Influence of Relevant Fluid Parameters on Pressure Pulsation of a Variable Lubricant Vane Pump Thomas Fischer, development/calculation Jan Fischer, development/testing Nico Jäkel, development/construction Mercedes-Benz Berlin Plant Frankfurt/Main, October 21. 2013
Outline 1. Introduction 2. Configuration of the Simulation Model in GT Suite 3. Calibration of the Simulation Model Based on Measurements on the Reduced Main Unit Test Bench 4. Calculation of the Influence of Relevant Fluid Parameters 5. Summary
1. Introduction
1. Introduction Structure and Function of the Vane-type Pump Pressure port Chain drive Vane type pump Pressure-relief valve Pressure control valve Suction port Electromagnetic valve Lubricant vane type pump of the new inline-4 gasoline engine for Mercedes-Benz passenger cars
1. Introduction Structure and Function of the Vane-type Pump Outlet Port Chamber Chamber Inlet Port The fluid is sucked in and displaced by the change in volume of the chambers. The volumetric flow of the pump is proportional to the volume change of the chambers over the rotation angle of the pump rotor.
1. Introduction Structure and Function of the Vane-type Pump Outlet Port Chamber Chamber Inlet Port The fluid is sucked in and displaced by the change in volume of the chambers. The volumetric flow of the pump is proportional to the change in volume of the chambers over the rotation angle of the pump rotor. The change in volume of the chambers, and with that, the volumetric flow of the pump, is varied by the displacement of the set collar.
1. Introduction Task Description for the Simulation 7000 6000 Measurement of the dynamic oil pressure curve on a real engine 5000 4000 3000 2000 1000 0 speed pressure cooler inlet pressure cooler outlet 0 25 50 75 100 125 150 Time [s] Speed over time Pressure on the oil cooler inlet and outlet vs. time
1. Introduction Task Description for the Simulation Which factors significantly influence the amplitudes 7000 of the pressure pulsation? 6000 Can the calculated pressure curve be calibrated in 5000 line with the measurements by varying the relevant 4000 influencing factors? 3000 Can the effect of the non-influenceable fluid parameters on the pressure curve be reduced? 2000 1000 0 speed pressure cooler inlet pressure cooler outlet Increasing the robustness of the system 0 25 50 75 100 125 150 Time [s] Measurement of the dynamic oil pressure curve on a real engine Speed over time Pressure on the oil cooler inlet and outlet vs. time
1. Introduction Task Description for the Simulation Avoidance of component damage through: 1. Optimization of the components relevant to pressure pulsation during the digital assembly stage, 2. Calculation of reliable load collectives for the technical specifications of components and assemblies, Damage to an oil-water heat exchangers in the test engine 3. Computational validation of component changes.
2. Configuration of the Simulation Model in GT Suite
2. Configuration of the Simulation Model in GT Suite GT Map The geometry of the conveying chamber and the inlets and outlets are measured in CAD. Engine oil circuit highly simplified
2. Configuration of the Simulation Model in GT Suite GT Map The geometry of the conveying chamber and the inlets and outlets are measured in CAD. Engine oil circuit highly simplified
2. Configuration of the Simulation Model in GT Suite Modeling of the Fluid Oil-air mixture with a variable proportion of free air in the oil Fluid-Liquid-Aeration Aeration Model Object Initial Gas Fraction Bunsen Coefficient Gas Properties Object Liquid Properties Object Time Constant for free => dissolved Time Constant for dissolved => free Oil Properties Properties of air
3. Calibration of the Simulation Model Based on Measurements from the Reduced Main Unit Test Bench
3. Calibration of the Simulation Model to Correspond to Measurement Data GT map for the calibration of the vane type pump Simplification of the test rig in the assembly laboratory Adaptation of the simulation model to the simplified test rig
3. Calibration of the Simulation Model to Correspond to Measurement Data Comparison of the results with measurements on the reduced Main Unit Test Stand Pressure according to pump over time n=2,800 rpm 2800rpm Measure Time Constant for Free=>Dissolved Air T f=>d =0.05 s 2800rpm GTI-Simulation InitialGasFraction=0 2800rpm GTI-Simulation InitialGasFraction=0,1% 103.38 103.385 103.39 103.395 103.4 time [s] The air in the pressure range is fully dissolved.
