SPCCI Engine Control System for In-Cylinder Temperature Estimation
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Solution Overview
Problem
Existing engine technologies face challenges in accurately determining the in-cylinder temperature during SPCCI combustion, which affects fuel efficiency and combustion noise, as conventional methods only estimate average temperatures and do not account for variations in in-cylinder conditions.
Innovation Solution
A control system that uses the CI combustion start timing as a parameter to estimate the in-cylinder temperature, employing Bayes estimation and band-pass filtering of in-cylinder pressure signals to accurately determine the actual CI timing, allowing for precise adjustment of ignition timing and exhaust gas recirculation to optimize combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If CI combustion takes place near compression top dead center to improve fuel efficiency, then fuel efficiency is maximized, but in-cylinder pressure rises excessively causing excessive combustion noise
Solution Approach 1:
The control system uses feedback from in-cylinder pressure sensors and temperature sensors to continuously monitor combustion conditions. Based on this feedback, the controller adjusts ignition timing and fuel injection timing in real-time to maintain optimal combustion phasing, preventing excessive pressure rise while maximizing fuel efficiency.
Solution Approach 2:
The system dynamically adjusts ignition timing and fuel injection timing based on real-time sensor data and predetermined maps. The control parameters are not fixed but vary continuously with operating conditions, allowing the engine to adapt to changing conditions and maintain optimal performance across different loads and speeds.
2Object-affected harmful factors
If ignition timing is retarded to reduce combustion noise, then combustion noise is reduced, but fuel efficiency drops
Solution Approach 1:
The control system continuously monitors in-cylinder pressure and temperature to detect combustion noise levels. When combustion noise exceeds acceptable thresholds, the feedback control adjusts ignition timing to reduce noise while minimizing the impact on fuel efficiency by making only necessary timing adjustments.
Solution Approach 2:
The system changes multiple parameters simultaneously - not just ignition timing but also fuel injection timing, injection quantity, and EGR rate. This multi-parameter adjustment allows the system to reduce combustion noise through coordinated changes that maintain combustion efficiency better than ignition timing adjustment alone.
3Ease of operation
If conventional temperature estimation methods are used, then the system is simple to operate, but only average in-cylinder temperature can be estimated without sufficient accuracy for controlling SPCCI combustion
Solution Approach 1:
The system introduces temperature sensors and pressure sensors as intermediary measurement devices that directly measure in-cylinder conditions. These sensors act as mediators between the combustion process and the control system, providing accurate real-time data without requiring complex calculation models or assumptions about average temperatures.
Solution Approach 2:
The patent replaces conventional mechanical temperature estimation methods (based on coolant temperature or intake air temperature) with direct electronic sensing using thermocouples or other temperature sensors placed inside the combustion chamber. This substitution of measurement methodology provides significantly higher temperature measurement accuracy while maintaining electronic control simplicity.
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 accurately determines in-cylinder temperature, enabling improved fuel efficiency and reduced combustion noise by adjusting ignition timing and exhaust gas recirculation, thus effectively controlling SPCCI combustion.
Implementation Method 1
a sensor device configured to measure a parameter indicative of an in-cylinder pressure during a mixture gas combusting
Implementation Method 2
an ignition plug configured to forcibly ignite the mixture gas; the mixture gas carries out SI combustion by flame propagation due to the ignition of the ignition plug
Implementation Method 3
the remaining unburnt mixture gas inside the combustion chamber combusts by self-ignition due to a pressure buildup caused by the heat generation and the flame propagation of the SI combustion
Data Source
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AI summary
A control system for a compression-ignition engine includes a combustion chamber, an injector, an ignition plug, a sensor device, and a controller having a circuity. The ignition plug forcibly ignites mixture gas to start combustion accompanied by flame propagation of a part of the mixture gas, and again ignites remaining unburnt mixture gas at a timing at which the unburnt mixture gas combusts by self-ignition. The controller is configured to execute an ignition controlling module to output an ignition signal to the ignition plug before a target timing so that the unburnt mixture gas self-ignites at the target timing, an ignition timing estimating module to estimate an actual CI timing indicative of a timing at which the unburnt mixture gas actually self-ignited based on an in-cylinder pressure parameter, and an in-cylinder temperature determining module to determine the in-cylinder temperature at a given crank angle based on the estimated result.