Method for calculating the sliding bearing of a piston engine and compressor

A one-dimensional model for calculating the sliding bearing of a piston engine and compressor is proposed. The results of approximation of the graphs by analytical dependences of the relative eccentricity on the bearing load coefficient for different values of the ratio of the working length of the bearing to the diameter of the crankshaft journal are presented in the form of exponential functions. Keywords: sliding bearing, heat balance, piston compressor, piston engine, friction [email protected]; [email protected]; [email protected]

Application of recurrence dynamic analysis to running-in state recognition

Purpose The purpose of this paper is to study the dynamic features of friction coefficient during running-in state based on recurrence analysis, so as to recognize the running-in state of crankshaft journal bearings. Design/methodology/approach The friction coefficient was measured in the friction experiments and the dynamic features are analyzed by recurrence plots (RPs), unthreshold recurrence plots (URPs) and recurrence quantification analysis. Findings During the running-in process, RPs have gone through disrupted patterns, drift patterns and homogeneous patterns successively. URP shows that the phase trajectory spirals in the disrupted pattern gradually converge in the drift pattern and remain stable in the homogeneous pattern. Three independent measures, recurrence rate, entropy and laminarity, are chosen to characterize friction coefficient from the perspective of point, diagonal line and vertical line structures of the RPs. Originality/value The results provide a feasible way to monitor the running-in process and recognize the running-in state.

Investigations of the Friction Losses of Different Engine Concepts: Part 3: Friction Reduction Potentials and Risk Assessment at the Sub-Assembly Level

One of the biggest requirements of today’s engine development process for passenger cars is the need to reduce fuel consumption. A very effective and economic approach is the use of low-viscosity lubricants. In this work, sub-assembly resolved friction reduction potentials and risks are presented for three different engine concepts. By using a developed combined approach, the friction losses of the base engines are separated to the sub-assemblies piston group, crankshaft journal bearings, and valve train over the full operation range of the engines. Unique analyzing of boundary conditions makes it possible for the first time to compare friction reduction potentials and possible risks, not only between diesel and gasoline engines for passenger car applications, but also with particular focus on the power density of the three engines. Firstly, the engines have been specifically chosen regarding their specific power output. Secondly, one identical SAE 5W30 lubricant suitable for all engines is used to neglect influences from different lubricant properties. Thirdly, identical test programs have been conducted at the same thermal boundary conditions at engine media supply temperatures of 70 ∘ C and 90 ∘ C. For the crankshaft journal bearings, high reduction potentials are identified, while risks arising occur at the valve train and the piston group systems.

Investigations of the Friction Losses of Different Engine Concepts. Part 1: A Combined Approach for Applying Subassembly-Resolved Friction Loss Analysis on a Modern Passenger-Car Diesel Engine

This work presents the application of a combined approach to investigate the friction losses in a modern four-cylinder passenger-car diesel engine. The approach connects the results from engine friction measurements using the indication method and the results from journal-bearing simulations. The utilization of the method enables a subassembly-resolved friction loss analysis that yields the losses of the piston group, crankshaft journal bearings, and valve train (including the timing drive and crankshaft seals). The engine and engine subassembly friction losses are investigated over the full speed and load range, covering more than 120 engine operation points at different engine media supply temperatures ranging from 70 to 110 ∘ C. The subsequently decreasing lubricant viscosity due to higher engine media supply temperatures allow for the identification of friction reduction potentials as well as possible risks due to an onset of mixed lubrication. Furthermore, additional strip-tests have been conducted to determine the friction losses of the crankshaft radial lip seals, the timing drive, and the crankshaft journal bearings, thus enabling a verification of the calculated journal-bearing friction losses with measurement results. For the investigated diesel engine, a friction reduction potential of up to 21% could be determined when increasing the engine media supply temperature from 70 to 110 ∘ C, at engine speeds higher than n = 1500 rpm and part load operating conditions. At low engine speeds and high load operations, the friction loss reduction potential is considerably decreased and below 8%, indicating mixed lubrication regimes at the piston group and valve train.

