US2233036A - Device for governing the engine speed of a multicylinder injection internal combustion engine - Google Patents

Description

DEVICE FOR GOVERNING THE ENGINE SPEED OF A MULTICYLINDER Feb. 25, 1941. SCHWElZER 2,233,036

v INJECTION INTERNAL COMBUSTION ENGINE Filed June 3, 1958- y Q ////////l Patented Feb. 25, 1941" '1 -9 DEVICE ron' oovaaume rim ,nmnm sPEEn'or A m'ncrmmsa mmcrron mama comnusrron ENGINE 1 Alfred Schweizer, Vaihingen-on-the-Filders, Ger.

many, assignor to Robert Bosch Gcsellschaft mit beschriinkter Haftung, Stuttgart, Germany Application June 3, 1938, Serial No. 211,682 I In Germany June 17,1937

The present invention relates to devices for governing the engine speedof multicylinder injection internal combustion engines with the aid of a control member, which displaces the member 5 of the injection pump, adjusting the fuel delivery amount and which divides the governor casing into two chambers and is moved against a return force by a governingforce produced against a constant pneumatic pressure, especially atmospheric pressure, by an air pressure drop, which force varies with the engine speed and can be influenced by the voluntary adjustment of a throttle member. 1

If, in governors of this kind, one force which helps to determine the air pressure drop is formed by atmospheric pressure, and if the atmosphere has direct free admission to the governor chamber situated on one side of the control member, then foreign bodies, especially dust, which hinder A 34 the free mobility of the control member, can

easily get into this chamber. It has been proved that, owing to its to and fro movements, which are often rapid on a rapid change of engine speed, the control member also sucks dust into the con- 25 trol chamber together with the air, and the dust then settles on the walls of the governor or on' the control member itself. If the control member has a piston which is guided in the governor casing so as to be airtight, this'piston can be 30 hindered in motion by the dust, especially when the engine has been stationary for some time. If the control member consists of an oil impregnated leather diaphragm, the diaphragm loses its resilience owing to the dirt which settles on it, 35 and becomes easily broken and leaky.-

Now the external air could be cleaned by a filter before entering the governor chamber. Since, however, free passage through the filter gradually becomes constricted owing to the impurities, the 40 external air pressure can no longer be transmitted without hindrance to the interior of the chamber, so that the governor no longer responds quickly to pressure difference.

In order to avoid the drawbacks set forth, ac- 4 cording to the present invention, one of the two governor chambers in which roughly atmospheric pressure always prevails is connected with the atmosphere only through a chamber, the capacity 60 of which is so great that even rapid movements of the control member cannot produce any substantial pressure difference in this space, in which the pressure is independent of the engine speed and roughly corresponds toatmospheric pressure. The invention is more particularly described with reference to the accompanying drawing, in which- Figure 1 is a side elevation of an internal com bustion engine with the example of construction, and

Figure 2 is an enlarged longitudinal section through the example of construction. v

The crank case a of an internal combustion engine of a motor vehicle carries the cylinder block b with the cover c and an injection pump d, m to which fuel is fed through a pipe e.

The injection pump is driven through toothed wheels I. The sixpump outlets are connected through six pressure pipes a to the injection nozzles (not shown) of the internal combustion 15 engine. On the inlet side of the engine induction pipe h is flanged a branch pipe i, which carries a filter k for the air sucked in, and in which is rotatably mounted a throttle valve m, on the shaft of which is secured a lever n. A' pedal 0, which can be rocked by the driver. is pivotally connected with the lever n by means of a rod p. ,and is tensioned by a spring q which tends to keep the pedal 0 in the position shown, in which the throttle valve is approximately closed.

In Figure 2, the casing l of an air pressure governor is secured to the casing of the injection pump d. The governor casing consists of two parts, a ring 2 flanged to the pump casing,

and a part 3 which is placed over the reduced rim of the ring. Between the contact surfaces of the two parts 2 and 3 is clamped the outer part of a leather diaphragm 4, which divides the internal space of the governor casing into two parts 5 and 6, and the central part of which is connected by means of two plates 1 with that end of a control rod 8 which projects into the left hand chamber 5 of the governor casing, with which control rod the pump pistons, which are provided with oblique edges and are not shown, can be turned for the purpose of uniform and uni-directional control of the delivery amount of the separate pumps. 'A spring 9 accommodated in the chamber 6 abuts on one hand on the plate I of the diaphragm 4 and on the other hand on the base of the chamber, and tends to push the control rod completely to the left, whereby it sets the separate pumps to the full delivery amount.

In the wall of the casing part 3 of the governor is secured a short tubular element l0, and in the wall of the induction pipe 2' is secured another tubular element ll. Over the free ends of the two tubular elements l0 and II are placed the ends of a flexible pipe H, which transmits the depression prevailing in the suction pipe behind the throttle valve on to the governor chamber C.

Into the chamber I of the governor is placed a little lubricating oil, which impregnates the leather diaphragm and keeps it pliant. A short tubular element I3 is secured in the upper part of the governor casing. A short tubular element It is likewise fitted in the wall of the crank casing a of the internal combustion engine. The tubular element ll opens into the governor chamber and the tubular element ll opens into the air-filled part of the crank casing a, which is in communication with the atmosphere by means of an air filter pipe l5 provided with an air filter shown conventionally at lia. Over the two wide tubular elements l3 and I4 are placed the ends of a flexible pipe It, so that the governor chamber 5 and the inner space of the crank case are in communication with each other.

In the position of the throttle valve shown in Figure 1, the engine is running under no load and a high vacuum prevails behind the throttle valve and in the depression chamber 6 61 the governor. -At the position of the diaphragm which corresponds to no load, equilibrium is present between the forces engaging on the membrane. In this position, the control rod is well to the right, in a position in which it has set the pumps to small fuel delivery. Now if the driver opens the throttlevalve completely by depressing the pedal, then the pressure in the suction pipe and in the vacuum chamber rises, and; since the pressure drop prevailing on both sides of the diaphragm suddenly decreases, the spring can displace the diaphragm rapidly to the left. Thus the air displaced from the chamber 5 by the diaphragm will escape rapidly through the wide flexible pipe towards the crank casing. Since the air space in the crank casing is very large in relation to the volume of the chamber 5, the pressure in this chamber becomes balanced immediately against the pressure in thecrank casing,,which pressure corresponds approximately to atmospheric pressure.

In the converse case ota sudden falling of the pressure inthe vacuum chamber 6-, for instance,

airbymeansoianair tuations in the crank case. Since oil vapours are present in the crank casing, these vapours are carried over into the governor chamber.

These vapours keep the leather diaphragm pliant,

so that it cannot become brittle or even leaky- I declare that what I claim is: l. A device for governing the fuel supply to a multicylinder injection internal combustion engine in dependence on the engine speed comprising, in combination, a fuel injection pump having a fuel delivery adjusting member, a governor housing. a control member therein, said control member dividing said housing into two chambers and being operatively connected to said adjusting member, said engine having an induction pipe and an adjustable throttle member in said induction pipe, a pipe connecting one of said chambers with that part of the induction pipe lying between the throttle member and the engine to reduce the pressure on one side of said control member, resilient means for resisting movement of said control member as the pressure in said chamber is reduced, a large chamber containing clean air at substantially atmospheric pressure, and a pipe leading from the other governor chamber to said large chamber, the volume of said large chamber being many times larger than that 01 the other governor chamber so that movements of said control member cannot produce any substantial pressure difference within said large. chamber.

2. A device according to claim '1, in which the large chamber is the crank case of the engine.

3. A device according to claim 1, in which the large chamber is in communication with the open filter.

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