In-Cylinder Injection Valve Checking for Fuel Accuracy
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Solution Overview
Problem
Existing diagnostic techniques for in-cylinder injection valves during compression strokes face challenges in accurately detecting minute fuel injection due to increased in-cylinder pressure and noise interference, especially when the fuel injection time is short and the fuel amount is minimal.
Innovation Solution
A control apparatus for internal combustion engines that performs a checking injection after the main injection, using the in-cylinder injection valve to inject a minute amount of fuel, and calculates the actual fuel amount based on in-cylinder air and exhaust gas air-fuel ratios, with controlled valve opening times and ignition timing to ensure accurate fuel injection, and adjusts the main injection fuel amount based on the difference between actual and theoretical fuel amounts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the in-cylinder injection valve is driven during a compression stroke to inject a minute amount of fuel, then the fuel injection amount is reduced, but the signal caused by fuel injection becomes weak and noise influence becomes unavoidable
Solution Approach 1:
The patent performs a checking injection before the actual sub-injection to preliminarily verify the injection valve's functionality. By injecting a slightly larger amount of fuel during the checking injection, a detectable signal is generated to confirm proper valve operation before proceeding with the minute fuel injection of the sub-injection.
Solution Approach 2:
The patent creates a copy of the injection process by performing a checking injection that mimics the sub-injection conditions. This copying allows verification of the injection valve's performance without relying on detecting the weak signal from the actual minute fuel injection, thereby solving the measurement precision problem.
2Duration of action of moving object
If the in-cylinder injection valve is driven during a compression stroke, then the injection timing is extended, but the increased in-cylinder pressure affects the fuel amount that is actually injected
Solution Approach 1:
The patent uses feedback by detecting the in-cylinder pressure during the compression stroke and using this information to determine the appropriate timing for the checking injection. The detected pressure conditions are fed back to the control system to adjust the injection timing, ensuring accurate fuel delivery despite pressure variations.
Solution Approach 2:
The patent changes the injection timing parameter dynamically based on the detected in-cylinder pressure conditions. By adjusting when the checking injection occurs within the compression stroke, the system compensates for pressure variations that would otherwise affect the actual fuel injection amount.
3Reliability
If a checking injection is performed to verify fuel injection accuracy, then the diagnostic capability is improved, but the engine operation complexity increases
Solution Approach 1:
The patent makes the injection valve universal by enabling it to perform multiple functions: the main injection function, the sub-injection function, and the checking injection function. This multi-functionality allows the same hardware component to provide diagnostic capability without requiring separate testing equipment, thereby improving reliability without proportionally increasing device complexity.
Solution Approach 2:
The injection valve performs self-diagnosis by executing a checking injection that verifies its own functionality. The control device uses the engine's existing sensors and control systems to monitor the checking injection results, allowing the system to self-verify injection accuracy without external diagnostic equipment, thus improving reliability while minimizing added complexity.
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 allows for accurate verification of sub-injection fuel delivery, enhances checking accuracy, and ensures catalyst warm-up by adjusting the main injection fuel amount, thereby improving combustion stability and reducing catalyst warm-up time.
Implementation Method 1
a minute amount of fuel is injected from an in-cylinder injection valve in a compression stroke
Implementation Method 2
a spark plug that is controlled so as to perform ignition after the sub-injection
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
In the case of performing a main injection, and a sub-injection that injects a minute amount of fuel in a region (i) in Fig. 3, a check is conducted to determine whether or not the minute amount of fuel is injected accurately. In a specific cycle at a time of cold starting when catalyst warm-up control is performed, the main injection is omitted and a checking injection corresponding to a sub-injection is performed. Injection conditions of the in-cylinder injection valve 28 are made uniform between the checking injection and the sub-injection. A fuel amount that is actually injected from the in-cylinder injection valve 28 in the specific cycle is calculated based on the air-fuel ratio of exhaust gas discharged from the engine 10 and an in-cylinder air amount, and is compared with a fuel amount that theoretically should be injected from the in-cylinder injection valve 28.