Crankcase Pressure Control via Electric Drive Speed
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Solution Overview
Problem
Existing crankcase ventilation systems in internal combustion engines face challenges in regulating pressure within specific limits without the use of a pressure sensor, particularly in supercharged engines where insufficient negative pressure is available, leading to potential oil leaks or excessive oil suction.
Innovation Solution
Regulating the speed of the electric drive that powers the pumping device based on performance parameters such as current, voltage, and torque, allowing the system to maintain crankcase pressure within target ranges without the need for a pressure sensor, by comparing actual and desired current values and adjusting the speed accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a pressure sensor is installed in the crankcase to accurately regulate pressure, then pressure control precision is improved, but device complexity and cost increase
Solution Approach 1:
The system uses the electric drive's own performance parameters (current, voltage, power consumption) as feedback signals to infer crankcase pressure conditions. The control unit monitors these self-generated parameters to determine whether the crankcase pressure is within the target range, eliminating the need for external pressure sensors while maintaining effective pressure regulation.
Solution Approach 2:
The patent replaces the mechanical/electrical pressure sensing system with an electrical parameter monitoring system. Instead of using a pressure sensor to directly measure crankcase pressure, the system substitutes this with monitoring of the electric drive's electrical parameters, which indirectly reflect the pressure conditions through the pump's workload.
2Reliability
If the pump's output is regulated to maintain crankcase pressure within limits, then pressure control is improved, but the system requires additional pressure measurement devices
Solution Approach 1:
The system establishes a feedback loop where the control unit continuously monitors the electric drive's performance parameters and adjusts the pump's operation accordingly. When the electrical parameters indicate that crankcase pressure is outside the target range, the control unit modifies the pump's pumping action to restore pressure within acceptable limits, creating a closed-loop control system without additional sensors.
Solution Approach 2:
The electric drive's electrical parameters serve as an intermediary indicator of crankcase pressure conditions. Instead of directly measuring pressure, the system uses these electrical parameters (current, voltage, power consumption) as intermediate signals that correlate with pressure states, allowing indirect but effective pressure monitoring and control.
3Device complexity
If performance parameters of the electric drive are used to infer crankcase pressure, then the need for pressure sensors is eliminated, but measurement precision may be reduced
Solution Approach 1:
The system uses readily available electrical parameter measurements from the existing electric drive components rather than investing in expensive, dedicated pressure sensing equipment. The electrical parameters are already being monitored for other control functions, so utilizing them for pressure inference adds minimal cost while avoiding the need for additional expensive sensors.
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 effectively maintains crankcase pressure within desired limits, minimizing oil leaks and excessive suction, while eliminating the need for a pressure sensor, thus enhancing the efficiency and reliability of the crankcase ventilation system.
Implementation Method 1
a pump device driven by an electrical drive
Implementation Method 2
an oil mist separator, wherein the pump device and the oil mist separator are arranged in the suction line
Data Source
Figure 1~3
Figure 4~5
Figure 6~7
AI summary
The invention relates to a method for controlling a pressure (26) to a target pressure (27) in a crankcase (14) of an internal combustion engine (10) by means of a crankcase venting device (18), wherein the crankcase venting device (18) comprises a suction line (20), by means of which blow-by gas (16) can be removed from the crankcase (14), a pumping device (22) driven by an electric drive (28), and an oil mist separating device (24), and wherein the pumping device (22) and the oil mist separating device (24) are arranged in the suction line (20). In order to render a pressure-measuring device in the crankcase unnecessary, a rotational speed of the electric drive (28), according to the invention, is controlled in a closed-loop and/or open-loop manner, the rotational speed of the electric drive (28) is used as a manipulated variable (41) for the control of the pressure (26) in the crankcase (14), and at least one performance parameter of the electric drive (28) is evaluated in order to infer the pressure (26) in the crankcase (14).