Straddled Vehicle Motor Crankshaft Stabilization

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Solution Overview

Problem

Existing straddled vehicle acceleration systems, such as those in motorcycles, face performance deterioration due to low crankshaft inertia and inefficient gas supply management, leading to delayed acceleration and reduced power output.

Innovation Solution

A straddled vehicle equipped with a single-cylinder engine, a permanent magnet type motor connected to the crankshaft, and a control device that assists piston operation by applying force promptly when the mixed gas supply increases, using a logical OR condition to trigger assistance based on throttle valve operation and rate of increase, ensuring high kinetic energy for gas compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the crankshaft inertia is reduced to improve acceleration response, then the acceleration response improves, but the crankshaft rotation speed becomes unstable and power output decreases

Engineering Contradiction:
Improveacceleration responseVSAvoidcrankshaft rotation speed stability
Core Design Contradiction:
SpeedVSStability of the object's composition

Solution Approach 1:

The control device performs preliminary action by detecting the rate of change in throttle valve opening degree and proactively determining to operate the permanent magnet type motor before the piston compression becomes problematic. This advance intervention allows the motor to apply force to the crankshaft in anticipation of the gas supply increase, preventing rotation speed instability before it occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The permanent magnet type motor serves as an intermediary between the battery and the crankshaft system. It mediates the energy transfer by converting electrical energy to mechanical torque, which is then applied to the crankshaft to stabilize rotation speed. This intermediary component allows precise control of the force applied to maintain stability without directly modifying the crankshaft inertia.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Stability of the object's composition

If the permanent magnet type motor operates continuously to stabilize crankshaft rotation, then rotation stability improves, but energy consumption increases

Engineering Contradiction:
Improvecrankshaft rotation speed stabilityVSAvoidbattery energy consumption
Core Design Contradiction:
Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the permanent magnet type motor operation based on real-time throttle valve opening rate. The motor operates only when the rate of change exceeds a threshold value, making the stabilization action dynamic and conditional rather than continuous. This dynamic approach maintains rotation stability only when gas supply changes threaten stability, minimizing unnecessary energy consumption.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control device monitors the rate of change parameter of the throttle valve opening degree and uses this parameter to trigger motor operation. By changing the operational state based on this parameter threshold, the system optimizes the balance between maintaining rotation stability and conserving battery energy, operating the motor only when parameter changes indicate potential instability.

Inventive Principle:
Principle #35Parameter changes

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 configuration enhances acceleration performance by promptly utilizing engine combustion power, stabilizing crankshaft rotation speed, and improving power output even with reduced crankshaft inertia, resulting in better acceleration and performance.

Implementation Method 1

a permanent magnet type motor including a rotor and a permanent magnet, the rotor connected directly or indirectly to the crankshaft so as to be rotatable in response to rotation of the crankshaft

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

the piston moved to and fro by combustion of a mixed gas containing air and a fuel

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP3301280B1Straddled vehicle
Publication Date: 2020.03.04 YAMAHA MOTOR CO LTD
  • EP3301280B1 patent drawingFigure 1
  • EP3301280B1 patent drawingFigure 2
  • EP3301280B1 patent drawingFigure 3

AI summary

An engine unit includes a single-cylinder engine, a drive wheel, an acceleration command part, a throttle valve, a permanent magnet type motor, a battery, an inverter having switching parts, and a control device. The control device controls the plurality of switching parts so as to assist a piston operation by directing the permanent magnet type motor to apply a force to a piston via a crankshaft such that the force cooperates with a force generated by combustion in the single-cylinder engine to move the piston to and fro, the control triggered by the acceleration command part being displaced such that the degree of opening of the throttle valve is increased so as to satisfy at least one of a condition regarding the amount of operation on the acceleration command part and a condition regarding the rate of increase in the amount of operation on the acceleration command part.