US2848986A

US2848986A - Fuel injection system

Info

Publication number: US2848986A
Application number: US650389A
Authority: US
Inventors: Lawrence C Dermond
Original assignee: Motors Liquidation Co
Current assignee: Motors Liquidation Co
Priority date: 1957-04-03
Filing date: 1957-04-03
Publication date: 1958-08-26
Anticipated expiration: 1975-08-26

Description

United The present invention relates to a fuel injection system and more particularly one in which the quantity of fuel supplied during idling and cold running operation is made responsive to engine operating temperatures.

While various thermostatic devices have been utilized to facilitate cold operation of fuel injection systems most of such devices have been complicated, expensive to install and have not functioned satisfactorily. There has also frequently been a duplication of thermostatic devices through which the various mechanisms of a fuel injection system have been controlled.

.In the'present device a thermostatic mechanism, positioned to accurately reflect engine operating temperatures, is adapted to control the quantity of idle air flow and at the same time actuate other devices providing modulating signals for supplementing the control of the fuel metering system when cold. The present thermostatic control mechanism also permits the elimination of the normal throttle fast idle cam.

Additional objects and advantages of the present fuel injection system will be apparent from a perusal of the following detailed description.

In the drawings:

Figure l is a diagrammatic representation of the fuel control system;

Figure 2 is an enlarged sectional view of the thermostatic control mechanism;

Figure 3 is a view along line 33 of Figure 2; and

Figure 4 is a view along line 44 of Figure 2.

In the diagrammatic representation of Figure l, a fuel induction passage is shown generally at 12 and includes a venturi 14 posterior of which is a throttle valve 16. A fuel supply source is indicated generally at 18 and includes a float controlled type valve mechanism 20, an engine speed responsive pump 22 and a fuel metering valve generally indicated at 24. The metering valve is under the control of a diaphragm 26 through a linkage mechanism 28. The preceding elements and devices function in the same manner as described in copending application 646,081, filed March 14, 1957. It will sufl'ice to note that fuel is supplied to the metering valve 24 by pump 22 under a pressure which is proportional to engine speed. Valve 24 then delivers fuel to a distributor supply line 30 in accordance with the actuation of the control mechanism 2628 which primarily is under the control of vacuum in passages 32 and 34. The vacuum in passage 32 is proportional to the mass of air flowing through the induction passage 12 and hence causes diaphragm 26 to move valve 24 to a position increasing the flow of fuel to line 30 as said mass air flow increases. Manifold vacuum is available in conduit 34 when the throttle 16 is closed as described in copending application Serial No. 608,797 Olson, filed September 10, 1956.

A fuel cut-off mechanism is shown'generally at 36 and includes a solenoid valve 38, an engine speed governor 40 and a throttle controlled switch 42. The fuel cutoff device is the subject matter of copending application 648,300, filed March 25, 1957 and for the purposes of the subject invention it is enough to note that this device is intended to cut off the flow of fuel during engine decelerating conditions.

An idle air bypass network is indicated generally at 44 and includes a passage 46 communicating with the induction passage anterior of throttle 16, a passage 48 Patent communicating with the induction passage posteriorly of the throttle and a chamber 50 interconnecting

passages

46 and 48. Normally a manually adjustable valve is disposed in such network and which valve is adjusted for an average idle air flow. It is apparent that'such average adjustment of a manual valve is necessarily a compromise setting and is neither correct when the engine. is hot nor when it is cold. Further, such a manual valve usually requires frequent adjustment due to normal engine operation. In the present device a thermostatically controlled valve 52 is interposed in chamber 50 and is adapted to accurately control the idle air flow in accordance with the varying requirements of the engine as determined by engine temperature. In order that the temperature responsive valve accurately reflectengine temperature, a housing 54, within which the thermostatically controlled valve 52 is disposed, is mounted upon the engine cooling system and more specifically the water cross-over passage 56. A thermostat 58 is mounted in housing 54 and fixed at one end 60 to the housing and at the other end to the valve shaft 62. In order to provide an initial cold running setting for the valve 52 an adjusting screw 64 is provided which acts through a lever 66 fixed to shaft 62.

As shown in Figure 2 with the engine cold, valve 52 will be in its maximum open position as determined by screw 64 permitting the maximum quantity of air to be bypassed around throttle valve 16 insuring suflicient air to provide faster than normal engine idling speeds under cold conditions. Through this device the normal fast idle cam, which sets the throttle idling position in accordance with engine temperatures, is eliminated. Accordingly, under idling conditions the throttle may always be closed with the variations in the quantity of the idling mixture being controlled in the idle air bypass network as described.

To secure adequate fuel enrichment when the engine is running cold additional means are provided to supplement the normal venturi vacuum signal acting on the upper side of metering valve control diaphragm 26.

