JPS5817337B2 - engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel-air ratio control system for overriding the governor means of an engine to prevent an increase in fuel supplied to the engine during reductions in air pressure in the engine's intake manifold. .

Supercharged engines, especially those with exhaust-powered superchargers, produce large amounts of undesirable exhaust emissions when subjected to rapid acceleration.

The reason is that the fuel adjustment member of the engine is moved forward, χ and λ.
This is because the engine speed cannot immediately follow it and therefore the supercharger cannot immediately supply enough air to burn all the fuel injected.

As a result, a large amount of unburned fuel is discharged as exhaust gas.

Furthermore, engines equipped with the above type of supercharger are in a lag condition (
lug) with bad exhaust.

A lag condition occurs when the engine resistance or load increases to such an extent that the engine speed decreases below that indicated by the governor setting while at wide open throttle and maximum power conditions.

Under these conditions, the engine governor attempts to restore the engine speed indicated by its settings by automatically advancing the engine's fuel rack to provide more fuel, but the engine decelerates. The resulting reduction in supercharger speed does not provide sufficient air to the engine to maintain complete combustion of the injected additional fuel.

U.S. Pat. No. 2,767,700 attempts to overcome this problem by using a pressure-responsive mechanism resisted by a spring member and interacting with a fuel adjustment member to restrain the adjustment member by a movable stop. is taught.

As disclosed in the above-mentioned patent, when the inlet manifold pressure is relieved, the spring member moves the movable stop and thus moves the fuel control member toward the fuel depletion position.

As the inlet manifold air pressure increases, the pressure responsive mechanism compresses the spring member, allowing the main governor spring to move the movable stopper and fuel adjustment member toward the fuel increase position.

Although theoretically operable, this type of fuel-air ratio control system has been found to impose certain limitations on the overall performance of the engine.

First, the spring member holds the movable stopper and the fuel adjustment member in the reduced fuel position, making it difficult to provide sufficient fuel for starting.

Second, the governor spring must be allowed to move the fuel adjustment member toward the fuel increase position to maintain engine speed with increasing load or to serve its primary purpose of increasing engine speed. .

At the same time, the spring member interacting with the pressure responsive mechanism must provide sufficient force to constrain the governor spring until the pressure responsive mechanism is activated by inlet manifold air pressure.

If the preload force applied to the spring member is greater than the preload force applied to the governor spring, engine acceleration will be inhibited to a degree that is detrimental to engine performance.

If the preloading force of the spring member is less than the preloading force of the governor spring, the fuel control member will not be reliably restrained by the movable stop and acceleration will increase, but overfueling and therefore undesirable exhaust will occur.

Therefore, the initial preload force on the spring member must be greater than the governor spring, and a stop means must be used to establish the predetermined preload.

The fuel adjustment member is moved toward the fuel increase position before engaging the movable stop.

The governor spring allows the fuel control member to move toward the fuel increase position, but the spring member provides sufficient restraint until the force on the fuel control member is counteracted by the increasing inlet manifold air pressure.

In this way, a compromise between engine acceleration and undesired engine emissions is obtained.

Also, a characteristic of superchargers is that there is a delay in supplying air to the intake manifold under certain conditions, such as when accelerating from low speeds and light loads.

This results in negative pressure being generated in the suction manifold.

The fuel-air ratio controller of the above patent cannot respond to such manifold negative pressures because the pressure-responsive mechanism originally presses against the adjustment stop used to establish the preload force of the spring member. This is because it is usually arranged as follows.

U.S. Pat. No. 3,077,873 overcomes some of the above drawbacks by providing a servo mechanism having a movable member that acts on a valve member with a pressure responsive mechanism acting on a valve spool.

Fluid pressure is used to balance the forces between the governor member, spring member, and suction air pressure response mechanism.

Using a servo system, the spring member is balanced to improve response when interacting with the pressure responsive mechanism.

However, the main disadvantage of this device is the necessary maintenance of the servo piston as a separate unit and the use of an intermediate movable member to control the valve.

As a result, the shape is complex and relatively expensive.

According to the present invention, there is provided a supercharger having an integrated servo piston/valve unit arranged in a restraining relationship with respect to a governor connected to a fuel control member and supplying air to the engine via an intake manifold. A fuel air ratio control device for a supercharged engine is provided.

The servo piston is actuated by fluid force controlled by movement of a valve spool, which slides open and close through an opening provided in a portion of the servo piston.

The valve spool is secured to a pressure responsive mechanism that communicates with the engine intake manifold.

Resilient means counteract the reaction of the pressure response mechanism against the suction manifold pressure.

