Electrically Heated Catalyst Power Management via Secondary Storage
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Solution Overview
Problem
Existing exhaust gas treatment systems for internal combustion engines, such as oxidation catalyst (OC) and selective catalytic reduction (SCR) devices, are ineffective during cold starts due to the need to reach a light-off temperature, leading to deep discharge of vehicle batteries when using electrically heated catalyst (EHC) devices and resulting in dimming of vehicle lighting.
Innovation Solution
An exhaust gas treatment system that includes a generator, primary and secondary energy storage devices, and a control module to selectively power an electrically heated catalyst (EHC) device, disconnecting the primary energy storage when fully charged and using the secondary energy storage to maintain vehicle electrical system power, preventing deep discharge and ensuring efficient heating to light-off temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the primary energy storage device is used to power the electrical heater of the EHC device, then the catalyst can be heated to light-off temperature effectively, but the primary energy storage device will be deeply discharged, impacting battery life
Solution Approach 1:
The energy storage function is segmented between two devices: the primary energy storage device (battery) and the secondary energy storage device (capacitor). The capacitor handles the high-power transient demand of the EHC heater, while the battery provides steady-state power and maintains voltage stability, thus preventing deep discharge of the battery.
Solution Approach 2:
The secondary energy storage device (capacitor) acts as an intermediary between the primary energy storage device (battery) and the EHC heater. It buffers the high-current transient demand, protecting the battery from deep discharge while ensuring sufficient power delivery for catalyst heating.
2Power
If power is supplied to the EHC device from the primary energy storage device, then the catalyst heating function is achieved, but the vehicle lighting will substantially dim due to voltage drop
Solution Approach 1:
The power delivery function is segmented between two energy storage devices. The secondary energy storage device (capacitor) is dedicated to supplying high transient power to the EHC heater, while the primary energy storage device (battery) maintains system voltage and powers other electrical loads including vehicle lighting, thus preventing dimming.
Solution Approach 2:
The secondary energy storage device serves as an intermediary that absorbs the transient power demand of the EHC heater, preventing voltage drops that would otherwise affect other electrical systems such as vehicle lighting. This isolation protects lighting intensity while enabling effective catalyst heating.
3Temperature
If the primary energy storage device is used to power the EHC device during cold start, then the catalyst reaches light-off temperature, but the state of charge of the primary energy storage device will be significantly reduced
Solution Approach 1:
The secondary energy storage device (capacitor) is pre-charged during normal operation and then deployed in advance during cold start conditions to provide the high transient power needed for EHC heater operation. This preliminary energy storage prevents significant discharge of the primary energy storage device (battery).
Solution Approach 2:
The secondary energy storage device acts as an intermediary energy buffer that handles the high-power transient demand of catalyst heating during cold starts. This protects the primary energy storage device from significant state of charge reduction while ensuring the catalyst reaches light-off temperature effectively.
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
The system prevents deep discharge of primary energy storage devices, extends battery life, and reduces dimming of vehicle lighting by using secondary energy storage to power the EHC device, ensuring effective emission reduction at cold starts.
Implementation Method 1
The EHC device has an electric heater that is selectively connected the generator for receiving energy and a selectively activated catalyst that is heated to a respective light-off temperature
Data Source
AI summary
An exhaust gas treatment system for an internal combustion engine is provided. The exhaust gas system includes an exhaust gas conduit, a generator, a vehicle electrical system, a primary energy storage device, a rechargeable secondary energy storage device, an electrically heated catalyst (“EHC”) device, and a control module. The primary energy storage device is selectively connected to the generator. The primary energy storage device has a threshold state of charge (“SOC”). The rechargeable secondary energy storage device is selectively connected to the generator and the vehicle electrical system. The EHC device is in fluid communication with the exhaust gas conduit. The EHC device has an electric heater that is selectively connected the generator for receiving energy and a selectively activated catalyst that is heated to a respective light-off temperature.