Supercapacitor Charge Control for Hybrid Engine Start
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Solution Overview
Problem
In hybrid vehicles with 'Stop and Start' technology, users are uncertain about the necessity of waiting for the supercapacitor to charge before starting the engine and lack information on the minimum waiting time, as the electrical power required to start the heat engine is influenced by the engine temperature, and the battery alone may not suffice.
Innovation Solution
A method for controlling the man-machine interface that calculates the charging time required for a supercapacitor to reach a predetermined voltage setpoint based on current voltage and charge current, and informs the user through the interface when it is safe to start the engine after a determined waiting period, which is capped to limit excessive waiting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the supercapacitor is used to provide electrical power for engine starting when battery power is insufficient, then the engine can be started even at low temperatures, but the user does not know whether to wait for charging or can start immediately
Solution Approach 1:
The system continuously monitors the supercapacitor charge state and provides real-time feedback to the user through the display unit. The control unit calculates whether the supercapacitor is sufficiently charged and communicates this status immediately to the user, eliminating uncertainty about engine starting readiness.
Solution Approach 2:
The system performs preliminary charging of the supercapacitor before the engine start is attempted. The control unit assesses the charge state in advance and either allows immediate starting or indicates that waiting is necessary, preparing the system beforehand to ensure reliable starting when needed.
2Reliability
If the user is required to wait for the supercapacitor to charge fully before starting the engine, then sufficient electrical power is guaranteed, but the waiting time may be excessively long and inconvenient
Solution Approach 1:
The system does not require full charging of the supercapacitor to the maximum capacity before allowing engine start. Instead, it determines whether sufficient charge is adequate, enabling the engine to start with enough electrical power without requiring complete charging, thus reducing unnecessary waiting time.
Solution Approach 2:
The control unit dynamically adjusts the charge threshold parameter based on engine temperature and starting conditions. When the engine is warm, a lower charge threshold suffices, reducing waiting time. When cold, the threshold increases appropriately, ensuring reliable starting while minimizing wait.
3Ease of operation
If the battery alone is used to start the engine, then the system is simpler to operate, but the engine cannot be started when temperature is low and battery power is insufficient
Solution Approach 1:
The electrical system is designed with multi-functionality, where the battery can operate alone for simple starting conditions, and the supercapacitor can be engaged for demanding conditions like cold starts. The system automatically selects the appropriate configuration, providing both simplicity when possible and enhanced capability when needed.
Solution Approach 2:
The system dynamically adapts its configuration based on real-time conditions such as engine temperature and battery charge state. The control unit switches between battery-only mode for simplicity and combined battery-super Capacitor mode for enhanced capability, optimizing both ease of operation and adaptability to various starting conditions.
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 method ensures the supercapacitor is adequately charged to provide sufficient electrical power for engine starting, and engine temperature measurements help determine if the battery alone can start the engine, optimizing the charging process and user notification.
Implementation Method 1
a supercapacitor (16) intended to be connected: in series with the battery (12) so as to be able to supply a surplus of electrical energy to the starter (8) or to the alternator-starter (10) when the voltage at the terminals of the battery (12) is too low for the machine (6) to be able to start the heat engine (4) being powered solely by the battery (12)
Data Source
Figure 1~2
AI summary
The invention relates to a method for controlling a man/machine interface of a hybrid motor vehicle, characterised in that said method comprises: a) calculating (66) a charge time Tc in order to reach a pre-determined voltage set value Uc at the terminals of a super-capacitor used to power an electric starter of a heat engine of the vehicle, said calculation being performed as a function of a measurement (62) of the current voltage Ua at the terminals of the super-capacitor; and b) controlling (70) the man/machine interface in order to indicate that the start-up of the heat engine can be triggered once a time period Δt has elapsed, said time period Δt being determined by the following relationship: Δt = min (Tc, S), wherein min is the minimum function, and S is a pre-determined time period.