Variable valve driving mechanism of engine, and engine

An engine variable valve driving mechanism, comprising:

• a rocker arm configured to control opening and closing of a valve;
• a servo rocker arm arranged in parallel to the rocker arm, the servo rocker arm including a swing end extending over a swing end of the rocker arm such that a valve adjustment gap is formed between the servo rocker arm and the rocker arm in a swing direction of the servo rocker arm and the rocker arm;
• and
• a gap compensating device configured to enable a late closing or an early opening of the valve when the gap compensating device selectively extends between the servo rocker arm and the rocker arm so as to close the valve adjustment gap,
• wherein the gap compensating device comprises a plunger ejection structure at the swing end of the rocker arm, the plunger ejection structure configured to engage a press block arranged at the swing end of the servo rocker arm,
• wherein the plunger ejection structure comprises a plunger cavity arranged on the rocker arm, an ejector rod configured to alternately extend out of and retract into the plunger cavity, and a plunger located in the plunger cavity, the plunger configured to engage the ejector rod,
• wherein an open end of the plunger cavity is provided with a cover plate configured to seal the plunger cavity, and the ejector rod slides through the cover plate via an ejector rod extend-retract hole defined on the cover plate,
• wherein the ejector rod comprises an extending portion configured to engage the ejector rod extend-retract hole, a guiding portion configured to engage an inner wall of the plunger cavity, an ejector rod step defined between the extending portion and the guiding portion, and an ejector rod spring arranged along an outer circumference of the extending portion and pressed between the ejector rod step and the cover plate,
• wherein a control oil passage is defined in a shaft hole of the rocker arm, the control oil passage configured to communicate with the plunger cavity, an upper end of the plunger abuts against the guiding portion, and a lower end of the plunger communicates with the control oil passage,
• wherein the plunger ejection structure further comprises an ejector rod limiting structure configured to limit an extending length of the ejector rod,
• wherein the ejector rod limiting structure comprises a plunger hole located in the guiding portion so as to be coaxially arranged with the ejector rod, the plunger hole configured to slidably receive the plunger,
• wherein the plunger hole comprises a plunger return spring arranged between the plunger and a bottom of the plunger hole, the plunger return spring configured to bias the plunger to an initial position;
• wherein the ejector rod further comprises a radially extending control pin extending hole configured to connect the plunger hole to the plunger cavity, a control pin is arranged in the control pin extending hole, the control pin configured to engage a limiting annular groove defined in the inner wall of the plunger cavity when the control pin is actuated by the plunger.