Self-Contained Compression Brake Control Module for Engine Noise Reduction
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Solution Overview
Problem
Existing compression-release engine brake systems for internal combustion engines are costly, time-consuming to develop, and generate excessive noise, limiting their use in urban areas due to high mechanical loading and noise emissions, while also being custom-designed for specific engine models, which increases development time and cost.
Innovation Solution
A self-contained compression brake control module integrated with an exhaust rocker assembly that includes a hollow casing and actuation piston, with a reset check valve and compression brake actuator, allowing for hydraulic control of exhaust valve lift and phase angle, reducing size and improving assembly efficiency, and enabling both 'dedicated cam' and 'lost motion' engine braking modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional compression-release engine brake systems are used, then significant braking power is achieved, but high mechanical loading and noise emissions occur
Solution Approach 1:
The patent replaces the conventional mechanical valve train system with a hydraulic actuation system. The hydraulic actuator uses fluid pressure to control valve timing and lift, eliminating the need for high-stress mechanical components and reducing noise from mechanical impacts while maintaining braking power.
Solution Approach 2:
The invention introduces a hydraulic control system with actuators that use pressurized fluid to control exhaust valve timing and lift during engine braking. This hydraulic approach provides smoother operation and reduced noise compared to traditional mechanical systems while achieving the required braking force.
2Power
If conventional compression-release engine brake systems are used, then significant braking power is achieved, but substantial development time and cost are required
Solution Approach 1:
The hydraulic actuator design is engineered to be universal across different engine types and configurations. By using standardized hydraulic components and control logic that can adapt to various valve train arrangements, the system reduces development time for new engine applications while maintaining effective braking power.
Solution Approach 2:
The system employs dynamic control of valve timing and lift through hydraulic actuators that can be programmed with different cam profiles and timing strategies. This dynamic adaptability allows a single base design to serve multiple engine applications, reducing overall development time and cost.
3Ease of manufacture
If exhaust brake systems with restrictor elements are used, then lower cost is achieved, but braking power is reduced
Solution Approach 1:
The patent replaces simple exhaust restrictors with an active hydraulic valve control system that precisely manages exhaust gas flow. This allows the system to achieve effective braking power by controlling valve timing and lift, rather than relying on restrictive flow paths that increase backpressure and reduce performance.
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
The solution reduces development time and cost, enhances performance, and minimizes noise by allowing for more compact and robust brake systems that can be easily assembled, improving engine braking efficiency and reducing noise emissions.
Implementation Method 1
The reset check valve is configured to hydraulically lock the actuation piston cavity when the pressure of the hydraulic fluid within the actuation piston cavity exceeds the pressure of the hydraulic fluid in a supply port
Implementation Method 2
The reset check valve is biased closed by a biasing spring
Implementation Method 3
pressurized hydraulic fluid supplied from a source to the compression brake control module
Data Source
AI summary
An exhaust rocker assembly for operating an exhaust valve of an engine during a compression-release engine braking operation. The exhaust rocker assembly comprises an exhaust rocker arm and a self-contained compression brake control module (CBCM) mounted to the exhaust rocker arm and operatively coupled to the exhaust valve for controlling a lift and a phase angle thereof. The CBCM includes a casing, an actuation piston disposed outside the casing so as to define an actuation piston cavity, a reset check valve provided between the casing and the actuation piston, and a compression brake actuator disposed in the casing. The actuation piston reciprocates relative to the casing. The compression brake actuator includes a control piston. The control piston engages the check valve when deactivated so as to unlock the actuation piston cavity and disengages from the check valve when activated so as to lock the actuation piston cavity.