Browse Topic: Camshafts

Items (150)

Frontloading of cam bearing friction and lubrication assessment through EHD analysis

2022-01-076803/29/2022

One of the key thrust areas in engine design and development is achieving friction reduction between rotating parts in engine bearings. Valvetrain and cam bearing friction losses contribute to around 15% of all friction losses. Inline to cranktrain bearings, cam bearings are also supplied oil through oil gallery. Hence, cam bearings also operate under mixed lubrication regime. There is an opportunity to frontload cam bearing assessment through EHD simulation with similar approach as in cranktrain EHD modeling. This paper discusses about simulation methodology developed for cam bearing EHD in AVL Excite Powerunit. Crantrain dynamic model has been extended by appending complete valvetrain dynamic model. A substructure of camshaft has been used to drive valvetrain. Engine is also defined as a substructure with retained nodes at cam bearing interface. These nodes are connected to camshaft using EHD joints. Timing of each cam has been defined to allow synchronous valve opening and closure

Bhattacharya, Anup

Numerical Study of an I4 Engine Oil Ejection During an Accidental Cap-off Running Condition for Two Baffle Designs

2022-01-047203/29/2022

Three-dimensional transient numerical simulations are conducted to mimic the operating conditions of a four-cylinder internal combustion engine running without its engine-oil cap on. Navier-Stokes equations are solved together with the multiphase Volume of Fluid (VOF) model and the k-ϵ turbulence model. The engine crank shaft is mechanically connected to two cam shafts through a chain, which operates below the oil-cap open boundary. A baffle is located between the chain and the oil-cap opening to minimize oil spills. The chain geometry and dynamics are captured accurately through volume remesh and conformal mapping techniques. The motion of the four pistons, crank shaft, and two cam shafts is also considered. Retaining all these mechanical and geometrical details in the simulations is essential to obtain accurate oil ejection results. The crank shaft rotates at 1200 RPM and the study is conducted for two different baffle designs. Experimental results indicate a steady-state oil

Jorda Juanos, Albert, Schlautman, Jeff, Parsons, Neal, Pandey, Ashutosh

Design Challenges & Solution in Modifying Compact 4-Stroke Diesel Engine while Adapting D-Cycle Technology

2022-01-072503/29/2022

This paper reviews application of 2-Stroke D-Cycle (i.e. Differential Stroke) technology to compact tractor 4-Stroke 2.7L 4-Cylinder CRS (Common Rail System) Naturally aspirated (NA) Diesel engine for improving efficiency & power. The study considers design challenges that are presented for accommodating D-cycle technology in engine. The paper also covers resolving those challenges with established technical solutions. Study focuses on modifying conventional compact 4-stroke diesel engine with the intention of keeping design changes minimal for incorporating differential stroke technology. Designing of vertically splitting lightweight piston crown which can smoothly engaged and separated from main piston body without any impact, stem rod which connects piston crown with rocker arm, hollow connecting rod and rocker arm which is actuated by additional camshaft in addition to present camshaft. Lubrication of additional camshaft is done by extending existing oil galleries. Gear train

Telshinge, Pravin, Paulraj, Lemuel

Cryogenic Cam Butterfly Valve

TBMG-3459606/01/2019

Typical butterfly valves cannot seal at both ambient and cryogenic temperatures. At cryogenic temperatures, valves grow and shrink, changing critical dimensions such as distance between the disc and seat. Ideally, valves would compensate. The inability of existing butterfly valves to do this led to the design of the Cryogenic Cam Butterfly Valve (CCBV) in which the disc rides on a cam shaft and is held rigid by a torsion spring that provides both axial movement of the disc in addition to the standard 90-degree rotation of a standard butterfly valve. Because the valve’s disc can rotate and translate, it can hold a tighter seal, preventing leakage despite dimensional changes caused by changing operating temperatures.

Power Cylinder Friction: Mechanisms

J2904_201805 (Historical)

05/16/2018

This document covers the mechanisms from the power cylinder which contribute to the mechanical friction of an internal combustion engine. It will not discuss in detail the influence of other engine components or engine driven accessories on friction.

Piston and Ring Standards Committee

Influence of Miller Cycles on Engine Air Flow

03-11-02-001104/18/2018

The influence of the intake valve lift of two Miller cycles on the in-cylinder flow field inside a DISI engine is studied experimentally since changes of the engine flow field directly affect the turbulent mixing and the combustion process. For the analysis of the impact of the valve timing on the general flow field topology and on the large-scale flow structures, high-speed stereo-scopic particle-image velocimetry measurements are conducted in the tumble plane and the cross-tumble plane. The direct comparison to a standard Otto intake valve lift curve reveals evidently different impacts on the flow field for both Miller cam shafts. A Miller cycle that features late intake valve closing shows a flow field comparable to the standard Otto valve timing and a tumble vortex of strong intensity can be identified. Hence, turbulent mixing is as sufficient as for the standard Otto valve timing, although the Miller cycle intake valve timing leads to a pressure reduction of approximately 20%. In

