A Study of the Effects of Ceramic Valve Train Parts on Reduction of Engine Friction

1997 ◽  
Author(s):  
Hiromu Izumida ◽  
Takao Nishioka ◽  
Akira Yamakawa ◽  
Masamichi Yamagiwa
Keyword(s):  
Valve Train ◽  
Engine Friction

Engine Friction Characteristics Under Cold Start Conditions

2001 ◽  
Author(s):  
Paul J. Shayler ◽  
John A. Burrows ◽  
Clive R. Tindle ◽  
Michael Murphy
Keyword(s):  
Fuel Injection ◽  
Cold Start ◽  
Operating Conditions ◽  
Valve Train ◽  
Bulk Temperature ◽  
Oil Viscosity ◽  
Engine Operation ◽  
Warm Up ◽  
Injection Pump ◽  
Engine Friction

Abstract Most studies of engine friction have been carried out at fully-warm operating conditions. Relatively little attention has been given to frictional losses when the engine is running cold, although these can be considerably higher and have a strong influence both on cold-start characteristics and fuel consumption during warm-up. The losses which effect the indicated load on the engine are rubbing losses and loads associated with driving auxiliaries. The equivalent frictional mean effective pressures (fmep) are generally highest during the first seconds of engine operation. These decay rapidly onto a characteristic variation which depends upon oil viscosity, and which fmep follows throughout the warm-up period. The oil viscosity can be evaluated at the bulk temperature of oil in the sump or main gallery. Breakdown motoring tests have been carried out on a series of diesel engines to examine how the friction contribution of various sub-assemblies in the engine contribute to the total and how this varies with temperature and speed. Tests were carried out using a compact cold cell and engine motoring facility. The engine was cold soaked to a target test temperature and then motored to a target speed and the variation of motoring torque recorded. Sets of tests were carried out at several stages of breaking the engine down. This enables the contributions due to the valve train, piston and big end assembly, crankshaft, fuel injection pump, and auxiliary load to be determined.

An Engine-Starting Simulation With Friction Estimation: Background and Model Validation

2003 ◽  
Author(s):  
Rassem R. Henry
Keyword(s):  
Performance Prediction ◽  
Engine Performance ◽  
Friction Torque ◽  
Valve Train ◽  
Physical Parameters ◽  
Test Results ◽  
First Case ◽  
Friction Models ◽  
Engine Friction ◽  
Friction Estimation

This paper describes an engine-starting simulation that uses models of the electrical, engine dynamics and engine thermodynamics subsystems combining them with engine friction models. One of these friction models uses the physical parameters of the engine as basis for estimating the friction torque. This allows engine performance prediction, hence the ability to size the electrical starting system, without engine availability. The resultant simulation is developed using SIMULINK/MATLAB™ and it has been validated for two engines; the first is a 4-cylinder engine with a conventional valve train, and relatively high friction by today’s standards, and the second is a more recent 3-cylinder engine with lowfriction. Validation of the first engine was done based on matching its published starting tests with results obtained using this paper’s simulation. The validation of the second engine was carried out by comparing engine test results with simulation results. Tests in the first case were for engine starting including firing and in the second case were for cranking only conditions.

Effect of Engine Operating Conditions and Lubricant Rheology on the Distribution of Losses in an Internal Combustion Engine

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Riaz A. Mufti ◽  
Martin Priest
Keyword(s):  
New Technologies ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Valve Train ◽  
Boundary Friction ◽  
Component Level ◽  
Frictional Losses ◽  
Engine Component ◽  
Engine Friction ◽  
Piston Assembly

With new legislation coming into place for the reduction in tail-pipe emissions, the OEMs are in constant pressure to meet these demands and have invested heavily in the development of new technologies. OEMs have asked lubricant and additive companies to contribute in meeting these new challenges by developing new products to improve fuel economy and reduce emissions. Modern low viscosity lubricants with new chemistries have been developed to improve fuel consumption. However, more work is needed to formulate compatible lubricants for new materials and engine technologies. In the field of internal combustion engines, researchers and scientists are working constantly on new technologies such as downsized engines, homogeneous charge compression ignition, the use of biofuel, new engine component materials, etc., to improve vehicle performance and emissions. Mathematical models are widely used in the automotive and lubricants industry to understand and study the effect of different lubricants and engine component materials on engine performance. Engine tests are carried out to evaluate lubricants under realistic conditions but they are expensive and time consuming. Therefore, bench tests are used to screen potential lubricant formulations so that only the most promising formulations go forward for engine testing. This reduces the expense dramatically. Engine tests do give a better picture of the lubricants performance but it does lack detailed tribological understanding as crankcase oil has to lubricant all parts of the engines, which do operate under different tribological conditions. Oil in an engine experiences all modes of lubrication regimes from boundary to hydrodynamic. The three main tribological components responsible for the frictional losses in an engine are the piston assembly, valve train, and bearings. There are two main types of frictional losses associated with these parts: shear loss and metal to metal friction. Thick oil in an engine will reduce the boundary friction but will increase shear losses whereas thin oil will reduce shear friction but will increase boundary friction and wear. This paper describes how engine operating conditions affect the distribution of power loss at component level. This study was carried out under realistic fired conditions using a single cylinder Ricardo Hydra gasoline engine. Piston assembly friction was measured using indicated mean effective pressure method and the valve train friction was measured using specially designed camshaft pulleys. Total engine friction was measured using pressure-volume diagram and brake torque measurements, whereas engine bearing friction was measured indirectly by subtracting the components from total engine friction. The tests were carried out under fired conditions and have shown changes in the distribution of component frictional losses at various engine speeds, lubricant temperatures, and type of lubricants. It was revealed that under certain engine operating conditions the difference in total engine friction loss was found to be small but major changes in the contribution at component level were observed.

