Numerical investigation of a fueled pre-chamber spark-ignition natural gas engine

Abstract

Pre-chamber spark-ignition (PCSI) is a leading advanced ignition concept for internal combustion engines with the potential to enable diesel-like efficiency in medium-duty/heavy-duty (MD/HD) natural gas (NG) engines. By leveraging distributed ignition sources from multiple turbulent jets, the PCSI technology can deliver extremely short combustion duration in ultra-lean mixtures and significantly improve the engine thermal efficiency. However, in the automotive industry there is a lack of adequate science base and predictive simulation tools required for commercial development of PCSI engines. In this study, Reynolds-Average Navier-Stokes simulations are carried out to describe the combustion process in lean-burn NG engines, focusing on the combustion modeling approach. Two combustion models, multi-zone well-stirred reactor (MZ-WSR) and G-equation, are used to simulate the combustion process in an MD NG engine equipped with a fueled-PCSI system for four operating conditions close to the lean operating limit. A skeletal chemical mechanism and a laminar flame speed tabulation are used to compute the combustion accurately. Simulation results are compared with experimental data regarding measured cylinder pressure, heat release rate, and combustion duration. By dividing the PCSI combustion process into four distinct phases, the difference between the two models’ results for each phase is analyzed in detail. The MZ-WSR model overestimates the combustion duration for early flame kernel growth in the pre-chamber due to the lack of a specific formulation to take turbulence-chemistry interaction into account. Despite the prolonged combustion duration and low pressure built-up inside the pre-chamber, the model matches the combustion rate in the main-chamber. In contrast, the G-equation model delivers good agreements for the pre-chamber combustion and turbulent jet-driven combustion processes. However, the model starts to underestimate the combustion rate in the main-chamber, especially under ultra-lean mixture conditions. Finally, improvements are needed for both models to simulate the later combustion stage that occurred in the near-wall regions.

Keywords

Natural gas engine pre-chamber spark-ignition turbulent jet ignition ultra-lean combustion combustion model evaluation computational fluid dynamics

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References

U.S. EPA Office of Transportation and Air Quality. Fast facts: U.S. transportation sector greenhouse gas emissions 1990–2017. Report no. EPA-420-F-19-047, June 2019.

Toulson

Schock

Attard

. A review of pre-chamber initiated jet ignition combustion systems. SAE technical paper 2010-01-2263, 2010.

Ricardo

. Internal-combustion engine. 1918. Ricardo H. R. Internal-Combustion Engine. Patent 1,271,942, USA, 1918.

Abramovich

G. L.

Method of Prechamber-Torch Ignition in Internal Combustion Engines. Patent 3,230,939, USA, 1966.

Honda. Introducing the CVCC/1972, https://global.honda/heritage/episodes/1972introducingthecvcc.html (accessed 15 May 2021).

Najt

Rask

Reuss

. Dual mode engine combustion process. US Patent 6,595,181, 2003.

Bunce

Blaxill

. Sub-200 g/kWh BSFC on a light duty gasoline engine. SAE technical paper 2016-01-0709, 2016.

Wärtsilä Corporation. Gas and multi-fuel power plants, August 2017, pp 8–14.

Clarke Energy. Jenbacher type-6 engine, https://www.clarke-energy.com/gas-engines/type-6-gas-engines/ (accessed 15 May 2021).

10.

Wärtsilä Corporation. Product Guide, Wartsila 31SG, September 2019.

11.

Shah

Tunestal

Johansson

. Effect of relative mixture strength on performance of divided chamber ‘avalanche activated combustion’ ignition technique in a heavy duty natural gas engine. SAE technical paper 2014-01-1327, 2014.

12.

Shah

Tunestal

Johansson

. Investigation of performance and emission characteristics of a heavy duty natural gas engine operated with pre-chamber spark plug and dilution with excess air and EGR. SAE Int J Engines 2012; 5: 1790–801.

13.

Shah

Tunestal

Johansson

. Scalability aspects of pre-chamber ignition in heavy duty natural gas engines. SAE technical paper 2016-01-0608, 2016.

14.

Wright

Kyrtatos

Bardis

Schiliro

Boulouchos

. Experimental and numerical investigation of the engine operational conditions’ influences on a small un-scavenged pre-chamber’s behavior. SAE Int J Engines 2017; 10(5): 2414-2428.

15.

Hlaing

Echeverri Marquez

Bhavani Shankar

Cenker

Ben Houidi

Johansson

. A study of lean burn pre-chamber concept in a heavy duty engine. SAE technical paper 2019-24-0107, 2019.

16.

Onofrio

Garcia Valladolid

, et al. Experimental and numerical assessment of active pre-chamber ignition in heavy duty natural gas stationary engine. SAE technical paper 2020-01-0819, 2020.

17.

Yamaguchi

Ohiwa

Hasegawa

. Ignition and burning process in a divided chamber bomb. Combust Flame 1985; 59: 177–187.

