Monotherm, a New Forged Steel Piston Design for Highly Loaded Diesel Engines

While steel pistons have been in use for a long time in commercial vehicle diesel engines, the first series production applications for passenger car diesel engines are currently imminent. The main reason for the use of steel pistons in high speed diesel engines is not, as maybe initially hypothesized, the increasing requirements on the component strength due to increasing mechanical loads, but rather challenges based on the actual CO2-legislation. The increasing requirements to reduce the fuel consumption necessitate new innovative technologies. The imminent penalties for exceeding the prescribed CO2 emissions seem to make the steel piston a viable alternative today, despite its higher manufacturing costs. So far, the CO2-benefits using steel pistons were mainly ascribed to the reduced friction between piston and cylinder liner due to no thermal interference.

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Analysis of Aluminum and Steel Pistons: Comparison of Friction, Piston Temperature, and Combustion

Volume 2: Fuels; Numerical Simulation; Engine Design, Lubrication, and Applications ◽

10.1115/icef2013-19114 ◽

2013 ◽

Cited By ~ 1

Author(s):

Kai Schreer ◽

Ingo Roth ◽

Simon Schneider ◽

Holger Ehnis

Keyword(s):

Fuel Consumption ◽

Diesel Engines ◽

High Speed ◽

Process Analysis ◽

Combustion Process ◽

Cylinder Liner ◽

Thermodynamic Efficiency ◽

Series Production ◽

Steel Piston ◽

Wide Range

While steel pistons have been in use for a long time in commercial vehicle diesel engines, the first series production applications for passenger car diesel engines are currently imminent. The main reason for the use of steel pistons in high speed diesel engines is not, as maybe initially hypothesized, the increasing requirements on the component strength due to increasing mechanical loads, but rather challenges based on the actual CO2-legislation. The increasing requirements to reduce the fuel consumption necessitate new innovative technologies. The imminent penalties for exceeding the prescribed CO2 emissions seem to make the steel piston a viable alternative today, despite its higher manufacturing costs. So far, the CO2-benefits using steel pistons were mainly ascribed to the reduced friction between piston and cylinder liner due to no thermal interference. Fuel consumption measurements at vehicle manufacturer and research institutes hypothesize also an influence of the steel piston on the thermodynamic efficiency. MAHLE uses engine tests to investigate one piston variant made of aluminum (series production piston with cooled ring carrier) and one of steel (MAHLE TopWeld) in a detailed system comparison. Using a fully indicated engine, a combustion process analysis is performed and used as the basis for a loss analysis. The engine set-up parameters can be adjusted fully variable using a flexible ECU. The effect that the piston variant has on the combustion process is captured and balanced, e.g., by adjusting the parameters to obtain identical emissions. The analysis records the potential of the variants for each engine operating map area. The thermal conditions for the piston and the piston wall temperature on the combustion chamber side are varied over a wide range using a conditioning device for piston cooling. The influence of this intervention on the thermal load of the piston and the combustion and also the influence of different combustion mappings is measured directly by telemetric piston temperature measurement. MAHLE recently completed a system comparison [3] between aluminum and steel pistons with detailed measurements on a fully indicated engine, covering friction and temperature behavior as well as influences on combustion.

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DEVELOPMENT OF THE COMBUSTION CHAMBER OF GAS ENGINE, CONVERTED ON THE BASIS OF DIESELS D-120 OR D-144 ENGINES TO WORK FOR ON LIQUEFIED PETROLEUM GAS

Avtoshliakhovyk Ukrayiny ◽

10.33868/0365-8392-2019-3-259-2-8 ◽

2019 ◽

pp. 2-8

Author(s):

Serhii Kovalov

Keyword(s):

Combustion Chamber ◽

Compression Ratio ◽

Diesel Engines ◽

Combustion Engine ◽

Motor Fuel ◽

Liquefied Petroleum Gas ◽

Gas Engine ◽

Chamber Volume ◽

Motor Fuels ◽

Dynamic Cycle

The expediency of using vehicles of liquefied petroleum gas as a motor fuel, as com-pared with traditional liquid motor fuels, in particular with diesel fuel, is shown. The advantages of converting diesel engines into gas ICEs with forced ignition with respect to conversion into gas diesel engines are substantiated. The analysis of methods for reducing the compression ratio in diesel engines when converting them into gas ICEs with forced ignition has been carried out. It is shown that for converting diesel engines into gas ICEs with forced ignition, it is advisable to use the Otto thermo-dynamic cycle with a decrease in the geometric degree of compression. The choice is grounded and an open combustion chamber in the form of an inverted axisymmetric “truncated cone” is developed. The proposed shape of the combustion chamber of a gas internal combustion engine for operation in the LPG reduces the geometric compression ratio of D-120 and D-144 diesel engines with an unseparated spherical combustion chamber, which reduces the geometric compression ratio from ε = 16,5 to ε = 9,4. The developed form of the combustion chamber allows the new diesel pistons or diesel pistons which are in operation to be in operation to be refined, instead of making special new gas pistons and to reduce the geometric compression ratio of diesel engines only by increasing the combustion chamber volume in the piston. This method of reducing the geometric degree of compression using conventional lathes is the most technologically advanced and cheap, as well as the least time consuming. Keywords: self-propelled chassis SSh-2540, wheeled tractors, diesel engines D-120 and D-144, gas engine with forced ignition, liquefied petroleum gas (LPG), compression ratio of the internal com-bustion engine, vehicles operating in the LPG.

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