Hybrid Engine Cold Start Control Using Pre-Fueling Airflow
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Solution Overview
Problem
Hybrid vehicles experience higher emissions during cold starts of the internal combustion engine due to the engine being started while cold, which affects the efficiency and emissions of the exhaust system.
Innovation Solution
A system and method that utilizes an electric motor to rotate the crankshaft of the engine without fueling, allowing air to flow and moisture to be removed from oxygen sensors, followed by heating the sensors and then starting the engine when the sensors reach a predetermined temperature, and subsequently charging the battery using the electric motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine is started while cold, then the engine can begin operation quickly, but emissions increase due to inefficient catalyst lightoff
Solution Approach 1:
The system performs preliminary actions before engine start by heating the oxygen sensor and ensuring catalyst readiness in advance. The control module monitors sensor temperature and prepares the exhaust system before fueling begins, so that when the engine starts, emissions are already minimized through pre-conditioned catalyst and sensor systems.
Solution Approach 2:
The system dynamically adjusts the start strategy based on real-time sensor temperature readings and catalyst state. Rather than using a fixed cold start procedure, the control module continuously monitors conditions and adapts the fueling and heating strategies to achieve optimal emissions performance at the moment of engine start.
2Temperature
If the oxygen sensor is heated immediately during cold start, then the sensor reaches operating temperature faster, but energy is wasted heating the sensor before sufficient air flow is available
Solution Approach 1:
The control module uses feedback from air flow sensors and temperature sensors to determine the optimal moment to activate sensor heating. By continuously monitoring air mass flow rate and sensor temperature, the system waits until sufficient air is flowing through the engine before initiating heating, ensuring energy is only consumed when it will be effective and the sensor can be efficiently warmed by the passing air stream.
3Power
If the engine is fueled immediately at cold start, then power is available right away, but emissions are higher before the catalyst and sensors are ready
Solution Approach 1:
The system performs preliminary preparation by pre-heating the catalyst and oxygen sensor before introducing fuel to the engine. This ensures that when combustion begins, the emissions control systems are already at optimal temperature, immediately reducing harmful emissions without delaying power availability since the electric motor can bridge the gap during the brief preparation phase.
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 reduces exhaust emissions by ensuring efficient catalyst lightoff and reduces fuel consumption by deactivating engine cylinders when the battery is fully charged, thereby minimizing cold start emissions and improving engine efficiency.
Implementation Method 1
A motor and engine control system for a vehicle includes: a driver torque request module configured to determine a driver torque request based on driver input; a motor control module configured to selectively control application of power from a battery to an electric motor of the vehicle based on the driver torque request
Implementation Method 2
allowing air to flow and moisture to be removed from oxygen sensors
Implementation Method 3
allowing air to flow and moisture to be removed from oxygen sensors
Implementation Method 4
followed by heating the sensors and then starting the engine when the sensors reach a predetermined temperature
Implementation Method 5
once the predetermined mass of air has flowed into the engine, the engine control module is configured to (a) apply power to the oxygen sensor and heat the oxygen sensor
Implementation Method 6
the engine of the vehicle based on the driver torque request... selectively start fueling the engine
Implementation Method 7
reduces exhaust emissions by ensuring efficient catalyst lightoff
Data Source
AI summary
A system includes: a motor control module and an engine control module, where, when a temperature of an oxygen sensor in an exhaust system of an engine is less than a predetermined temperature while the engine is off: the motor control module is configured to apply power to an electric motor based on a driver torque request and drive rotation of a crankshaft; the engine control module is configured to, while the motor control module is applying power to the electric motor based on the driver torque request, not fuel the engine and not apply power to the oxygen sensor until a predetermined mass of air has flowed into the engine; and once the predetermined mass of air has flowed into the engine, the engine control module is configured to (a) apply power to the oxygen sensor and heat the oxygen sensor and (b) selectively start fueling the engine.