Internal combustion engine and method for manufacturing internal combustion engine

Abstract

A cylinder block of an internal combustion engine includes an oil drain hole that opens in a lower surface of the cylinder block. An oil pan is fixed to a lower part of the cylinder block and configured to collect oil. A balancer device is arranged inside the oil pan below a crankshaft. A baffle plate is flat and arranged inside the oil pan between the crankshaft and the balancer device covering the balancer device from above. An oil flow passage extends through the baffle plate in a thickness-wise direction. The oil flow passage is arranged in the baffle plate at a location overlapped with an oil falling path that extends from the oil drain hole to a bottom surface of the oil pan.

What is claimed is: 
     
         1 . An internal combustion engine, comprising:
 a cylinder block including an oil drain hole that opens in a lower surface of the cylinder block;   an oil pan fixed to a lower part of the cylinder block and configured to collect oil;   a balancer device arranged inside the oil pan below a crankshaft;   a flat baffle plate arranged inside the oil pan between the crankshaft and the balancer device covering the balancer device from above; and   an oil flow passage extending through the baffle plate in a thickness-wise direction and arranged at a location in the baffle plate overlapped with an oil falling path extending from the oil drain hole to a bottom surface of the oil pan.   
     
     
         2 . The internal combustion engine according to  claim 1 , wherein the oil flow passage is located directly below an opening of the oil drain hole in a lower surface of the cylinder block in a vertical direction in a state in which the internal combustion engine is installed in a vehicle. 
     
     
         3 . An oil pan, comprising:
 a crankcase fixed to a lower part of a cylinder block of an internal combustion engine and configured to collect oil, wherein the cylinder block includes an oil drain hole that opens in a lower surface of the cylinder block;   a balancer device arranged inside the crankcase below a crankshaft;   a flat baffle plate arranged inside the crankcase between the crankshaft and the balancer device to cover the balancer device from above; and   an oil flow passage that extends through the baffle plate in a thickness-wise direction and is arranged at a location in the baffle plate overlapped with an oil falling path extending from the oil drain hole to a bottom surface of the crankcase.   
     
     
         4 . A method for manufacturing an internal combustion engine, the method comprising:
 providing a cylinder block including an oil drain hole that opens in a lower surface of the cylinder block;   preparing an oil pan fixed to a lower part of the cylinder block and configured to collect oil;   arranging a balancer device inside the oil pan downward from a crankshaft;   arranging a flat baffle plate inside the oil pan between the crankshaft and the balancer device to cover the balancer device from above; and   arranging an oil flow passage at a location in the baffle plate overlapped with an oil falling path extending from the oil drain hole to a bottom surface of the oil pan in the baffle plate, wherein the oil flow passage extends through the baffle plate in a thickness-wise direction.