Battery-less Ignition Control Using Generator Speed Calculation

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Solution Overview

Problem

In battery-less internal combustion engines, the lack of a battery-supplied power source makes it difficult to control ignition timing accurately, leading to potential reverse rotation and kickback issues during startup.

Innovation Solution

An ignition control apparatus that calculates the rotational speed of the engine using a polarity signal and rotation signal, allowing for timely ignition timing determination and prevention of reverse rotation by supplying power to the ignition coil based on calculated rotational speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a battery-less engine uses manual startup (recoil-start or kick-start), then the engine can be started without a battery, but the microcomputer cannot be started up early enough to control ignition timing accurately

Engineering Contradiction:

Improvebattery-less operation capabilityVSAvoidignition timing control reliability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system performs preliminary action by calculating rotational speed using generator output signals before the microcomputer is fully started up. The rotational speed calculation unit computes engine speed based on the alternating current generator's output voltage polarity and rotation signals, enabling the ignition timing determination unit to prepare ignition timing data in advance. This preliminary calculation allows the system to supply power to the ignition coil at the correct timing even during the microcomputer's startup period, preventing kickback while maintaining battery-less operation capability.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by stationary object

If the microcomputer is started up after engine cranking begins, then power consumption is reduced, but ignition timing cannot be controlled at the earliest stage of engine rotation

Engineering Contradiction:

Improvepower consumptionVSAvoidignition timing control delay

Core Design Contradiction:

Use of energy by stationary objectVSLoss of time

Solution Approach 1:

The system introduces an intermediary mechanism by using the alternating current generator's output signals as a intermediate source for rotational speed calculation. Instead of waiting for the microcomputer to process and start up, the system directly uses the generator's alternating current output voltage polarity and rotation signals to calculate rotational speed through a dedicated calculation unit. This intermediary approach bypasses the microcomputer startup delay, enabling early ignition timing control while keeping the microcomputer in low-power mode until needed.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If ignition timing is not controlled accurately during startup, then the system remains simple, but the engine may reversely rotate or kickback

Engineering Contradiction:

Improvecontrol system complexityVSAvoidreverse rotation and kickback

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The system replaces complex mechanical kickback prevention mechanisms with an electrical control approach. Instead of using mechanical devices to prevent reverse rotation, the system uses electrical signals from the alternating current generator to calculate rotational speed and determine ignition timing electronically. The ignition timing determination unit processes the generator's output voltage polarity and rotation signals to compute the correct ignition timing, then supplies power to the ignition coil at the precise moment. This electronic substitution eliminates the need for complex mechanical prevention systems while effectively preventing reverse rotation and kickback.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

Enables accurate ignition timing control even without battery power, preventing reverse rotation and improving startability by determining rotational speed early in the engine startup process.

Implementation Method 1

an alternating current generator that generates an alternating current output voltage when a rotor of the alternating current generator is driven to rotate

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a regulator that receives the alternating current output voltage generated by the alternating current generator and converts the alternating current output voltage into a direct current output voltage

Methodology Applied

Scientific EffectRectification:

Implementation Method 3

a pulser provided at a predetermined rotational position where the rotation of the rotor can be identified

Methodology Applied

Scientific EffectMagnetic field detection: Magnetic Field

Data Source

PatentUS11401908B2Ignition control apparatus for internal combustion engine and control system for internal combustion engine

Publication Date: 2022.08.02 MAHLE INT GMBH

AI summary

An ignition control apparatus, e.g., for an internal combustion engine, includes a rotational speed calculation unit that calculates a rotational speed of an alternating current generator. A rotor of the alternating current generator is driven to rotate in synchronization with reciprocating motion of a piston of the internal combustion engine. An ignition timing determination unit determines an ignition timing of the internal combustion engine based on the rotational speed calculated by the rotational speed calculation unit. An ignition control unit supplies electric power to an ignition coil such that the internal combustion engine is ignited at the timing determined by the ignition timing determination unit.