Feed Pump Control for Waste Heat Recovery Systems
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Solution Overview
Problem
Waste heat utilization systems in motor vehicles with internal combustion engines face issues such as inefficient energy use and potential pump damage due to mechanical coupling and the use of water-based working media that can freeze, leading to increased fuel consumption and risk of pump failure.
Innovation Solution
A waste heat recovery system with a feed pump equipped with a temperature sensor connected to a control unit that deactivates the pump drive when the working medium temperature falls below a freezing threshold, and uses a clutch or solenoid valve to manage pump operation, ensuring the pump does not start up in frozen conditions and can be heated by the engine's cooling circuit to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the feed pump is mechanically coupled to the internal combustion engine, then the pump speed is coupled to the engine speed, but this causes unnecessary energy consumption and increased fuel consumption when the full mass flow is not required
Solution Approach 1:
The patent applies a controllable coupling mechanism (clutch or electromechanical coupling) that allows the feed pump to dynamically switch between mechanical coupling to the engine and decoupled operation. This enables the pump to adapt its operation to actual system needs, running only when necessary rather than continuously being driven by the engine, thus reducing unnecessary energy consumption and fuel usage while maintaining required productivity.
Solution Approach 2:
The invention changes the operational parameters of the feed pump by introducing temperature-based control thresholds. The pump operation is activated or deactivated based on temperature conditions (e.g., when coolant temperature exceeds a threshold during engine warm-up), allowing the system to optimize between maintaining mass flow availability and reducing energy consumption under varying thermal conditions.
2Temperature
If water-based working media are used in the waste heat utilization system, then heat transfer efficiency is improved, but the media freezes at low temperatures causing pump damage
Solution Approach 1:
The system performs preliminary detection of temperature conditions before pump operation begins. Temperature sensors continuously monitor the working medium temperature, and the control unit activates the pump only when the temperature exceeds a predetermined threshold, ensuring the medium is thawed before pumping starts. This preliminary temperature verification prevents frozen medium from entering the pump and causing damage.
Solution Approach 2:
The invention implements a feedback control system where temperature sensors provide continuous information about the working medium temperature to the control unit. Based on this feedback, the control unit automatically activates or deactivates the pump drive, ensuring the pump operates only under safe temperature conditions and preventing damage from frozen medium while maintaining efficient heat transfer when temperatures are appropriate.
3Ease of operation
If the pump operates continuously during engine warm-up, then mass flow is always available, but energy is wasted pumping unnecessary media mass flow
Solution Approach 1:
The patent implements periodic or conditional pump operation based on temperature thresholds rather than continuous operation. The pump is activated only when the coolant temperature exceeds a predetermined threshold during engine warm-up, and deactivated when the threshold is not met. This periodic activation pattern maintains system readiness when needed while avoiding continuous operation and the associated energy waste from pumping unnecessary mass flow.
4Reliability
If a temperature sensor and control unit are added to control pump operation, then pump damage protection and energy optimization are achieved, but device complexity increases
Solution Approach 1:
The control system is designed to be relatively simple and self-regulating, using straightforward temperature threshold comparisons to control pump operation. The control unit automatically activates or deactivates the pump based on sensor input without requiring complex control algorithms or user intervention. This self-service approach provides reliable pump protection and energy optimization while minimizing the added complexity of the control system.
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 solution prevents pump damage from frozen media, optimizes energy use by controlling pump operation based on temperature and engine conditions, and ensures safe and efficient operation by interrupting speed coupling during braking or overrun, thereby reducing fuel consumption and extending system lifespan.
Implementation Method 1
at least one temperature sensor for directly or indirectly detecting the current working medium temperature is arranged in the waste heat utilization system
Implementation Method 2
water-based media, in particular water with or without organic additives, can be used as working media. These media have the negative property that they freeze to form a hard body at low temperatures
Implementation Method 3
the feed pump has to work against the frozen working medium... the coolant can be routed through channels in the housing of the feed pump, so that the frozen working medium quickly thaws and liquefies
Data Source
Figure 1~2
Figure 3
AI summary
The system has a feed pump (1), and temperature sensors (Ta, Tg) for direct or indirect detection of a current working medium temperature. The sensors are attached to a control unit (S) for controlling a pump drive. A temperature threshold value is preset in the control unit, and compared with the temperature. The drive and a pump conveying unit are deactivated by the control unit during falling below the value. The drive and the conveying unit are switched on during exceeding the value or another temperature threshold value, which is defined high relative to the former threshold value. The pump drive is a mechanical pump drive. The working medium is water. An independent claim is also included for a method for operating a waste heat utilization system.