Internal Combustion Engine Cold Start Emission Control
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Solution Overview
Problem
Heavy-duty diesel engines face challenges in reducing emissions, particularly during cold starts, due to the time required to heat exhaust after-treatment systems (EATS) to optimal operating temperatures, which affects catalytic converter light-off and subsequent emission control.
Innovation Solution
An internal combustion engine (ICE) arrangement that selectively uses diffusion combustion of a first fuel and flame propagation combustion of a second fuel to rapidly heat the EATS, with valve control strategies to manage fuel injection and exhaust timing based on catalytic converter temperature, ensuring reduced emissions before and after light-off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the EATS is heated to optimal operating temperature using conventional diesel combustion, then the catalytic converter achieves effective emission control, but the time required to reach light-off is excessive during cold starts
Solution Approach 1:
The patent applies preliminary action by using a second fuel (gasoline or petrol) to perform a preliminary combustion cycle before the EATS reaches light-off temperature. This preliminary combustion rapidly heats the catalytic converter to light-off temperature, after which the first fuel (diesel) is used for normal operation. This resolves the contradiction by preparing the EATS in advance for effective emission control.
Solution Approach 2:
The patent changes the combustion parameters by switching from conventional diesel diffusion combustion to a two-fuel system where a second fuel (gasoline/petrol) is used for flame propagation combustion. This parameter change enables faster heating of the EATS while maintaining controllability of the combustion process, thereby reducing the time to reach light-off.
2Loss of time
If flame propagation combustion of a second fuel is used to rapidly heat the EATS, then light-off is achieved faster, but the complexity of fuel injection control increases
Solution Approach 1:
The patent segments the fuel injection control into distinct phases: a first phase using a second fuel (gasoline/petrol) for flame propagation combustion to heat the EATS, and a second phase using the first fuel (diesel) for normal operation after light-off. This segmentation simplifies the control strategy by dividing the complex heating process into manageable stages with specific fuel types and combustion modes.
Solution Approach 2:
The patent applies dynamics by making the fuel injection system adaptable and switchable between different fuel types based on the operational requirement. The control system dynamically selects whether to use the first fuel (diesel) or second fuel (gasoline/petrol) based on the EATS temperature and light-off status, optimizing both heating speed and emission control while managing system complexity.
3Power
If diffusion combustion of diesel fuel is used, then efficient torque delivery is achieved, but emission control is ineffective during cold starts before catalytic converter light-off
Solution Approach 1:
The patent applies preliminary action by using a second fuel (gasoline or petrol) to perform a preliminary combustion cycle that rapidly heats the catalytic converter to light-off temperature. During this preliminary phase, the EATS is heated while producing controlled emissions, and only after light-off is achieved does the system switch to the first fuel (diesel) for normal torque-delivery operation with effective emission control.
Solution Approach 2:
The patent introduces a second fuel (gasoline or petrol) as an intermediary substance that facilitates the transition from cold start to effective emission control. This intermediary fuel enables rapid heating of the catalytic converter and serves as a bridge between the cold-start phase and the post-light-off phase, allowing the system to achieve both heating efficiency and emission control.
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 significantly reduces emissions during cold starts by rapidly increasing the catalytic converter temperature, achieving faster light-off and maintaining efficient operation while minimizing emissions before the EATS is fully operational.
Implementation Method 1
the time needed to heat the EATS to its optimal operating temperature
Implementation Method 2
diffusion combustion of a first fuel, or flame propagation combustion of a second fuel
Implementation Method 3
a catalytic converter comprised in the EATS has reached so-called light-off, where the catalytic converter achieves at least 50% conversion of, for example, nitrous oxides
Data Source
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AI summary
The invention relates to a method of controlling operation of an ICE arrangement (1), comprising acquiring (100) a first signal indicative of a required torque; acquiring (102) a second signal indicative of a temperature (T) of an EATS (23); and when the second signal indicates that the temperature (T) of the EATS (23) is lower than a predefined first threshold temperature (T1): determining (108; 118) an amount of second fuel (17) needed to deliver the required torque; supplying the amount of second fuel (17); controlling (112; 122) an inlet valve (19) to allow flow of a second fuel-air mix into the cylinder (3); injecting first fuel (13) into the cylinder (3) when the second fuel-air mix is compressed by the piston (9), resulting in flame propagation ignition of the second fuel-air mix; and controlling (116; 126) and outlet valve (21) to allow flow of exhaust from the cylinder (3) during an exhaust stroke (ES) of the piston (9).