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In this paper an air path model is presented for control system design. The model was developed for direct injected, turbocharged and intercooled commercial vehicle diesel engines which are equipped with compressed air booster system (PBS® - Pneumatic Booster System) [12], high pressure exhaust gas recirculation (EGR) with EGR-cooler and exhaust br...
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... They have been designed and mounted onto the engine in the last few years. Table 2. Engine parameters (Bárdos and Németh, 2013) The air path system of the engine is depicted in Figure 1. It has two EGR systems and four support valves. ...
My approach to the marginal cost debate for road transport published in the Vol 2 of Cognitive Sustainability
... They have been designed and mounted onto the engine in the last few years. Table 2. Engine parameters (Bárdos and Németh, 2013) The air path system of the engine is depicted in Figure 1. It has two EGR systems and four support valves. ...
Modern Diesel engines contain sophisticated control systems to keep their environmental impact low for sustainable road transport. One of these systems is the dual loop exhaust gas recirculation, which can change combustion properties in several ways. This article presents an engine dyno measurement based on analyzing the duel loop EGR with a medium-duty Diesel engine. Intake throttles and exhaust brakes for the highest freedom in the air-fuel ratio setting support the EGR systems. The EGR modes are compared from fuel consumption, NOx emission, and exhaust gas opacity in steady and transient operations. There are expected results, for instance, in the HP EGR’s faster reaction time or the LP EGR’s boost pressure holding property. Unexpected results are also presented. Contrary to theory, LP EGR generally provides a fuel consumption advantage in many operation points due to its higher boost pressure. Typically, HP EGR can provide lower fuel consumption at higher engine power. In the emission results, LP EGR is favourable both in NOx emission and exhaust gas opacity, whereas the intake throttle-supported HP EGR usually shows the highest emission. Besides, with high EGR rates at lower engine loads, LP EGR can realize low-temperature combustion, where both emissions decrease. No difference can be detected between the LP EGR’s support valves’ results. HP EGR was faster in the transient operation, with about half the reaction time. The results can be utilized for dual-loop EGR layout and control design.
... Due to the periodic operation, several parameters change effectively in the engine speed function-for example, the volumetric efficiency can have a significant change. A smaller speed range achieves that several parameters can be simplified to constants [2,3]. Thus, commercial vehicles' engines' modeling needs a different approach and has new research opportunities in model simplification [4]. ...
... The control synthesis for dual loop EGR systems is an up-to-date research area in the last decade [2,4,5,[13][14][15][16][17][18]. The first step in controlling is usually the modeling of the system. ...
... Engine models can be based on several physical properties in the air path system. One typical modeling type is based on the pressures and mass flow rates [2,3,15]. In these models, the EGR mass flow rate can be estimated by the orifice equation between the exhaust and the intake side [2]. ...
Modern Diesel engines have complex exhaust gas recirculation (EGR) systems. Due to the high temperatures, it is a typical issue to measure EGR mass flow rates in these complex control systems. Therefore, it is expedient to estimate it. Several sensed values can help the estimation: the fresh air mass flow rate, the fuel consumption, pressures, temperatures and mass fractions in the air path system. In most of the articles, the EGR mass flow rate estimation is done by the pressures. However, gas composition based models usually would be better for control aims. In this paper, nine EGR estimation methods will be presented: an important outcome is to present the required sensor architectures and estimation challenges. The comparison will be made by measurement results both in stationary operation points and transient cycles. The estimated EGR mass flow rates will be evaluated by verification conditions. The results will prove that the intake and exhaust side oxygen sensors can give verifiable signals for EGR mass flow rate estimation. In contrast, the applied fresh air mass flow rate and the nitrogen-oxide signals are not accurate enough to provide verifiable EGR mass flow rates in every operating condition. The effects of sensor inaccuracies will also be considered.
... Engine air path models can be written to many gaseous states [14,15] but basically there are two types of control oriented engine models: pressure-based models (for example in [16] and in [17]) and composition-based models (for example in [18] and in [19]). The developed engine model will be based on pressures in the pre-defined volumes and on the mass flow rates between these volumes. ...
... The research has much connection with previously published papers (for example [21]). Besides the published model has many solutions from [17] and [22]. ...
