Retarded Compression Injection Timing for Alcohol Fuel Cold Start
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Advancing injection timing in alcohol-fuelled engines to take advantage of charge cooling effects can lead to reduced engine startability and degraded combustion stability during cold-start conditions due to excessive cooling and slower fuel evaporation, resulting in reduced fuel economy and increased exhaust emissions.
Innovation Solution
Implementing compression direct fuel injection with a retarded timing as the fuel alcohol content increases, along with increased fuel rail pressure and multiple injections, to enhance air-charge and valve temperatures for efficient evaporation and homogeneous mixture formation, thereby improving engine startability and reducing fuel losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If injection timing is advanced to take advantage of charge cooling effects of alcohol fuel, then peak torque output is improved, but engine startability is reduced and combustion stability is degraded during cold-start
Solution Approach 1:
The injection timing is made dynamic and adaptive based on engine operating conditions. The system switches between advanced injection timing (for normal operation to maximize torque) and retarded injection timing (for cold-start to ensure reliable ignition). This dynamic adjustment resolves the contradiction by allowing the system to optimize for different operational priorities at different times.
Solution Approach 2:
The injection timing parameter is changed based on fuel alcohol content and engine temperature conditions. When alcohol content is high during cold-start, the injection timing is retarded to allow sufficient evaporation time. When engine is warm or alcohol content is low, timing is advanced to maximize torque. This parameter adaptation resolves the contradiction by adjusting the timing to match operational requirements.
2Power
If injection timing is advanced to increase charge density, then torque output is improved, but fuel evaporation efficiency is reduced during cold-start
Solution Approach 1:
The injection timing is dynamically adjusted based on engine temperature and fuel composition. During cold-start with high alcohol content, timing is retarded to prioritize evaporation. During warm operation, timing is advanced to prioritize torque output. This dynamic switching resolves the contradiction by allowing the system to optimize for evaporation when needed and for power when conditions permit.
Solution Approach 2:
The injection timing parameter is changed in response to engine temperature and alcohol content measurements. The system retards timing when temperature is low and alcohol content is high to ensure evaporation, then advances timing when temperature increases to maximize torque. This parameter adaptation resolves the contradiction by matching timing to thermal conditions.
3Quantity of substance
If injection timing is advanced to cool the intake system, then charge density is increased, but combustion stability is reduced during cold-start
Solution Approach 1:
The injection timing is dynamically adjusted to maintain combustion stability during cold-start while still achieving adequate charge density. During cold-start, timing is retarded to ensure complete fuel evaporation and homogeneous mixture formation, which stabilizes combustion. Once the engine warms up, timing is advanced to increase charge density for maximum torque. This dynamic adjustment resolves the contradiction by prioritizing stability when temperature is low and density when temperature is adequate.
Solution Approach 2:
The injection timing parameter is changed based on engine temperature and alcohol content to balance charge density and combustion stability. During cold-start with high alcohol content, timing is retarded to ensure complete evaporation and stable combustion. When engine warms up, timing is advanced to maximize charge density and torque output. This parameter adaptation resolves the contradiction by matching timing to thermal conditions.
4Reliability
If injection timing is retarded to improve fuel evaporation during cold-start, then engine startability is improved, but charge cooling effect is reduced
Solution Approach 1:
The injection timing is dynamically adjusted to optimize for startability during cold-start, then switched to advance timing for torque optimization during warm operation. During cold-start, timing is retarded to ensure complete fuel evaporation and reliable ignition. Once the engine is running and warm, timing is advanced to maximize torque output. This dynamic switching resolves the contradiction by allowing the system to prioritize different performance aspects at different operational stages.
Solution Approach 2:
The injection timing parameter is changed based on engine temperature and operational stage. During cold-start, timing is retarded to ensure complete evaporation and reliable start. After engine warms up, timing is advanced to maximize torque output. This parameter adaptation resolves the contradiction by matching timing to the engine's thermal state and operational requirements.
5Power
If injection timing is advanced to maximize charge cooling effect, then fuel economy is degraded during cold-start, but this is acceptable for normal operation
Solution Approach 1:
The injection timing is dynamically adjusted to optimize fuel economy during cold-start by retarding timing to ensure complete evaporation and efficient combustion. During normal warm operation, timing is advanced to maximize charge cooling effect and torque output, where fuel economy is less critical. This dynamic adjustment resolves the contradiction by prioritizing fuel economy when the engine is cold and power when the engine is warm.
Solution Approach 2:
The injection timing parameter is changed based on engine temperature and operational conditions. During cold-start, timing is retarded to ensure complete evaporation and efficient combustion, improving fuel economy. During normal operation, timing is advanced to maximize charge cooling effect and torque output. This parameter adaptation resolves the contradiction by matching timing to thermal conditions and operational priorities.
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 improves fuel evaporation and combustion stability at cold-start conditions, enhancing engine startability, fuel economy, and reducing cold-start exhaust emissions without the need for pilot fuel injections.
Implementation Method 1
enhance air-charge and valve temperatures for efficient evaporation and homogeneous air-fuel mixture formation
Implementation Method 2
take advantage of the increased charge cooling effects of the alcohol fuel's higher heat of vaporization
Implementation Method 3
combustion of alcohol-fuelled engines
Data Source
AI summary
Systems and methods of operating an engine, the engine including an injector configured to directly inject fuel into an engine cylinder. One example method comprises, during an engine cold start, performing compression direct fuel injection, and retarding a timing of the compression injection as a fuel alcohol content of the fuel increases.