Abstract
The purpose of the ELEVATE (European Low Emission V4 Automotive Two-stroke Engine) industrial research project is to develop a small, compact, light weight, high torque and highly efficient clean spark ignition 2-stroke engine of 120 kW which could industrially replace the relatively big existing automotive spark ignition or diesel 4-stroke engine used in the top of the mid size or in the large size vehicles, including the minivan vehicles used for multi people and family transportation.
This paper describes the design process of this new engine concept based on the combined implementation on a 4-stroke bottom end of several 2-stroke engine innovative technologies such as the IAPAC compressed air assisted direct fuel injection with CPS (Cam Profile Switching), the CAI (Controlled Auto-Ignition) combustion process with flexible ignition system, the D2SC (Dual Delivery Screw SuperCharger) for both low pressure engine scavenging and higher pressure
IAPAC air assisted DI and the ETV (Exhaust charge Trapping Valve).
The design process is extensively supported by 1D and 3D CFD simulation studies. A specific 1D software model has been developed to simulate the D2SC performance. In parallel, a preliminary D2SC compressor has been designed and experimentally tested in order to validate this new software. Then, the validated software has been coupled with an already existing 1D gas dynamics software in order to be able to simulate the whole V4 ELEVATE engine configuration. With the complete 1D software package obtained, several simulations have been performed to study the influence of various design parameters such as the IAPAC valve diameter, lift and profile, the D2SC compressor speed as well as its volume and pressure ratio for both LP and HP deliveries, and the ETV opening profile and timing.
Such simulations have been useful to give preliminary V4 ELEVATE engine design specifications corresponding to the expected performance targets. Based on these specifications, a representative single cylinder research and development engine has been designed and manufactured. Preliminary results of this experimental engine are presented, the purpose of such single cylinder step of work being to determine and fix the final configuration of the V4 engine which will be presented in future work.