Effects of Intake-Air Heating on a Light-Duty CNG-Diesel Reactivity-Controlled Compression Ignition Engine Indian Institute of Technology Bombay

Format:

Book

Conference/Event

Author/Creator:

Navaneethakrishnan, P., author.

Contributor:

Sarangi, Asish K.

Singh, Arvind Kumar

Sreedhara, Seshadri

Suman, Abhishek

Conference Name:

SETC2025: 29th Small Powertrains and Energy Systems Technology Conference (2025-11-10 : Florence, Italy)

Language:

English

Physical Description:

1 online resource cm

Place of Publication:

Warrendale, PA SAE International 2025

Summary:

Reactivity controlled compression ignition (RCCI) is a promising low-temperature combustion strategy that offers high thermal efficiency with reduced nitrogen oxides (NOx) and soot emissions. However, at low loads, RCCI operation often suffers from incomplete combustion, leading to elevated partial combustion products, such as, unburned total hydrocarbons (THC) and carbon monoxide (CO) emissions. Intake-air heating is a potential strategy to address these issues by enhancing fuel reactivity and promoting more complete combustion. In this study, the effects of intake-air heating (from ambient to ~95°C) on performance, combustion, and emissions were experimentally investigated in a light-duty diesel engine operated in compressed natural gas (CNG)-diesel RCCI mode. Experiments were conducted at low and intermediate loads at various engine speeds. A single injection strategy was employed for low-load, while a double-injection strategy was used at intermediate-load operating conditions. CO and THC emissions were significantly reduced at low loads with intake-air heating, but at intermediate-loads no significant reductions in CO and THC emissions were observed. However, NOx emissions increased and combustion stability improved with intake-air heating at all the investigated operating conditions. Furthermore, increased intake-air temperature at low-load high-speed operation with single injection strategy resulted in significant combustion oscillations due to end-gas auto-ignition. The presence of oscillations was confirmed by a fast Fourier transform (FFT) analysis of the in-cylinder pressure that revealed significant resonance in the first circumferential mode at higher intake temperatures. Furthermore, with intake-air heating, an increase in the energy substitution by CNG from 50% to 70%, and a marginal increase in EGR from 45 to 55%, improved the THC-NOx trade-off in RCCI operation

Notes:

Vendor supplied data

Publisher Number:

2025-32-0003

Access Restriction:

Restricted for use by site license