Electric Turbine and Phaser for Cold Start Emission Reduction
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Solution Overview
Problem
Cold start emissions of internal combustion engines are high due to excessive airflow during initial startup when the catalyst has not reached operating temperature, leading to increased noise, vibration, and harshness (NVH), and existing solutions like variable lift camshafts are expensive.
Innovation Solution
An engine system utilizing an electromechanical cam phaser and electric turbine to create a pathway for air to be drawn out of the manifold before starting, reducing manifold pressure and thus emissions, with a controller managing the operation of these components to achieve optimal conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If variable lift camshafts with small lift are used to reduce airflow during cold start, then emissions are reduced, but manufacturing cost increases
Solution Approach 1:
The system performs preliminary action by using the electric motor to rotate the turbine and create negative manifold pressure before the engine starts. This pre-conditioning of the airflow path reduces emissions during cold start without requiring expensive variable lift camshaft hardware. The ePhaser is also positioned in advance to create the appropriate valve timing for the flush operation.
2Ease of operation
If excess airflow is allowed during cold start, then engine startup is simpler, but emissions and noise vibration harshness increase
Solution Approach 1:
The turbine acts as an intermediary device that actively manages airflow during cold start. By rotating the turbine with the electric motor, the system creates a controlled negative pressure in the manifold, which mediates the airflow to reduce emissions and NVH while still enabling proper engine startup. This intermediary mechanism allows the system to balance simplicity with emission reduction.
3Object-generated harmful factors
If the throttle is closed during cold start to reduce airflow, then emissions decrease, but manifold vacuum creation becomes more difficult
Solution Approach 1:
The system replaces the traditional mechanical throttle-based vacuum creation with an electrically-driven turbine system. The electric motor rotates the turbine to actively pump air out of the manifold, substituting the passive mechanical throttle closure with an active electromagnetic mechanism. This allows the throttle to remain closed for emission reduction while the turbine creates the necessary manifold vacuum through electrical power.
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 decreases emissions and NVH by reducing airflow and fuel consumption during engine startup without the need for additional hardware, providing a cost-effective solution by leveraging existing eTurbine and ePhaser technology.
Implementation Method 1
The eTurbine is driven by an electric motor and is configured to deliver air toward and away from the manifold. The controller further sends a signal to the electric motor to rotate the eTurbine in a direction that moves air out of the manifold.
Implementation Method 2
The ePhaser is configured to adjust timing of the intake and exhaust valves. The controller determines an ICE start request and, based on the ICE start request, sends a signal to the ePhaser to open identified valves of the intake valves and the exhaust valves creating a pathway through the ICE.
Data Source
AI summary
An engine system that delivers torque to a driveline of a vehicle includes an internal combustion engine (ICE), a manifold, an engine phaser (ePhaser), an electric turbine (eTurbine) and a controller. The ICE includes intake valves and exhaust valves. The ePhaser is configured to adjust timing of the intake and exhaust valves. The eTurbine 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, sends a signal to the ePhaser to open identified valves of the intake valves and the exhaust valves creating a pathway through the ICE. The controller further sends a signal to the electric motor to rotate the eTurbine in a direction that moves air out of the manifold. The eTurbine is used to deplete air in the manifold before starting the ICE and reduce emissions at startup.