Engine Start-Stop Controller Logic for Fuel Economy
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Solution Overview
Problem
Existing engine start-stop systems in vehicles lack efficient control mechanisms to optimize fuel economy by automatically starting or stopping the engine based on various vehicle conditions, leading to suboptimal fuel consumption and emissions.
Innovation Solution
A method and system that utilize a controller to output engine commands for auto-start or auto-stop based on detection of specific vehicle conditions, such as gear shifts, battery parameters, HVAC activations, and time thresholds, to optimize fuel economy by determining when to engage or disengage the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is automatically stopped to reduce fuel consumption, then fuel economy is improved, but the system complexity increases due to multiple detection parameters and control logic
Solution Approach 1:
The control system segments the decision-making process into distinct detection modules: gear position detection, brake state detection, time threshold detection, and condition evaluation. Each module independently monitors a specific parameter and feeds results to the control unit, which synthesizes the information to make start-stop decisions. This modular segmentation reduces overall system complexity by making each component's function clear and manageable.
Solution Approach 2:
The system performs preliminary detection and evaluation of multiple conditions (gear position, brake state, time thresholds, vehicle speed) before executing the engine start-stop command. By pre-assessing all necessary parameters and preparing the control logic in advance, the system avoids complex real-time decision-making during critical moments, thereby reducing control complexity while maintaining fuel efficiency.
2Speed
If the engine auto-start is triggered immediately upon gear shift, then responsiveness is improved, but fuel economy deteriorates due to unnecessary engine starts
Solution Approach 1:
The system dynamically adjusts the engine start decision based on real-time evaluation of multiple conditions rather than using a fixed immediate response. The control unit continuously monitors gear position changes, brake state, time thresholds, and vehicle speed, adjusting the start command timing and execution accordingly. This dynamic adaptation allows the system to respond quickly when necessary while avoiding unnecessary starts, optimizing both responsiveness and fuel consumption.
Solution Approach 2:
The system incorporates feedback mechanisms where the control unit continuously monitors the results of condition detections (gear shift, brake release, time elapsed) and uses this feedback to make informed start-stop decisions. The feedback loop evaluates whether the detected conditions genuinely warrant an engine start before executing the command, preventing premature or unnecessary starts while maintaining appropriate responsiveness to legitimate driver needs.
3Use of energy by moving object
If multiple detection parameters are monitored to optimize start-stop decisions, then fuel economy is improved, but the difficulty of detecting and measuring conditions increases
Solution Approach 1:
The control unit serves multiple functions simultaneously: it detects gear position, monitors brake state, measures time intervals, evaluates vehicle speed, and executes start-stop commands. By designing a universal control component that performs all these functions, the system reduces the need for separate specialized sensors and processing units for each parameter, thereby improving fuel economy through comprehensive monitoring while reducing the overall difficulty of detection and measurement.
Solution Approach 2:
The system merges the detection and control functions for multiple parameters (gear position, brake state, time measurement, speed monitoring) into a single integrated control unit. This consolidation combines what would otherwise be separate detection systems into one unified component, reducing the complexity of implementing and maintaining multiple independent detection systems while enabling comprehensive condition monitoring to optimize fuel economy.
Data Source
AI summary
A method to control engine start-stop in a vehicle is provided. The method includes outputting via a controller an engine command to auto-start the engine based on detection of a predetermined vehicle condition affecting fuel economy of the vehicle, detection of a shift from neutral to another gear position, and whether a predetermined time threshold has expired following the shift in response to detection of a presence of an engine auto-stop mode and a neutral gear position. The predetermined vehicle condition may be a movement of the vehicle in a reverse direction. The predetermined vehicle condition may be a battery parameter being outside of predetermined range. The predetermined range may be based on a battery state of charge, a battery temperature, a battery voltage, or a battery load current. The predetermined vehicle condition may be a HVAC component activation.