This paper presents a new model used to describe the propagation of pressure waves at the inlet systems of internal combustion engine. In the first part, an analogy is made between the compressible air in a pipe and a mechanical ideal mass damper spring system. A new model is then presented and the parameters of this model are determined by the use of an experimental setup (shock tube test bench). With this model, a transfer function is defined in order to link directly the pressure and the air mass flow rate. In the second part, the model is included into an internal combustion engine simulation code. The results obtained with this code are compared to experimental ones which are measured on a one-cylinder engine test bench. This last one is driven by an electric motor in order to study only the effect of the pressure waves on the engine behavior. A good agreement is obtained between the experimental results and the numerical ones and the new approach is an alternative method for modeling the pressure wave phenomena in an internal combustion engine manifold.
Pressure wave propagation in the inlet and exhaust manifolds of internal combustion engines is an important phenomenon which affects the filling and emptying of the cylinders. The objective of this paper is to present a new methodology that takes into account this phenomenon without the use of a one-dimensional resolution scheme. First, an analogy is made between the compressible air in a pipe and a mechanical ideal mass–damper–spring system. A multi-frequency model is then presented. The principle of the model is to define a link between the pressure and the flow velocity by means of the impedance. The parameters of this model can be determined using a flow bench working in unsteady conditions and called the ‘dynamic flow bench’. The new model is then tested with a more complex geometry. The latter corresponds to a specific air intake system of an internal combustion engine. It is then possible to introduce the new model into an internal combustion engine simulation code and to compare the numerical results with the experimental data. Good agreement is obtained between the two, and the new multi-frequency model appears to be an alternative method for modelling the pressure waves in the intake and exhaust systems of internal combustion engines. It is therefore possible to reduce the computational times.
The flows at the intake and the exhaust of an internal-combustion engine are most of the time simplified to a single space dimension, and the hyperbolic partial differential equations that govern the compressible and unsteady air flow are discretized and solved numerically. This method is the basis of today's engine simulation codes. Models for complex parts such as the charge air coolers often need calibration with experimental engine data essentially for the pressure drop coefficients and the corrected lengths. Another technique for understanding wave action inside the pipes of an internal-combustion engine is to use the reciprocating nature of the engine itself and to gain access to the frequency spectrum of the pressure and the mass flow signals. This was achieved in this paper using a dedicated dynamic bench that identifies a transfer matrix which is defined in terms of the pressure and the mass flow rate. This new transfer matrix technique permits the dynamic pressure and the mass flow to be identified under similar conditions to those encountered in an engine. The transfer matrix is measured for two charge air cooler geometries and validated using experimental engine measurements. The results and methodology are explained in the frequency domain and the time domain, and the future objectives and perspectives discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.