Electric Compressor Manifold Depletion for Cold Start Emission Reduction
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Solution Overview
Problem
Cold start emissions of internal combustion engines are high due to excess airflow during initial engine starts, leading to increased noise, vibration, and harshness (NVH). Existing solutions, such as variable lift camshafts, are costly.
Innovation Solution
An engine system that uses an electric compressor (eCompressor) to deplete the manifold air pressure before starting the engine, reducing airflow and subsequently emissions and NVH. The eCompressor is operated in reverse to draw air out of the manifold, and the throttle is kept open during this process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If variable lift camshafts with small lift are used to reduce airflow into the cylinder, then cold start emissions are reduced, but the system cost increases
Solution Approach 1:
The eCompressor, originally designed for charging the air suspension system, is repurposed to perform the additional function of reducing manifold air pressure during cold starts. This multi-functionality eliminates the need for separate expensive hardware like variable lift camshafts while achieving the same emissions reduction goal
Solution Approach 2:
The system uses its own existing eCompressor component to solve the cold start emissions problem, rather than introducing external specialized hardware. The eCompressor serves itself by being controlled to deplete the manifold before engine start, making the system self-sufficient and cost-effective
2Speed
If excess airflow is allowed into the engine during cold start, then the engine starts quickly, but emissions and noise vibration harshness increase
Solution Approach 1:
The eCompressor performs a preliminary action by depleting the manifold air pressure before the engine cranking begins. This pre-conditioning of the manifold creates a pressure differential that facilitates quicker engine start while simultaneously reducing the excess airflow that causes emissions and NVH problems
Solution Approach 2:
The system applies preliminary anti-action by removing air from the manifold before engine start, counteracting the natural tendency for excess air to be present. This pre-removal of air prevents the harmful effects of excess airflow during the critical cold start period
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 effectively reduces cold start emissions and NVH by minimizing airflow into the engine during startup, while also offering a cost-effective solution by repurposing existing eCompressor technology.
Implementation Method 1
The compressor is driven by an electric motor and is configured to deliver air toward and away from the manifold. The controller determines an ICE start request and, based on the ICE start request, sends a signal to the electric motor to rotate the compressor in a direction that moves air out of the manifold.
Implementation Method 2
The compressor is driven by an electric motor and is configured to deliver air toward and away from the manifold
Data Source
AI summary
An engine system that delivers torque to a driveline of a vehicle includes an internal combustion engine (ICE), a manifold, a compressor and a controller. The manifold selectively communicates air into the ICE. The compressor is driven by an electric motor and is configured to deliver air toward and away from the manifold. The controller determines an ICE start request and, based on the ICE start request, sends a signal to the electric motor to rotate the compressor in a direction that moves air out of the manifold. The eCompressor is used to deplete air in the manifold before starting the ICE. As a result, a reduction in fuel used and therefore a reduction in emissions at startup is achieved.