TopWeld<sup>®</sup> Steel Piston for High Speed Diesel Engines

Gabriel, Dieter; Hettich, Thomas

doi:10.4271/2015-01-1723

Cited by 4 publications

(6 citation statements)

References 3 publications

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“…Both of these trends are consistent with the experimental data. Note here that the increase in energy transferred to the oil with the steel piston (Figures 4 to 7 inclusive) observed in the current work is contrary to previously reported studies within the literature [14,15]. The authors attribute this apparent disagreement to differences in piston cooling arrangements between the current study and the referenced works.…”

Section: = − ( + ) (3)contrasting

confidence: 99%

“…Thus, the reduced energy transfer to the coolant in the jacket-for all operating conditions and EGR rates-when operating with the steel piston is consistent with the reduced frictional losses associated with the design as shown in Figure 8. It is also consistent with the expected effects of the reduced skirt length and longer con-rod length associated with the steel piston, and in full agreement with the literature [14,15]. It should be recognized however that the energy transfer to coolant in the jacket is also affected by heat conduction through the piston ring pack and that the observed changes may not be due to frictional effects alone.…”

Section: = − ( + ) (3)supporting

confidence: 89%

“…The literature suggests that the lower thermal conductivity of steel will lead to higher piston surface temperatures [15], which would result in reduced heat flux between the hot combustion gases and the piston bowl and crown. Without direct measurement in the current work it is not possible to confirm or quantify changes in piston surface temperature; however the observations of reduced ignition delay in the present work ( Figure 12) are consistent with the effects of increased piston surface temperature reported in the literature [23].…”

Section: = − ( + ) (3)mentioning

confidence: 99%

“…Recently, steel pistons have found their way into light-duty diesel applications, and apart from their structural benefits over the aluminium pistons, researchers have reported improvements in both brake and indicated fuel efficiency [14,15].…”

Section: Introductionmentioning

confidence: 99%

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Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Papaioannou¹,

Leach²,

Davy³

2019

SAE Technical Paper Series

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Chromium-molybdenum alloy steel pistons, which have been used in commercial vehicle applications for some time, have more recently been proposed as a means of improving thermal efficiency in lightduty applications. This work reports a comparison of the effects of geometrically similar aluminium and steel pistons on the combustion characteristics and energy flows on a single cylinder high-speed direct injection diesel research engine tested at two speed / load conditions (1500 rpm / 6.9 bar nIMEP and 2000 rpm / 25.8 bar nIMEP) both with and without EGR. The results indicate that changing to an alloy steel piston can provide a significant benefit in brake thermal efficiency at part-load and a reduced (but nonnegligible) benefit at the high-load condition and also a reduction in fuel consumption. These benefits were attributed primarily to a reduction in friction losses. In terms of energy transfer, switching to the steel piston design was shown to reduce heat transfer to the coolant, consistent with lower friction work and reduced conduction through the ring pack, and increase the energy transfer to the oil. Piston blowby was also greatly reduced. Ignition delay times and overall combustion durations were reduced with the steel piston design, possibly indicative of higher piston surface temperatures.

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Section: = − ( + ) (3)contrasting

confidence: 99%

Section: = − ( + ) (3)supporting

confidence: 89%

Section: = − ( + ) (3)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Papaioannou¹,

Leach²,

Davy³

2019

SAE Technical Paper Series

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“…The heavy-duty diesel engine piston which adopts 42CrMo4 as the piston top and 38MnVS6 as the piston skirt can withstand high mechanical load and thermal load. It is beneficial to improve the combustion efficiency of the engine and reduce the fuel consumption [1][2][3][4]. The core problem of heavy truck diesel engine pistons is the jointing of 42CrMo4 with 38MnVS6.…”

Section: Introductionmentioning

confidence: 99%

Effect of Preheating Temperature on Microstructure and Properties of 42CrMo4/38MnVS6 Heterogeneous Laser Welded Joint

