Tài liệu Investigation of cylinder deactivation strategies on part load conditions

See discussions, stats, and author profiles for this publication at: https://www.researchgate.net/publication/267038900 Investigation of Cylinder Deactivation (CDA) Strategies on Part Load Conditions Article in SAE Technical Papers · October 2014 DOI: 10.4271/2014-01-2549 CITATIONS READS 3 384 5 authors, including: Mohd Farid Muhamad Said Azhar abdul aziz Universiti Teknologi Malaysia Universiti Teknologi Malaysia 44 PUBLICATIONS 137 CITATIONS 81 PUBLICATIONS 164 CITATIONS SEE PROFILE SEE PROFILE Zulkarnain Abdul Latiff Amin Mahmoudzadeh Andwari Universiti Teknologi Malaysia University of Tehran 32 PUBLICATIONS 38 CITATIONS 18 PUBLICATIONS 106 CITATIONS SEE PROFILE SEE PROFILE Some of the authors of this publication are also working on these related projects: Two stroke engine improvement View project Ethanol Fuelled HCCI engine Development View project All content following this page was uploaded by Mohd Farid Muhamad Said on 21 October 2014. The user has requested enhancement of the downloaded file. Downloaded from SAE International by Universiti Teknologi Malaysia, Sunday, October 19, 2014 Investigation of Cylinder Deactivation (CDA) Strategies on Part Load Conditions 2014-01-2549 Published 10/13/2014 Mohd Farid Muhamad Said, Azhar Bin Abdul Aziz, Zulkanain Abdul Latiff, and Amin Mahmoudzadeh Andwari ADC, Universiti Teknologi Malaysia Shahril Nizam Mohamed Soid MSI, Universiti Kuala Lumpur CITATION: Muhamad Said, M., Abdul Aziz, A., Abdul Latiff, Z., Mahmoudzadeh Andwari, A. et al., "Investigation of Cylinder Deactivation (CDA) Strategies on Part Load Conditions," SAE Technical Paper 2014-01-2549, 2014, doi:10.4271/2014-01-2549. Copyright © 2014 SAE International Abstract Introduction Many efforts have been invested to improve the fuel efficiency of vehicles mainly for the local consumers. One of the main techniques to have better fuel efficiency is cylinder deactivation system. In this paper, the main research area is focus on the investigation of cylinder deactivation (CDA) technology on common engine part load conditions within common Malaysian driving condition. CDA mostly being applied on multi cylinders engines. It has the advantage in improving fuel consumption by reducing pumping losses at part load engine conditions. Here, the application of CDA on 1.6 liter four cylinders gasoline engine is studied. One-dimensional (1-D) engine modeling is performed to investigate the effect of intake and exhaust valve strategy on engine performance with CDA. The 1-D engine model is constructed starts from the air-box cleaner up to exhaust system according to the 1.6 liter actual engine geometries. The model is simulated at various engine speeds with full load condition. The simulated results show that the constructed model is well correlated to measured data. This correlated model is then used to investigate the effect of valves timing configurations on engine performance. The model is then used to determine the optimum intake and exhaust valve lift and timing for CDA application at part load conditions. Also, the effects on the in-cylinder combustion as well as pumping losses are presented. The study shows that the effects of valves strategies are very significant on the engine performance. Pumping losses is found to be reduced, thus improving fuel consumption and engine thermal efficiency. Recent technologies for gasoline engines include lean combustion technologies including direct injection and homogenous charged compression ignition [1, 2, 3, 4], the optimizing intake and exhaust valve timing and valve lift [5, 6] and the cylinder deactivation systems (CDA). These technologies have been applied to improve the engine efficiency and reduce the amount of fuel usage. Cylinder deactivation (CDA) is promising method in reducing fuel consumption and emission at part load in SI engines [7]. Deactivation of half the engine cylinders require the remaining firing cylinder to operate at a higher IMEP (Indicated Mean Effective Pressure) to provide similar overall BMEP (Brake Mean Effective Pressure) or engine torque. In other term, the work required by the firing cylinder is much more than normal operation. Hence, in order to supply required work with only half the cylinders, each cylinder needs more air and fuel than it would with all cylinders firing [8]. Therefore, the intake manifold pressure must be higher (less throttled), which seriously reduce the pumping work of the engine [9]. In cylinder deactivation mode, the combustion chambers of the unfired cylinders are kept shut by the closed valves. As a result, the enclosed air works like a pneumatic spring which is periodically compressed and decompressed without overall pumping work [10]. Cylinder deactivation creates an effective variable displacement engine, where the engine provides the optimum power based on demand with the fuel economy benefits without sacrifices the overall actual power. Downloaded from SAE International by Universiti Teknologi Malaysia, Sunday, October 19, 2014 Table 1. Engine technical specifications Engine Modeling Model Construction The engine model has been built starts from the intake airbox system until exhaust tailpipe system (Figure 1). This is to make sure that the constructed model represents the real engine condition. For the intake and exhaust systems, almost all components are modeled as pipes. In GT-Power, pipes are used to represent these systems as tubes and they are connected by junctions. The flow model involves the solution of Navier-Stokes equations, namely the conservation of continuity, momentum and energy equations. Detail about the flow model can be referred to GT-Suite manual [11]. In achieving better engine performance, it depends on the characterization of the technology used. It is important to understand the details of CDA technology, their interaction and parameters that effect on engine performance. Therefore, a one dimensional (1D) fluid dynamic computation simulation is used to assess the CDA engine performances. Here, software called GT-Power is applied to construct an engine model of natural aspirated, 1.6 L CamPro, spark-ignition engine. This 1.6 L engine is used in normal passenger car. The technical specifications of the engine are listed in Table 1. Here, the purpose of engine model construction is to understand the effect of intake and exhaust valves profiles configuration on CDA engine performance. This paper presents the model construction, correlation with actual test data and simulation of engine performance with CDA mode. In order to model the airbox in the GT-Power environment, a 3D CAD geometry of this component is used. The 3D geometry is discretized using GEM3D module in GT-Power to convert into the model file. Inlet and outlet diameters of each pipe (snorkel, duct, zip-tube) as well as their length are defined in GT-Power environment. Upper and lower airbox are defined by their volume. Discharge coefficient is also introduced to represent pressure losses of the air filter. A similar discretization process is applied to the intake and exhaust manifold. Here, the intake and exhaust runners are modeled using bend pipe object. Basically, this object will take into account the pressure loss due to the effect of bending geometry. The diameters of inlet and outlet, as well as the angle and bending radius are defined to model these runners. Intake plenum is defined using Y-split part, where the volume of each runner section is applied. Methodology This work focuses on the investigation of intake and exhaust valve profiles on the performance of CDA mode operation. In order to achieve that, a one dimensional (1D) engine simulation tool is used to construct the CDA engine model and to investigate the effect of intake variables on engine performance. Before the CDA engine model is constructed, four cylinder natural aspirated (NA) engine model is developed and correlated to measured data. A lot of input data are defined during the engine model construction. Some of the inputs are engine characteristics, cylinder geometry, intake and exhaust system geometries, fuel properties, injector characteristics, valve sizes, ambient conditions and engine operating conditions. The model is run at various engine speeds and at wide open throttle (WOT) conditions. To fully investigate the accuracy and reliability of the constructed model, the simulated results from the model are correlated to the measured data. In validation process, the constructed model is tuned so that the simulated results are well agreed to measured data. After both results are well compared, then the model is accepted as correlated model. This correlated model is then used to simulate the engine performance with CDA mode operation. View publication stats Figure 1. Constructed engine model of four cylinders 1.6 L engine. The most important step in engine modeling is to use the right combustion model. A fully-predictive combustion model known as ‘SI Turbulence’ function is applied. This combustion model more suitable for the prediction study of part load engine operation, exhaust gas recirculation (EGR), spark timing effect, cylinder knocking, combustion chamber design and spark plug gap [12]. This model predicts the combustion pressure as well as IMEP and other performances. Input data includes ‘.stl’ file of combustion chamber geometry, spark timing at each rpm at wide open throttle (WOT) condition, spark plug location and gap as well as fuel octane number are defined.