Hybrid Engine Torque Control via Cylinder Segmentation
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Solution Overview
Problem
Conventional engine control systems in hybrid vehicles fail to accurately control engine torque output and provide rapid responses, leading to noise, vibration, and harshness (NVH) during engine start operations.
Innovation Solution
A control system for hybrid vehicles that includes an engine speed control module, an air pressure control module, and an engine torque control module, which increases engine speed using the electric motor, decreases intake manifold pressure, and activates a subset of engine cylinders based on driver torque requests and predetermined thresholds to smooth engine start operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional engine control systems are used, then the system structure is simple, but the engine torque output cannot be controlled accurately and response is slow
Solution Approach 1:
The control system is segmented into three distinct modules: engine speed control module, air pressure control module, and engine torque control module. Each module handles specific control tasks independently, enabling precise torque control through coordinated action of multiple specialized components rather than a single complex system.
Solution Approach 2:
The engine speed control module increases engine speed during a first calibration period before actual fuel injection begins. The air pressure control module decreases intake manifold pressure during a second calibration period. These preliminary actions prepare the engine for smooth startup by establishing optimal conditions before combustion starts.
2Speed
If traditional engine control systems are used, then the system structure is simple, but the response to control signals is slow
Solution Approach 1:
The system performs preliminary calibration operations before actual engine operation: increasing engine speed during a first calibration period and decreasing intake manifold pressure during a second calibration period. This preliminary action allows the system to be pre-positioned for rapid response when actual torque control is needed.
Solution Approach 2:
The control system dynamically adjusts multiple parameters simultaneously: engine speed, intake manifold pressure, and the number of activated cylinders. This dynamic coordination of multiple variables enables rapid adaptation to changing torque demands while maintaining system manageability through modular architecture.
3Object-affected harmful factors
If engine starts immediately without calibration, then the startup is faster, but noise, vibration, and harshness occur
Solution Approach 1:
The system performs preliminary calibration actions before engine startup: increasing engine speed during a first calibration period and decreasing intake manifold pressure during a second calibration period. These preliminary actions smooth out the engine startup process by preparing optimal conditions before combustion begins, thereby reducing NVH without significantly extending total startup time.
Solution Approach 2:
The system changes key engine parameters during calibration periods: engine speed is increased and intake manifold pressure is decreased before fuel injection begins. These parameter changes create optimal conditions for smooth engine startup, reducing vibrations and harshness while maintaining acceptable startup timing.
4Ease of operation
If all cylinders are activated during engine start, then maximum torque is achieved, but torque delivery is less controlled and smoother
Solution Approach 1:
The engine cylinders are segmented and activated selectively rather than all at once. The engine torque control module activates N of M cylinders based on driver torque request and predetermined thresholds, allowing controlled torque delivery while maintaining the ability to scale power output as needed.
Solution Approach 2:
Instead of activating all cylinders immediately, the system activates only the necessary number of cylinders (N of M) based on current torque requirements. This partial action provides controlled and smooth torque delivery, with the capability to activate additional cylinders if higher power is subsequently needed.
Data Source
AI summary
A control system for a hybrid vehicle that includes an internal combustion engine and an electric motor includes an engine speed control module, an air pressure control module, and an engine torque control module. The engine speed control module increases engine speed during a first calibration period based on a driver torque request and a predetermined torque threshold. The air pressure control module decreases intake manifold pressure (MAP) of the engine during a second calibration period based on the driver torque request and the predetermined torque threshold. The engine torque control module starts the engine during a period after the first and second calibration periods by activating N of M cylinders of the engine, wherein N is based on the driver torque request and the predetermined torque threshold.