Water Injection Timing for Engine Knock and Torque Control
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Solution Overview
Problem
Existing engine control methods for alcohol-fueled engines, such as those using water injection to address engine knocking, often result in unexpected torque variations due to varying cylinder temperatures at the time of injection, leading to inconsistent engine performance.
Innovation Solution
The method involves adjusting the timing and amount of direct water injection based on engine operating conditions, knock intensity, and desired dilution, with throttle adjustments to compensate for torque variations, and using multiple injections of knock control fluid before intake valve closing to mitigate knock and maintain desired torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If water injection timing is adjusted to address engine knocking, then knock intensity is reduced, but torque variations occur due to changing cylinder temperatures
Solution Approach 1:
The control system continuously monitors cylinder temperature and knock intensity, then adjusts water injection timing and throttle position in real-time to maintain optimal engine performance while addressing knock conditions
Solution Approach 2:
The system dynamically changes injection timing parameters and throttle position based on detected knock intensity and cylinder temperature conditions, optimizing the balance between knock control and torque consistency
2Object-generated harmful factors
If water injection amount is increased to reduce NOx emissions, then emissions are improved, but engine torque is reduced due to charge displacement
Solution Approach 1:
The system dynamically adjusts water injection amount based on real-time engine operating conditions, throttle position, and knock detection, optimizing the balance between emissions control and power output
Solution Approach 2:
The control system varies injection quantity parameters according to engine load, speed, and emissions requirements, maintaining optimal torque while achieving desired NOx reduction
3Object-affected harmful factors
If multiple water injections are performed before intake valve closing to mitigate knock, then knock control is improved, but torque variations increase due to vaporization effects
Solution Approach 1:
The water injection process is divided into multiple staged injections before intake valve closing, with each injection carefully controlled to provide knock mitigation while minimizing torque variations through progressive charge cooling
Solution Approach 2:
The system monitors knock intensity and cylinder temperature during multiple injections, adjusting subsequent injection timing and quantity based on real-time feedback to maintain torque consistency
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 effectively addresses torque variations and improves engine performance by optimizing the timing and amount of water injection and throttle adjustments, ensuring consistent engine operation and reduced NOx emissions.
Implementation Method 1
The cooling and dilution effects of the injected water may be used to address cylinder knock
Implementation Method 2
the injected water may vaporize more, leading to more displacement of air-fuel charge
Implementation Method 3
The cooling and dilution effects of the injected water may be used to address cylinder knock
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 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, are coordinated with the direct injection to reduce torque and EGR transients.