Multicylinder internal combustion engine, especially for automobiles and method of operating same

A multicylinder internal combustion engine for automobiles comprising first and second cylinder groups, each group having fuel-air mixture feeding devices associated therewith, said first cylinder group being fed by its associated fuel-air mixture device during all operating ranges and said second cylinder groups being fed by its associated fuel-air mixture device only after a predetermined partial load range is exceeded, an air supply throttle valve arranged in an intake manifold associated with each group, and gas pedal responsive cam means for adjusting the degree of opening of the throttle valve of both cylinder groups, said cam means comprising:

• (a) an engine idling control configuration arranged to cause the throttle valve of the first cylinder group to be held in a closed position and simultaneously said second cylinder group throttle valve to be held open to a minor extent;
• (b) a first partial load control configuration arranged to cause both of said throttle valves to progressively open;
• (c) a second partial load control configuration arranged to progressively close the throttle valve of the second cylinder group while continuing to progressively open the throttle valve associated with the first cylinder group;
• (d) a third partial load control configuration arranged for progressively closing the throttle valve associated with the first cylinder group while progressively opening the throttle valve associated with second cylinder group;
• (e) a feeding device actuating configuration disposed for turning on the feeding device associated with the second cylinder group during a transfer from said second to said third partial load configurations;
• and
• (f) a full load control configuration arranged for bringing said throttle valves from an equal degree of opening to fully open positions at the same continuously opening rate.

A method of operating a multicylinder internal combustion engine for automotive vehicles, having a fuel-air mixture feeding means associated with two different cylinder groups and electromagnetically operable fuel injection valves, comprising feeding a fuel-air mixture to the first cylinder group in all operating ranges of the internal combustion engine and, in dependence on the position of the gas pedal, feeding only air to the second cylinder group from idling up to the end of a predetermined partial load range of the internal combustion engine and a fuel-air mixture to the second cylinder group from the end of the predetermined partial load range up to the full load condition of the internal combustion engine, and controlling the air supplied to each cylinder group with a throttle valve arranged in an intake manifold, the position of the throttle valve being varied by a gas pedal actuated cam disk, by way of control levers arranged on throttle valve shafts for rotation therewith and cooperating with configurations of the cam disk, and wherein the following control operations are performed:

• during idling of the internal combustion engine, the control lever of the first cylinder group is held in contact with a first control point (A) on the cam disk, whereby the first cylinder group throttle valve is closed, and air is fed to the first cylinder group via an idling adjustment means for the idling fuel-air mixture, and the control lever of the second cylinder group is held in contact with a second control point (B) on the cam disk, whereby the throttle valve is opened to a minor extent, so that air is fed to the second cylinder group with the fuel feed means being shut off;
• at the end of a predetermined partial load range of the internal combustion engine, the control lever of the first cylinder group is, on the one hand, in contact with a third control point (C) on the cam disk, the amount of fuel-air mixture fed to the first cylinder group being continuously increased up to this control point and, on the other hand, the control lever of the second cylinder group is initially in contact with a fourth control point (D) on the cam disk symbolizing the end of a first part of the predetermined partial load range, up to which point the amount of air fed to the second cylinder group is continuously increased, and is thereafter in contact with a fifth control point (E) symbolizing the end of the predetermined partial load range, up to which point the amount of air is continuously reduced to an air quantity approximating zero;
• a control cam arranged at the cam disk, actuating a switch upon reaching the third and fifth control points (C and E), said third and fifth points being arranged on a common control plane extending through an axis of rotation of the cam disk, by means of which switch the fuel injection nozzles for the second cylinder group are placed in operation;
• above the predetermined partial load range, the control lever of the first cylinder group being brought into contact, on the one hand, with a sixth control point (F) on the cam disk and, on the other hand, the control lever of the second cylinder group is in contact with a seventh control point (G) arranged on a plane extending through the axis of rotation of the cam disk, wherein the amount of fuel-air mixture fed to the first cylinder group up to these control points is continuously reduced, and the amount of fuel-air mixture fed to the first cylinder group is continuously increased, until the amounts of fuel-air mixture for both cylinder groups are of equal size at the sixth and seventh control points (F and G), the continuous reduction of the amount of fuel-air mixture fed to the first cylinder group being effected to a lesser extent than the continuous increase of the amount of fuel-air mixture fed to the second cylinder group;
• and
• during the full-load range of the internal combustion engine, the control lever of the first cylinder group is in contact with an eight control point (H) on the cam disk, and the control lever of the second cylinder group is in contact with a ninth control point (K) on the cam disk arranged with the control point (H) on a common control plane extending through the axis of rotation of the cam disk, wherein the amount of fuel-air mixture for both cylinder groups are continuously increased to the same extent by movement of the control levers between the sixth and eighth, and seventh and ninth control points, respectively.