US3662721A - Fuel injection device for internal combustion engines - Google Patents

Abstract

An injection device for internal combustion engines with injection valves and an excess pressure valve controllable by an adjustment of throttle valves for control of the pressure of the introduced fuel.

Description

United States Patent Klein 1 May 16, 1972 [54] FUEL INJECTION DEVICE FOR [561 References Cited INTERNAL COMBUSTION ENGINES UNITED STATES PATENTS [72] lnventor: Heinz Klein, Wolfsburg, Germany 2,136,959 1 1/ 1938 Winfield ..123/139.18 1,664,615 4/1928 French ..123/32 AB [73] Ass1gnee: Volkswagenwerk Aktiengesellschaft, Wolf- 1,679,159 7/1928 French W123 /32 AE Sburg, Germany R18,195 9 1931 French .....123/32 AB 2 Filed: N0 6, 19 9 2,310,773 2/1943 Fuscaldo .....l23/32 AE 2,410,728 11/1946 Fuscaldo 123/32 A13 [21] Appl. No.: 874,146 3,105,478 10/1963 Lyon ....123/139.18 3,319,613 5/1967 Begley et a1. ..l23/32 EA 1 Foreign ApPlication Priority Data Primary Examiner-Laurence M. Goodridge Assistant Examiner-Cort Flint Nov. 8, 1968 Germany ..P 18 07 773.1 A'tomey watson Cole Grindle & Watson [52] US. Cl. [23/32 AE, 123/119 [57] ABSTRACT 51 1111. C1 ..F02b 3/10 1 [53] Field of Search "1233/32 EA, 32 AE, 13913, 9, An injection device for internal combustion engines with in- 123/32 jection valves and an excess pressure valve controllable by an adjustment of throttle valves for control of the pressure of the introduced fuel.

3 Claims, 1 Drawing Figure FUEL INJECTION DEVICE FOR INTERNAL COMBUSTION ENGINES The invention relates to a device for the indirect injection of fuel for internal reciprocating combustion engines, that is, a device where the fuel is not injected directly at a high pressure into the cylinders but with a considerably lower pressure into the suction pipe in front of the inlet valves. Mechanical arrangements for the variable apportioning of the fuel are relatively expensive because of the high requirements for precision; therefore injection devices with electromatnetically controllable injection valves have been known where the fuel is injected at a constant pressure and a measured quantity of the fuel is provided by electric means through a change in the duration of the opening of the valve.

The present invention has for an object to make this device less expensive and to. achieve an increased operating reliability of such a device and it provides a measured fuel quantity by means of a-variable injection pressure while the time for opening of the valve remains constant. According to the invention, an excess pressure valve for control of the pressure of the introduced fuel is controllable through an adjustment of the throttle valves.

Further objects will be apparent from the following description when considered in connection with the accompanying drawing in which the single FIGURE is a diagrammatic view of a systemfor injecting fuel in an engine cylinder. I

The fuel is sucked in from tank 1 through a filter 2 by an eccentric pump 3 and is pumped with a variable pressure of 2 l5 atmospheres, depending on the engine conditions into the feed lines 4 to the injection valves 5. The'variable pressure is regulated within the range of 2 12 at. by an adjustable excess pressure valve 6. An eccentric 7, which, indicated by the broken line 8, is firmly connected with the throttle valve 9, imparts the smallest initial stress to the excess pressure valve 6 when the throttle valve 9 is closed and it imparts the greatest initial stress when the throttle valve 9' is open. In the case of idling, the pressure amounts to 2 at. and in the case of a maximum r.p.m., to 12 at. For a further increase in pressure during the time of acceleration of the motor vehicle, a magnetic shutoff valve 10 has been provided which can be closed by a contact switch 12 which is closed upon the fuel gas position of the gas or accelerator pedal 11. In that case, the flow resistance in the return line 13 and 130 will be increased. The pressure rises to 15 at. and is kept at this value through the excess pressure valve 14. The electric control of the magnetic shutoff valve 10 will be described further.

The throttle valve 9 and the eccentric 7 are operated by the gas pedal 11. An impulse transmitter 15 for the electronic control of the injection valves 5 is located in the distributor 16 and it runs with half the r.p.m. The eccentric pump 3 conveys four times the required quantity of fuel.

