Parallel Crankshaft Engine with Counter-rotating Gears
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Solution Overview
Problem
Internal combustion engines with parallel crankshafts in hybrid drives face challenges in balancing mass forces for smooth operation, high friction losses, and susceptibility to wear, making them unsuitable for quiet, vibration-free, and compact designs suitable for hybrid drive applications.
Innovation Solution
The internal combustion engine design features parallel cylinder axes with an inward offset, low-friction roller bearings for crankshafts, thermal insulation, dry sump lubrication, and a compact unitary casting to reduce friction, wear, and noise, enabling spontaneous starting and efficient interval operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If parallel crankshafts are used in internal combustion engine, then the engine structure is simplified, but mass forces are not balanced causing vibration and noise
Solution Approach 1:
The patent applies counterbalancing weights on the crankshafts to offset the unbalanced mass forces generated by the parallel cylinder configuration. The counterweights are positioned and dimensioned to create balancing forces that cancel out the primary and secondary vibrations, thereby reducing noise and vibration while maintaining the simplified parallel engine structure.
Solution Approach 2:
The patent introduces asymmetric positioning of the parallel cylinders relative to the crankshaft axes, creating an inward offset configuration. This asymmetric arrangement allows for optimized counterweight placement and distribution, enabling better balance of mass forces while maintaining structural simplicity.
2Device complexity
If conventional crankshaft bearings are used, then the engine structure is simple, but friction losses are high and wear susceptibility increases
Solution Approach 1:
The patent replaces conventional sliding bearings with roller bearings at the crankshaft supports. This substitution introduces rolling friction instead of sliding friction, dramatically reducing friction losses and wear susceptibility. The increased structural complexity of roller bearings is justified by the significant reduction in energy losses and improved reliability.
3Device complexity
If cylinders are positioned far apart, then the engine structure is simple, but lateral forces on pistons increase causing higher friction and wear
Solution Approach 1:
The patent employs an asymmetric inward offset configuration where the cylinder axes are positioned closer together than the crankshaft axes. This creates a convergent geometry that reduces the lateral component of piston forces while maintaining structural simplicity. The asymmetric arrangement optimizes the force distribution on pistons, reducing friction and wear.
4Adaptability or versatility
If the engine operates after long interruptions, then the engine can be stored, but cold starts occur increasing noise and wear
Solution Approach 1:
The patent implements thermal insulation measures that maintain engine temperature during storage periods. By preserving heat and preventing cooling during interruptions, the engine remains at optimal operating temperature ready for immediate startup. This preliminary thermal maintenance eliminates cold start conditions, reducing associated noise and wear during intermittent operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design achieves a quiet, low-vibration, and low-friction operation, reducing wear and noise, while allowing for a compact and space-saving arrangement suitable for hybrid drives, enhancing the engine's efficiency and suitability for intermittent operation.
Implementation Method 1
both crankshafts are mounted in low-friction roller bearings
Implementation Method 2
low-friction roller bearings
Implementation Method 3
the housing of the internal combustion engine has thermal insulation
Implementation Method 4
reduces the maximum lateral forces on the pistons and thus lower piston friction
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The machine combination of an internal combustion engine and the generator (41) of a hybrid drive has two cylinder-piston units, which are arranged parallel to each other in a common housing and each piston (3, 4) of which has a drive connection to an individual crankshaft via connecting rods (5, 6) associated with the pistons. The crankshafts have a counter-rotational connection to each other by means of one gear (9, 10) each. This coupling of the two crankshafts (7, 8) by means of gears (9, 10) allows the internal combustion engine to be combined with a generator in a particularly compact design, in that the shaft (44) of the generator bears a gear (45), which is arranged in the same plane as the gears (9, 10) of the crankshafts.