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FEA-based prediction and experimental validation of clutch transient temperature in automatic transmission
Abstract
Multiple-disk clutch packs are commonly used in automotive automatic transmissions to transfer power and to change gears. Owing to packaging-space restrictions and performance requests, many clutch packs have non-uniform loading characteristics, resulting in local stress and temperatures much higher than bulk targets. Extremely high local temperatures or temperature gradients in clutch packs can cause frictional material carbonisation, debonding, coning or many other failure modes. This paper describes the development of a Finite Element Analysis (FEA) model that is capable of predicting transient temperature in the multiple-disk clutch packs. The FEA predictions are correlated with experimental data. A good agreement, with 5% discrepancy in the clutch pack temperature rise during the first engagement is obtained. The developed method improves the understanding of the heat transfer characteristics during the clutch operating conditions, and reduces product development time and cost.
... Since the material properties of clutch parts are temperature dependent, many clutch failures, like pressure plate cracks may happen with high operating temperature (Fernandes et al., 2015). Extremely high operating temperature also has a negative influence on the wear (Balaji and Kalaichelvan, 2012) and debonding (Liao, 2007) of the facings, the cushion spring stiffness (Cappetti et al., 2012) and the clutch torque transmissibility (Lin et al., 2017;Orzelowski and Wicher, 2000). Since many years, ventilation channels have been applied into brake discs, which operate in contact with ambient air. ...
The main objective of this study is to conduct an experimental
research to investigate the effect of ventilation channels which have never been practised into the conventional automotive clutch pressure plate before. The purpose is to reduce its weight without compromising its thermo-mechanical performance. Both convective and conductive heat transfers of the clutch pressure plate have been enhanced in order to meet thermo-mechanical
performance requirements, by ventilation channels and by chemical composition adjustment, respectively. The novel design ventilated Ø430 size clutch pressure plates comprising different metallurgical structures have been experimentally investigated and compared with that of the conventional non-ventilated version. The results of this research have shown that it is
feasible to reduce the clutch pressure plate weight by 28% without compromising its thermo-mechanical performance. Thus, the weight reduction of the heaviest component of the clutch system would also help to meet greenhouse gas emissions policies of the vehicles.
... All literature results show that energy dissipation is not enough to prevent temperature rise of clutch frictional parts. Similar phenomenon has been observed also in wet type clutches (Liao, 2007). ...
This paper presents an approach to estimate the temperature on the
friction surface of a dry clutch. The study comprises both experimental measurements and transient thermal numerical analysis of heavy duty truck clutches for the successive engagements on a slope road. Compared to previous mathematical models in the literature; pressure plate surface convection coefficient, energy dissipation, engagement duration and variation of the clutch
housing air temperature were obtained on the basis of experimental data and have been applied as input in the 3D clutch transient thermal finite element analysis. Simulation results show that the design of clutch plate has a significant effect on the temperature rise at the friction surface.
... All literature results show that energy dissipation is not enough to prevent temperature rise of clutch frictional parts. Similar phenomenon has been observed also in wet type clutches (Liao, 2007). ...
This paper presents an approach to estimate the temperature on the friction surface of a dry clutch. The study comprises both experimental measurements and transient thermal numerical analysis of heavy duty truck clutches for the successive engagements on a slope road. Compared to previous mathematical models in the literature; pressure plate surface convection coefficient, energy dissipation, engagement duration and variation of the clutch housing air temperature were obtained on the basis of experimental data and have been applied as input in the 3D clutch transient thermal finite element analysis. Simulation results show that the design of clutch plate has a significant effect on the temperature rise at the friction surface.
... A finite element model of a dry clutch was established by Pisaturo and Senatore (2016) to simulate the temperature fields of friction components during the engagement process. The prediction model of temperature field was established and verified by experiments in Liao's (2007) research. Then, the temperature field and wear prediction of a wet clutch were studied by Li et al. (2016) using a 1D heat transfer model and sliding experiments. ...
The phenomenon of non-uniform pressure distribution among multi-disc friction pairs is investigated focusing on the effect produced by the circlip using a theoretical model and a 3D FEM model. A temperature field computational model of the discs is established based on the non-uniform pressure distribution. Sliding experiments are conducted to investigate the influence of circlip on non-uniform pressure distribution among the discs in the multi-disc clutches, and the temperature simulation results are verified by the experimental results. The obtained results show that the concentrated circlip constraint leads to the non-uniform pressure distribution in both the radial and axial directions, and in turn affects the temperature fields of discs. Unlike uniform pressure, the non-uniform pressure caused by the concentrated circlip constraint will lead to different temperature fields in different discs. Furthermore, the highest temperature and the maximum radial temperature difference both occur on the disc next to the circlip. Besides, the ratio coefficient of temperatures can effectively represent the pressure transfer coefficient among discs.
... A finite element model of a dry clutch was established by Pisaturo and Senatore (2016) to simulate the temperature fields of friction components during the engagement process. The prediction model of temperature field was established and verified by experiments in Liao's (2007) research. Then, the temperature field and wear prediction of a wet clutch were studied by Li et al. (2016) using a 1D heat transfer model and sliding experiments. ...