During engine starting, the valve spool and the mouth of the servo piston are open, disabling the servo unit and allowing unrestrained operation of the fuel control member.

The servo unit is then activated when the manifold air pressure is increased in a predetermined manner to displace the valve spool relative to the mouth of the servo piston, blocking it and controlling fluid flow to the servo piston.

Thereafter, while the manifold air pressure is decreasing, the servo unit functions to restrain the fuel control member from moving toward the fuel increase position.

When the air available in the intake manifold is insufficient to support proper combustion of fuel, the servo unit binds the fuel control member and prevents a disproportionate increase in fuel to the engine.

It is an object of the present invention to provide an improved fuel injection system that controls the injection of fuel into a supercharged engine in strict proportion to the air pressure available in the engine's intake manifold to override the governor and ensure complete combustion of the fuel by the engine. - To provide an air ratio control device.

It is another object of the present invention to provide an improved governor-ineffective fuel-air ratio control system that is responsive to both intake manifold air pressure and engine oil pressure, and that is responsive to both intake manifold air pressure and engine oil pressure, which control system provides reliable starting. Allows unrestrained movement of the engine's fuel control member during crank start to ensure sufficient fuel for the engine, but then automatically injects fuel into the engine precisely at the amount needed to operate the engine at maximum efficiency. limited to.

Other objects and advantages of the present invention will become more readily apparent upon reference to the accompanying drawings and the following description.

1 and 2, a fuel pump 10 has a plunger 12 that reciprocates vertically during engine operation to supply fuel to one cylinder of the engine through a fuel injection passage 11. There is one pump for each cylinder of the engine.

The longitudinal movement of the fuel adjustment member 17 with rack teeth 15 moves a gear 14 fixed to the plunger 12.

This pump is of the controlled type, in which angle adjustment of the plunger 12 changes the amount of fuel injected with each stroke.

The fuel adjustment member 17 is secured to a standpipe 18 having an extension link 19 to which a stopper member 20 is attached.

A pair of centrifugal weights 22 carried by a yoke 23 is driven by a gear 24 which is rotated by an engine timing gear (not shown) at a speed proportional to the engine speed.

When the centrifugal weight moves in the outer radial direction due to centrifugal force, this portion of the centrifugal weight is forced to act on the standpipe 18 to the left.

A spring 26 located between the standpipe and the collar 27 resists the displacement action of the centrifugal weight.

In order to cause the spring 26 to resist the force of the centrifugal weight 22, a movable lever 28 is positioned to provide a predetermined selected preload force.

Pressurized air is supplied to the engine air intake manifold 30 by a supercharger 31 driven by the engine.

A conduit 32 communicates between the suction manifold and a chamber 35 formed by an adapter 33 having a cover 36 secured by bolts 37 .

Control housing 39 has an inlet 40 connected to a source of fluid pressure, such as engine lubricating oil.

Orifice 43 communicates inlet 40 with a hole 44 formed in housing 39.

The servo unit 46 has a piston portion 47 that slides within the bore 44 and a valve means or sleeve portion 48 that slides within a bore 50 formed in the housing integral with the piston portion.

The valve means has an extension 49 with a shoulder 49a which is adapted to rest on the stopper member 2.
0.

An expansion chamber 53 is formed by the surface 51 of the piston 47, the surface 52 of the housing 39, and the hole 44.

Fluid from inlet 40 is directed to surface 52 traversed by orifice 43.
It is allowed to flow into the chamber 53 through a groove 54 in the interior.

A first set of passageways 56 within the valve means 48 communicates the chamber 53 with the bore 62 of the servo unit.

A second set of passageways 57 of valve means 48 communicates bore 62 with an annular groove 58 formed within bore 50 .

On the other hand, a discharge passage 60 of the housing 39 crosses the annular groove 58.

Another passage 91 is provided for communicating fluid leaking through the servo unit to the discharge.

The valve spool 63 that slides within the hole 62 has a pair of protrusions 64.
, 65, the passageway 56 is open when the protrusion 64 is positioned as shown in FIG.
The protrusion 65 is arranged so that the passage 57 is open and the chamber 53 communicates with the discharge passage 60.

A threaded portion 67 of the valve spool 63 is secured to a bowl member 68.

End 69 has a pin 70 extending from threaded portion 67 and engaging slot 36a in cover 36.

A first spring member 72 having a first spring rate is connected to the piston 4
7 and the bowl member 68.

A second spring member 73 having a second spring rate is disposed between the bowl member and the seat member 74.

A diaphragm 7 is installed between the adapter 33 and the housing 39.
6 is fixed, and this diaphragm is supported by a bowl member 68.

