US3000394A

US3000394A - Governor

Info

Publication number: US3000394A
Application number: US685341A
Authority: US
Inventors: Gold Harold; David M Straight
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-09-20
Filing date: 1957-09-20
Publication date: 1961-09-19
Anticipated expiration: 1978-09-19

Description

Sept. 19, 1961 H. GOLD EH1 3,000,394

GOVERNOR Filed Sept. 20, 1957 2 Sheets-Sheet 1 Fq- I LIKE zzzzl s Ham/0 6 0/0 United States Patent 3,000,394 GOVERNOR Harold Gold, Shaker Heights, and David M. Straight, North Olmsted, Ohio Filed Sept. 20, 1957, Ser. No. 685,341 4 Claims. (Cl. 137-480) This invention relates to a device for automatically regulating the rotational speed of air throttled internal combustion engines under varying conditions of idle running. The device functions with great advantage when applied to reciprocating Otto cycle engines that are used in automobiles. For this reason the device will be described with reference to this application. However, the device may be applied also to engines that are employed to power a wide variety of machines.

In the case of the automobile, the engine is considered to be idling whenever the engine is in operation while the vehicle is stationary. When the engine is coupled to the wheels of the vehicle through a non-slipping clutch, the engine can idle only when the clutch is disengaged and the engine runs free. The thermal power required to maintain an idle speed in the free running engine varies with the engine operating temperature. This occurs because the power absorbed by internal engine friction increases as the engine operating temperature is reduced. Engine temperatures considerably lower than normal operating temperatures are encountered at idle after the engine is started following a prolonged shut-down. This effect is pronounced in the case of vehicles operating in winter atmosphere. When an engine is started with engine temperatures well below normal, it is usually necessary to maintain the idle speed about 50 percent greater than the idle speed at normal temperatures.

When the engine is coupled to the wheels of a vehicle through a hydraulic transmission, the engine can idle both with the transmission engaged or disengaged. The power absorbed at idle by the transmission when it is engaged is considerably greater than when the transmission is disengaged.

With devices of the prior art, the rotational speed of the air-throttled internal combustion engine at idle is controlled by imposing a minimum value to which the throttle area can be reduced. This is usually obtained by means of a stop on the throttle operating linkage. Because of the varying power requirements at idle, as discussed above, the idle speed is subject to wide variation if a single stop is employed at all conditions. In some prior devices the throttle stop is varied by a thermally responsive actuator. This method of idle speed control can provide adequate adjustment of idle speed over a range of engine temperatures, but it cannot be employed to adjust the idle speed between automatic transmission engagements.

With systems that employ a minimum throttle stop for idle speed control, the maximum capacity of the engine to assist the wheel brakes during deceleration of the vehicle cannot be utilized. The maximum capacity of the engine to assist the wheel brakes is obtained by complete closure of the throttle.

The device described herein provides a means of obtaining automatic adjustment and regulation of the idle speed under all conditions of idle running. The device continuously modulates the throttle area at idle. Thereby the throttle area is automatically adjusted to meet all idle conditions. During deceleration the device functions to reduce the throttle area to substantially zero. These and other advantages of the device will be explained in the detailed description which follows.

This invention is more particularly described with reference to the accompanying drawings:

FIGURE 1 is a general cross-sectional view of the con- Patented Sept. 19, 1961 trol mechanism assembled with fragmentary portions of the induction pipe and engine manifold and embodying the usual throttle valve;

FIGURE 2 shows a graph with typical variations of engine air consumption and control mechanism air flow rate;

FIGURE 3 shows one state of the operating control valve embodied with this invention under influence of low pressure in engine manifold;

FIGURE 4 shows one stage of the operating control valve embodied with this invention under influence of slightly increased pressure in the engine manifold over that of FIG. 3;

FIGURE 5 shows one stage of the operating control valve embodied with this invention and influence of pressure greater than that of FIG. 4; and

FIGURE 6 shows one stage of the operating control valve embodied with this invention and under the influence of increased intake manifold pressure, substantially atmospheric.