New Design Solution for Crankshaft

The crankshaft is a key part moving in the internal combustion engine. It converts the reciprocating piston movement into rotary motion. It is exposed to different forces resulted from the pistons pressures, friction, bending stresses and others. The paper concentrates on protecting the crankshaft journals from the direct impact of the piston pressure and other forces. It presents a familiar new modular product design. From this concept, work has done on the additional of the so-called ‘load bearing’ (two halves of a highly finished surfaces sleeve) embedded within the crankshaft journal. The proposed load bearing isolates the crankshaft journal and takes the place in the contact with other rotary components. This is an experimental research because of the presence of an extensive variety of models and uses of crankshafts. A prototype of the new solution was made and implemented on a single piston four stroke internal combustion engine and put in operation for 250 hrs. A precise examination and analyses of parameters in contrast with conventional crankshaft was done for verification and validation.

Simulation Analysis of Engine-Oil inside the Clearance between Crankshaft Journal and Bearing Shells in the Ideal Stable Conditions

For the bush-burning problem in the course of the engine operation. Taking a certain kind of engine as reference, build a 3D geometric model of the engine-oil flow field in the ideal stable conditions with GAMBIT and conduct a simulation of it with FLUENT. It reveals that we can have an intuitive understanding of the flow state and pressure distribution of the engine-oil inside the clearance between the crankshaft main journal and crankshaft bearing as well as the rod journal and rod bearing which provides basis for a further refining of bearing lubrication system, improving the lubrication method and enhancing the efficiency of the lubrication.

Experimental Research on a Three-Dimensional Journal Orbit of a Crankshaft Bearing for an Internal Combustion Engine

The current experimental researches on the orbit of a journal center of a crankshaft bearing for an internal combustion engine were usually focused on the 2D movement locus of a crankshaft journal center in the cross section of the bearing. However, in the actual operation of an internal combustion engine, there exists the movement of a crankshaft journal along the bearing axis under the effect of various factors, such as the crankshaft deformation acted by load. Obviously the tribological performance of a crankshaft bearing is affected inevitably by the movement of the crankshaft journal along the bearing axis. In this paper, a four-stroke four-cylinder internal combustion engine was taken as the studying object, the 3D orbit (that includes the movement in the cross section of the bearing and the movement along the bearing axis) of the journal center of the crankshaft bearing for an internal combustion engine was measured under a number of operating conditions on the test bench of an internal combustion engine. The position of the journal in the crankshaft bearing was obtained by the measurement using eddy current gap sensors and the data post-process. The results show that there exists the movement of the crankshaft journal along the axial direction in the bearing for an internal combustion engine. The actual orbit of the journal center of the crankshaft bearing for an internal combustion engine is a 3D spatial curve. The orbit of the journal center of the crankshaft bearing in one operating cycle of an internal combustion engine is not a closed curve. There is relatively a large movement of the journal along the axial direction of the crankshaft bearing, and the numerical value of the movement is greater than the radial clearance of the bearing. The greater the rotational speed of the internal combustion engine, the larger the amount of axial movement of the journal. The periodic variation exists in the axial movement of the bearing journal in one operating cycle of the internal combustion engine at low engine speed, and the varying periodicity equals the number of engine cylinders. There is no obvious varying rule of the axial movement of the bearing journal in one operating cycle of the internal combustion engine at high engine speed.

The Effect and Analysis of the Crankshaft Journal Fillet Rolling for Runout

Comparing with the characteristic of the two materials using on the crankshaft firstly, list their advantages and disadvantages; Secondly,expounding the effect of the crankshaft journal fillet rolling for radial runout, and apply HyperMesh、ANSYS and processing data to analyze and verify, thus drawing a estimated mathematical formula that solve for optimal rolling force on the basis of the depth of rolled hardened layer; According to the actual processing data and the optimal rolling force, proposing the improved crankshaft journal radial runout distribution,Then verify the feasibility of the estimated mathematical formula; The final result plays a a positive role to that reduce the processing costs of crankshaft and improve the crankshaft life.