Simulation of a Single Cylinder Diesel Engine Under Cold Start Conditions Using Simulink

Abstract

A nonlinear dynamic model is developed in this study to simulate the overall performance of a naturally aspirated, single cylinder, four-stroke, direct injection diesel engine under cold start and fully warmed-up conditions. The model considers the filling and emptying processes of the cylinder, blowby, intake, and exhaust manifolds. A single zone combustion model is implemented and the heat transfer in the cylinder, intake, and exhaust manifolds are accounted for. Moreover, the derivations include the dynamics of the crank-slider mechanism and employ an empirical model to estimate the instantaneous frictional losses in different engine components. The formulation is coded in modular form whereby each module, which represents a single process in the engine, is introduced as a single block in an overall Simulink engine model. The numerical accuracy of the Simulink model is verified by comparing its results to those generated by integrating the engine formulation using IMSL stiff integration routines. The engine model is validated by the close match between the predicted and measured cylinder gas pressure and engine instantaneous speed under motoring, steady-state, and transient cold start operating conditions.

Review of Thermodynamic Diesel Engine Simulations under Transient Operating Conditions

“…They advanced to filling and emptying modeling [3,28], while investigating also the fundamental aspect of combustion and friction deterioration during transients [12]. Professor Henein's research group at the Wayne State University pioneered in the late eighties the study concerning engine starting based on phenomenological in-cylinder modeling [29,30]. Later, they included detailed fuel droplets and film evaporation sub-models [31,32].…”

“…With the notable exceptions from only five research groups [29,30,[39][40][41]44,45,69,88,146], friction modeling in transient simulation codes has always, in the past, been used in the form of 'mean fmep' relations, remaining constant for every degree crank angle in each cycle in the model simulation. This may be attributed to the fact that friction does not affect the heat release rate (and thus the interior engine 'indicating' properties and exhaust emissions) but only the crankshaft energy balance; the latter one being, nonetheless, essential for correct transient predictions.…”

“…For the engine cylinder it holds (index 4 corresponds to inlet manifold conditions and 5j to the j-th engine cylinder -see also Figure 2), (30) corresponds to the flow availability of the cylinder gas with x i the mole fraction of species i in the mixture and the chemical potential of species i at the true dead state (i.e., when there exists thermal, mechanical and chemical equilibrium with the environment). The term dI/dφ in Equation (29) is the rate of irreversibility production within the cylinder, which consists mainly of the combustion term, while inlet-valve throttling and mixing of the incoming air with the cylinder residuals contribute a little.…”

“…This may be attributed to the fact that friction does not affect the heat release rate (and thus the interior engine 'indicating' properties and exhaust emissions) but only the crankshaft energy balance; the latter one being, nonetheless, essential for correct transient predictions. Detailed friction (as well as blow-by) simulations are met in starting models [29,30], as these losses are particularly pronounced during cold start engine conditions.…”

Model-Based Condition and State Monitoring of Large Marine Diesel Engines

“…the interrelationship between system pressure, temperature and mass can be found in [6], [9], and [10].…”