FIGURE 1 shows the relationship of the mechanism of the device to the engine air throttle. The engine air throttle 11 is housed in throttle body 12. Throttle body 12 is open to the atmosphere at its upper end. Below the throttle 11 the throttle body communicates with the engine intake manifold M, shown in part. The idle speed mechanism housing 13 is close coupled to the throttle body. Throttle 11 is supported by a throttle shaft 14. Throttle shaft 14 is connected in the usual manner to the operators foot pedal (not shown). In the usual manner, the speed of the engine in the power range is controlled through the rotation of throttle 11. When the engine is idling, throttle 11 is in the full closed position as drawn. The airflow to the engine at idle passes into the idle speed mechanism housing 13 by way of inlet passage 15. The passage 15 is permanently in communication with the atmosphere and leads to valve orifice 16. Valve orifice 16 opens into chamber A. The interior of chamber A is divided into three

chambers

17, 24, and 32. The airflow passing into chamber A discharges into the engine intake manifold M by way of passage 18 and throttle body bore, or induction pipe 19. Passage 18 and bore 19 are made of suflicient cross-sectional area to allow 'the air to flow to the intake manifold with negligible pressure loss. By virtue of this, the pressure of the air in chamber 17 is substantially equal to the pressure in the intake manifold.

The open area of orifice 16 is varied by valve element 20. The valve element 20 thereby functions as an auxiliary throttle. The valve element 20 is formed on the end of valve shaft 21. The upper end of valve shaft 21 passes through wall 22 and is guided by valve guide 23. Shaft 21 passes into chamber 24 and is coupled to diaphragm guide 25 by nut 26. Beyond nut 26 shaft 21 passes into chamber 32 and through upper guide 27' and extends outwardly from the housing 13. The spring adjusting nut 28 is threaded onto shaft 21 and retains spring 29. Spring 29 seats on its opposite end against. housing 13 and thereby urges shaft 21 upward. Limp diaphragm 30 is fastened to diaphragm guide 25 by plate 31 and nut 26. Diaphragm 30 is clamped in housing 13 to form a movable air-tight wall between

chambers

24 and 32. Vent 33 communicates atmospheric pressure to chamber 32. The chamber 24 is in communication with chamber 17 by means of a narrow, or restricted opening, or passage 34 in wall 22. A threaded plug 35 having a conical end 35a extends into said passage 34 and forms a variable flow restriction in passage 34. The function of plug 35 will be explained later.

As now described, valve shaft 21 is urged upward by spring 29 and by the air pressure in chamber 24 (acting on diaphragm 30) and is urged downward by the atmospheric pressure in chamber 32 (acting on diaphragm 30). As previously described, the pressure in chamber 24 is (in steady running) substantially equal to the pressure in the intake manifold. At idle running the pressure in the intake manifold is substantially lower than atmospheric 7 pressure. Hence, in the operating range of the device the net force resulting from the pressures that are communicated is downward. This force is biased out by spring 29. By virtue of the pressure communication and the spring bias, valve shaft 21 is caused to move upward when the intake manifold pressure increases and downward when the intake manifold pressure decreases. Therefore, in the operating range of the device the airflow to the engine is increased when the intake manifold pressure increases and the airflow is decreased when the intake manifold pressure decreases. The rate of response of valve shaft 21 to variations in intake manifold pressure is adjustable by means of plug 35. Movement of 1 the plug 35 inward restricts the flow of air in passage 34 and thereby retards the rate of change of pressure in chamber 24- following a variation in intake manifold pressure. This retardation of pressure change in chamber 24 provides a means of introducing damping to the system.