Devices which have been used heretofore to insure an enriched starting mixture have been unsatisfactory from economy and performance standpoints since they are active to the same extent irregardless of engine temperature. The result of this type of temperature insensitive operation is to supply an overly enriched starting mixture to a partially warm engine wasting fuel and making engine performance sluggish. To eliminate this problem, the pres ent device provides vacuum boost signals which are modulated in accordance with engine temperature and which thus preclude overenrichment of the starting mixture since the latter is always keyed to engine temperature.

In order to provide a metering diaphragm modulating signal a conduit 70 connects the metering diaphragm to a point posterior to the throttle 16. In the diagrammatic disclosure of Figure 1 a branch 71 of conduit 70 connects with idle air bypass passage 48, which as noted, connects with the induction passage 12 posteriorly of the throttle 16. A first valve device 72 is disposed in conduit 70 for controlling the amount of manifold vacuum transmitted to the diaphragm 26. Valve device 72 includes a member 74 slidably disposed in casing 76 and which member is suitably articulated to the thermostatically controlled lever 66. Thus, when the engine is cold the valve will be in the position shown in Figure 1 transmitting the maximum amount of manifold vacuum available in line 71 to the diaphragm 26. As the engine warms lever 66 a passage 84 therethrough for transmitting the vacuum force to diaphragm 26. If desired, passage 84 may be utilized to reduce the vacuum force available to act on the diaphragm and in this way act as an orifice in line 70.

An additional valve device 90, in parallel with valve 72, is disposed in the manifold vacuum circuit and is adapted to provide additional manifold vacuum during the cranking operation of the engine under which condition a particularly rich starting mixture is desired. Device 90 likewise includes a member 92 slidably disposed within casing 94 and which also includes a tapered section 96 for metering the manifold vacuum flow to the diaphragm in inverse proportion to engine temperature. Valve device 90 also has associated in series therewith a ball check valve 160 which upon the starting of the engine is adapted to cut-ofl the manifold vacuum flow through the branch circuit 102. Thus during cranking of the engine valve devices 72 and 90 are each transmitting a manifold vacuum force to the diaphragm 26. As soon as the engine begins to run, however, the cranking modulating signal is cut off and manifold vacuum modulation takes place only through valve 72.

In the event a warm engine is re-started the sliding members 74 and-92 will be in a position to modulate the manifold vacuum to supplement venturi vacuum ,or to eliminate the manifold vacuum force entirely dependent on the residual engine warmth. The valve devices 72 and 90 are shown in their cold running positions. As noted, with increasing engine temperatures the sliding members 74 and 92 are gradually shifted to the left, asviewed in Figure 1, by thermostatically controlled lever 66 toreduce and ultimately eliminate the force of manifold vacuum on diaphragm 26.

While 72 and 90 have inthe diagrammatic representation of Figure 1 been shown as individual valve devices, they may, in fact, be combined in a single housing as shown in Figures 24. In these figures it willbeseen that idle air bypass valve 52, thermostat 58 and a bifurcated crank 110 are all mounted ona common shaft-112. Further a common housing 114 encloses all of these elements and includes

bores

116 and 118 within which the respective valve members 74 and 92 may be slidably disposed. The members 74 and 92 may be articulated through links 12d and 122 to the respective arms on bifurcated member 110 such that as the thermostat 58 rotates shaft 112 members 74 and '92 will be moved in unison to respectively control manifold vacuum flow to provide their irrespective modulating vacuum signals. The idle stop 64 is adjustably mounted in casing114 so as to engage the bifurcated crank 110 to set the cold idle position of the valve members 74 and 92 as well as idle air valve 52.

As seen in Figures 2 and 3 casing-114 is suitably bored at 130 to receive

idle air passages

46 and 48. Passage-7l is drilled, or otherwise provided, in casing 114 and taps into bore 130 permitting manifold vacuum to be communicated tovalve members-74 and 92 the latter through passage 102.

I claim:

1. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source .to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metcring valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle when closed, a valve in said passage, means responsive to the temperature of said engine for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine temperature, additional passage means communicating at one end with said induction passage posteriorly of said throttle and atthe other end with said metering valve control device whereby manifold vacuum is adapted to actuate said device to increase the flow of fuel to said cylinders, valve means in said additional passage for modulating the flow of manifold vacuum through said passage, and means connecting said modulating valve means with said temperature responsive means whereby the manifold vacuum acting on said control device is inversely proportional to engine temperature.

2. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metering valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle when closed, a valve in said passage, a thermostat mounted on the engine cooling system for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine temperature, additional passage means communicating at one end with said induction passage posteriorly of said throttle and at .the other end with said metering valve control device whereby manifold vacuum is adapted to actuate said device to increase the flow of fuel tojsaid cylinders, valve means in said additional passage for modulating the flow of manifold vacuum through saidrpassage, means connecting said modulating valve means witlrsaid temperature responsive means whereby the manifold vacuum acting on said control device is inversely proportional to engine temperature, and a casing for housing said bypass control valve, said modulating valve means and said thermostat.

