The embodiment of the invention provides a cylinder cover
assembly, a horizontally-opposed engine, a
hybrid power
assembly and a vehicle, the cylinder cover
assembly comprises a body, an air flow channel and a cooling liquid channel are arranged in the body, and the body comprises a lower side and an upper side which are arranged in a deviating mode in the vertical direction; the
airflow channel comprises an air inlet and an air outlet, the air inlet is formed in the lower side, and the air outlet is formed in the upper side; the cooling liquid channel surrounds at least part of the
airflow channel and comprises a water inlet and a water outlet, the water inlet is formed in the lower side, and the water outlet is formed in the upper side. The air inlet of the
airflow channel and the water inlet of the cooling liquid channel are formed in the lower side, and the exhaust port of the airflow channel and the water outlet of the cooling liquid channel are formed in the upper side, so that the influence of bubbles on cooling liquid flowing can be reduced, accumulation of the bubbles can be avoided, and the
cooling effect of the cylinder cover assembly can be improved.