EV Engine Stop Position Control for Reliable Generator Restart
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Solution Overview
Problem
In electric vehicles, starting the engine while ensuring the revolution position is proper can be challenging, especially when the battery state of charge (SOC) is low, leading to potential inefficiencies in fuel consumption and emissions, and risk of damaging the side seal during backward engine rotation.
Innovation Solution
A control apparatus for electric vehicles that includes a first motor for traveling, a second motor for electricity generation, an engine mechanically connected to the second motor, and controllers for managing engine start, electricity generation, and stop position adjustment. The second controller uses the second motor to start the engine and charge the battery when SOC is low, and adjusts the engine's stop position after charging is complete, ensuring proper revolution alignment and minimizing battery power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine revolution position is adjusted using a motor before engine start, then the engine can start from a proper position, but the battery SOC is further reduced and fuel efficiency deteriorates
Solution Approach 1:
The control device performs preliminary action by adjusting the engine revolution position to a proper start position using the motor during electricity generation operation, before the engine actually starts. This ensures that when the engine starts subsequently, it begins from an optimal position, improving start reliability while utilizing available battery power during charging conditions.
Solution Approach 2:
The system dynamically adjusts the engine revolution position based on real-time conditions. The control device monitors battery SOC and electricity generation status, and only performs position adjustment when conditions are favorable (during electricity generation when battery power is being replenished), making the system adaptable to varying operational states.
2Use of energy by moving object
If the engine is started without adjusting revolution position, then battery power consumption is reduced, but fuel efficiency and exhaust emission performance deteriorate
Solution Approach 1:
The control device performs preliminary adjustment of the engine revolution position to a proper start position using the motor during electricity generation operation, before the engine actually starts. This ensures that when the engine starts subsequently, it begins from an optimal position, improving start reliability while utilizing available battery power during charging conditions.
Solution Approach 2:
The system dynamically adjusts the engine revolution position based on real-time conditions. The control device monitors battery SOC and electricity generation status, and only performs position adjustment when conditions are favorable (during electricity generation when battery power is being replenished), making the system adaptable to varying operational states.
3Use of energy by moving object
If the engine is started without adjusting revolution position, then battery power consumption is reduced, but start completion time increases
Solution Approach 1:
The control device performs preliminary adjustment of the engine revolution position to a proper start position using the motor during electricity generation operation, before the engine actually starts. This ensures that when the engine starts subsequently, it begins from an optimal position, improving start reliability while utilizing available battery power during charging conditions.
Solution Approach 2:
The system dynamically adjusts the engine revolution position based on real-time conditions. The control device monitors battery SOC and electricity generation status, and only performs position adjustment when conditions are favorable (during electricity generation when battery power is being replenished), making the system adaptable to varying operational states.
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 solution allows for efficient engine starting with proper revolution alignment, reducing fuel inefficiencies and emissions, while preventing side seal damage by adjusting the engine's stop position after charging, thus optimizing battery usage and engine performance.
Implementation Method 1
a second motor for electricity generation which is electrically connected with the battery; an engine that has a shaft with which the second motor is mechanically connected and that produces a driving force for moving the second motor
Implementation Method 2
an electricity generation control unit which causes the second motor to perform electricity generation driving after the engine is started such that the battery is charged
Data Source
AI summary
A control apparatus for an electric vehicle includes a first motor (traveling motor) for traveling, a battery (high-voltage battery), a second motor (generator motor) for electricity generation, an engine (rotary engine), a first controller (engine ECU), a second controller (motor ECU), and a sensor (voltage-current sensor). The second controller is configured to start the engine by causing the second motor to perform power running, cause the second motor to perform electricity generation driving such that the battery is charged, and adjust a stop position of the engine by causing the second motor to perform power running subsequently to a stop of the engine by the first controller in a case where a state of charge of the battery becomes high and the second motor finishes the electricity generation driving.