Variable Valve Timing Control for Engine Pumping Loss Reduction

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Solution Overview

Problem

Existing engine technologies with continuously variable valve timing devices face challenges in minimizing fuel consumption at low load conditions and maximizing engine output at high load conditions, failing to effectively adapt to various driving demands.

Innovation Solution

A control method for an engine with a variable valve timing device that selects between two modes, retarding the intake cam to a predetermined angle range in one mode and advancing it in another, allowing for increased overlap of intake and exhaust valve opening, reducing pumping loss and enhancing torque and output.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the intake cam is retarded to reduce pumping loss in low load conditions, then fuel consumption is reduced, but engine output is decreased

Engineering Contradiction:

Improvepumping lossVSAvoidengine output

Core Design Contradiction:

Loss of energyVSPower

Solution Approach 1:

The patent applies dynamics by making the valve timing adjustable rather than fixed. The intake cam timing is dynamically changed between retarded and advanced positions based on driving conditions (low load vs. high load), allowing the system to adapt to different operational requirements and resolve the contradiction between reducing pumping loss and maintaining engine output.

Inventive Principle:

Principle #15Dynamics

2Power

If the intake cam is advanced to increase intake air amount in high load conditions, then engine output is increased, but fuel consumption is increased

Engineering Contradiction:

Improveengine outputVSAvoidfuel consumption

Core Design Contradiction:

PowerVSUse of energy by moving object

Solution Approach 1:

The system dynamically adjusts the intake cam timing based on load conditions. In high load conditions, the cam is advanced to increase intake air amount and engine output. In low load conditions, the cam is retarded to reduce fuel consumption. This dynamic adaptation allows the system to optimize the trade-off between power output and fuel consumption.

Inventive Principle:

Principle #15Dynamics

3Device complexity

If a fixed valve timing is used, then device complexity is reduced, but adaptability to various driving demands is reduced

Engineering Contradiction:

Improvevalve timing controlVSAvoidadaptability to driving demands

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent implements a variable valve timing device that can dynamically adjust the intake cam timing between retarded and advanced positions. This dynamic capability enables the system to adapt to various driving demands (low load vs. high load conditions) while maintaining reasonable device complexity through a controlled two-position system.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS9194305B2Engine having continuous variable timing device

Publication Date: 2015.11.24 HYUNDAI MOTOR CO LTD

AI summary

A control method of an engine having a variable valve timing may include selecting one of a first mode and a second mode as a driving mode, retarding an intake cam to a first predetermined angle range in the first mode, and advancing an intake cam to a second predetermined angle range in the second mode.