Validation of the Fuel Saving Potential of Downsized and Supercharged Hybrid Pneumatic Engines Using Vehicle Emulation Experiments

Abstract

The pneumatic hybridization of power trains is especially effective when it is combined with stnmg downsizing and supercharging of spark ignited engines. This paper presents measurement results obtained from such an engine. Specifically, performance measurements for all additional engine modes are shown. The pneumatic motor mode and the pneumatic pump mode are individually optimized over their whole operating range for maximum recuperation efficiency. Jointly with the conventional combustion mode and the pneumatic supercharged mode, they are implemented in one engine control svstem, thereby enabling the switching between all modes. A dynamometer simulates the longitudinal dynamics of two series production vehicles for the modifled engine. This experimental setup, defltied as emulation, is used to accurately measure the engine's fuel ccmsumption in the MVEG-95 and federal test procedure (FTP) drive cycles. Causal and noncausal energy management strategies are presented and used for choosing the engine mode during a drive cycle. Fuel savings of up to 35% are measured when comparing the modifled engine to the vehicles' statidard engines with the same rated power. Hybrid pneumatic vehicles (HPVs) may prove to be a viable alternative to hybrid electric vehicles since fuel savings and driveability are cotnparable, while the added cost is expected to be substantially lower for HPVs.

System Design and Analysis of a Directly Air-Assisted Turbocharged SI Engine with Camshaft Driven Valves

“…The authors of [10] proposed to only have a fully variable CV in order to reduce costs and complexity. With this configuration, fuel savings of 31% were achieved on the New European Drive Cycle (NEDC) [11]. Downsizing enabled by the boost mode contributed 25%, while the contributions of the stop/start capability and of the pneumatic motor mode each amounted to 3%.…”

“…In [11] the mode selection of the HPE was effected based on the solution of an optimal control problem. The optimization was necessary because for certain driving conditions the torque could have been provided by either the combustion mode or the pneumatic motor mode.…”

“…Both engines have approximately the same rated power. In [11], a fuel-saving potential of 28% was validated by experiments on the FTP for this replacement. The pneumatic motor mode was not used.…”

Hybrid-Electric Vehicle with Natural Gas-Diesel Engine

“…The supervisory controller determines the torque split between engine and electric motor and the desired gear. For more information on vehicle emulation, see for example [14][15][16][17]. The powertrains investigated are shown in Figure 3.…”

Experimental studies of the air hybrid engine charging operation

“…Authors in [5][6] have done the experiments on a 0.75litre twin cylinder engine with a fully variable actuated charging valve. The charging valve replaces the position of one exhaust valve.…”