3. Calibration of the Simulation Model in Line With Measurement Data Comparison of the results with measurements on the reduced Main Unit Test Stand Pressure Good consistency of the calculated pressure curve with the measured pressure curve according to pump over time n=2,800 rpm Time Constant for Free=>Dissolved Air T f=>d =5 s 2800rpm Measure 2800rpm GTI-Simulation InitialGasFraction=0,1% TC(Fr The air is entirely free. 103.38 103.385 103.39 103.395 103.4 time [s]
4. Calculation of the Influence of Relevant Fluid Parameters
4. Calculation of the Influence of Relevant Fluid Parameters Factors Involved in the Calculation Factor Level Initial Gas Fraction 0 0,1 % 5% 10% 20 % Bunsen Coefficient 0,07 0,09 Time Constant for free => dissolved Time Constant for dissolved => free 0,01 0,05 1 5 1E-5 1E-2 Oil Properties Oil "A" Oil "B" 2x DOE run with 80 Cases per run
4. Calculation of the Influence of Relevant Fluid Parameters Graphic showing the effects of the factors on the amplitude sum of the pressure pulsation Initial gas content and the dissolved time constant have a clear effect The freed time constant has a minimal effect The Bunsen coefficient and oil type have negligible effects
4. Calculation of the Influence of Relevant Fluid Parameters Comparison of the results with measurements on the running engine 7000 6000 Pressure on the inlet of the oilwater heat exchanger over time 5000 4000 n=6,300 rpm T=115 deg 3000 2000 1000 0 speed pressure cooler inlet pressure cooler outlet 0 25 50 75 100 125 150 Time [s]
4. Calculation of the Influence of Relevant Fluid Parameters Comparison of the results with measurements on the running engine 7000 6000 Pressure on the inlet of the oilwater heat exchanger over time 5000 4000 n=6,300 rpm T=115 deg 3000 2000 1000 0 speed pressure cooler inlet pressure cooler outlet 120.58 100 25 120.582105 50 120.584 110 75 120.586 100 115120.588 125 120.59 150 Time [s]
4. Calculation of the Influence of Relevant Fluid Parameters Comparison of the results with measurements on the running engine 7000 6000 Pressure on the inlet of the oilwater heat exchanger over time 5000 4000 n=6,300 rpm T=115 deg 3000 2000 1000 speed Measure real engine Oil Temp pressure 115deg cooler, n=6300rpm inlet GTI-Simulation n=6300rpm pressure DOE-Set cooler 18 outlet 0 120.58 120.58 100 120.582 25 120.582105 120.584 50 120.584 110 75 120.586 120.586 100 115 120.588 125 120.59 150 Time time [s]
4. Calculation of the Influence of Relevant Fluid Parameters Comparison of the results with measurements on the running engine Pressure on the inlet of the oilwater heat exchanger over time n=6,300 rpm T=115 deg Measure real engine Oil Temp 115deg, n=6300rpm GTI-Simulation n=6300rpm DOE-Set 19 120.58 120.582 120.584 120.586 120.588 120.59 time [s]
5. Summary Summary The fluid parameters "Initial Gas Fraction" and "Time Constant for free => dissolved" are the main influencing factors on the result of the simulation. Through the variation of the relevant fluid parameters, the simulation result can be very effectively calibrated in line with testing. Reliable load collectives can be calculated with the existing simulation model. The effect of geometric modification can be calculated up to a certain point. The effect of localized pseudo-cavitation effects on complex geometries cannot be calculated.
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