Internal Combustion Engine Starting via Oscillating Crankshaft
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Solution Overview
Problem
Existing electric starting systems for internal combustion engines, such as starter motors and starter-generator units, add weight and complexity to vehicles, reducing fuel efficiency and handling, and require additional assembly steps, while starter-generator units need to be larger and heavier to provide sufficient torque for starting.
Innovation Solution
An electrical actuator, such as a motor-generator, is used to oscillate the crankshaft to gain momentum, purging combustion gases and replacing them with fresh air before fuel injection and ignition, allowing for a smaller and lighter system to start the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a starter motor or starter-generator unit is used to turn the crankshaft, then the engine can be started, but the system adds weight and complexity to the vehicle
Solution Approach 1:
The electrical actuator performs only partial action by oscillating the crankshaft through a limited angular range (e.g., 60-120 degrees) rather than completing a full rotation. This partial oscillation is sufficient to initiate engine starting by creating the necessary momentum and pressure differential, eliminating the need for a heavy-duty starter motor designed for full rotations
Solution Approach 2:
The invention changes the operational parameters of the starting system by using oscillatory motion instead of continuous rotation. The electrical actuator operates at high frequency oscillations (e.g., 10-100 Hz) over a limited angular displacement, which fundamentally alters the torque and speed requirements compared to traditional starting systems, enabling the use of lighter actuators
2Force
If a starter-generator unit is sized to provide sufficient torque for starting, then the engine can be started reliably, but the unit becomes larger and heavier
Solution Approach 1:
The electrical actuator provides excessive oscillatory torque over a short duration and limited angular range, which is more than sufficient to initiate engine starting. This excessive partial action allows the use of a smaller actuator that would be inadequate if it had to provide torque for a full crankshaft rotation
Solution Approach 2:
The starting mechanism uses periodic oscillatory motion of the crankshaft rather than continuous rotation. The electrical actuator applies torque in repeated cycles of oscillation, building momentum gradually until engine starting occurs. This periodic action reduces the peak torque requirements compared to traditional starting systems
3Ease of operation
If traditional electric starting systems are used, then the engine can be started conveniently, but additional assembly steps and space are required during manufacturing
Solution Approach 1:
The invention merges the starting system with the existing electrical system of the vehicle. The electrical actuator can be integrated with the vehicle's battery and wiring harness, eliminating the need for a dedicated starter motor mounting structure and reducing assembly complexity. The actuator connects directly to the crankshaft, simplifying the mechanical linkage required in traditional systems
Solution Approach 2:
The electrical actuator serves multiple functions: it can start the engine, and potentially serve other purposes such as auxiliary power or integration with hybrid systems. This multi-functionality reduces the need for dedicated single-purpose components, thereby reducing overall system complexity and part count
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
The method enables efficient engine starting with reduced weight and complexity, improving fuel efficiency and handling by using an electrical actuator that provides sufficient torque without needing to turn the crankshaft fully, thus minimizing the size and weight of the starting system.
Implementation Method 1
the electrical actuator moves the crankshaft back and forth, thereby making the crankshaft oscillate. As the crankshaft oscillates, it gains momentum.
Implementation Method 2
As the crankshaft oscillates, the reciprocations of the pistons cause combustion gases present in the combustion chamber to be purged from the combustion chambers via the exhaust ports of the engine and these gases are replaced with fresh air.
Implementation Method 3
fuel is injected and ignited in the combustions chambers
Data Source
AI summary
A vehicle has a frame, a front suspension assembly, a pair of skis, an endless drive track, and an internal combustion engine. The engine has: a motor-generator having a rotor and a stator, the motor-generator being operable in motor mode and in generator mode; a recoil starter operable to rotate a crankshaft of the engine via the rotor in a same direction as does the motor-generator in generator mode; at least one sensor adapted for sensing at least one engine parameter; and an engine control unit (ECU) receiving a signal from the at least one sensor, the ECU controlling a rotation of the crankshaft by one of the motor-generator and the recoil starter based on the signal.