A washer 77 arranged near and behind the diaphragm 76 acts as a seat for a third spring element 78 between the cover 36 and the washer.

The spring rates of the three spring members are chosen so that the forces on the diaphragm are balanced when no pressure is present in chamber 35.

Prior to starting the engine, the fuel-air ratio control system of the present invention assumes an inactive position as follows.

The spring member 72 biases the servo unit 46 to the right as viewed in FIG. 1, and moves the shoulder portion 49a so as not to engage with the stopper 20.

Movement of the lever 28 in a counterclockwise direction compresses the spring 26 and moves the fuel adjustment member 17 to the right toward the overfueling position.

During cranking of the engine, i.e., when starting the engine, the valve spool 63 is maintained in this position and communicates with the passages 56, 57 through the annular chamber 66 by the balance of the spring members 73, 78 acting on the diaphragm 76.

Pressurized fluid entering chamber 53 from inlet 40 flows through passages 56, 57,
60, thus blocking the application of fluid forces to the piston 47 and thus preventing its leftward movement.

After the engine starts and speed increases to a predetermined amount, the air pressure in the intake manifold 30 increases and the pressure in the chamber 35 increases.

At this time, the diaphragm 76 is acted upon by the increase in air pressure within the chamber 35.

Therefore, the spring members 72 and 73 are compressed and the valve spool 63 is moved to the right.

This movement eventually causes the protrusion 64 to cover the passageway 56.

Fluid is thus prevented from exiting chamber 53 and internal fluid pressure increases pushing piston 47 to the left into the control operating position.

During this leftward movement, shoulder 49a engages stopper member 20 and moves fuel adjustment member 17 to the reduced fuel position as shown in FIG.

This mechanism is ready and operative when positioned as shown in FIG.

When the engine is running idle, the air pressure in the intake manifold and chamber 35 is not sufficient to overcome the bias of spring member 72.730 acting on diaphragm 76 in conjunction with the bias of spring member 78.

The valve spool 63 is restrained in the left position by the diaphragm 76 and the piston is in an operative position in which the valve spool protrusion 64 effectively restricts the passageway 56 to allow only a predetermined amount of fluid to flow from the chamber 53 and the piston 47. Maintain it in the position shown in Figure 2.

Passage 57 is out of alignment with annular groove 58 and drainage passage 60 to prevent fluid evacuation.

As previously mentioned, when lever 28 is moved counterclockwise, spring 26 is compressed to move fuel adjustment member 17 to the right toward the fuel increase position.

However, when the fuel-air ratio controller operates, the spring members 73,78 tend to position the valve spool 63 to the left.

Thus, servo unit 46 and shoulder 49a permit slight movement of the fuel control member toward the fuel increase position.

When the engine is accelerating from a low speed with a light load (when negative pressure is temporarily generated between the manifold 30 and the chamber 35, the diaphragm 76 is pulled to the left and the servo unit 46 moves slightly in the same direction). I am forced to do it.

The stopper 20 moves to the right to satisfy the demand (increasing the amount of fuel) so that the shoulder 49a engages the stopper.

However, as engine speed increases, air pressure within chamber 35 increases slightly, causing diaphragm 76 and valve spool 6 to
Move 3 to the right.

Spool protrusion 64 moves to slightly open passageway 56, allowing fluid to exit the opening and exit via passageway 74a.

Fuel adjustment member 17 is then allowed to pull the servo unit to the right as long as the air pressure in chamber 35 is increasing, and valve spool 63 is moved to the right to cause fluid to exit chamber 53.

When the engine is operating within a predetermined speed and load range as defined by the governor's centrifugal weight, the governor maintained in a position that does not restrict the slightest movement that it may undergo.

However, if the engine load increases to the point that the engine speed decreases, the air pressure within chamber 35 will decrease by a corresponding amount causing spool projection 64 to restrict passageway 56 and cause chamber 35 to decrease by a corresponding amount.
3 causes the piston 47 to move slightly to the left so that the shoulder 49a constrains the stopper 20 to prevent injecting a disproportionate amount of fuel to the available air.

When the operator moves the lever 28 to accelerate the engine, sufficient air is available in the chamber 35 and the servo unit 46
The stopper 20 is restrained by the shoulder 49a until the stopper 20 is moved to the right by the fuel adjustment member 17.

A variation of the invention is shown in FIG.

A plurality of different spring members are provided to oppose the pneumatically responsive diaphragm 76 in a manner somewhat similar to the first embodiment of the invention.

Parts common to both embodiments are given the same reference numerals.

