Direct Injection of CNG on High Compression Ratio Spark Ignition Engine: Numerical and Experimental Investigation Renault

Format:

Conference/Event

Author/Creator:

Douailler, Douailler, author.

Contributor:

Delpech, Vivien

Kumar, Rajesh

Ravet, Frederic

Reveille, Benjamin

Soleri, Dominique

Conference Name:

SAE 2011 World Congress & Exhibition (2011-04-12 : Detroit, Michigan, United States)

Language:

English

Physical Description:

1 online resource

Place of Publication:

Warrendale, PA SAE International 2011

Summary:

CNG is one of the most promising alternate fuels for passengercar applications. CNG is affordable, is available worldwide and hasgood intrinsic properties including high knock resistance and lowcarbon content.Usually, CNG engines are developed by integrating CNG injectorsin the intake manifold of a baseline gasoline engine, therebyremaining gasoline compliant. However, this does not lead to abi-fuel engine but instead to a compromised solution for bothGasoline and CNG operation.The aim of the study was to evaluate the potential of a directinjection spark ignition engine derived from a diesel engine coreand dedicated to CNG combustion. The main modification was the newdesign of the cylinder head and the piston crown to optimize thecombustion velocity thanks to a high tumble level and goodmixing.This work was done through computations. First, a 3D model wasdeveloped for the CFD simulation of CNG direct injection. Numericaltests were carried out on the injection test bench configuration inorder to achieve good correlations between calculations andexperiments. Once validated, the model was implemented in thenumerical setup of the engine and different designs of thecombustion chamber were computed to compare mixing level, turbulentenergy level, trapped mass and IMEP for homogenous stoichiometricoperation. The best design was then manufactured and tested on asingle-cylinder research engine.Comparing test bench results of CNG port injection and CNGdirect injection configurations showed the potential of directinjection: - later injection timings lead to higher volumetricefficiency, - later spark ignition timings lead to higher burningspeed for a better indicated fuel consumption.Finally, the test bench results were extrapolated to construct anumerical model of a multi-cylinder engine as well as a vehicle.NEDC cycle simulations using a DI CNG-engine-powered Light-DutyVehicle have shown a 27% reduction of CO₂ emissions compared to thesame vehicle equipped with a diesel engine, making DI CNG engines acredible alternative for the European market

Notes:

Vendor supplied data

Publisher Number:

2011-01-0923

Access Restriction:

Restricted for use by site license