The impulse transmitter 15 consists of a collecting ring 17 shown separately in the right-hand upper part of the figure of the drawing, with a trapezoid shaped impulse cam 17a. The impulse cam 1711 has an upper width which transmits a current impulse of 2 msec. to the corresponding injection valve 5 in the case of the idling r.p.m. With an increasing r.p.m., a centrifugal device 18 will lift the collecting ring 17 in such a way that the impulse cam 17a will each time have the effective width which corresponds to the impulse time of 2 msec. In the case of an idling r.p.m. of 1,000 r.p.m. and a full load r.p.m. of

5,000 r.p.m., the lower width of the cam must then be five times wider than the upper width of the cam.

The current supply from battery 20 to the injection valves 5 is accomplished each time whenever the sliding contact 21, which slides continuously on the current conducting ring 17b, is connected with the sliding contact 22 by means of the im-- pulse cam 17a. The leading edge of the impulse contact 17a, viewed in the rotational direction, has been developed slantingly while the rear edge runs perpendicularly. In this way, the opening phase of the injection valves 5 with the duration of injection remaining the same, will be advanced in time as is desirable in operation. I

The current supply for the magnetic valve 10 is likewise controlled by means of the collecting ring 17. ln the case of low r.p.m. of the engine and in the case of the gas pedal being pushed completely to the floor, the contact element 19 will slide on the current conducting element 17b of the collecting ring 17. In the case of higher r.p.m., the collecting ring 17 is lifted up and the flow of current is interrupted, since the contact element 19 now slides on the lower currentless part of the collecting ring 17. The injection pressure can then amount to only a maximum of 12 at.

I claim:

1. An injection device for internal reciprocating combustion engines having injection valves mounted in a suction pipe and controllable by electrical impulses for introducing fuel under variable pressure from a fuel supply, comprising;

a'fuel return line connected to said fuel supply,

an adjustable excess pressure valve'for controlling the pressure of the fuel from said fuel supply to said injection valves by varying the fuel flow resistance in said fuel return line,

a throttle vaLve mounted in said suction pipe,

an engine accelerator,

means for connecting said throttle valve and said excess pressure valve to said engine accelerator for simultaneous operation of said adjustable pressure valve and said throttle valve with acceleration and deceleration of said engine, electromagnetic valve means mounted in said return line for raising the fuel pressure to said injection valves when operated,

switching means actuated by said engine accelerator for operating said valve means only under substantially full acceleration conditions,

and a contact device for operating said valve means depending on the r.p.m. ofsaid engine.

2. An injection device as in claim 1 further comprising a distributor having means responsive to the varying centrifugal force of the rotation of said distributor, means for generating constant duration electrical impulses for controlling said injection valves and responsive to said centrifugal force means.

3. An injection device as in claim 2 wherein said means for generating electrical impulses includes adjustable means connected to said means responsive to a centrifugal force to be adjusted by said centrifugal force inversely proportional to the r.p.m. of said engine, an impulse cam driven by said adjustable means, a pair of spaced slidable contacts intermittently interconnected to said impulse cam, and each of said slidable contacts is respectively connected to the engine battery and said injection valves.

Claims (3)

1. An injection device for internal reciprocating combustion engines having injection valves mounted in a suction pipe and controllable by electrical impulses for introducing fuel under variable pressure from a fuel supply, comprising; a fuel return line connected to said fuel supply, an adjustable excess pressure valve for controlling the pressure of the fuel from said fuel supply to said injection valves by varying the fuel flow resistance in said fuel return line, a throttle vaLve mounted in said suction pipe, an engine accelerator, means for connecting said throttle valve and said excess pressure valve to said engine accelerator for simultaneous operation of said adjustable pressure valve and said throttle valve with acceleration and deceleration of said engine, electromagnetic valve means mounted in said return line for raising the fuel pressure to said injection valves when operated, switching means actuated by said engine accelerator for operating said valve means only under substantially full acceleration conditions, and a contact device for operating said valve means depending on the r.p.m. of said engine.

2. An injection device as in claim 1 further comprising a distributor having means responsive to the varying centrifugal force of the rotation of said distributor, means for generating constant duration electrical impulses for controlling said injection valves and responsive to said centrifugal force means.

3. An injection device as in claim 2 wherein said means for generating electrical impulses includes adjustable means connected to said means responsive to a centrifugal force to be adjusted by said centrifugal force inversely proportional to the r.p.m. of said engine, an impulse cam driven by said adjustable means, a pair of spaced slidable contacts intermittently interconnected to said impulse cam, and each of said slidable contacts is respectively connected to the engine battery and said injection valves.

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