Compression Ignition Engine Fuel Injection Timing Control
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Solution Overview
Problem
Existing compression ignition type internal combustion engines face challenges in stabilizing the ignition timing of main injection fuel, leading to issues such as rapid heat release, combustion noise, reduced engine output, and misfires, due to deviations in ignition timing from the optimum timing.
Innovation Solution
A control system where a smaller amount of auxiliary injection fuel is injected before the main injection fuel, igniting by premixed charge compression ignition, and the heat generated stabilizes the ignition timing of the main injection fuel by causing premixed charge compression ignition after the main injection fuel is started.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If auxiliary fuel is injected after completion of main fuel injection to control ignition timing, then ignition timing can be controlled, but ignition timing stability deteriorates and causes combustion noise and misfires
Solution Approach 1:
The patent applies preliminary action by injecting auxiliary fuel before the main fuel injection is completed, rather than after. This timing allows the auxiliary fuel to ignite first and stabilize the combustion chamber temperature and pressure conditions, ensuring that when the main fuel ignites, the ignition timing is stable and reliable. This resolves the contradiction by establishing proper combustion conditions in advance.
2Power
If ignition timing deviates from optimum timing, then engine output may increase temporarily, but combustion noise increases and misfires occur
Solution Approach 1:
The patent employs feedback control by using a crank angle sensor to detect the actual ignition timing and comparing it with the target ignition timing. The ECU adjusts the auxiliary fuel injection timing and amount based on this feedback to maintain optimal ignition timing, thereby preventing combustion noise and misfires while maintaining engine output.
Solution Approach 2:
The patent changes the parameter of fuel injection timing by injecting auxiliary fuel before main fuel completion, and adjusts the amount of auxiliary fuel based on engine operating conditions. This parameter optimization ensures ignition timing remains at the optimum point, balancing engine output with reduction of combustion noise and misfires.
3Power
If rapid heat release occurs due to unstable ignition timing, then engine power may increase, but combustion noise increases significantly
Solution Approach 1:
The patent applies preliminary action by having the auxiliary fuel ignite before the main fuel, which pre-heats the combustion chamber and stabilizes the ignition conditions. This prevents rapid, uncontrolled heat release from the main fuel, thereby reducing combustion noise while maintaining engine power through controlled sequential combustion.
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 effectively stabilizes the ignition timing of the main injection fuel, reducing fluctuations and ensuring consistent engine performance by controlling the injection timing of the auxiliary fuel to align with the target compression ignition timing, thereby minimizing combustion noise and maintaining optimal engine output.
Implementation Method 1
a smaller amount of auxiliary injection fuel QN than the main injection fuel QM is injected from the fuel injector 3 before the main injection fuel QM to ignite the auxiliary injection fuel QN by the premixed charge compression ignition
Implementation Method 2
the heat generated by the premixed compression ignition of the auxiliary injection fuel QN causes premixed charge compression ignition of the main injection fuel QM
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
An action of injection of the main injection fuel (QM) from the fuel injector (3) is started within a range of crank angle from 10 degree before the compression top dead center to 10 degree after the compression top dead center. A smaller amount of the auxiliary injection fuel (QN) than the main injection fuel (QM) is made to be injected from the fuel injector (3) before the main injection fuel (QM) so as to make the auxiliary injection fuel (QN) ignite by the premixed charge compression ignition. The injection timing of the auxiliary injection fuel (QN) is controlled to a timing whereby a heat generated by the premixed charge compression ignition of the auxiliary injection fuel (QN) causes the premixed charge compression ignition of the main injection fuel (QM) after the start of injection of the main injection fuel (QM).