Sensorless Camshaft Phaser Motor Back-Drive Commutation

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Solution Overview

Problem

Conventional camshaft phaser systems with electric motors are complex and costly due to the need for additional circuitry and internal hall-effect sensors for commutation, which increases the size and weight of components.

Innovation Solution

A sensorless brushless DC electric motor system that uses a controller to determine the rotational position and speed of the motor through back-drive signals from the crankshaft, allowing for commutation and actuation of the phaser without internal sensors, reducing complexity and size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If brushless DC electric motors with internal hall-effect sensors and commutation circuitry are used, then control precision and response time are improved, but device complexity and manufacturing cost increase

Engineering Contradiction:

Improvecontrol precisionVSAvoiddevice complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the internal hall-effect sensors and complex commutation circuitry from the brushless DC motor, retaining only the essential brushless motor structure. The controller externally determines rotor position by monitoring back-EMF signals, removing the need for internal sensing components while maintaining control capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The motor system uses its own back-EMF signals, generated during normal operation, to provide the position information needed for commutation. This self-service approach eliminates the need for separate sensing systems, as the motor's operational signals are repurposed for control feedback.

Inventive Principle:

Principle #25Self-service

2Extent of automation

If internal hall-effect sensors and commutation circuitry are added to brushless DC motors, then commutation control is improved, but manufacturing cost and assembly complexity increase

Engineering Contradiction:

Improvecommutation controlVSAvoidmanufacturing cost

Core Design Contradiction:

Extent of automationVSEase of manufacture

Solution Approach 1:

The controller performs multiple functions: it drives the motor, monitors back-EMF signals, determines rotor position, and executes commutation logic. This multi-functionality consolidates what would otherwise require separate dedicated components, simplifying the overall system and reducing manufacturing complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces the mechanical/electrical sensing system (hall-effect sensors and dedicated commutation circuitry) with an electronic signal processing approach. The controller uses software-based commutation logic to interpret back-EMF signals, substituting physical sensing components with electronic control intelligence.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If brushless DC motors with additional circuitry are used, then motor control capability is improved, but component size and weight increase

Engineering Contradiction:

Improvemotor control capabilityVSAvoidcomponent size

Core Design Contradiction:

Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent merges the motor control functions with the existing motor structure by using the motor's own electrical characteristics (back-EMF) for sensing. The controller integrates position detection and commutation control into a unified process, eliminating the need for separate sensor assemblies and reducing overall component volume.

Inventive Principle:

Principle #5Merging (Combining)

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 solution significantly reduces the complexity, cost, and packaging size of the electric motor and its components, enhancing operational performance and efficiency while maintaining superior control over camshaft phase adjustment.

Implementation Method 1

rotation of the crankshaft back-drives the electric motor and the electric motor subsequently generates a signal

Methodology Applied

Scientific EffectBack-drive: Electromagnetic Induction

Data Source

PatentUS10119431B2Camshaft phaser systems and method of commutating an electric motor for the same

Publication Date: 2018.11.06 BORGWARNER INC

AI summary

A system (42) including a phaser (28), a motor (38), and a controller (40) for controlling the phase between a camshaft (18) and a crankshaft (16) of an engine (10). The phaser (28) is attached to the camshaft (18), is in communication with the crankshaft (16), and is configured to adjust the phase of the camshaft (18). The motor (38) actuates the phaser (28) and is operatively attached to and in communication with the phaser (28) such that rotation of the crankshaft (16) back-drives the motor (38) to subsequently generate a signal. The controller (40) is in electrical communication with the motor (38), is responsive to the signal, and uses the signal to determine the rotational speed of the motor (38) to thereby commutate the motor (38) and subsequently drive the motor (38) so as to actuate the phaser (28) and control the phase of the camshaft (18).