Charge Motion Control Valve Engine Burn Rate
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Solution Overview
Problem
Existing engine control systems face challenges in managing high engine loads, leading to elevated cylinder pressures and potential structural and NVH issues due to increased air flow and reduced spark retard, which can result in premature engine degradation.
Innovation Solution
A method involving a charge motion control valve (CMCV) that decreases engine burn rate at high loads while increasing injection of a knock control fluid, with an engine controller adjusting the CMCV based on the availability of knock control fluid to balance engine performance and knock prevention.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the CMCV is adjusted to increase air flow at high engine loads, then engine power is improved, but cylinder peak pressures and rates of pressure rise become excessively high causing structural and NVH issues
Solution Approach 1:
The system changes the burn rate parameter by adjusting CMCV position at high engine loads. By controlling the burn rate to be within a specific range (5-15% per degree crank angle), the system achieves optimal balance between power output and pressure management, preventing excessive cylinder peak pressures while maintaining engine power.
2Power
If the CMCV is adjusted to increase air flow at high engine loads, then engine power is improved, but structural and NVH issues occur due to elevated pressure effects
Solution Approach 1:
The system implements dynamic parameter control by adjusting the CMCV to maintain burn rate within 5-15% per degree crank angle at high loads. This parameter optimization prevents premature engine degradation and NVH issues while preserving power output, thereby improving overall engine reliability.
3Stress or pressure
If the CMCV is opened to decrease engine burn rate at high engine loads, then cylinder peak pressures are reduced, but engine knock propensity increases
Solution Approach 1:
The system optimizes the burn rate parameter to fall within 5-15% per degree crank angle at high engine loads. This controlled burn rate reduction decreases cylinder peak pressures while maintaining sufficient combustion speed to prevent engine knock, resolving the trade-off between pressure management and knock prevention.
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 cylinder peak pressures, improves engine NVH, and allows higher torque operation by judiciously using spark retard and knock control fluid injection, addressing the propensity for engine knock and structural loads.
Implementation Method 1
take advantage of the charge-cooling effect of the high octane alcohol fuel
Implementation Method 2
adjusting the position of the valve, the flow of air through the valve to a downstream cylinder may be selectively restricted or unrestricted
Data Source
AI summary
Methods and systems are provided for improving fuel usage while addressing knock by adjusting the use of spark retard and direct injection of a knock control fluid based on engine operating conditions and the composition of the injected fluid. One or more engine parameters, such as EGR, VCT, boost, throttle position, and CMCV, are coordinated with the direct injection to reduce torque and EGR transients.