Throttle Valve Control for Engine Pumping Loss Reduction
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Solution Overview
Problem
Mild hybrid vehicle control systems face inefficiencies in managing engine pumping losses during deceleration fuel shutoff events, requiring extensive calibration and memory storage due to complex, non-linear empirical approaches.
Innovation Solution
A control system that detects deceleration fuel shutoff events, determines desired engine pumping losses based on battery system parameters, adjusts the throttle valve position using a combination of feedforward estimation and closed-loop proportional-integral control to minimize pumping losses and maximize electrical energy generation for battery charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex non-linear empirical approach with many calibration tables is used to determine desired pumping loss and throttle valve position, then the control precision of throttle valve is improved, but the device complexity and calibration effort increase significantly
Solution Approach 1:
The patent replaces the complex empirical control approach with a physics-based model. Instead of using multiple calibration tables and non-linear empirical relationships, the system uses a pumping loss model based on fundamental engine parameters (engine speed, airflow, throttle position) to calculate desired throttle valve position. This substitution of physics-based modeling for empirical calibration reduces control system complexity while maintaining precision.
Solution Approach 2:
The patent changes the approach from using fixed calibration tables to dynamically calculating throttle position based on real-time engine parameters. The desired pumping loss is computed as a function of engine speed, airflow, and throttle position, allowing the system to adapt to varying operating conditions without requiring extensive pre-calibration for each scenario.
2Loss of energy
If the throttle valve is opened to reduce engine pumping losses, then the fuel economy is improved, but the MGU may not be able to absorb the pumping loss reduction achieving electrical energy generation
Solution Approach 1:
The patent implements a feedback control mechanism where the actual pumping loss is continuously estimated based on measured engine parameters (airflow, engine speed, throttle position) and compared to the desired pumping loss. The throttle valve position is adjusted based on the difference between desired and actual pumping loss, ensuring that the MGU can effectively absorb the pumping loss reduction and convert it to electrical energy for battery charging.
Solution Approach 2:
The system dynamically adjusts the throttle valve position based on real-time conditions rather than using fixed opening positions. The desired throttle position is continuously recalculated based on current engine speed, airflow demands, and battery state of charge, allowing the system to optimize the balance between pumping loss reduction and electrical energy generation capability of the MGU.
3Loss of energy
If the MGU operates as a torque consumer to charge the battery system during DFSO events, then the overall vehicle efficiency is improved, but the control complexity increases due to operational constraints
Solution Approach 1:
The patent simplifies control by changing from a complex multi-constraint control approach to a parameter-based control strategy. The desired pumping loss is determined as a function of key parameters (engine speed, airflow, battery state of charge), and the throttle valve position is adjusted based on the difference between desired and actual pumping loss. This parameter-based approach reduces control complexity while maintaining efficiency improvements during DFSO events.
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 allows for precise throttle valve control, reducing engine pumping losses and enhancing battery charging efficiency while minimizing calibration efforts and maintaining vehicle drivability, thus improving overall fuel economy.
Implementation Method 1
a motor generator unit (MGU) physically coupled to a crankshaft of an engine and electrically connected to a battery system of the vehicle
Implementation Method 2
belt-driven starter generator (BSG) system
Data Source
AI summary
Techniques for a mild hybrid vehicle utilize a control system for detecting a deceleration fuel shutoff (DFSO) event where fueling to an engine is disabled and in response to detecting the DFSO event: determining a desired pumping loss for the engine based on a parameter of a battery system, the desired pumping loss corresponding to a desired amount of electrical energy that a motor generator unit (MGU) of a belt-driven starter generator (BSG) system will generate to charge the battery system; commanding a throttle valve of the engine to an initial position determined based on the desired engine pumping loss and a speed of the engine; estimating an actual pumping loss of the engine based on an estimated airflow into the engine; and adjusting the position of the throttle valve based on a difference between the desired and actual engine pumping losses.