Engine Idle Speed Control via Indicated Torque Feedback
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Solution Overview
Problem
Existing engine idle speed control systems face challenges in maintaining consistent engine speed due to combustion variability, requiring frequent adjustments in spark timing and calibration tables, which is time-consuming and costly, especially as engine conditions change, such as during warming up.
Innovation Solution
An engine idle speed control system that determines indicated torque and desired torque, then calculates new spark timing based on these values, using multiple tables to account for varying engine conditions, allowing for efficient and adaptive spark timing adjustments without the need for extensive calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If spark timing is adjusted frequently to compensate for combustion variability, then engine speed control is improved, but calibration complexity and time consumption increase
Solution Approach 1:
The patent transforms the control approach from directly adjusting spark timing to adjusting indicated torque parameters. By changing the control variable from temporal (spark timing angles) to mechanical (torque values), the system achieves better adaptability to combustion variability without requiring complex calibration tables for every operating condition.
Solution Approach 2:
The patent introduces indicated torque as an intermediary parameter between spark timing and engine speed control. Instead of directly linking spark timing adjustments to speed control, the system uses indicated torque as a mediator that simplifies the control logic and reduces calibration requirements while maintaining control effectiveness.
2Measurement precision
If multiple calibration tables are used to cover different engine idle speeds, then control accuracy is improved, but system complexity and calibration time increase
Solution Approach 1:
The patent creates a universal control approach using indicated torque that works across multiple engine idle speeds and operating conditions without requiring separate calibration tables. This single unified method replaces multiple condition-specific tables, reducing calibration time while maintaining accuracy across the full operating range.
Solution Approach 2:
By changing from spark timing-based control to indicated torque-based control, the system achieves universal applicability across different engine speeds and loads. The indicated torque parameter naturally adapts to varying operating conditions without requiring pre-defined calibration tables for each scenario.
3Loss of energy
If torque reserve is reduced for systems with smaller unanticipated loads, then engine efficiency is improved, but the slope of torque vs. spark timing curve changes rapidly, making control difficult
Solution Approach 1:
The patent implements feedback control using indicated torque to continuously monitor and adjust spark timing based on actual engine conditions. This feedback mechanism automatically adapts to changing torque-reserve requirements and operating conditions, maintaining ease of control even when torque reserve is reduced for improved efficiency.
Solution Approach 2:
The system dynamically adjusts spark timing based on real-time indicated torque measurements rather than using fixed calibration tables. This dynamic approach allows the control system to easily adapt to rapidly changing operating conditions and torque-reserve requirements without sacrificing control ease or efficiency.
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 system ensures consistent engine speed control across a wide range of conditions with minimal calibration requirements, effectively managing torque reserve and adapting to changing engine loads, thereby improving engine performance and reducing operational complexity.
Implementation Method 1
The air and fuel mixture is combusted within the cylinder to reciprocally drive the piston within the cylinder
Implementation Method 2
Combustion is initiated by creation of a spark in the cylinder by a spark plug
Data Source
AI summary
An engine idle speed control system for regulating an idle speed of an internal combustion engine includes a first module that determines an indicated torque of the engine based on a current spark timing and a second module that determines a desired indicated torque based on the indicated torque. A third module determines a new spark timing based on the desired indicated torque and a fourth module that regulates operation of the engine based on the new spark timing.