... Pressures in each volume can change in two ways: by the difference between the incoming and the leaving mass flow rates and by heat transfer. If the temperature of the incoming mass flow rate is different from the temperature inside, the change can be handled as a mass flow rate into the volume (without temperature differences) and an additional external heat transfer [17,26]. Besides to have a simpler model it is expedient to neglect as many temperature changes as many possible under the validation criteria. ...
Due to the new European emission norms internal combustion engines have to comply stricter rules. The new norms contain new requirements that were not included in previous regulations for example the decreased temperature of the cold start or the real driving emission part. The emission cycles for passenger vehicles are completely news, the stricter emission norms for commercial vehicles will follow them within a few years. Despite the increasing spread of alternative transmission systems in road transport Diesel engines are going to be remain in commercial vehicles in the next decades due to their good torque and fuel consumption performance. The emission of Diesel engines can be kept low by several way: by the modification of combustion processes, or by exhaust gas after treatment. To comply future regulations both of them seems to be necessary. By exhaust gas recirculation systems alternative Diesel combustion processes can be realized which can provide lower nitrogen-oxide emission and in several operation points also lower fuel consumption. Exhaust gas recirculation systems also can support the thermal management of a Diesel engine. To utilize the advantages of the recirculated exhaust gases a complex system is necessary to get a freedom in control possibilities: duel loop exhaust gas recirculated systems supplemented with supporter valves on the intake or on the exhaust side. In this paper a pressure and mass flow rate based control oriented engine model will be presented which contains high and low pressure exhaust gas recirculation systems and both of them are supported by exhaust brakes. The model considers four balance volumes and it has five state variables. The model is validated by an engine dyno measurements on a medium duty Diesel engine.
... A complete air path model of a diesel engine was validated and published in Bárdos and Németh (2013). The model presented below is derived from the aforesaid paper by suitable simplifications. ...
... Preliminarily a complete air path model of a diesel engine was validated and published in (Bárdos and Németh, 2013). The model presented below was derived from the referenced work by suitable simplifications. ...
Modern engine exhaust restriction valves can be applied not only as retarders. A suitable pressure generation can assist the aftertreatment system (exhaust gas temperature management) and raw emission control as well. To provide these functionalities the exhaust backpressure has to be controlled arbitrarily. In this paper a model-based controller design is demonstrated to minimize calibration effort. A first engineering principle based, mean-value, nonlinear model was described and converted into linear parameter-varying (LPV) form. To satisfy the demands of the above applications the controller needs to be a high dynamic, stabilizing, tracking controller which is robust in the whole relevant engine operation range. The exhaust processes of the individual cylinders generate comparable amplitude pressure oscillations to the expected control accuracy. To fulfill the above requirements and manage the challenge of the exhaust pressure waves an H-infinity controller design method was chosen. In order to handle the saturation of the control signal a high gain anti-windup was applied. Seeking for the lowest possible computational demand the controller order reduction was proposed based on Hankel singular values. Finally the controller performance was demonstrated and evaluated in software-in-the-loop simulations.
https://pp.bme.hu/tr/article/view/8470
Developers of modern diesel engines have to face rigorous restrictions in emission of nitrogen-oxides and particulate matter. Among several methods (DPF, SCR, improved injection etc) which are used to handle these exhaust gas components precise control of the cylinder charge composition seems to be a cost effective solution. The oxygen concentration of the intake gas has a significant impact on the combustion process hence on the pollutant formation. Moreover the precise adjustment of the cylinder charge oxygen concentration can be used to control low temperature combustion processes. The amount of the backflowing exhaust gases is limited by the pressure difference on the EGR duct. To solve this problem the authors suggest the use of novel exhaust brakes with extended functionality: backpressure adjustment for the precise control of the intake gas composition. This way arbitrary EGR rates can be achieved in any engine operation point. For the implementation of such a function the design of an intake manifold oxygen controller is needed, where the control inputs are the EGR valve and the exhaust throttle. This paper demonstrates the development of a control oriented model of the air path system as the first step of this task. The model considers three balance volumes in the air path and has five state variables. Its performance has been evaluated and validated with engine dyno measurements on a medium duty diesel engine.
https://www.sciencedirect.com/science/article/abs/pii/S0957415817300399