The manner in which the device functions to control the rotational speed of an engine of the class referred to will be explained in conjunction with FIG. 2. FIG. 2 shows a plot of the typical variation of engine air consumption and control mechanism air flow rate with intake manifold pressure. The lines labeled Engine Air Consumption Characteristics at Constant Speed represent typical reciprocating engine characteristics, i.e., the air consumption increases in a substantially linear progression with intake manifold pressure at constant engine rotational speed; the rate of the progression being linearly proportional to the rotational speed. The lines marked 41, 42 and '43 show the change in this characteristic at several speeds. Line 41 represents normal idle speed. Line 42 represents the higher idle speed for a cold engine. Line 43 represents a speed at the upper limit of the idle range. Also presented in FIG. 2 are typical equilibrium operating lines in the idle speed range. The line marked Free running-warm represents the variation of engine air consumption and intake manifold pressure as the speed of the free running engine is varied in the idle speed range by variation in air throttle open area. It will be noted that the line intersects the constant speed characteristic lines at progressively lower engine speeds while the intake manifold pressure increases and hence that the air consumption diminishes while the intake manifold pressure increases. This negative airflow characteristic is due to the reduction in engine volumetric efficiency with reduction in engine speed in the idle speed range. In the case of the free-running cold engine the equilibrium operating line is transposed toward higher intake manifold pressures. This shift is the result of the increased internal engine friction that exists in the cold engine. idling with a hydraulic transmission engaged, the engine air consumption increases rapidly when the intake manifold pressure increases through an increase in air throttle open area. This positive air flow characteristic is. due to the rapid torque increase of the hydraulic transmission with engine speed as the speed is increased above idle. For the cold engine idling with a hydraulic transmission engaged, the equilibrium operating line shifts toward higher intake manifold pressure because of higher internal friction and increased transmission drag. V

The final characteristic represented in FIG. 2 is the airfiow characteristic of the speed control mechanism of this invention. The particular characteristic shown has been selected to yield constant speed idle for a warm engine running free or with a hydraulic transmission engaged and to yield a high idle speed when the engine is cold.

The dashed line denotes the 'air'flo'wchar'acteristic of the device. The nonlinear characteristic shown is obtained by proper shaping of the valve element 20. The action In the case of the warm engine of valve shaft 21 in conjunction with valve element Zil is shown in FIG. 3. In FIG. 3 view A shows the position of valve element 20 in relation to orifice 16 to maintain the warm engine idle speed. As shown in FIG. 3 valve element 20 consists of the end of valve shaft 21 and a cylindrical section'36 of reduced diameter. In the region of operation represented by view A, the minimum (and controlling) valve area is the cylindrical area formed between the periphery of orifice 16 and the shoulder 37 of element 20. This provides the linear airflow characteristic that intersects the free running-warm idling engine 7 equilibrium line at point (A) in FIG. 2. The engine speed that results from this intersection is determined by the constant speed air consumption line that passes through the intersection. In this instance the three lines intersect on the normal engine idle speed line (line 41). Because of the negative slope of the engine equilibrium line, the system is very stable in spite of the very rapid increase of control mechanism airflow with intake manifold pressure. Further lifting of shoulder 37 by the increased intake manifold pressure that occurs in cold engine idle, as shown in FIG. 4, moves the line intersection to point (B) in FIG. 2. As may be seen, intersection (B) occurs on a higher constant speed air-consumption line; hence, the control mechanism causes the engine to idle at a higher speed when the engine is cold. When the engine is idled with a hydraulic transmission engaged,

the high positive slope of the equilibrium engine line requires for system stability a reduced slope of the airflow rate characteristic of the speed control mechanism. The reduction in slope is obtained by proportioning the diameter and length of cylindrical projection 20 so that the annular area between projection 20 and orifice 16 is the limiting area, in this range of intake manifold pressures. This fixed area results in a constant airflow delivery by the control mechanism over the range of intake manifold pressure. This constant air delivery is indicated by the horizontal dashed line.. The horizontal line intersects the engine equilibrium line at point (C) on the normal engine idle speed line to yield a constant idle speed between the free running warm engine and the warm engine with a hydraulic transmission engaged. The relation of projection 20 in orifice 16 at this condition is shown in FIG. 5. The zero slope of the control mechanism airflow characteristic provides for very stable op eration at this idle condition in spite of the steep slope of the engine equilibrium line. In the case of the cold engine idling with a hydraulic transmission engaged, the increased intake manifold pressure causes projection 29 to lift entirely out of orifice 16, as shown in FIG. 6, so that the' open area of orifice 16 provides the airflow limit of the control device. This limit is represented by theupper horizontal line in FIG. 2. This line intersects the engine equilibrium line at point (D) to yield the higher idle speed for the cold engine. As drawn in FIG. 2, the speed defining intersections occur at two precise speeds. In practice it is only necessary to have these intersections occur approximately as shown for satisfactory operation. 7

If the vehicle is rapidly decelerated (warm or cold), the intake manifold pressure will be reduced to below that existing at normal idle. In this case shoulder 37 is driven against orifice 16 to completely cut off the airflow to the engine. In this manner the maximum capacity of the engine in assisting the Wheel brakes is obtained.