Qiu

Xing

et al. 2019

Metals

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Laser-welded forged steel pistons can meet the needs of the new era of heavy truck engines. 42CrMo4 and 38MnVS6 are widely used as piston materials due to the good mechanical properties. This study investigates the influence of preheating on microstructure and mechanical properties of 42CrMo4/38MnVS6 laser welding joint. The experimental results show preheating increases the laser absorption capacity of the metal, which can lead to an increase in weld width. The microstructure of weld is the high-hardness and poor toughness twin martensite without preheating. As the temperature of preheating increases, the twin martensite in the weld begins to transform into lath martensite and regenerates ferrite and bainite. As the preheating temperature increases, the plane fracture toughness (K1C) of the weld increases and then decreases, reaching the highest value of 2322.94 MPa·mm −1/2 at 150 • C. Compared with no preheating conditions, the tensile strength of the welded joint after preheating is improved. The fracture mode of welded joints changes from brittle fracture to ductile fracture. When the preheating temperature is 100-200 • C, the tensile strength of the welded joint reaches 1018.1-1032.5 MPa; when the preheating temperature is 250 • C-300 • C, the tensile strength decreases. the heat input is in the range of 275 J/mm 0.5 ·s 0.5 to 435 J/mm 0.5 ·s 0.5 , and there was no defect in the weld [12]. Kuryntsev et al. studied the effect of heat treatment on laser welded joints of 0.349C-1Cr-1Si steel. The results showed that the laser welded joint had the characteristics of high hardness and low elongation. After heat treatment, the elongation and ductility of the welded joint are improved [13]. Laser welding has a high energy density, and the base metal is not easy to deform after welding. It can optimize the piston structure and is conducive to the full combustion of fuel. Therefore, the development of laser welding forged steel piston has become one of the development directions of piston structure [14][15][16][17]. Preheating before welding can increase the laser absorption rate of the metal and reduce the cooling rate of the weld, adjust the stress distribution of the welded joint, avoid the generation of hardened structure in the weld, and is one of the welding methods to effectively improve the mechanical properties of the welded joint [18,19].At present, there are more studies on laser welding of aluminum alloy and low carbon steel with preheating, but less on medium carbon steel [20][21][22]. In this paper, the effect of preheating on the weld structure of 42CrMo4/38MnVS6 laser welding is studied, and the mechanical properties of welded joints under different preheating temperature are compared and analyzed, which provides the basis of experimental and theoretical for the application of laser welding technology in a forged steel piston. Materials and Methods Materials

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Prediction of NOx Emissions for a Range of Engine Hardware Configurations Using Artificial Neural Networks

Papaioannou

Fang

Leach

et al. 2020

ASME 2020 Internal Combustion Engine Division Fall Technical Conference

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The predictive ability of artificial neural networks where a large number of experimental data are available, has been studied extensively. Studies have shown that ANN models are capable of accurately predicting NOx emissions from engines under various operating conditions and different fuel types when trained well. One of the major advantages of an ANN model is its ability to relearn when new experimental data is available, thus continuously improving its accuracy. The present work explored the potential of an ANN model to predict NOx emissions for various engine configurations outside its training envelop. This work also looked into quantifying the amount of new data required to improve the accuracy of the model when exposed to unknown conditions. The chosen ANN model was constructed using data from a high-speed direct injection diesel engine and is capable of accurate NOx emissions over a wide range of operating conditions. The optimized network utilized 14 input parameters and is using 6 neurons in a single hidden layer feed-forward neural network. Experimental data from the various engine configurations tested, were then used to predict NOx from the existing ANN model. The results indicate that when the new data are within the baseline training envelop, the ANN model is capable of accurate NOx prediction even when there are substantial changes in engine configuration such as piston material. Similar results were also observed when the injector nozzle is changed. However, the model’s performance drops significantly when new data, outside the baseline training envelop, were employed indicating that additional training is required. As such, various methods for retraining the ANN model were explored with the selected method showing the best compromise between new-data accuracy and old-data accuracy retention. The retrained ANN model developed was found to be an effective tool in predicting NOx emissions for different engine configurations and operating conditions.

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TopWeld^® Steel Piston for High Speed Diesel Engines

Cited by 4 publications

References 3 publications

Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Effect of Preheating Temperature on Microstructure and Properties of 42CrMo4/38MnVS6 Heterogeneous Laser Welded Joint

Prediction of NOx Emissions for a Range of Engine Hardware Configurations Using Artificial Neural Networks

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TopWeld® Steel Piston for High Speed Diesel Engines

Cited by 4 publications

References 3 publications

Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Thermal Analysis of Steel and Aluminium Pistons for an HSDI Diesel Engine

Effect of Preheating Temperature on Microstructure and Properties of 42CrMo4/38MnVS6 Heterogeneous Laser Welded Joint

Prediction of NOx Emissions for a Range of Engine Hardware Configurations Using Artificial Neural Networks

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Product

Resources

About

TopWeld^® Steel Piston for High Speed Diesel Engines