Valve Timing Control via Region-Based Phase Acquisition

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Solution Overview

Problem

Existing valve open-close timing control devices for internal combustion engines require additional time to accurately determine the relative rotation phase due to inaccuracies in pulse signal counting by cam angle sensors, leading to delayed engine actuation and valve timing control.

Innovation Solution

A valve open-close timing control device with a phase adjusting mechanism using an electric motor, a sensor unit comprising a crank angle sensor and a cam angle sensor that detects signals at unequal angles, and a storage system to quickly acquire the relative rotation phase by specifying the correct divided region based on crank angle signals and reference crank angle signals.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the cam angle sensor detects pulse signals by counting projections on a signal plate, then the relative rotation phase can be calculated, but the counting accuracy deteriorates when the rotation detection device is positioned between regions, causing delayed phase acquisition

Engineering Contradiction:

Improverelative rotation phase measurement accuracyVSAvoidtime for phase acquisition

Core Design Contradiction:

Measurement precisionVSLoss of time

Solution Approach 1:

The cam shaft rotation is divided into multiple divided regions with different divided lengths, and the rotation detection device detects which specific divided region it is in. This segmentation approach replaces the traditional pulse counting method, enabling accurate phase determination without relying on counting projections, thus solving the problem of inaccurate counting when positioned between regions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The divided regions are preliminarily set with different divided lengths stored in advance in the storage unit. When the rotation detection device detects a divided region, the control unit immediately retrieves the corresponding divided length information to calculate the relative rotation phase, eliminating the need for additional rotation to accumulate sufficient pulse counts.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If the system waits for accurate counting of cam angle sensor pulses before determining relative rotation phase, then measurement accuracy is improved, but engine actuation is delayed

Engineering Contradiction:

Improverelative rotation phase detection accuracyVSAvoidengine actuation speed

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The divided regions and their corresponding divided lengths are preliminarily configured and stored before engine operation. The rotation detection device immediately identifies the current divided region upon startup, and the control unit instantly retrieves the stored divided length to calculate the relative rotation phase, enabling rapid engine actuation without waiting for pulse accumulation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The mechanical pulse counting method is replaced with an information-based system where divided region positions and lengths are stored as data in the storage unit. The control unit retrieves and processes this stored information to determine the relative rotation phase, replacing the need for continuous mechanical pulse counting and enabling immediate phase determination.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If the cam shaft rotates further to ensure accurate counting of projections, then measurement reliability is improved, but the time for valve timing control increases

Engineering Contradiction:

Improvephase calculation reliabilityVSAvoidvalve timing control delay

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The cam shaft rotation is segmented into distinct divided regions with unique divided lengths. The rotation detection device determines which divided region it is currently in, and the control unit uses the corresponding stored divided length to calculate the relative rotation phase. This segmentation ensures reliable phase calculation from the detected position without requiring additional rotation for accuracy.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The storage unit acts as an intermediary that stores the divided length information corresponding to each divided region. When the rotation detection device detects a divided region, the control unit retrieves the pre-stored divided length from the storage unit to calculate the relative rotation phase, eliminating the need for further rotation to ensure counting accuracy.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11242776B2Valve open-close timing control device

Publication Date: 2022.02.08 AISIN CORP

AI summary

A valve open-close timing control device includes a driving rotator, a driven rotator, a phase adjusting mechanism, a sensor unit, a storage configured to store the plurality of divided regions consecutively provided, as a plurality of divided length information pieces corresponding to divided lengths of the divided regions, and an actual phase acquisition unit configured to start acquisition of the crank angle signal and the cam angle signal along with start of actuation control of actuating the internal combustion engine, specify one of the divided regions by referring to the divided length information pieces stored in the storage in accordance with the crank angle signal at timing set in accordance with the cam angle signal, and acquire the relative rotation phase as an actual phase in accordance with the crank angle signal corresponding to the boundary of the divided region thus specified and the reference crank angle signal.