When the engine throttle'is suddenly closed and the wheel brakes applied, the momentary high shaft torque imposed by a hydraulic transmission combined with the lack of vehicleinertia often causes engine stall. To avoid this occurrence of stall, plug 35 in passage 34 delays the effect of the sudden drop in intake manifold pressure that accompanies a sudden closing of the air throttle and causes shaft 21 to move downward at a slow rate thereby maintaining engine output torque for a suflicient time interval.

We claim as our invention:

1. An induction pipe for an internal combustion engine, raid induction pipe having an aperture therein and a throttle valve upstream of said aperture, the improvement which comprises a housing attached to the induction pipe and passaged to communicate said induction pipe with atmosphere through the aperture in said pipe, valve means in said housing, and diaphragm means on said valve means dividing the housing interior into a plurality of chambers, one of which is in communication with atmosphere through said passage in the housing and with said induction pipe aperture, said housing being apertured to communicate another chamber with atmosphere, means biasing the valve means to an open position, and said valve means being movable upon closure of the throttle valve and creation of a pressure difierential between said chambers to control the air supply through the housing passage from atmosphere to said induction pipe.

2. An induction pipe for an internal combustion engine, said induction pipe having an aperture and a throttle valve therein, the improvement which comprises a housing attached to the induction pipe and passaged to communicate said induction pipe through said aperture with atmosphere downstream of the throttle valve, a flexible diaphragm and a transverse wall spaced therefrom dividing the housing interior into lower, center and upper chambers, said lower chamber communicating with said housing passage, said wall being apertured to communicate the center chamber with the lower chamber and said housing being apertured to communicate the upper chamber with atmosphere, valve means on said diaphragm slidable within said transverse wall and movable upon closure of the throttle valve and creation of a pressure differential between the center and upper chambers to control the air supply from atmosphere through the housing passage and lower chamber to said induction pipe, and means biasing the valve means to an open position.

3. An induction pipe for an internal combustion engine, said induction pipe having a throttle valve therein and an aperture downstream of said throttle valve, the improvement which comprises a housing attached to the induction pipe and passaged to communicate said induction pipe with atmosphere through said aperture, a flexible diaphragm and a transverse wall spaced therefrom dividing the housing interior into lower, center and upper chambers, said lower chamber communicating with said housing passage, said wall being apertured to communicate the center chamber with the lower chamber and said housing being apertured to communicate the upper chamber with atmosphere, valve means on said diaphragm slidable within said transverse wall and movable upon closure of the throttle valve in creation of a pressure differential between the center and upper chambers to control the air supply from atmosphere through the housing passage in said lower chamber to said induction pipe, means biasing the valve means to an open position, and auxiliary valve means supported by said transverse wall and varying the aperture in said wall to retard pressure changes in the center chamber following variations in the pressure in said induction pipe downstream of the throttle valve.

4. An induction pipe for an internal combustion engine, said induction pipe having a throttle valve therein and an aperture downstream of said throttle valve, the improvement which comprises a housing having an air chamber therein communicating with the aperture in said induction pipe, means at one end of said housing defining a valve orifice communicating with said chamber, valve means in said housing having a stem portion thereon receivable in said orifice, means defining an inlet passage communicating said orifice and said induction pipe through said aperture with atmosphere, resilient means connecting with said valve means to normally urge said valve stem away from the valve orifice to admit atmospheric air to said induction pipe through said inlet passage, and pressure sensitive means in said chamber and connected to said valve means opposing the action of the resilient means to move the valve stem portion to an orifice closing position upon a pressure decrease in the induction pipe following closure of the throttle valve therein.

References Cited in the file of this patent UNITED STATES PATENTS 1,022,407 Cramer Apr. 9, 1912 2,152,028 Church Mar. 28, 1939 2,631,600 Flanagan Mar. 17, 1953 2,754,185 Ensign July 10, 1956 FOREIGN PATENTS 487,875 Canada Nov. 11, 1952