Electric Oil Pump Cold Start Volumetric Efficiency Control
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Solution Overview
Problem
Conventional lubrication systems, particularly electric oil pumps, face challenges in delivering adequate oil volume at low temperatures due to high viscosity oil, leading to reduced volumetric flow rates and inefficiency, especially in cold-start conditions of vehicles like snowmobiles.
Innovation Solution
The system manipulates the oil pump command signal by adjusting the drive time and frequency based on temperature and engine speed to enhance volumetric efficiency, ignoring initial ineffective pump actuations and using temperature corrections to maintain the desired fuel/oil ratio, thereby improving oil delivery in cold conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric oil pump operates at cold temperatures with high viscosity oil, then the oil pump can deliver oil to the engine, but the volumetric flow rate decreases and pumping efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the pump drive frequency and drive time variable rather than fixed. The ECU dynamically adjusts the pump control signal parameters based on engine temperature, allowing the pump to adapt its operation to cold temperature conditions. This dynamic control compensates for the reduced volumetric efficiency at low temperatures by increasing the frequency and duration of pump actuations.
Solution Approach 2:
The patent changes the operational parameters of the oil pump system by manipulating the pump control signal's drive time and frequency based on temperature. The ECU modifies these parameters in response to cold temperature conditions, increasing drive time and frequency to compensate for high oil viscosity. This parameter adjustment directly addresses the reduced volumetric flow rate while maintaining reliable oil delivery.
2Quantity of substance
If the pump drive frequency is increased to compensate for cold temperatures, then oil delivery volume increases, but the fuel/oil ratio may become unbalanced
Solution Approach 1:
The patent implements feedback control through the ECU, which continuously monitors engine temperature and adjusts the pump control signal parameters accordingly. The system uses temperature feedback to determine the appropriate drive time and frequency adjustments, ensuring that oil delivery is compensated for cold temperatures without causing fuel/oil ratio imbalance. This closed-loop control prevents over-oiling by basing adjustments on actual thermal conditions.
Solution Approach 2:
The system dynamically adjusts pump operation parameters based on real-time temperature conditions rather than using fixed parameters. The ECU modifies drive time and frequency in response to temperature changes, creating a dynamic balance between compensating for cold temperature viscosity effects and maintaining proper fuel/oil ratio. This dynamic adjustment prevents both under-oiling and over-oiling conditions.
3Adaptability or versatility
If the electric oil pump is remotely mounted on the vehicle, then packaging flexibility is improved, but the pump is not subject to engine heating and remains at lower temperatures
Solution Approach 1:
The patent replaces the mechanical thermal coupling system with an electronic control system. Instead of relying on mechanical proximity to the engine for thermal heating (as with mechanically driven pumps), the system uses electronic sensing of temperature and electronic manipulation of pump control signals to compensate for the lower pump temperature. The ECU substitutes the thermal field interaction with an electronic control field, allowing remote mounting while maintaining proper oil delivery through parameter adjustments.
Data Source
AI summary
An apparatus and method for controlling an electric oil pump with a pump control signal generated by an electronic control unit (ECU) of a vehicle. The pump control signal has a variable drive time portion during which the electric oil pump is actuated to supply oil to an engine of the vehicle and a variable cycle time defining a frequency of the pump control signal.