Alternator Excitation Control for Engine Speed Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing alternator control systems struggle to stabilize engine speed at idle due to rapid torque increases, particularly when the engine is started or cold, as they do not effectively interact with changes in on-board voltage or motor RPM, leading to difficulties in maintaining a stable load.
Innovation Solution
A method and system for controlling the progressive load of a motor vehicle alternator that incorporates an auxiliary correction block to limit the excitation signal duty cycle based on engine parameters such as angular acceleration, speed of rotation, and temperature, using a 'feed forward' loop to adjust the duty cycle and prevent sudden deceleration or excessive torque draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the excitation current is increased rapidly to meet electrical load demands, then the voltage stabilization is improved, but the engine speed stability deteriorates due to sudden torque increases
Solution Approach 1:
The system performs preliminary assessment of engine operating conditions (idle detection, temperature monitoring) before allowing full excitation current increases. The progressive load function pre-limits the excitation signal based on detected conditions, preventing sudden torque draws that would destabilize engine speed while still enabling voltage regulation when conditions permit.
Solution Approach 2:
The system dynamically adjusts the progressive load limitation based on real-time engine parameters including RPM, temperature, and idle detection. The excitation current increase rate is continuously adapted according to engine load conditions, allowing faster response when engine can accommodate it and slower response when engine stability is at risk.
2Stability of the object's composition
If the progressive load function systematically limits excitation current increase, then the engine speed stability is maintained, but the response to voltage changes becomes insufficient
Solution Approach 1:
The system continuously monitors on-board voltage and compares it to the setpoint value. When voltage deviates beyond a threshold, the feedback signal triggers increased excitation current delivery within the progressive load constraints. This feedback mechanism ensures the system responds appropriately to voltage changes while maintaining engine stability through the progressive limitation framework.
3Device complexity
If the LRC function operates as open-loop systematic action, then the control simplicity is maintained, but the interaction with voltage changes and RPM variations is insufficient
Solution Approach 1:
The progressive load function automatically detects and responds to engine operating conditions without requiring complex external control logic. It self-adjusts the excitation current limitation based on detected parameters such as engine RPM, temperature, and load conditions, making the system adaptable while maintaining relatively simple control architecture.
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 ensures stable voltage supply to the on-board network by dynamically adjusting the alternator load according to engine conditions, preventing engine stalling and maintaining efficient speed regulation, especially during idle or cold starts.
Implementation Method 1
an alternator (1) capable of producing a supply voltage (Ub+) for an on-board network (2) of the vehicle
Implementation Method 2
controlling an excitation signal (7) of variable pulse width type controlling an excitation current flowing in an excitation winding of the alternator
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
The method according to the invention involves limiting the charging of a vehicle alternator by only authorizing progressive augmentation of a current duty cycle (DC) of an excitation signal (7) of the alternator from an initial duty cycle to an expected duty cycle (EpsU) calculated by a control loop (1, 5, 6) of the alternator. According to the invention, a complementary limitation of the charging of the alternator involves limiting the increase of the current duty cycle (DC) according to at least one parameter of the heat engine involving an angular acceleration (mot) and/or a rotation speed (Nmot) of the heat motor. In particular, this complementary limitation can additionally involve limiting the increase of the current duty cycle (DC) according to a negative value of the angular acceleration (mot).