A new type of internal combustion engine based on the porous-medium combustion technique

Abstract

At present, the emissions of internal combustion engines can only be improved by catalytic treatments of the exhaust gases. Such treatments, however, result in high costs and relatively low conversion eYciency. This suggests that a new combustion technique should be developed to yield improved primary combustion processes inside the engine with drastically reduced exhaust gas emissions. In this paper, the authors report on such a technique that is applicable to direct injection, internal combustion engines, either diesel or gasoline fuelled. This technique is based on the porousmedium (PM ) combustion technology previously developed in the authors' laboratory for steady state household and industrial combustion processes.It is shown that the PM combustion technique can be applied to internal combustion engines, i.e. it is demonstrated that improvements obtained in steady state combustion are also realizable in unsteady combustion processes. Theoretical considerations are presented for internal combustion engines, indicating that an overall improvement in thermal eYciency can be achieved for the PM engine. This is explained and the general performance of the new PM engine is demonstrated for a single-cylinder, air-cooled, direct injection diesel engine. Veri cation experiments are described that were carried out as part of the present study. Initial results are presented and an outlook is given on how the present developments might continue in the future.

Application of macro-cellular SiC reactor to diesel engine-like injection and combustion conditions

“…Application of a combustion porous reactor to engine allows realization of homogeneous and flameless combustion process characterized by a near-zero emissions level [1,2,9]. Internal heat recuperation in porous reactor may allow increase of engine-cycle efficiency resulting in reduction of CO 2 emissions and results in significantly lowered combustion temperature permitting nearly-zero NOx level.…”

“…Homogeneous combustion process in porous reactor as applied to internal combustion engine must be performed under complex mixture formation and combustion conditions: the process is non-stationary, is performed under high pressure and the fuel is injected directly inside the combustion reactor [1][2]. A special role in the thermodynamics of the engine cycle with heat release in porous reactor plays the reactor heat capacity resulting in lowering of combustion temperature as well as in internal heat recuperation during the engine cycle [3].…”

“…The reactor temperature together with fuel injection and mixture formation inside the porous reactor define the conditions for thermal ignition and following heat release (combustion) process. A novel kind of engine with a combustion process in highly porous threedimensional reactors that could satisfy the above conditions has been proposed by Durst and Weclas [1][2]. This engine concept has great potential not only for high cycle efficiency but especially for a nearly-zero emission level allowing combustion temperature control below thermal NOx-formation.…”

Analysis of an Internal Combustion Engine Using Porous Foams for Thermal Energy Recovery

“…Homogeneous mixture preparation and controllable combustion are the most effective methods for lowering energy use and emissions in internal combustion engines [4]. The porous media (PM) engine is a new concept, first proposed by Durst and Weclas [5], for implementing homogeneous combustion in internal combustion engines. The PM engine concept is based on the PM combustion technique and reduces energy use and emissions.…”

“…The PM engine concept is based on the PM combustion technique and reduces energy use and emissions. Durst and Weclas [5] proposed two types of PM engines: permanent contact and periodic contact. In the permanent contact type of PM engine, the operation is similar to that of conventional internal combustion engines.…”