Riassunto analitico
Nella prima fase si è proceduto allo studio dei componenti idraulici come: 1) e_Pump: pompa idraulica collegata al motore elettrico attivata quando il motore endotermico si spegne. 2) e_PR: valvola di sicurezza che protegge i componenti da sovrappressioni nel circuito.
Nella seconda fase, si è simulata la manovra complessiva per verificare che tutti i componenti funzionassero correttamente e per rilevare, eventuali, anomalie nel sistema ad esempio: 1) Anomalia e_Pump: flusso in direzione opposta a quello di normale funzionamento. 2) Riempimento della camera di alimentazione della frizione. Nella terza fase, si è provveduto ad elaborare opportune strategie per risolvere l'anomalia dell'e_Pump attraverso: 1) Chiusura forzata dell' ePR attraverso la PV4 e PV5. 2) Riduzione della pressione nel ramo di bassa pressione.
Nella quarta fase, si è passati ad elaborare delle strategie per migliorare il riempimento della frizione: 1) Aumento numero di giri dell'e_Pump. 2) Aumento corrente alla valvola PV1.
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Abstract
In the first phase, it has been studied the main components of Hydraulic circuit of DCT for instance:
1) Epump: it is the pump moved by electric motor and it is turned on, for a short range of time, in order to keep and guarantee a high level of pressure of the Hydraulic circuit when the main pump is switched off.
2) ePR: it is also called as Pressure relief Valve which protects components from over pressure and it is normally closed.
Through the AMESim's Table Editor, it has been built the volumetric and hydrodynamic efficiency maps of the pump and tested it for each pressure and temperature conditions of our interest. The successfully design of components and the systems is a crucial step because allows to compare the simulation results with the experimental one, a good design and validation of the Epump is fundamental to correctly detect and analyse the dynamics of pressure in the hydraulic circuit.
In the second phase, firstly it has been reproduced the real maneuver with all essential component, already checked and validate,to reduce the computational costs and simulation time. Secondly, it has been run to detect possible anomalies and optimization of target parameters and the results are:
1) Anomaly of ePump: Reverse Flow because of opening ePR.
2)Optimization of Clutch Filling in terms of pressure and time.
In the third phase, it has been fixed the anomaly of ePump that happens when the main pump and ePump, for a really short time, work together in which the ePR remains open due to input pressure is too high. Consequently, there will be a reverse flow toward the ePR and it forces the ePump to a reverse rotation motion that could damage the component itself and be dangerous for the whole system. The issue was fixed through the implementation of two different strategies:
1) Forced Closing of ePR with PV4 and PV5 command signal.
2)Reduce the pressure in the low pressure circuit through the CCV1 and CCV2 command signals.
In the fourth phase, it has been dedicated to the improvement of the filling clutches by two strategies:
1) Increasing the speed of Epump [rpm].
2) Increasing of excitation current [mA] delivered to PV1 which in turn allow the engagement/disengagement of odd clutch.
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