In this study, we examine the effectiveness of microjet air injection as a means of suppressing thermoacoustic instabilities in a swirl-stabilized, lean-premixed propane/air combustor. High-speed stereo PIV measurements, taken to explore the mechanism of combustion instability, reveal that the inner recirculation zone plays a dominant role in the coupling of acoustics and heat release that leads to combustion instability. Six microjet injector configurations were designed to modify the inner and outer recirculation zones with the intent of decoupling the mechanism leading to instability. Microjets that injected air into the inner recirculation zone, swirling in the opposite sense to the primary swirl were effective in suppressing combustion instability, reducing the overall sound pressure level by up to 17 dB within a certain window of operating conditions. Stabilization was achieved near an equivalence ratio of 0.65, corresponding to the region where the combustor transitions from a 40 Hz instability mode to a 110 Hz instability mode. PIV measurements made of the stabilized flow revealed significant modification of the inner recirculation zone and substantial weakening of the outer recirculation zone.
By considering the players and the activity levels simultaneously, we propose a consistent solution which is a generalization of the equal allocation of nonseparable costs (EANSC) on fuzzy games. We also adopt two pre-existing concepts from traditional game theory and reinterpret them in the framework of fuzzy games. First, based on the consistency which related to an extended reduced game, we offer two axiomatizations of the extended EANSC. Second, by applying the excess function, we propose a dynamic process to illustrate that the extended EANSC can be reached by players who start from an arbitrary efficient solution and make consecutive amendments.
Deleted in Liver Cancer 1 (DLC1) is a GTPase-activating protein (GAP) with specificity for RhoA, RhoB, and RhoC that is frequently deleted in various tumor types. By inactivating these small GTPases, DLC1 controls actin cytoskeletal remodeling and biological processes such as cell migration and proliferation. Here we provide evidence that DLC1 binds to phosphatidylinositol-4,5-bisphosphate (PI(4,5)P(2)) through a previously unrecognized polybasic region (PBR) adjacent to its RhoGAP domain. Importantly, PI(4,5)P(2)-containing membranes are shown to stimulate DLC1 GAP activity in vitro. In living cells, a DLC1 mutant lacking an intact PBR inactivated Rho signaling less efficiently and was severely compromised in suppressing cell spreading, directed migration, and proliferation. We therefore propose that PI(4,5)P(2) is an important cofactor in DLC1 regulation in vivo and that the PBR is essential for the cellular functions of the protein.
In this paper, a very accurate model of optical modulators in silicon-on-insulator technology is developed and validated using experimental results reported in literature. Using an optimized nanometer MOS structure, a significant bandwidth increase (around 45%), length decrease (around four times), and power consumption reduction (three times) with respect to the state-of-the-art have been obtained.
This paper describes phenomena influencing value of the limiting torque transmitted by a friction clutch of a motor vehicle. This value sets bounds to dynamic loads of the components of the power transmission system of the vehicle and has direct influence on their durability. A mathematical model of the friction clutch has been built and experimentally verified. Numerical simulation and analysis of parametric sensitivity of the model enabled evaluation of the influence of various design parameters of the clutch on its ability to transmit torque.
The simplified isothermal model for wet clutch engagement previously developed by Berger Sadeghi, and Krousgrill (1997a) was extended to include fluid thermal effects. The modified Reynolds and thermal diffusion equations were simultaneously solved to obtain torque and temperature characteristics during wet clutch engagement. The modified Reynolds equation was integrated using the Adams-Gear scheme and the alternating direction implicit method (ADI) finite difference technique was used to solve the thermal diffusion equation. The model was used to study the effects of speed, temperature, and load on the torque transfer and lubricant temperature variation during wet clutch engagement. A comparison of thermal and isothermal results indicates that the thermal model generally predicts a longer engagement time and smaller peak torque than the isothermal model. Comparison of analytical and experimental results indicates that including fluid thermal effects in the model is critical for achieving good correlation between analytical and experimental results.
This article presents the transient thermoelastic behaviors of carbon/carbon composite brake disks in the brake housing during braking action. The heat transfer problem from frictional heat and the elastic problem dealing with thermomechanical deformation in brake contact are coupled to each other. The coupled heat and elastic analysis were carried out using the finite element method. The fully implicit transient scheme for the thermoelastic analysis was newly implemented to improve the accuracy of calculations at every time step. Since the heat capacity of carbon/carbon composite is very large, the high temperature of the brake disk system is confined to only the narrow regions near the friction surfaces. Therefore, the thermoelastic behaviors of carbon/carbon composite brake disk system were little affected by the thermal boundary conditions in the brake housing during braking action.
The paper presents a model of transient thermomechanical phenomena occurring in a pack of friction discs of a multidisc wet clutch or a brake. Account is taken of the couplings between phenomena appearing on various friction surfaces. Numerical methods permitting an effective investigation of these are described.Results of calculations are presented for the case when the thermoelastic instability effect appears. A mechanism for the growth of non-uniformities in normal pressure distributions on friction surfaces as well as couplings between phenomena occurring on various surfaces are discussed. It is also shown that the phenomena arising on friction surfaces strongly affect the thermal stresses inside the discs.