B, 12C and 13A, 13B and 13C. Each
of the three switch poles 11, 12 and 13 are ganged to be operated
together and if desired, may be centered by centering springs 14
and 15 to the second position 11B, 12B and 13B which may be
designated as the normal running position of the switch. Poles 11
and 12 are electrically connected together by the wire connection
16. Pole 13 is electrically connected by the wire connection 17 to
one terminal 18 of the battery source 19 whose other terminal is
grounded at 20.
A main or running control switch 21 similar in function to the
conventional ignition switch of an automobile engine is connected
to the one terminal 18 of the power source 19 and through normally
closed contacts 22A of the safety relay 22 to the second position
11B for the first pole 11 of the switch 10. The second position 11B
of the first pole 11 is also connected to the third position 11C by
means of the wire connection 23. Therefore, when the main switch 21
is closed, the electric fuel actuator 30 will be energized through
the normally closed contacts 22A of the safety relay 22,
considering that its other terminal is connected to the other
terminals of the battery source 19 at ground 20. Also, any
auxiliary equipment that is to be electrically energized during the
running of the engine such as shown at 31 will be energized the
same as the electric fuel actuator 30 so long as the main switch 21
is closed and the safety relay 22 is not energized.
One of one or more pre-heating glow plugs is shown at 40 and may be
connected to the one terminal of the battery source 20 and ground
in series with either the first or third positions 13A and 13C for
the third pole 13 of the switch 10. Thus, when the starting and
running switch 10 is in either the first and pre-heating position
13A, or in the third and starting position 13C, the glow plugs 40
will be connected to the battery source 19 to be energized for
pre-heating the diesel engine.
The second or running position 12B for the second pole 12 of the
starting and running switch 10 is connected by the wire connection
24 in series with the operating coil of the safety relay 22 and any
one of the safety switches such as the oil pressure switch 25 or
the high water temperature switch 26 to the other grounded terminal
20 of the battery. Thus, when the diesel engine is running and the
starting and running switch 10 is in the running position, i.e.,
the second position, the safety relay coil 22 can become energized
in the event of operation and closure of either one of the normally
open safety switches 25 or 26. For example, if the oil pressure for
the diesel engine should drop below a safe level, the switch 25
will close to complete the operating circuit for the safety relay
coil 22 which will then operate to open its normally closed
contacts 22A and deenergize the electric fuel actuator 30 and
auxiliary equipment 31 thus stopping the engine. The safety relay
22 is a typical bi-stable circuit breaking relay switch as well
known in the art, which, when operated to open its' circuit
breaking contacts 22a will not reclose such contacts until the
contacts are manually moved to the contact closed position. An
example of such a relay is the subminiature circuit breaker switch
known as the SM-3 series sold by the Heinemann Electric Co. of
Trenton, New Jersey as advertised in their bulletin number 3504
issued in December, 1965. It will be noted that the safety relay 22
cannot be operated unless the starting and running switch 10 is in
the running position with the circuit completed through contacts
11B, pole 11, pole 12 and contacts 12B. Also it will be noted that
the fuel actuator 30 can be energized only when the starting and
running switch 10 is in either the second or third positions, i.e.,
running or starting positions, through the circuits including
contacts 11B or 11C and pole 11. Also it will be noted that when
the switch 10 is in the first or pre-heat position only the glow
plug 40 is connected to be energized and no other circuits may be
energized from the source 19.
Various modifications will occur to those skilled in the art. For
example, although a safety relay 22 had been specifically
described, it will be obvious to anyone skilled in the art, that
various well known forms of safety circuit breakers and devices
such as heat operated switches may be used to be energized and
operated when abnormal conditions such as low oil pressure are
encountered during the running of the engine with the switch 10 in
the run position.
* * * * *