PDI Fuel Trim Estimation Across Port and Direct Injection Splits
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Solution Overview
Problem
Conventional fuel delivery systems in internal combustion engines, particularly those utilizing port and direct injection (PDI), face inaccuracies in long term fuel trims that can lead to increased emissions, especially during purge operations, due to unlearned data cells and inconsistent fueling errors between port fuel injection (PFI) and gasoline direct injection (GDI) modes.
Innovation Solution
A control strategy for a PDI fuel delivery system that uses a linear equation to predict long term fuel trims by determining a slope and offset based on split-ratios, allowing for accurate fueling adjustments and reducing emissions by populating unlearned data cells with learned values, thereby ensuring consistent fuel-air ratios across different engine operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If port timing and valve overlap are optimized for high-speed operation, then high-RPM power is improved, but low-end torque deteriorates
Solution Approach 1:
The valve timing system is made dynamically adjustable through variable valve timing (VVT) technology, allowing the valve overlap duration to be modified in real-time based on operating conditions. This enables the engine to optimize valve timing for both high-RPM power and low-end torque scenarios, resolving the contradiction between speed performance and low-speed torque production.
2Productivity
If valve overlap is increased to improve high-RPM power, then breathing efficiency at high speed is improved, but scavenging efficiency deteriorates
Solution Approach 1:
The valve overlap parameter is made variable rather than fixed, allowing it to be changed based on engine operating conditions. At high RPM, increased valve overlap improves breathing efficiency by enhancing charge motion. At low RPM, reduced valve overlap maintains scavenging efficiency by preventing excessive exhaust gas retention. This parameter variation resolves the contradiction between breathing and scavenging efficiency.
3Device complexity
If fixed valve timing is used for simple construction, then device complexity is reduced, but performance across all RPM ranges deteriorates
Solution Approach 1:
The valve timing system transitions from a fixed mechanical arrangement to a dynamically adjustable system using VVT technology. This allows the engine to adapt valve timing to different operating conditions, significantly improving overall performance across the RPM range while accepting increased system complexity. The performance gains outweigh the added complexity through electronic control mechanisms.
Data Source
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AI summary
A port and direct fuel injection (PDI) fuel delivery system for a vehicle having an engine configured to selectively operate between a port fuel injection (PFI) mode, a gasoline direct injection (GDI) mode, and a PDI mode includes a PFI system including plurality of PFI injectors, and a GDI system including a plurality of GDI injectors. The PFI and GDI systems are configured to provide various split-ratios of fuel mass injection to the engine based on a particular engine operating condition. A controller is programmed to identify a known first long term fuel trim (LTFT) for a first split-ratio, identify a known second LTFT for a second split-ratio, generate a linear equation based on the known first and second LTFTs, and determine an unknown third LTFT for a third split-ratio by utilizing the linear equation to facilitate reducing fueling errors and emissions.