Internal Combustion Engine Knocking Sensor Pre-Injection Control
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Solution Overview
Problem
Existing methods for operating internal combustion engines face challenges in controlling peak pressure gradients in combustion chambers, which can lead to engine damage due to non-linear dependencies on pre-injection volume and the high cost and complexity of cylinder pressure sensors.
Innovation Solution
A method utilizing a knocking sensor to detect sound signals from combustion, calculating evaluation points based on energization duration, and determining an optimum energization duration to regulate peak pressure gradients, thereby reducing component load and preventing damage, while being more cost-effective and robust than traditional cylinder pressure sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cylinder pressure sensors are used to determine peak pressure gradients, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent introduces knocking sensors as intermediary devices that indirectly measure peak pressure gradients through acoustic emissions from combustion. Instead of directly measuring pressure with complex pressure sensors, the system uses simpler knocking sensors that detect sound waves generated during combustion, which correlate with pressure gradient characteristics. This intermediary approach maintains measurement capability while significantly reducing device complexity and cost.
Solution Approach 2:
The patent replaces the mechanical pressure sensing system with an acoustic detection system. Rather than using mechanical pressure sensors that require direct contact with combustion gases and complex installation, the system uses piezoelectric or piezoresistive knocking sensors that detect acoustic vibrations through the engine block. This substitution maintains the ability to determine peak pressure gradients while eliminating the complexity of direct pressure measurement systems.
2Reliability
If pre-injection volume is increased to reduce peak pressure gradient, then reliability is improved, but manufacturing precision requirements increase due to non-linear dependency
Solution Approach 1:
The patent implements a feedback system where knocking sensors continuously monitor combustion characteristics and provide real-time information about peak pressure gradients. The control unit processes this feedback signal and adjusts pre-injection parameters dynamically to maintain optimal pressure gradient levels. This closed-loop feedback compensates for manufacturing tolerances and aging effects, allowing reliable operation without extremely tight manufacturing precision on the injector side.
Solution Approach 2:
The patent transitions from static pre-injection volume settings to dynamic adjustment of pre-injection parameters based on real-time combustion feedback. The system can adaptively modify pre-injection timing, duration, and volume in response to changing operating conditions and detected combustion characteristics. This dynamic approach compensates for the non-linear relationship between pre-injection volume and peak pressure gradient, maintaining reliability across varying conditions without requiring perfect manufacturing precision.
3Measurement precision
If exact control of injector is implemented to achieve precise pre-injection volume, then measurement precision is improved, but ease of manufacture deteriorates due to tight tolerances and robust design requirements
Solution Approach 1:
The patent enables the injector system to self-adjust and self-optimize through feedback from knocking sensors. Rather than requiring precision-manufactured injectors that maintain exact pre-injection volumes under all conditions, the system allows the injector to operate with normal manufacturing tolerances and uses the feedback control system to compensate for variations. This self-service approach shifts the precision requirement from the mechanical injector component to the electronic control system, significantly improving ease of manufacture.
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 method allows for simple and cost-effective regulation of peak pressure gradients, reducing the risk of engine damage by accurately determining the optimum energization duration based on knocking sensor data, which correlates with pressure gradients, and is more reliable and precise than existing methods.
Implementation Method 1
at least one knocking sensor...a first signal of the at least one knocking sensor is detected
Data Source
AI summary
A method for operating an internal combustion engine: detecting a first signal from a knock sensor in a temporal measurement window for a first load point and for a first energization duration—assigned to a pre-injection—of an injector for an operating cycle; calculating a first first evaluation point from the first signal by a first metric; detecting a second signal from the knock sensor in the temporal measurement window for the first load point and for a second energization duration—assigned to the pre-injection—of the injector for the operating cycle; calculating by the first metric a second first evaluation point from the second signal; determining an optimum energization duration as an optimum of the first first evaluation point and the second first evaluation point; and storing and/or applying the optimum energization duration to the first load point and the first combustion chamber.