CVVD Valve Duration Control for Engine NVH Reduction

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Solution Overview

Problem

Internal combustion engines with continuous variable valve timing (CVVT) and continuous variable valve lift (CVVL) systems experience variations in combustion, leading to pressure and torque variations, which result in noise, vibration, and harshness (NVH) issues due to factors like fueling, charge preparation, and exhaust residuals, complicating engine operation and vibration transmission.

Innovation Solution

A vehicle control system that includes an electronic control unit (ECU) to adjust the continuously variable valve duration (CVVD) of intake and exhaust valves based on input data from various systems, such as driver demand and environmental conditions, using predetermined calibration values to set desired NVH profiles, thereby increasing or decreasing the overlap area of valve opening/closing durations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If CVVT and CVVL systems are implemented to enable variable valve timing and lift, then engine performance and fuel efficiency are improved, but device complexity increases and NVH issues worsen due to combustion variations

Engineering Contradiction:

Improveengine performanceVSAvoidvalve mechanism complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements continuous variable valve duration (CVVD) control that dynamically adjusts valve opening and closing timing based on engine operating conditions. The system uses an ECU to receive sensor inputs and send control signals to the valve mechanism, enabling real-time adaptation of valve duration to optimize performance while managing complexity through electronic control rather than mechanical complexity

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the valve duration parameter continuously based on engine speed, load, and other operating conditions. By adjusting the duration parameter dynamically, the system optimizes combustion efficiency and fuel economy while the ECU manages the complexity of coordinating these parameter changes across different operating states

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If CVVT and CVVL systems are used to optimize valve operation, then fuel economy is improved, but NVH performance deteriorates due to pressure and torque variations

Engineering Contradiction:

Improvefuel economyVSAvoidNVH (noise, vibration, harshness)

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The system incorporates feedback control where the ECU receives input from sensors monitoring engine operating conditions and combustion characteristics. Based on this feedback, the ECU adjusts the CVVD settings to optimize fuel economy while simultaneously managing NVH by correcting combustion variations detected through the feedback loop

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The valve duration is dynamically adjusted based on real-time engine conditions rather than fixed timing. This dynamic control allows the system to optimize fuel economy across varying operating states while reducing NVH by adapting valve timing to compensate for combustion variations that occur under different loads and speeds

Inventive Principle:

Principle #15Dynamics

3Power

If valve timing is optimized for performance, then power output is improved, but idle stability deteriorates due to combustion variations

Engineering Contradiction:

Improvepower outputVSAvoididle stability

Core Design Contradiction:

PowerVSStability of the object's composition

Solution Approach 1:

The system changes valve duration parameters based on engine operating conditions, including idle state. At idle, the ECU adjusts CVVD to optimize stability by compensating for combustion variations, while under load it optimizes for power output. This parameter adaptation resolves the contradiction between power and idle stability

Inventive Principle:

Principle #35Parameter changes

4Device complexity

If fixed valve timing is used, then device complexity is reduced, but adaptability to different operating conditions deteriorates

Engineering Contradiction:

Improvevalve control simplicityVSAvoidoperating condition adaptability

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent replaces complex mechanical valve timing adjustment mechanisms with an electronic control system. The ECU receives sensor inputs and sends electronic signals to control the valve duration, substituting mechanical complexity with electronic adaptability. This allows the system to maintain simple hardware while achieving high adaptability to different operating conditions through software-based control logic

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentUS11261818B2System and method for controlling NVH in an engine containing CVVD technology

Publication Date: 2022.03.01 HYUNDAI MOTOR CO LTD

AI summary

A vehicle control system for a powertrain including an internal combustion engine having an intake valve and an exhaust valve in a vehicle includes an electronic control unit (ECU) operable to control a continuously variable valve duration (CVVD) of the intake and exhaust valves in the engine, a communicator operable to receive an input data from at least one input system, and a storage device having predetermined calibration value. The ECU of the vehicle control system is configured to reference the predetermined calibration values based on a received input data, determines to adjust the CVVD of the intake and exhaust valves, and send a signal to the engine for changing an overlap area of the CVVD. The vehicle control system operates a process for controlling the CVVD of the engine as a method.