Intake manifold for automotive fuel injection system

Claim 2

An intake manifold of a fuel injection system of an internal combustion engine comprising a main throttle valve chamber open to the atmosphere, a main throttle valve mounted in said main throttle valve chamber and operated by an accelerator pedal, an air chamber communicating with said main throttle valve chamber downstream of said throttle valve, a plurality of branches leading from said air chamber to respective cylinders of the engine, an auxiliary throttle valve chamber open to the atmosphere and communicating with said air chamber at a position spaced from said main throttle valve chamber, an auxiliary throttle valve mounted in said auxiliary throttle valve chamber, means responsive to the speed of the engine and auxiliarythrottle-valve-actuating means connected with said main throttle valve and with said speed responsive means for opening said auxiliAry throttle valve only when said main throttle valve is open not less than a selected amount and when the engine speed exceeds a selected value.

Claim 3

An intake manifold according to claim 1, wherein the value of engine speed above which said auxiliary throttle valve is opened by said actuating means is the value at which the engine torque with said auxiliary valve closed reaches a maximum value.

Claim 4

An intake manifold according to claim 1, wherein said actuating means operates to open said auxiliary throttle valve fully when said main throttle valve is open not less than said selected amount and the engine speed reaches said selected value.

Claim 5

An intake manifold according to claim 1, wherein said actuating means operates to open said auxiliary throttle valve progressively when said main throttle valve is open not less than a selected amount and the engine speed goes above said selected value.

Claim 6

An intake manifold according to claim 1, wherein one said throttle valve chamber communicates with said air chamber at one end thereof and the other said throttle valve chamber communicates with said air chamber intermediate its ends.

Claim 7

An intake manifold as set forth in claim 1, wherein said air chamber is connected with the main throttle valve chamber at one end thereof and said auxiliary throttle valve chamber is connected with the other end thereof.

Claim 8

An intake manifold as set forth in claim 1, wherein said branches are formed straight whereby the intake air tends to be accelerated by the intake vacuum in the cylinder and then tends to enter the cylinder abruptly.

Claim 9

An intake manifold as set forth in claim 1, wherein said actuating means is a control device for mechanically opening and closing the auxiliary throttle valve and including an angled lever pivotally connected to the vehicle body and having two arms one of which is connected with said main throttle valve to cause said lever to be interconnected with the main throttle valve, a first lever pivotally connected with the vehicle body at one end and connected at an intermediate point with the other arm of said angled lever to cause the first lever to be interconnected with the angled lever and a roller mounted at the other end of said first lever, a centrifugal governor driven by the engine and having a plurality of weights, a plurality of angled levers each connected at one end with the weight, a first rod having a disc fixed at one end thereof and engaged at one surface with the other ends of the angled levers and inserted at the other through a first hole formed in the vehicle body, a spring so disposed between the disc of the rod and the vehicle body as to press the disc against the centrifugal force of the weights applied to the other surface of the disc, a second lever supported at an intermediate point by the vehicle body and interconnected with the auxiliary throttle valve at one end, a second rod slidably inserted into a second hole formed in the vehicle body and connected at one end with the other end of the second lever, a third lever pivotally supported at an intermediate portion by said roller on the first lever and connected at one end with the other end of the second rod and with a second spring which is fixed at one end to the vehicle body for biasing the second lever and engaged with the end of the first rod at the other end, said intermediate portion of said third lever being so formed with a recess as to move the auxiliary throttle valve in response to the movement of the main throttle valve and engine speed, and a stop for limiting the movement of the third lever.

Claim 10

An air intake manifold as set forth in claim 1, wherein said actuating means comprises a control device for electrically opening and closing the auxiliary throttle valve and including an accelerator switch connected with the accelerator pedal interconnected with the main throttle valve to operate to open or close its contact in response to the opening of the main throttle valve so that when the maIn throttle valve fully opens or substantially opens the contact of the switch closes, a generator for generating a voltage proportional to the engine speed, a control relay, a voltage control device for energizing said relay when the engine speed reaches a predetermined speed so that the generator generates a voltage corresponding to the predetermined engine speed and accordingly the contact of the relay closes by the energization of the voltage control device, a solenoid connected with the auxiliary throttle valve and energized when the main throttle valve fully opens or substantially opens, and an electric power source for energizing the solenoid through said switch and relay.