Variable Stroke Oil Pump Thermal Management
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Solution Overview
Problem
Existing methods for controlling oil pumps in heat engines fail to adequately accelerate passenger compartment heating in cold conditions, leading to insufficient thermal performance and increased engine friction losses.
Innovation Solution
A method for controlling a variable displacement oil pump that operates in a mechanically regulated mode to maximize pressure in the oil circuit when outside or passenger compartment temperatures are low, or when combustion efficiency is degraded, increasing thermal losses and energy transfer to the passenger compartment, while switching to controlled mode when temperatures rise to prevent overconsumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the oil pump operates in controlled mode to reduce mechanical engine losses, then fuel consumption is reduced, but thermal energy transfer to the passenger compartment is insufficient
Solution Approach 1:
The oil pump operates in two distinct modes: controlled mode during normal operation to minimize friction losses, and mechanically regulated mode during cold conditions to maximize thermal energy transfer. The system dynamically switches between modes based on temperature sensors and engine operating conditions, resolving the contradiction between energy efficiency and heating performance.
Solution Approach 2:
The system changes the operational parameters of the oil pump by adjusting the spool position, which controls the variable displacement. In mechanically regulated mode, the spool position is adjusted to increase pump displacement and maximize thermal losses, while in controlled mode, the displacement is optimized for fuel efficiency. This parameter change allows the system to adapt to different thermal requirements.
2Temperature
If the oil pump increases thermal losses to heat the passenger compartment, then heating efficiency is improved, but engine friction losses increase
Solution Approach 1:
The oil pump operates periodically in mechanically regulated mode only when cold conditions are detected, rather than continuously. The control system monitors temperature conditions and activates the heating mode temporarily until the passenger compartment reaches the desired temperature, then switches back to controlled mode. This periodic operation minimizes the cumulative friction losses while still providing effective heating when needed.
3Productivity
If the oil pump operates at maximum capacity to accelerate heating, then thermal performance is improved, but fuel consumption increases
Solution Approach 1:
The system applies partial action by operating the oil pump at maximum capacity only partially - specifically, only when cold conditions are detected and only until the heating objective is achieved. During normal operating conditions, the pump operates at optimized displacement rather than maximum capacity. This partial application of excessive action provides accelerated heating when needed without the continuous fuel penalty of maximum operation.
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 approach enhances thermal energy transfer to the passenger compartment, saving nearly 4% of energy and optimizing heating efficiency, while limiting engine friction losses by adjusting the pump's operation based on temperature thresholds.
Implementation Method 1
The invention also concerns an engine computer (10) for controlling a variable displacement controlled oil pump (3) in a motor vehicle comprising a water-oil heat exchanger for transferring thermal energy from the cooling system to the oil circuit
Implementation Method 2
an oil pump designed to minimize inherent friction between the engine's moving parts and the hydraulic torque, thereby reducing mechanical engine losses
Data Source
Figure 1~2
AI summary
The invention relates chiefly to a method for controlling a controlled variable-stroke oil pump (3) intended to supply pressurized oil to the moving parts of a motor vehicle combustion engine (1) via an oil circuit (1), characterized in that it comprises the step of running the oil pump (3) in a mechanically regulated mode so as to maximize a pressure in said oil circuit (1) when at least one of the following conditions is met: - an outside temperature is lower than a first calibratable threshold and/or a temperature in a passenger compartment of the vehicle is lower than a second calibratable threshold; and/or - a combustion engine (1) downgraded combustion output strategy has been activated in order to raise the temperature inside the passenger compartment. Another subject of the invention is the corresponding engine management system.