Cold start emissions are a significant contributor to air pollution, particularly in urban areas. According to a study, over 70% of emissions from ships may be measurable up to 400 km inshore and have a significant contribution to an increase in concentrations of particulate matter. The study also found that emissions of NOx and particles from maneuvering ships are significant, with a significant contribution to an increase in concentrations of particulate matter.
Understanding Cold Start Emissions
Cold start emissions refer to the increased emissions that occur when an engine is started from a cold state, as opposed to a warm or hot state. This is because the engine’s catalytic converter and other emissions control systems are not yet at their optimal operating temperature, leading to higher levels of pollutants being released into the atmosphere.
Factors Affecting Cold Start Emissions
Several factors can influence the level of cold start emissions, including:
- Ambient Temperature: Colder ambient temperatures can lead to higher cold start emissions, as the engine and emissions control systems take longer to reach their optimal operating temperatures.
- Engine Design: The design of the engine, including the type of fuel injection system, can impact the level of cold start emissions.
- Emissions Control Systems: The effectiveness of the engine’s emissions control systems, such as the catalytic converter and particulate filters, can affect the level of cold start emissions.
- Driving Conditions: The driving conditions, such as stop-and-go traffic or frequent idling, can also contribute to higher cold start emissions.
Measuring Cold Start Emissions
Remote sensing of motor vehicle exhaust emissions is a useful tool for measuring and monitoring cold start emissions. According to a white paper by the International Council on Clean Transportation, remote sensing can provide air pollutant emission rates for the fleet across a wide range of driving conditions, including cold start emissions.
The paper notes that remote sensing can be used to evaluate the effect of parameters, such as engine load and ambient temperature, on vehicle emissions, and to evaluate the durability of emissions control systems and to track the emissions performance of vehicles over time.
Regulatory Efforts to Reduce Cold Start Emissions
The Environmental Protection Agency (EPA) has implemented rules to reduce air pollution from highway heavy-duty vehicles and engines. These regulations include:
- Exhaust Emission Standards: The EPA has set exhaust emission standards for engines using the fuel type on which the engines in the engine family are designed to operate.
- Cold Start Emission Reduction Strategy Monitoring: The EPA has regulations for monitoring the effectiveness of cold start emission reduction strategies in heavy-duty engines.
- Continuous Circuit Operation: The EPA requires engines that incorporate a specific engine control strategy to reduce cold start emissions to have continuous circuit operation to ensure the effectiveness of the strategy.
EPA Regulations for Cold Start Emission Control
The EPA’s regulations for cold start emission control are detailed in the following sections of the Code of Federal Regulations (CFR):
- 40 CFR Part 1036: This part covers the control of emissions from new and in-use heavy-duty engines and vehicles, including requirements for cold start emission reduction strategies.
- 40 CFR Part 86 Subpart A: This subpart provides the general provisions for heavy-duty engines and vehicles, including requirements for cold start emission testing and monitoring.
These regulations specify the technical requirements and test procedures for manufacturers to demonstrate compliance with the EPA’s cold start emission control standards.
Emerging Technologies for Cold Start Emission Control
Researchers and manufacturers are continuously working on developing new technologies to further reduce cold start emissions. Some of the emerging approaches include:
- Improved Catalytic Converters: Advancements in catalytic converter design and materials can help them reach their optimal operating temperature more quickly, reducing cold start emissions.
- Electrically Heated Catalysts: These systems use electrical heating to rapidly warm up the catalytic converter, reducing cold start emissions.
- Cylinder Deactivation: Some engines can temporarily deactivate certain cylinders during cold start to improve fuel efficiency and reduce emissions.
- Hybrid and Electric Powertrains: Hybrid and electric vehicles can reduce or eliminate cold start emissions by using electric motors during the initial start-up phase.
Conclusion
Cold start emissions are a significant contributor to air pollution, and addressing this issue is crucial for improving air quality, particularly in urban areas. The use of remote sensing technology, combined with regulatory efforts and the development of new emission control technologies, can help to significantly reduce the impact of cold start emissions on the environment.
References:
- Chu Van Thuy et al., “Effect of cold start on engine performance and emissions from diesel engines using IMO-Compliant distillate fuels,” ScienceDirect, accessed May 14, 2024, https://www.sciencedirect.com/science/article/abs/pii/S0269749119313648
- “Remote sensing of motor vehicle exhaust emissions,” International Council on Clean Transportation, January 2, 2018, https://theicct.org/sites/default/files/publications/Remote-sensing-emissions_ICCT-White-Paper_01022018_vF_rev.pdf
- “Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engines and Vehicles,” Environmental Protection Agency, accessed May 14, 2024, https://www.epa.gov/system/files/documents/2023-01/new-motor-veh-air-poll-control-hd-eng-veh-stnd-frm-2022-12-20.pdf
- “40 CFR Part 1036 — Control of Emissions from New and In-Use Heavy-Duty Engines and Vehicles,” U.S. Government Publishing Office, accessed May 14, 2024, https://www.ecfr.gov/current/title-40/chapter-I/subchapter-U/part-1036
- “40 CFR Part 86 Subpart A — General Provisions for Heavy-Duty Engines and Vehicles,” U.S. Government Publishing Office, accessed May 14, 2024, https://www.ecfr.gov/current/title-40/chapter-I/subchapter-C/part-86/subpart-A
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