Engine friction: The influence of lubricant rheology

1997 ◽  
Vol 211 (3) ◽  
pp. 235-246 ◽  
Author(s):  
R. I. Taylor
Keyword(s):  
Shear Rate ◽  
Gasoline Engine ◽  
Hydrodynamic Lubrication ◽  
Valve Train ◽  
Boundary Friction ◽  
Friction Modifier ◽  
Cold Starting ◽  
Engine Friction ◽  
Viscosity Variation ◽  
Lubricant Viscosity

The sensitivity of engine friction to lubricant viscometry has been determined for a modern fuelefficient engine, the Mercedes Benz M111 2.0 litre gasoline engine, under both cold starting and fully warmed-up conditions. The study has taken into account realistic lubricant viscometric parameters such as the lubricant viscosity variation with shear rate and temperature. Results are reported for the variation of engine friction with different monograde and multigrade lubricants, including the distribution of friction losses between valve train, piston assembly and bearings with the different lubricant types. The work also enabled estimates to be made of the proportion of hydrodynamic and boundary friction in the engine, since the vast majority of boundary lubrication occurs in the valve train. Knowledge of the ratio of boundary to hydrodynamic lubrication was found to be important since the two key lubricant parameters that can be varied are (a) viscosity and (b) the introduction of a friction modifier additive. The viscosity of the lubricant will affect the hydrodynamically lubricated parts of the engine whereas the presence of a friction modifier will reduce boundary friction in the engine. Brief comparisons are made of the lubricant sensitivity of the Mercedes Benz M111 engine with other important fuel-efficient engines (such as the Ford Sequence VI and Ford Sequence VIA engines).

How much mixed/boundary friction is there in an engine — and where is it?

2019 ◽  
Vol 234 (10) ◽  
pp. 1563-1579 ◽  
Author(s):  
RI Taylor ◽  
N Morgan ◽  
R Mainwaring ◽  
T Davenport
Keyword(s):  
Boundary Lubrication ◽  
Mixed Boundary ◽  
Operating Conditions ◽  
Valve Train ◽  
Friction Modifier ◽  
Direct Measurements ◽  
Full Discussion ◽  
Engine Friction ◽  
The Individual ◽  
The Impact

Automotive engines are believed to operate predominantly in the hydrodynamic regime, as evidenced by the (1) the successful strategy of reducing lubricant viscosity to reduce engine friction and improve vehicle fuel consumption, and (2) for most engine operating conditions, direct measurements of engine friction (either motored or fired) find that engine friction increases with increasing engine speed. However, certain components in an engine are known to operate mainly in the mixed/boundary lubrication (e.g. the valve train) and other components (such as the piston rings) operate in the mixed/boundary regime for a portion of the time. In order to quantify the amount of mixed/boundary lubrication in an engine, and in the individual components of the engine, motored and fired friction tests have been carried out for a range of lubricants (of differing viscosity grade, and with/without friction modifier additives). A full discussion of the implications of this work, which includes the impact of fuel dilution and “running-in” is included with insights given into how the work reported here guides the development of future fuel-efficient engine lubricants.

scholarly journals Combining an innovative measurement technique with accurate simulation to analyze engine friction

2018 ◽  
Author(s):  
Hannes Allmaier ◽  
Christoph Knauder ◽  
David E Sander ◽  
Franz M. Reich
Keyword(s):  
Measurement Technique ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Valve Train ◽  
Power Losses ◽  
Friction Power ◽  
Low Viscosity ◽  
Full Load Operation ◽  
Engine Friction ◽  
The Individual

The entanglement of an innovative measurement technique with an accurate simulation yields in total a powerful tool to investigate the friction power losses in engines under realistic operating conditions, as will be discussed in the following. While the total engine friction power losses and the friction of the valve train are measured experimentally, the friction power losses of the crank train journal bearings are calculated using simulation. The result is in an efficient and powerful determination of the individual engine subassemblies under realistic operating conditions ranging from idle to full load operation. The presented method can be used to assess the efficiency of various friction reduction measures like cylinder deactivation, (ultra)low viscosity lubricants or coatings and won in 2014 the Innovation award of Magna Logistics Europe.

Cylinder Deactivation with Mechanically Fully Variable Valve Train

2012 ◽  
Vol 5 (2) ◽  
pp. 207-215 ◽  
Author(s):  
Rudolf Flierl ◽  
Frederic Lauer ◽  
Michael Breuer ◽  
Wilhelm Hannibal
Keyword(s):  
Valve Train ◽  
Cylinder Deactivation ◽  
Variable Valve Train ◽  
Variable Valve

Variable Valve Train Concept for Compliance with Future Diesel Emission Standards

MTZ worldwide ◽  
2021 ◽  
Vol 82 (2) ◽  
pp. 36-41
Author(s):  
Michael Elicker ◽  
Wolfgang Christgen ◽  
Jahaazeb Kiyanni ◽  
Maximilian Brauer
Keyword(s):  
Valve Train ◽  
Emission Standards ◽  
Variable Valve Train ◽  
Diesel Emission ◽  
Variable Valve
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