Digital Hydraulic Engine Preheating for CNG and Ammonia
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Solution Overview
Problem
Compression ignition engines face challenges in utilizing fuels like compressed natural gas (CNG) and ammonia (NH3) due to their high self-ignition temperatures and storage limitations, which hinder efficient combustion and widespread adoption.
Innovation Solution
A fully flexible, self-optimizing, digital hydraulic engine design with electronically controllable valves and fuel injectors, incorporating a Heat Exchanger between the Air Rail and Exhaust Manifold to preheat air and fuel, achieving effective compression ignition by simulating high compression ratios without the need for liquefaction or additional ignition sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If compression ignition engines use fuels like CNG and ammonia, then fuel efficiency and carbon-free operation are improved, but high self-ignition temperatures and storage limitations prevent effective combustion
Solution Approach 1:
The patent applies preliminary action by preheating the intake air using exhaust heat before combustion occurs. This preheating raises the air temperature closer to the self-ignition temperature of fuels like ammonia and CNG, enabling compression ignition to proceed effectively without requiring excessively high compression ratios or additional ignition sources.
Solution Approach 2:
The patent uses an intermediary approach by introducing a heat exchanger that mediates between the exhaust system and the intake air. This heat exchanger transfers thermal energy from the hot exhaust gases to the cooler intake air, creating the necessary temperature conditions for combustion of high self-ignition temperature fuels.
2Reliability
If compression ignition engines operate with high compression ratios to ignite high self-ignition temperature fuels, then combustion effectiveness is improved, but engine complexity and mechanical stress increase
Solution Approach 1:
The patent applies parameter changes by modifying the temperature parameter of the intake air through preheating. Instead of increasing the compression ratio to achieve effective combustion, the system changes the temperature parameter of the air-fuel mixture, thereby reducing the required compression ratio and simplifying the engine design while maintaining combustion effectiveness.
3Quantity of substance
If fuels like ammonia are stored in liquid form, then storage efficiency and renewability are improved, but high self-ignition temperatures make ignition difficult
Solution Approach 1:
The patent applies preliminary action by preheating the intake air before combustion. This preheating step raises the temperature of the air-fuel mixture closer to the ignition temperature of ammonia, enabling reliable ignition while allowing the fuel to be stored in liquid form for efficient storage.
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 efficient combustion of gaseous fuels like CNG and ammonia by maintaining ambient intake air temperature and using preheating to achieve high combustion cylinder temperatures, reducing NOx formation and extending engine range by allowing flexible fuel injection strategies.
Implementation Method 1
incorporating a Heat Exchanger between the Air Rail and Exhaust Manifold to preheat air and fuel
Implementation Method 2
achieving effective compression ignition by simulating high compression ratios
Data Source
AI summary
The engines include compression cylinders, combustion cylinders, an air rail, and a heat exchanger. The methods of operating a compression ignition engine include taking air into a compression cylinder of the engine, compressing the air in the compression cylinder to raise the pressure and temperature of the air, passing the compressed air through a heat exchanger, and from the heat exchanger into a combustion cylinder, further compressing the compressed air during a compression stroke of the combustion cylinder, igniting fuel in the combustion cylinder at or near the end of the compression stroke by compression ignition, followed by a power stroke, and opening an exhaust valve at the end of the power stroke and passing at least some of the exhaust in the combustion cylinder through the heat exchanger to heat air that has been compressed in the compression cylinder and is then passing through the heat exchanger.