Engine Fuel Injection Control for Stable Low-Temperature Ignition
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Solution Overview
Problem
Existing control systems for internal combustion engines struggle to maintain stable ignitionability during low temperature or low load conditions, as they degrade ignitionability when attempting to control fuel injection similar to high-load conditions.
Innovation Solution
A control system that includes a compression end temperature estimator, a target compression end temperature setter, and a fuel injection controller, which performs multiple pilot injections to adjust the fuel injection amount in the first pilot injection to match the target compression end temperature, set according to engine operating conditions, and uses a cylinder pressure detector and heat release amount calculator to accurately control fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pilot injection amount is increased to raise compression end temperature for improving ignitionability in low temperature conditions, then ignitionability is improved, but combustion noise increases and ignitionability degrades in high load conditions
Solution Approach 1:
The patent applies dynamics by making the fuel injection control system adaptive to different operating conditions. The control unit dynamically adjusts the pilot injection amount based on real-time detection of compression end temperature and operating conditions (load, speed). This allows the system to optimize ignitionability in low-temperature conditions while preventing excessive combustion noise in high-load conditions, resolving the contradiction between improving ignitionability and reducing harmful factors.
Solution Approach 2:
The patent changes the parameter of fuel injection amount based on detected compression end temperature and operating conditions. By varying the pilot injection amount according to temperature parameters and load conditions, the system achieves stable ignitionability across different operating ranges while avoiding the harmful effects of excessive injection in high-load scenarios.
2Temperature
If high load control strategy is applied in low temperature conditions to increase pilot injection amount, then compression end temperature increases, but ignitionability degrades due to excessive fuel injection
Solution Approach 1:
The patent implements feedback control by detecting the actual compression end temperature and using this information to adjust the pilot injection amount. The control unit receives feedback from temperature detection and operating condition sensors, then optimizes the fuel injection quantity to achieve the target compression end temperature. This prevents both insufficient heating (poor ignitionability) and excessive heating (ignitionability degradation) by continuously adapting the injection amount to actual conditions.
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 ensures stable ignitionability by accurately controlling the compression end temperature and heat release amount, improving ignition quality especially in low temperature or low load conditions.
Implementation Method 1
a compression end temperature estimator for estimating a compression end temperature in the combustion chamber
Implementation Method 2
a heat release amount calculator for calculating a heat release amount in a predetermined crank angular range according to a pressure detected by the cylinder pressure detector
Implementation Method 3
internal combustion engine in which compression ignition is performed
Data Source
AI summary
A control system for an internal combustion engine having at least one fuel injection valve for injecting fuel into a combustion chamber of the engine. A compression end temperature in the combustion chamber is estimated. A target compression end temperature is calculated according to an operating condition of the engine. A main injection and a plurality of pilot injections before the main injection are performed by at least one fuel injection valve. A fuel injection amount in a first-performed pilot injection of the plurality of pilot injections is controlled so that the estimated compression end temperature coincides with the target compression end temperature.