Dual Mode Engine Brake Torque Control via EPG and ITV
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Solution Overview
Problem
Existing engine brake systems, particularly those with turbo compound engines, face limitations in controlling engine brake torque due to the on/off regulation of the compression brake, resulting in inability to achieve continuous or small discrete steps of torque regulation, leading to inadequate control during certain engine conditions.
Innovation Solution
Implementing a dual engine brake mode system where the exhaust pressure governor (EPG) and intake air throttle valve (ITV) are controlled using closed-loop and feed-forward control methods based on engine speed and demanded brake torque, allowing for smooth transitions and precise regulation of braking torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the compression brake is controlled with an on/off valve, then the system structure is simple, but the engine brake torque cannot be regulated continuously or in small discrete steps
Solution Approach 1:
The patent transforms the static on/off control of the compression brake into a dynamic control system by introducing an intake air throttle valve (ITV) that can be positioned at multiple angles. This allows the compression brake torque to be modulated continuously according to engine operating conditions, resolving the contradiction between simple structure and flexible torque regulation.
Solution Approach 2:
The patent changes the control parameter from binary (on/off) to continuous by using the ITV opening angle as the control variable. The controller adjusts the ITV position based on engine speed and demanded brake torque, enabling precise regulation of engine brake torque across a wide range while maintaining relatively simple hardware architecture.
2Measurement precision
If the EPG and ITV are both controlled with closed-loop control, then the control precision is high, but the control system complexity increases
Solution Approach 1:
The patent segments the control system into two distinct modes: a first mode where EPG is controlled with closed-loop control using exhaust pressure feedback, and a second mode where ITV is controlled with closed-loop control using exhaust pressure feedback. This segmentation allows the system to achieve high control precision through selective closed-loop control of the appropriate component based on operating conditions, while avoiding the complexity of continuously controlling both components in all situations.
Solution Approach 2:
The patent implements dynamic switching between two different control configurations based on real-time engine operating conditions. The controller selects which component (EPG or ITV) receives closed-loop control signals, adapting the control architecture to match the current operational requirements, thereby achieving high precision without permanent system complexity.
Data Source
AI summary
A method and system to control an engine brake of a vehicle is provided. The vehicle is provided with a combustion engine having cylinders, an exhaust pressure governor (EPG) regulating the air flow out of the cylinders, an intake air throttle valve (ITV) regulating the air flow into the cylinders, pressure sensing means for sensing a pressure downstream of the cylinders, wherein an engine braking torque can be regulated in two different engine braking modes (a, b), ⋅a first engine braking mode (a), in which the air flow through the EPG is regulated by a closed loop control using the pressure downstream of the cylinders and the ITV is regulated in a feed forward control dependent of the engine speed and a demanded brake torque; ⋅a second engine braking mode (b), in which the EPG is regulated in a feed forward control dependent of the engine speed and the demanded brake torque, and the ITV regulates the braking torque by a closed loop control using the pressure downstream of the cylinders.