Variable Compression Diesel Engine for Ethanol Auto-Ignition
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Solution Overview
Problem
Heavy work vehicles typically use diesel engines that generate undesirable emissions, and ethanol, a low cetane fuel derived from renewable resources, is not suitable for these applications due to ignition challenges in cold start and low load conditions.
Innovation Solution
A power system with a compression ignition engine that uses low cetane fuels like ethanol, featuring piston-cylinder sets with adjustable compression ratios controlled by a controller to achieve auto-ignition temperatures, especially at low loads and cold conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a compression ignition engine uses low cetane fuel like ethanol, then renewable resource utilization and emission reduction are improved, but reliable ignition cannot be achieved in cold start and low load conditions
Solution Approach 1:
The piston actuation arrangement dynamically adjusts the compression ratio of the combustion chamber based on operating conditions. During cold start and low load conditions, the system increases the compression ratio to achieve reliable auto-ignition of low cetane fuel, while during normal operation it maintains an optimized compression ratio for efficiency and power output.
Solution Approach 2:
The system changes the compression ratio parameter dynamically by repositioning the piston actuation arrangement. This parameter change enables the engine to adapt to different operating conditions, ensuring reliable ignition of low cetane fuel when needed while maintaining optimal performance during normal operation.
2Reliability
If the compression ratio is increased to enable auto-ignition of low cetane fuel, then ignition reliability is improved, but the engine complexity increases due to the piston actuation arrangement
Solution Approach 1:
The piston actuation arrangement serves multiple functions: it controls the compression ratio for ignition reliability, manages the piston position for optimal combustion, and adapts to different operating conditions. By consolidating these functions into a single mechanism, the system achieves reliable ignition of low cetane fuel without proportionally increasing overall system 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
Enables reliable ignition and combustion of low cetane fuels like ethanol in heavy work vehicles, reducing emissions and improving performance and efficiency.
Implementation Method 1
a compression ignition engine configured to receive, ignite, and combust intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas
Implementation Method 2
a fuel injector configured to inject fuel into the combustion chamber
Implementation Method 3
a plurality of piston-cylinder sets configured to receive, ignite, and combust intake gas that includes the charge air from the intake arrangement to generate mechanical power and exhaust gas
Data Source
AI summary
A power system for a work vehicle includes a compression ignition engine with piston-cylinder set that defines a compression ratio. The engine further includes a piston actuation arrangement coupled to the piston of the first piston-cylinder set and configured to be repositioned to dynamically modify the compression ratio of the first piston-cylinder set. The system includes a controller coupled to command the first piston actuation arrangement such that, in an auto-ignition assistance mode, the first piston actuation arrangement places the first piston into a first configuration resulting in a first compression ratio; and in a nominal mode, the first piston actuation arrangement places the first piston into a second configuration resulting a second compression ratio that is lower than the first compression ratio.