This variation, as discussed below, applies a variable displacement force to the diaphragm in order to more accurately tailor the fuel-air ratio controller to the needs of a particular engine.

The spring rate of a single spring opposite a pressure responsive diaphragm is linear.

However, the suction manifold pressure of a supercharged engine does not necessarily increase at a linear rate.

This imbalance between the spring rate and the change in intake manifold pressure results in a fuel-air ratio control in which slowly increasing air pressure changes linearly while the fuel adjustment member moves toward the fuel increase position. When approaching the spring force of the device, an imbalance in the fuel-to-air ratio occurs.

This results in a rise of incompletely combusted gas called a second exhaust column.

The fuel-air ratio controller shown in FIGS. 1 and 2 reduces or limits these secondary exhaust columns to acceptable limits for most engines.

However, in some engines the exhaust column was found to be unacceptably large.

In these engines, in which the theoretical air pressure available in the intake manifold varies in a curved manner with a gradient that gradually increases with increasing rack eccentricity, springs with different spring rates are connected in series. (Figure 3), or the well-known variable rate springs (i.e., springs with non-linear extension changes for unit load increases) may be used to counteract the pressure-responsive diaphragm. It becomes necessary.

This method makes it possible to adapt the function of the fuel-air ratio control device to specific engine characteristics.

As shown in FIG. 3, the first spring member 80 is connected to the seat member 81.
and the piston 47.

The seat member 81 slides within the hole 82 of the housing 39.

The second spring member 84 is arranged between the seat member 81 and the intermediate bowl-shaped member 85.

A third spring member 86 is disposed between the bowl flange 88 and the arm member 68.

The fourth spring member 78 is attached to the cover 36 as in the first embodiment.
and washer 77.

Each spring member has a specific spring rate.

In the illustrated example, the spring rate of the first spring member 80 is greater than the spring rate of the second spring member 84, and the spring rate of the second spring member 84 is greater than 2, and the third spring member 86 is greater than the spring rate of the second spring member 84. The spring rate is selected such that the seat member 81 is first seated on the stopper 83 by the air pressure in the chamber 35, and then the bowl-shaped member 85 is seated on the seat member 81, as will be described later. .

Therefore, the first diaphragm 76 is supported. Second. third and fourth spring members;

The composite spring rate based on 80.84.86 and 78 is until the seat member 81 is seated on the stopper 83 (however, K4
is the spring constant of the fourth spring member 78) After the seat member 81 is seated on the stopper 83 and until the arm-shaped member 85 is seated on the seat member 81, After the bowl-shaped member 85 is seated on the seat member 81, K4+ becomes 3.

Therefore, the magnitude of the load (pressure inside the chamber 35) acting on the diaphragm with respect to the amount of deviation of the diaphragm (the amount of rack deviation) is expressed as three consecutive linear line graphs with increasing gradients ( However, when the horizontal axis is the deviation amount and the vertical axis is the load), the above-mentioned engine characteristics, that is, an engine in which the required air pressure changes in a curved manner with a gradient that gradually increases as the rack deviation increases. It is possible to approach the characteristics of

The spring rate of each spring can be determined as follows.

For example, the required spring rate of third spring member 860 is calculated by determining the amount of rack movement (excursion) relative to the force (load) acting on diaphragm 76 during a given period of operation.

The spring equation, deflection (third spring member) The spring rate is obtained.

The required spring rate of the second spring member 840 is the same as that of the third spring member 8.
6 is calculated by the amount of rack operation (excursion) relative to the force (load) acting on the diaphragm 76 during a predetermined period of engine operation immediately preceding the period of engine operation controlled by 6.

Spring equation, deflection (second spring member), K4. If 3 (third spring member) is known for the deflection and load, then 2 is obtained for the ratio of the second spring member.

The required spring rate of the first spring member is calculated by the amount of deflection with respect to the load acting on the diaphragm 76 just before the period restrained by the second spring member.

The spring equation is K3, where the deflection (first spring member) is 4, the deflection and the load are known. If 2 has already been determined, then the ratio of the first spring member is obtained.

In operation, the first spring member 80, which has a relatively low spring rate, is initially used to slide the dust 81 to the left within the hole 82.

The initial air pressure in chamber 35 is therefore small, but acts on a relatively weak spring.

When the air pressure further increases, the spring members 84 and 86, which have a relatively higher force than the spring member 80, act on the spring 80 through the seat member 81, and the seat member presses against the stopper 83, and at this time, the spring member 80 A second spring member 84 having a slightly greater spring rate counteracts the air pressure in chamber 35.

