Ammonia-DME Engine Operation Using Self-Igniting Pre-Injection
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Solution Overview
Problem
Ammonia is not self-igniting and requires an initial ignition in every operating cycle of an internal combustion engine, necessitating complex dual-fuel systems or spark plugs, which are wear parts.
Innovation Solution
Operate the engine with an azeotropic mixture of ammonia and dimethyl ether, utilizing a pre-injection of self-igniting fuel to ignite the main injection, and separate the components for efficient fuel management and exhaust treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ammonia is used as a primary fuel for internal combustion engine, then CO2-neutral fuel operation is achieved, but self-ignition capability is lost requiring complex dual-fuel systems
Solution Approach 1:
The patent extracts the ignition function from the main fuel system by using a separate, small amount of self-igniting fuel (dimethyl ether) only for ignition purposes, while the main fuel (ammonia) remains separate. This allows ammonia to be used as the primary CO2-neutral fuel without requiring the entire system to be complex dual-fuel infrastructure.
Solution Approach 2:
Dimethyl ether serves as an intermediary substance that enables the combustion of ammonia without being the primary fuel. It provides the necessary ignition capability while allowing ammonia to remain the main CO2-neutral fuel source, thus mediating between the conflicting requirements of emissions reduction and ignition capability.
2Reliability
If spark plug is used for ignition, then ignition of non-self-igniting fuel is achieved, but wear and maintenance requirements increase
Solution Approach 1:
The patent replaces the mechanical wear-prone spark plug system with a chemical ignition system using dimethyl ether. Instead of relying on an electrical spark from a wear-prone plug, the system uses the self-igniting properties of dimethyl ether under compression to ignite the ammonia, eliminating mechanical wear components.
Solution Approach 2:
The patent changes the ignition mechanism from electrical (spark plug) to chemical (self-igniting fuel combustion). By altering the ignition parameter from electrical discharge to controlled chemical reaction, the system achieves reliable ignition without the wear and maintenance issues of spark plugs.
3Ease of operation
If multiple injectors per cylinder are provided, then dual-fuel injection is enabled, but device complexity and cost increase
Solution Approach 1:
The patent segments the fuel injection system into two separate, simple injection paths: one for dimethyl ether and one for ammonia. Rather than using multiple injectors in a single complex system, it divides the function into two independent, simpler injection systems that can be managed separately, reducing 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
Simplifies fuel handling, reduces the need for separate fuel types and maintenance, enhances combustion properties, and optimizes exhaust gas treatment without additional components.
Implementation Method 1
igniting the mixture introduced into the combustion chamber
Implementation Method 2
utilizing the expansion of the ignited mixture to drive the internal combustion engine
Implementation Method 3
liquefying the mixture by generating an overpressure, preferably by an overpressure of at least 5 bar
Implementation Method 4
liquefying the mixture by generating an overpressure
Implementation Method 5
a self-igniting pre-injection and subsequently a main injection with the non-self-igniting fuel, so that ignition of the self-igniting pre-injection leads to ignition of the main injection
Data Source
Figure 1
AI summary
The present invention relates to a method for operating an internal combustion engine with a mixture of ammonia and dimethyl ether, comprising the steps of: injecting or blowing the liquefied or gaseous mixture into a combustion chamber, igniting the injected or blown-in mixture in the combustion chamber, and using the expansion of the ignited mixture for driving the internal combustion engine, preferably also comprising the step, prior to the injection or blowing step; liquefying the mixture by generating an overpressure, preferably an overpressure of at least 5 bar, preferably of 8 bar, and particularly preferably of 9 bar and an overpressure of at most 20 bar, preferably of 15 bar, and particularly preferably of 10 bar.