Fuel Delivery Pump Shutdown Control for Rapid Pressure Build-up
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Solution Overview
Problem
In existing fuel delivery systems for internal combustion engines, the pump elements of the high-pressure pump are not completely filled with fuel during shutdown, leading to delayed pressure build-up when the engine is restarted, especially when using automatic start-stop systems.
Innovation Solution
Operating the feed pump during the shutdown phase to deliver fuel to the suction side of the high-pressure pump, ensuring the pump elements are filled before engine stoppage, and using a spring-loaded inlet valve to allow fuel delivery at higher pressures than the valve's opening pressure, along with a regulated feed pump to control fuel quantity, and employing a proportional or clocked valve for volume regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If the feed pump is not operated during shutdown phase, then the system is simpler and consumes less energy, but the pump elements are not filled with fuel leading to delayed pressure build-up upon engine restart
Solution Approach 1:
The feed pump is operated during the shutdown phase to deliver fuel to the high-pressure pump's suction side, preliminarily filling the pump elements with fuel before the engine actually stops. This preliminary action ensures that when the engine is restarted, the pump elements are already filled and pressure can build up rapidly without requiring additional complex components.
2Productivity
If the feed pump delivers fuel at high pressure during shutdown, then the pump elements fill faster, but the inlet valve may not open if pressure exceeds opening pressure
Solution Approach 1:
The system utilizes the spring-loaded inlet valve's pressure-dependent opening characteristic. By controlling the feed pump to deliver fuel at a pressure that exceeds the valve's opening pressure during shutdown, the valve reliably opens and allows fuel to enter the pump elements. The spring mechanism ensures the valve opens at the appropriate pressure threshold while maintaining reliable operation.
3Ease of operation
If additional components are added for fuel quantity regulation, then fuel delivery control is improved, but the device complexity increases
Solution Approach 1:
The spring-loaded inlet valve serves multiple functions: it acts as a pressure-regulating component that opens at a specific pressure threshold, controls fuel flow into the pump elements during shutdown, and eliminates the need for separate fuel quantity regulation components. This multi-functionality achieves ease of operation while minimizing device complexity.
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 method enables rapid pressure build-up in the high-pressure area upon engine restart, reducing start-up times and allowing for quicker engine reactivation, especially in automatic start-stop systems, without requiring additional components for fuel quantity regulation.
Implementation Method 1
The high-pressure pump (16) has at least one spring-loaded inlet valve (30) on the suction side for each pump element (22)
Data Source
Figure 1
AI summary
A method is proposed for operating a fuel delivery device of an internal combustion engine having an electrically driven delivery pump (10) and having at least one high-pressure pump (16) with at least one pump element (22). Fuel is conveyed by the delivery pump (10) to the suction side of the high-pressure pump (16), and fuel is conveyed by the high-pressure pump (16) into a high-pressure area (18). Furthermore, the fuel delivery device has a device (34) for quantity regulation of the drawn-in fuel quantity of the high-pressure pump (20) and an electric control device (46) which actuates the delivery pump (10) and the device (34) for quantity regulation of the fuel quantity in a variable manner. When the internal combustion engine is stopped and/or during the switching-off phase of the internal combustion engine, the delivery pump (10) and/or the device (34) for quantity regulation of the drawn-in fuel quantity are/is driven at least temporarily such that fuel is conveyed to the suction side of the high-pressure pump (16). In the high-pressure pump (16), the pump piston of at least one pump element (22) is situated in the region of the bottom dead centre when the internal combustion engine is stopped. When the internal combustion engine is stopped and/or during the switching-off phase of the internal combustion engine, fuel at a higher pressure than the opening pressure of the inlet valve (30) is conveyed to the high-pressure pump (16) by the delivery pump (10) and/or the device (34) for quantity regulation of the fuel quantity.