3. A .fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in saidipassage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metering valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle, a valve in said passage, means responsive to the tempe rature of said engine for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine temperature, additional passage means communicatingat one end with said induction passage posteriorly of said throttle and at the other end with'said metering valve control device whereby manifold vacuum is adapted to actuate said device to increase the flow of fuel to said cylinders, first valve means in said additional passage for modulating the flow of manifold vacuum through said passage, second valve means disposed in said additional passage in parallel relation to the first valve means for also modulating the quantity of manifold vacuum acting therethrough, means connecting the first and second valve means to said temperature responsive means whereby said valve means transmit manifold vacuumto said valve control device in inverse proportion to engine temperature, andmeans for rendering said second valve inoperative when the engine begins to run.

4.,A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metering valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle during idling conditions, a valve in said passage, a thermostatic device for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine tem perature, additional passage means communicating at one end with said induction passage posteriorly of said throttle and at the other end with said metering valve control device whereby manifold vacuum is adapted to actuate said device to increase the flow of fuel to said cylinders, first valve means in said additional passage for modulating the flow of manifold vacuum through said passage, second valve means disposed in said additional passage in parallel relation to the first valve means for modulating the quantity of manifold vacuum acting therethrough, means connecting the first and second valve means to the thermostatic device whereby said valve means transmit manifold vacuum to said valve control device in inverse proportion to engine temperature, and valve means actuated by manifold vacuum for rendering said second valve inoperative when the engine begins to run.

5. A fuel injection system as set forth in claim 4 in which said first and second valve means each includes a casing and a member slidable in said casing, each member including a tapered portion which progressively meters manifold vacuum acting on said control device as the member slides in said casing.

6. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a diaphragm for controlling said metering valve, conduit means communicating said venturi with said diaphragm to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle during idling conditions,

, a valve in said passage, additional passage means communicating at one end with said induction passage posteriorly of said throttle and at the other end with said metering valve control diaphragm whereby manifold vacuum is adapted to actuate said diaphragm to increase the flow of fuel to said cylinders, first valve means in said additional passage for modulating the flow of manifold vacuum through said passage, second valve means disposed in said additional passage in parallel relation to the first valve means for also modulating the quantity of manifold vacuum acting therethrough, a common shaft for actuating said bypass valve and said first and second valve means, a thermostatic device for operating said shaft in accordance with engine temperature whereby the flow through the respective valves varies inversely with changes in said temperature, and valve means for rendering said second valve means inoperative when the engine begins to run.

7. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel sources and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for con 6, trolling said metering valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle, a valve in said passage, and means responsive to the temperature of said engine for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine temperature.

8. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a diaphragm for controlling said metering valve, conduit means communicating said venturi with said diaphragm to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle, a valve in said passage, and a thermostatic device disposed on the engine cooling system for actuating said valve to control the flow of air through said bypass passage in inverse proportion to engine temperature.

9. A fuel injection system for an internal combustion engine comprising a fuel induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source to the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinders, a device for controlling said metering valve, conduit means communicating said venturi with said control device to position the metering valve in accordance with the mass of air flowing through the induction passage, passage means for bypassing air around said throttle, a valve in said passage, additional passage means communicating at one end with said induction passage posteriorly of said throttle and at the other end with said metering valve control device whereby manifold vacuum is adapted to actuate said device to increase the flow of fuel to said cylinders, valve means in said additional passage for modulating the flow of manifold vacuum through said passage, a common shaft for actuating said bypass valve and said modulating valve means, a thermostatic device for operating said shaft in accordance with engine temperature whereby the fiow through the respective valves varies inversely with changes in said temperature.

10. A fuel injection system for an internal combustion engine comprising an air induction passage, a venturi in said passage, a throttle valve in said passage posterior to said venturi, a source of fuel under pressure, conduit means for communicating said fuel source with the cylinders of said engine, a valve disposed intermediate said fuel source and said conduit means for metering the quantity of fuel flowing to said cylinder, a diaphragm for controlling said metering valve, first conduit means communicating said venturi with said diaphragm to normally position the metering valve in accordance with the mass of air flowing through the induction passage, second conduit means communicating manifold vacuum with said diaphragm, valve means in said second conduit means for modulating the manifold vacuum delivered to said control device, said valve means comprising first and second valve elements connected in parallel with respect to said second conduit, means for rendering one of said elements inoperative to transmit manifold vacuum when the engine begins operating, and a thermostatic device adapted to actuate said valve means whereby the manifold vacuum in said second conduit means is inversely proportional to engine temperature.

No references cited.