Vehicle Start-Up Control for Engine Stop-Start Systems
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Solution Overview
Problem
Hybrid vehicles equipped with 'stop and start' technology face challenges in quick and efficient starting, particularly due to delicate clutch control and the risk of engine stalling when torque requirements exceed engine capabilities, especially in vehicles with controlled mechanical gearboxes.
Innovation Solution
A method for controlling the start of a vehicle by actuating the clutch once the engine is autonomous, with the engine speed controlled to a predefined setpoint, and utilizing a hill start assistance device to ensure forward movement without reverse, based on predefined thresholds and durations related to engine temperature and atmospheric pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is controlled delicately during start-up to prevent engine stalling, then the reliability of engine operation is improved, but the start-up time increases and productivity deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining the clutch closing profile and engine speed setpoint before the actual start-up occurs. The control system prepares the clutch actuation sequence and engine speed trajectory in advance, allowing the engine to reach autonomous operation quickly while maintaining reliable control throughout the transition.
Solution Approach 2:
The patent implements dynamics by making the clutch closing process adaptive rather than static. The clutch actuation is dynamically adjusted based on real-time engine speed feedback, allowing the system to optimize the balance between preventing stalling and achieving quick start-up. The engine speed is actively slaved to a predefined setpoint during the transition, enabling rapid yet controlled engagement.
2Productivity
If the clutch closes quickly to enable fast start-up, then the productivity is improved, but the risk of engine stalling increases and reliability deteriorates
Solution Approach 1:
The patent applies feedback by continuously monitoring engine speed during clutch engagement and using this information to adjust the clutch actuation in real-time. The engine speed feedback allows the control system to detect approaching stall conditions and modify the clutch closing rate accordingly, enabling fast start-up while preventing stalling through active control.
Solution Approach 2:
The system dynamically adjusts the clutch closing profile based on engine response during the start-up process. Rather than using a fixed closing rate, the clutch actuation is continuously adapted to match the engine's torque characteristics and speed requirements, allowing rapid engagement while maintaining stability throughout the transition.
3Stability of the object's composition
If the engine speed is controlled to a predefined setpoint during clutch closing, then the stability of engine operation is improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by designing the engine control system to automatically regulate its own speed during clutch engagement without requiring complex external intervention. The engine speed is slaved to a predefined setpoint through integrated control logic that uses the engine's own sensors and actuators to maintain stability, reducing the need for additional complex control devices.
Solution Approach 2:
The control system implements multi-functionality by using the same engine management unit to perform both normal operation control and start-up clutch coordination. The predefined engine speed setpoint serves multiple purposes: it guides the clutch engagement process, ensures stable engine operation, and integrates with the existing engine control architecture, avoiding the need for separate dedicated control systems.
4Reliability
If the hill start assistance device is activated with a predefined duration T1, then the reliability of forward movement without reverse is improved, but the loss of time increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing the optimal duration T1 for hill start assistance based on engine characteristics and operating conditions. This predetermined time value allows the control system to activate the hill start assistance device with the exact duration needed to ensure forward movement without reverse, eliminating the need for real-time adjustment and reducing actual time loss.
Solution Approach 2:
The system optimizes the time delay T1 by adjusting it as a variable parameter based on engine temperature, atmospheric pressure, and other operating conditions. Rather than using a fixed conservative value, the duration T1 is adapted to match actual engine performance characteristics, reducing unnecessary time delays while maintaining reliable forward movement control.
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
Enables quick and stable engine start-ups, preventing stalling and ensuring smooth forward movement by controlling the clutch and hill start assistance device in response to engine torque and environmental conditions.
Implementation Method 1
fuel injection into the combustion chambers of the heat engine... speed of the heat engine greater than a predefined threshold S1, threshold S1 being equal to an engine speed that cannot be reached without combustion in the combustion chambers
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling the start-up of a vehicle comprising an engine start-stop system, said method including the actuation (52) of the start-up of the vehicle. The invention is characterised in that the method also comprises the following steps: an autonomous engine state is indicated (62) in response to the simultaneous occurrence of (i) the injection of fuel into the combustion chambers of the heat engine and (ii) a heat engine speed above a pre-defined threshold S1, said threshold S1 being equal to an engine speed that cannot be achieved without combustion in the combustion chambers during the start-up of the vehicle; and, in response to the aforementioned autonomous engine state indication, the closing of a clutch is controlled (66) according to a pre-defined motor speed set value in order to slave the motor speed to said pre-defined set value.