Autonomous Machine Engine Braking Control via Exhaust Valve Actuation
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Solution Overview
Problem
Autonomous heavy machines face challenges with braking due to overheating and mechanical stresses from engine braking, leading to reduced service life and ineffective operations, as existing braking systems are not optimized for autonomous operation and dynamic work site conditions.
Innovation Solution
A braking system that includes sensors to detect engine and transmission operational characteristics, load, and work surface profiles, with a controller managing an actuator for exhaust port control and a valve for gear-ratio adjustment during engine braking, ensuring precise control and reducing thermal and mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine braking is employed to support the existing braking mechanism, then braking effectiveness is improved, but thermal stresses and mechanical stresses increase leading to component damage
Solution Approach 1:
The system dynamically adjusts the degree of exhaust valve opening to control the magnitude of engine braking, thereby regulating the thermal and mechanical stresses applied to brake components. By changing the parameter of valve opening degree, the system optimizes braking effectiveness while preventing excessive stress on components.
Solution Approach 2:
The control unit continuously monitors brake temperature and adjusts the exhaust valve opening degree in response to temperature feedback. When brake temperature exceeds a threshold, the system reduces exhaust valve opening to decrease engine braking intensity, thereby preventing excessive thermal stress and component damage.
2Reliability
If precise control of exhaust valve is implemented for engine braking, then braking performance is improved, but device complexity increases
Solution Approach 1:
The control unit utilizes the existing exhaust valve mechanism designed for engine operation and repurposes it for engine braking control. By making the exhaust valve serve dual functions (engine operation and braking control), the system achieves precise braking performance without adding dedicated complex braking components.
Solution Approach 2:
The system uses the engine's own exhaust valve and cylinder pressure dynamics to provide braking force, rather than relying on separate braking components. The engine braking mechanism serves itself by utilizing internal engine parameters (exhaust valve timing, cylinder pressure) already present in the powertrain system.
3Ease of operation
If transmission system is designed for human driving habits, then ease of operation is improved, but adaptability to autonomous engine braking is reduced
Solution Approach 1:
The transmission system incorporates dynamic gear ratio adjustment capability that adapts to autonomous operation conditions. The control unit can modify gear selection and ratios in real-time to optimize engine braking effectiveness, transitioning from static human-oriented gear patterns to dynamic autonomous-controlled patterns.
Solution Approach 2:
The system dynamically changes transmission parameters (gear ratio, gear selection) based on autonomous operation requirements and brake temperature conditions. By adjusting transmission parameters in response to operational context, the system maintains ease of operation while adapting to engine braking demands.
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 system enhances braking efficiency, reduces wear on existing brakes, and extends the service life of machine components by optimizing engine braking, providing a smooth and comfortable operation while minimizing thermal and mechanical stresses.
Implementation Method 1
The phenomenon of the engine braking leads to thermal stresses and mechanical stresses due to application of Joules-Thomson effect at an exhaust port of the engine.
Data Source
AI summary
A braking system for controlling braking of a machine is disclosed. The braking system includes a first set of sensors to detect a first set of information indicative of operational characteristics of an engine and a transmission system. The braking system includes a second set of sensors to detect a second set of information indicative of a load of the machine and a profile of a work surface. The braking system includes a receiving unit to receive a third set of information indicative of a predefined route of the machine. The braking system includes a controller configured to control an actuator for opening and closing of an exhaust port for engine braking, and to control a valve for achieving a predetermined gear-ratio during the engine braking, based on the first set of information, the second set of information, and the third set of information.