18.

Biswas

Tanvir

Wang

Qiao

. On ignition mechanisms of premixed CH4/air and H2/air using a hot turbulent jet generated by pre-chamber combustion. Appl Therm Eng 2016; 106: 925–937.

19.

Mastorakos

Allison

Giusti

, et al. Fundamental aspects of jet ignition for natural gas engines. SAE Int J Engines 2017; 10: 2429–2438.

20.

Malé

Staffelbach

Vermorel

Misdariis

Ravet

Poinsot

. Large Eddy simulation of pre-chamber ignition in an internal combustion engine. Flow Turbul Combust 2019; 103: 465–483.

21.

Chinnathambi

Bunce

Cruff

. RANS based multidimensional modeling of an ultra-lean burn pre-chamber combustion system with auxiliary liquid gasoline injection. SAE technical paper 2015-01-0386, 2015.

22.

Gholamisheeri

Wichman

Toulson

. A study of the turbulent jet flow field in a methane fueled turbulent jet ignition (TJI) system. Combust Flame 2017; 183: 194–206.

23.

Kotzagianni

Kyrtatos

Wright

Boulouchos

. Experimental and numerical investigations of the unscavenged prechamber combustion in a rapid compression and expansion machine under engine-like conditions. Combust Flame 2019; 204: 68–84.

24.

Wright

Schiliro

Boulouchos

. Characterization of combustion in a gas engine ignited using a small un-scavenged pre-chamber. Int J Engine Res 2020; 21: 1085–1106.

25.

Perini

Hiraoka

, et al. An efficient level-set flame propagation model for hybrid unstructured grids using the G-equation. SAE Int J Engines 2016; 9: 1409–1424.

26.

Kammel

Mair

Zelenka

, et al. Simulation based predesign and experimental validation of a prechamber ignited HPDI gas combustion concept. SAE technical paper 2019-01-0259, 2019.

27.

Gholamisheeri

Givler

Toulson

. Large eddy simulation of a homogeneously charged turbulent jet ignition system. Int J Engine Res 2019; 20: 181–193.

28.

Bolla

Shapiro

Tiney

Kyrtatos

Kotzagianni

Boulouchos

. Numerical simulations of pre-chamber combustion in an optically accessible RCEM. SAE technical paper 2019-01-0224, 2019.

29.

Syrovatka

Vitek

Vavra

Takats

. Scavenged pre-chamber volume effect on gas engine performance and emissions. SAE technical paper 2019-01-0258, 2019.

30.

Allison

de Oliveira

Giusti

Mastorakos

. Pre-chamber ignition mechanism: experiments and simulations on turbulent jet flame structure. Fuel 2018; 230: 274–281.

31.

Natural Gas Vehicle Research Workshop. http://www.nrel.gov/transportation/ngv-research-workshop.html (2017, accessed 15 May 2021).

32.

Heywood

. Internal combustion engine fundamentals. 1st ed. New York, NY: McGraw-Hill, 1988.

33.

Convergent Science Inc. CONVERGE CFD v2.4 Manual, 2018.

34.

Han

Reitz

. A temperature wall function formulation for variable-density turbulent flows with application to engine convective heat transfer modeling. Int J Heat Mass Transfer 1997; 40: 613–625.

35.

Yakhot

Orszag

. Renormalization group analysis of turbulence. I. Basic theory. J Sci Comput 1986; 1: 3–51.

36.

Senecal

Pomraning

Richards

, et al. Multi-dimensional modeling of direct-injection diesel spray liquid length and flame lift-off length using CFD and parallel detailed chemistry. SAE technical paper 2003-01-1043, 2003.

37.

Babajimopoulos

Assanis

Flowers

Aceves

Hessel

. A fully coupled computational fluid dynamics and multi-zone model with detailed chemical kinetics for the simulation of premixed charge compression ignition engines. Int J Engine Res 2005; 6: 497–512.

38.

Raju

Wang

Senecal

Som

Longman

. A reduced diesel surrogate mechanism for compression ignition engine applications. In: ASME 2012 internal combustion engine division fall technical conference, Vancouver, BC, 23–26 September 2012, pp.711–722.

39.

Metcalfe

Burke

Ahmed

Curran

. A hierarchical and comparative kinetic modeling study of C1 − C2 hydrocarbon and oxygenated fuels. Int J Chem Kinet 2013; 45: 638–675.

40.

Peters

. Turbulent combustion. Cambridge: Cambridge University Press, 2000.

41.

Ewald

Peters

. On unsteady premixed turbulent burning velocity prediction in internal combustion engines. Proc Combust Inst 2007; 31: 3051–3058.

42.

Kim

Scarcelli

Som

Shah

Biruduganti

Longman

. Assessment of turbulent combustion models for simulating pre-chamber ignition in a natural gas engine. In: ASME 2019 internal combustion engine division fall technical conference, Chicago, IL, 20–23 October 2019.