As the air pressure within chamber 35 increases further, spring member 84 is compressed through spring member 86, which has a higher spring rate than spring member 84.

At a predetermined air pressure in the chamber 35, the bowl-shaped member 85 comes into pressure contact with the seat member 81, and the air pressure in the chamber 35 begins to act on the spring member 86.

Accordingly, a selectively increasing spring rate is used to resist variably increasing air pressure within chamber 35.

In a first embodiment, the use of a single spring creates a linear force to resist variably increasing air pressure.

In a modified example (Figure 3), multiple springs with different spring rates are used in series in one device to generate a force that varies non-linearly with respect to the displacement of the rack, thereby variably Increased pneumatic force changes can be matched more uniformly.

Valve spool 63 operates in the manner previously described in the first embodiment.

Compression of the spring by the pressure responsive diaphragm acts to cause fluid to flow from chamber 53.

Therefore, the fuel adjustment member 17 is moved to the right toward the fuel increase position.

When multiple springs are used, the pressure responsive diaphragm is made more responsive to the pneumatic characteristics of the supercharger.

Although this invention has been described with reference to particularly preferred embodiments, it will be obvious that various modifications may be made within the spirit of the invention.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view schematically showing the supercharged engine intake manifold, governor and fuel pump mechanism and showing the fuel-air control system of the present invention in the engine starting position;
The figure is a vertical longitudinal cross-sectional view similar to FIG. 1 of the fuel-air conversion control device of the present invention, but with the governor omitted and the device shown in the engine operating position. FIG. 7 is a partial vertical sectional view of a modification of the control device. 10... Fuel pump, 17... Fuel adjustment member, 22... Centrifugal weight, 26... Spring, 28... Movable lever, 30...Suction manifold, 31...Supercharger, 35...
...Chamber, 39...Control housing, 46...
... Servo unit, 47 ... Piston part, 48 ... Valve means, 53 ... Expansion chamber,
56, 57, 60...Aisle, 58...
Annular groove, 63...Valve spool, 72.73,7
8... Spring member.

Claims (1)

Claims: 1. Fuel controlled by a governor movable in a first direction to increase fuel supplied to the engine and movable in a second direction to decrease fuel supplied to the engine. a regulating member, a supercharger for supplying pressurized air to the engine via an intake manifold, and a fuel-air ratio control device for selectively disabling the governor to restrain movement of the fuel regulating member in a first direction. In an engine comprising: a control housing; a flexible diaphragm mounted within the control housing and defining a chamber in fluid communication with the intake manifold; a valve spool having a pair of protrusions connected and defining an annular chamber therebetween, the valve spool being moved from an inactive position to an activated position in response to supercharged air supplied to the chamber from a suction manifold with the diaphragm; a valve spool movable to; positioned within the bore of the control housing;
and a piston portion, a sleeve portion slidably positioned within another aperture of the control housing, a longitudinal aperture extending through both the piston portion and the sleeve portion, and a radial aperture provided in the sleeve portion. a passageway, the valve spool being slidably disposed within the longitudinal bore, the valve spool protrusion and the annular chamber having a pressurized engine lubricating oil supply. of,
Alternatively, said diaphragm and valve spool may be directed toward an expansion chamber formed by a surface of a piston portion when in an operative position, and toward a discharge passage when said diaphragm and valve spool are in an inoperative position. a servo unit slidably interacting with said radial passage; a normal balanced relationship in which said diaphragm and valve spool are biased to an inoperative position when there is no supercharged air pressure in said chamber; a plurality of springs disposed on opposite sides of the diaphragm to maintain the servo unit in the first position;
and bias the diaphragm and valve spool toward the second direction (the first spring supported between the piston portion and the diaphragm and the diaphragm a plurality of springs including a second spring that biases the diaphragm and the valve spool in the second direction; and a third spring that biases the diaphragm and the valve spool in the first direction; a stopper member formed on the fuel adjustment member; and a shoulder formed on the servo unit; the servo unit is configured to operate when the diaphragm and valve spool are in an inoperative position during a starting cranking motion of the engine; The shoulder is urged by the opposing forces of the plurality of springs to assume a non-restrictive position relative to the stop member, so that a sufficient amount of fuel is supplied to the engine in accordance with the requirements set by the governor. The servo unit ensures an optimal ratio of fuel and air supply to the engine when the diaphragm and valve spool are in the operating position during normal engine operation under governor control following engine start-up; a position where the shoulder restrains against the stopper member in response to expansion of the expansion chamber being pressurized by engine lubricating oil to prevent excessive fuel supply during periods of air pressure reduction in the intake manifold; The engine was moved so as to take.