Hybrid Engine Fuel Injection Control for Lean-Burn Stability
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Solution Overview
Problem
Combustion stability is not secured in the transition section between theoretical air-fuel ratio and lean-burn combustion operations in hybrid vehicle engines, leading to potential fuel inefficiency and increased nitrogen oxide emissions.
Innovation Solution
A control apparatus and method for a hybrid vehicle engine that selectively switches between single and multiple fuel injection modes, with multiple injections occurring in overshoot sections to maintain stable air-fuel ratios during transitions from theoretical to lean-burn combustion regions, utilizing a triple injection mode where fuel is injected twice during the intake stroke and once during the compression stroke.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine transitions from theoretical air-fuel ratio operation to lean-burn combustion operation, then fuel efficiency is improved, but combustion stability deteriorates in the transition section
Solution Approach 1:
The fuel injection process is segmented into multiple injections (triple injection mode) during the transition period. The controller divides the total fuel quantity into multiple injection events: first injection at the beginning of the intake stroke, second injection at the end of the intake stroke, and third injection at the beginning of the compression stroke. This segmentation allows gradual fuel-air mixing and better control of combustion stability during the transition from theoretical air-fuel ratio to lean-burn operation.
Solution Approach 2:
The controller performs preliminary fuel injection actions in advance of the main combustion event. The first injection occurs at the beginning of the intake stroke, and the second injection occurs at the end of the intake stroke, before the compression stroke begins. This preliminary action ensures that fuel is progressively mixed with air before compression, preventing air-fuel ratio overshoot and maintaining combustion stability during the transition to lean-burn operation.
2Reliability
If the engine operates at theoretical air-fuel ratio, then complete combustion is realized, but nitrogen oxide emissions increase when transitioning to lean-burn combustion
Solution Approach 1:
The controller implements periodic fuel injection actions with specific timing intervals. The triple injection mode uses periodic injection events at predetermined crank angle positions: first injection at the beginning of the intake stroke, second injection at the end of the intake stroke, and third injection at the beginning of the compression stroke. This periodic action pattern ensures consistent fuel-air mixing and maintains complete combustion while controlling nitrogen oxide emissions during the transition to lean-burn operation.
3Stability of the object's composition
If multiple fuel injections are performed in the overshoot section, then air-fuel ratio stability is improved, but injection system complexity increases
Solution Approach 1:
The controller dynamically adjusts the fuel injection strategy based on real-time operating conditions. The triple injection mode is selectively activated during the transition period from theoretical air-fuel ratio to lean-burn combustion operation, while single injection mode is used in stable operating regions. The controller determines the transition period based on parameters such as engine speed, load, and target air-fuel ratio, making the injection system adaptable rather than statically complex.
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
Ensures combustion stability by smoothly mixing fuel and air, lowering intake air temperature through latent heat evaporation, thereby improving fuel efficiency and reducing nitrogen oxide emissions during transitions.
Implementation Method 1
lowering intake air temperature through latent heat evaporation
Implementation Method 2
lowering intake air temperature through latent heat evaporation
Data Source
AI summary
A control apparatus of an engine for a hybrid vehicle includes an engine including at least one cylinder that generates power required for vehicle driving by fuel combustion, an injector that injects fuel into the cylinder, a driving motor that assists the power of the engine, and a controller that selectively performs a single injection mode in which fuel is injected once into the cylinder of the engine through the injector and a multiple injection mode in which fuel is injected a plurality of times into the cylinder of the engine through the injector, in a transition region that transitions from a theoretical air-fuel ratio operating region in which the engine is operated at a theoretical air-fuel ratio to a lean-burn combustion operating region in which the engine is operated leaner than the theoretical air-fuel ratio.