Engine-Out Measurements and In-Cylinder Imaging of Cold-Start Particulate and Gaseous Emissions in a Single-Cylinder DISI Engine
2022-01-0522
03/29/2022
- Event
- Content
- Strategies to mitigate cold-start emissions are critical to meet stringent standards for particulate and regulated gaseous emissions from direct injection spark ignition (DISI) engines. The objective of the current work was to establish an experimental protocol for cold-start studies and to identify the in-cylinder phenomena important during engine warming in terms of engine power and stability and engine-out particulates, NOx, and unburned hydrocarbon emissions. Metal-engine experiments were conducted at T = 20 oC to quantify the sensitivity of the performance of a single-cylinder engine to timing of a strategy using two injection events per power cycle and late spark ignition. The results showed strong sensitivity to the timing of the second injection event and weak sensitivity to the timing of the first injection. Complementary high-speed imaging experiments were conducted with the same engine where the fuel spray and combustion characteristics were visualized during cold-start split-injection operation. The imaging data showed the sources of particulates were due to fuel impingement on combustion chamber surfaces and due to fuel rich regions, in particular regions where the fuel re-condensed due to the conditions associated with late ignition timing. The combination of engine-out particulate and imaging measurements indicated smaller particulates (8-20 nm) were associated with fuel impingement on surfaces, and larger particles were associated with larger partners (20-200 nm).
- Citation
- Gutierrez, L., Wooldridge, M., Petersen, B., and Wooldridge, S., "Engine-Out Measurements and In-Cylinder Imaging of Cold-Start Particulate and Gaseous Emissions in a Single-Cylinder DISI Engine ," SAE Technical Paper 2022-01-0522, 2022, .