Parallel Valve Pneumatic Control for Hydrodynamic Retarder
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pneumatic control devices for hydrodynamic retarders have a high probability of failure and are inefficient in quickly switching off the braking torque, particularly due to the reliability issues with directly controllable solenoid valves and the need for additional switching valves.
Innovation Solution
The implementation of two parallel outlet valves and two parallel inlet valves, designed as directly or indirectly controllable 2/2-way solenoid or pressure-controlled switching valves, with a common pilot valve for indirect actuation, provides a larger opening cross-section for venting and reduces the probability of failure by ensuring the system remains functional even if one valve fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If directly controllable solenoid switching valves are used for inlet and outlet valves, then the control response is fast, but the probability of failure increases due to electrical defects and control piston jamming
Solution Approach 1:
The patent introduces a pilot valve as an intermediary component that controls the main inlet and outlet valves. The pilot valve receives electrical control signals while the main valves are controlled pneumatically through control lines. This intermediary mechanism allows fast electrical signaling while using more reliable pneumatic actuation for the main valve operation, reducing direct exposure to electrical defects and control piston jamming in the solenoid valves.
Solution Approach 2:
The patent replaces direct electrical solenoid control of main valves with a hybrid system where electrical signals control a pilot valve that then uses pneumatic pressure to actuate the main inlet and outlet valves. This substitution reduces reliance on directly controllable solenoid valves with large control pistons that are prone to jamming, while maintaining fast response through the pilot valve mechanism.
2Reliability
If additional switching valves are added to improve reliability, then the probability of failure decreases, but the device complexity increases
Solution Approach 1:
The patent combines the control functions of multiple valves into a unified pilot valve system. The pilot valve integrates the control logic for both inlet and outlet valves, using a single electrical control signal to coordinate the operation of both main valves through shared control lines. This merging approach improves reliability through redundancy while avoiding the complexity of completely separate control systems for each valve.
Solution Approach 2:
The pilot valve serves multiple functions: it controls both the inlet valve and outlet valve, provides fail-safe operation by defaulting to a safe state when de-energized, and enables coordinated control of both valves through a single control signal. This multi-functionality reduces the need for separate dedicated control mechanisms for each valve, thereby improving reliability without proportionally increasing complexity.
3Speed
If the opening cross section of valves is increased to enable faster venting, then the switching off speed improves, but the valve size and control current requirements increase
Solution Approach 1:
The patent segments the valve control into two levels: a small pilot valve with minimal opening cross-section that requires low control current, and larger main valves with greater opening cross-sections for fast venting. The pilot valve controls the main valves through pneumatic pressure amplification, allowing the system to achieve fast venting capability without requiring the control valve itself to have a large opening cross-section, thus reducing control current consumption.
Solution Approach 2:
The patent uses pneumatic pressure amplification where a small control current operating the pilot valve generates pneumatic pressure that actuates the larger main valves. This pneumatic mechanism allows the system to achieve large opening cross-sections for fast venting while the control current only needs to operate the small pilot valve, significantly reducing the control current requirements compared to directly controlling large valves electrically.
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
This design allows for faster switching off and on of the retarder, reduces the risk of residual braking torque, and decreases the control current and power consumption, while maintaining a compact and cost-effective structure.
Implementation Method 1
The inlet valve (4) is designed as a 2/2-way solenoid switching valve and is closed in the de-energized state and opened in the energized state.
Implementation Method 2
In the stator impeller, the working fluid is deflected and transported inwards. Here, kinetic energy is converted into thermal energy, which means that the vehicle is braked as a result.
Implementation Method 3
If the air pressure introduced into the reservoir via the working pressure connection is increased, more working fluid is pressed into the housing of the retarder and the braking torque generated in the retarder is thereby increased.
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a pneumatic control device (32.1) for a hydrodynamic retarder, comprising a working pressure connection (10) that is connected to a reservoir of the retarder, at least one inlet valve (20) through which a working pressure line (8) leading to the working pressure connection (10) can be connected to a vent line (12) connected to a compressed air source (16), and at least one outlet valve through which the working pressure line (8) can be connected to a vent line (14) connected to a vent outlet (18). To enable particularly rapid shutdown of the retarder and to reduce the probability of failure of the control device (32.1), the control device is provided with two outlet valves (34, 36) connected in parallel to each other, through which the working pressure line (8) can be connected to the vent line (14).