Variable Capacity Engine Oil Pump Control System

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Solution Overview

Problem

Conventional engine oil pumps are designed for worst-case operating conditions, leading to excessive lubrication and drag on the crankshaft during non-worst-case conditions, which decreases torque output and fuel economy.

Innovation Solution

A control system with an oil pump module and diagnostic module that selectively switches between high and low pressure modes based on engine operating conditions, actively controlling and diagnosing the variable displacement oil pump to ensure optimal lubrication and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the engine oil pump is designed for worst-case operating conditions to ensure adequate lubrication, then lubrication reliability is improved, but drag on the crankshaft increases during non-worst-case conditions, decreasing fuel economy and torque output

Engineering Contradiction:

Improvelubrication reliabilityVSAvoidfuel economy

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The oil pump system transitions from a fixed displacement design to a variable displacement design with two operating modes (first pressure mode and second pressure mode). The pump dynamically adjusts its output based on real-time engine operating conditions, switching between modes to optimize the balance between lubrication reliability and energy efficiency.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operating parameters of the oil pump by switching between two distinct pressure modes. The first pressure mode provides higher oil flow and pressure for worst-case conditions, while the second pressure mode provides reduced oil flow and pressure for non-worst-case conditions, thereby reducing drag and improving fuel economy.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the engine oil pump operates in high pressure mode during all conditions to ensure adequate lubrication, then lubrication reliability is improved, but drag on the crankshaft increases during non-worst-case conditions, decreasing torque output

Engineering Contradiction:

Improvelubrication reliabilityVSAvoidtorque output

Core Design Contradiction:

ReliabilityVSPower

Solution Approach 1:

The oil pump system dynamically adjusts its operating mode based on real-time engine conditions. During non-worst-case conditions, the system switches to the second pressure mode, which reduces oil pump output and corresponding drag on the crankshaft, thereby preserving more torque for engine output while maintaining adequate lubrication.

Inventive Principle:

Principle #15Dynamics

3Loss of energy

If the oil pump switches between pressure modes based on engine conditions, then fuel economy is improved, but the complexity of the control system increases

Engineering Contradiction:

Improvefuel economyVSAvoidcontrol system complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The control system is segmented into distinct functional modules: an oil pump module that generates mode request signals based on engine operating conditions, and a diagnostic module that monitors transitions and detects faults. This modular segmentation organizes the control logic to manage complexity while enabling sophisticated variable displacement control.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The system incorporates feedback mechanisms where the diagnostic module monitors oil pressure changes during mode transitions and compares them against expected values. This feedback loop enables the system to detect pump faults and distinguish them from normal operating variations, ensuring reliable control despite the increased system complexity.

Inventive Principle:

Principle #23Feedback

4Measurement precision

If the diagnostic module actively tests the oil pump by initiating consecutive transitions, then pump fault detection is improved, but the frequency of mode changes increases, affecting engine performance

Engineering Contradiction:

Improvefault detection accuracyVSAvoidmode transition frequency

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The diagnostic module performs preliminary fault detection by initiating consecutive mode transitions when the engine is first started. This preliminary action allows the system to establish a baseline of pump functionality early in operation, enabling accurate fault detection before normal variable displacement control takes over.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8734122B2Control and diagnostic systems for a variable capacity engine oil pump and an engine oil pressure sensor

Publication Date: 2014.05.27 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A control system includes an oil pump module and a diagnostic module. The oil pump module, based on engine operating conditions, selectively generates a first mode request signal to initiate a first transition from operating an oil pump of an engine in one of a first pressure mode and a second pressure mode to operating the oil pump in another one of the first pressure mode and the second pressure mode. The second pressure mode is different from the first pressure mode. The diagnostic module, based on when a driver starts the engine, selectively generates a second mode request signal to initiate consecutive transitions from operating the oil pump in the second pressure mode to operating the oil pump in the first pressure mode. The diagnostic module diagnoses a pump fault when a first oil pressure change associated with the consecutive transitions is less than a first predetermined pressure change.