Divided Crankcase Engine with Offset Starting Motor Mount
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Solution Overview
Problem
Existing vehicle engine designs with starting motors positioned above the crankcase result in increased engine width and complexity, particularly due to the need for a motor mounting hole in the upper crankcase member, which complicates manufacturing and increases engine size.
Innovation Solution
The engine is designed with a divided crankcase, featuring a first motor mounting portion with a motor mounting hole on one side and a second motor mounting portion on the other, allowing the starting motor to be positioned near the cylinder bore center, reducing engine width and enabling compact arrangement of the starting gear train with multiple idle shafts for efficient space utilization and accurate machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the motor mounting hole is formed in the upper crankcase member, then the starting motor can be mounted, but the engine width increases and manufacturing time increases
Solution Approach 1:
The crankcase is divided into two separate crankcase members (first and second crankcase members) with the motor mounting hole formed in one of them. This segmentation allows the motor mounting hole to be created during the assembly process rather than requiring a complex hole through the entire upper crankcase member, thereby reducing manufacturing time while maintaining compact engine width.
2Volume of moving object
If the starting motor is arranged above the top wall of the crankcase, then the starting gear train can be arranged, but the engine size increases
Solution Approach 1:
The starting motor is positioned above the top wall of the crankcase in the vertical dimension, while the starting gear train is arranged in the horizontal dimension within the crankcase. This dimensional separation allows both components to be accommodated without increasing the overall engine size, as they occupy different spatial dimensions.
3Volume of moving object
If the starting gear train is arranged compactly, then the engine size is reduced, but the manufacturing precision requirements increase
Solution Approach 1:
The motor mounting hole is formed in the first crankcase member during the assembly process, and the starting motor is positioned and fixed before final assembly. This preliminary positioning allows for precise alignment and adjustment of the starting gear train components, ensuring high manufacturing precision while maintaining a compact engine design.
Data Source
AI summary
An engine for a vehicle includes a crankcase and a starting system having a starting motor arranged above a top wall of the crankcase and a starting gear train. The crankcase is divided into left and right crankcase members. For example the left crankcase member has a first motor mounting portion protruded upward from a top wall thereof, and having a motor mounting hole. The right crankcase member has a second motor mounting portion on a top wall thereof. One end of the starting motor is fitted in the first motor mounting hole and other end of the starting motor is fastened on the second mounting portion by bolts. The starting gear train includes two or more starting idle shafts.