Braun, Marco, Klaas, Michael, Schröder, Wolfgang

Parametric Study and Prediction of Lubrication Oil Film Thickness in Sliding and Rolling Interface Valve Trains

2018-01-093104/03/2018

To achieve acceptable valve train lubrication with low viscosity oil is challenging. Understanding the effect of valve train design parameter on valve train lubrication is important. In this study rocker arm valve train mechanism is analyzed to check the influence of valve train design parameters on lubrication at cam and rocker face interface. In valve train lubrication, lubrication oil film thickness play important role in valve train wear and friction. Main objective is to maintain acceptable oil film thickness at peak valve lift and minimizing the duration of critical minimum oil film thickness at cam flank to avoid wear at cam/ roller rocker follower interface when using low viscosity oil. Cam nose wear effect the engine performance and wear at cam flank change the dynamic characteristics of valve train. Lubrication oil entrainment velocity is an important parameter controlling the lubrication oil film thickness in elasto hydrodynamic lubrication zone at cam / roller rocker

Poonia, Sanjay, Singh, Amandeep, Singh, Jaspreet, Kumar, Narinder, Sharma, Shailender

Gear Whine Noise Due to Deformation- A Case Study

2017-01-112203/28/2017

Vehicle noise has reduced over the years due to the customer demand for quieter vehicles. As the background noises such as combustion noise, pumping noise, etc. have reduced, mechanical noises such as gear noise have become prominent and a major cause of customer complaints. Engine timing gear train uses gears for transferring torque to cam and accessory gears. As engines have become quieter by efforts to reduce the combustion noise, as well as, by moving away from mechanical fuel pumps to common rail fuel pumps, the gear train noise has come under increased scrutiny. Gear whine could be a result of multiple factors. Gear profile distortion is one of the factors. Gear torque variation also has a significant effect on gear whine. Operation of the accessory drives such as hydraulic pumps under variable loads and speeds, is one of the major challenges for resolving a gear whine issue in the engine gear train. ISO 10064 provides guidance on the distortion due to temperature effects, but

Joshi, Yashodhan V.

Valvetrain Ticking Noise Analysis

2017-01-105703/28/2017

Valvetrain ticking noise is one of the key failure modes in noise vibration harshness (NVH) evaluation at idle. It affects customer satisfaction inversely. In this paper, the root cause of the valvetrain ticking noise and key parameters that impact ticking noise will be presented. A physics based math model has been developed and integrated into a parameterized multi-body dynamic model. The analytical prediction has been correlated with testing data. Valvetrain ticking noise control is discussed.

Zeng, Paul, Paul, Debabrata, Solferino, Vincent, Stickler, Mark

Analysis of Engine Flywheel Wobbling Vibration

2017-01-102303/28/2017

Large axial displacement at the edge of a flywheel causes a clutch to fail to disengage in high-speed rotation. To find out the root cause, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston, and connecting rod was performed with AVL/Excite. The resulting CAE baseline model had good correlation with measurements. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalanced masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.

Jiang, Yaqun, Hsieh, C., Festag, Georg, Ahmed, Masood, Jiang, William

A Finite Element Method for Camshaft Cap Durability Analysis

2017-01-034103/28/2017

In this study, a finite element analysis method is developed for simulating a camshaft cap punching bench test. Stiffness results of simulated camshaft cap component are correlated with test data and used to validate the model accuracy in terms of material and boundary conditions. Next, the method is used for verification of cap design and durability performance improvement. In order to improve the computational efficiency of the finite element analysis, the punch is replaced by equivalent trigonometric distributed loads. The sensitivity of the finite element predicted strains for different trigonometric pressure distribution functions is also investigated and compared to strain gage measured values. A number of equivalent stress criteria are also used for fatigue safety factor calculations. The severity of the loading experienced by the camshaft caps depends on whether the under study cap is on intake or exhaust camshaft side as well as the location of the associated cylinder on the

Mortazavian, Seyyedvahid, Moraveji, Javid, Adimi, Reda, Chen, Xingfu

Test Component Specifications

J1802/1_201607 (Current)07/27/2016

This SAE Recommended Practice contains the reference information for SAE J1802.

Truck and Bus Foundation Brake Committee

A Model Based Design Analysis for a Gasoline Direct Injection Pump

2015-01-126704/14/2015

A high-pressure fuel pump in a GDI (Gasoline Direct Injection) engine has been increasingly applied on passenger vehicles because of its high fuel efficiency and reduction of exhaust emissions. The design specifications of principal components of GDI high-pressure pump should be validated prior to the manufacturing. This study presents the analytical results of the specifications for the design of a GDI pump of Motonic Co. by using computational model based simulation. The results are largely divided into two parts. First, cam-follower dynamics with the proper design of cam profile, and second, the discharge flow performance of the pump in consideration of the characteristics of inlet control valve.

Lee, Jae-Cheon, Liu, Hao, Noh, Yoo-Jeong, Shin, Hyun Myung, Shin, Yong Nam, Kang, Myung Kweon

Novel Conceptual Approaches for Improvements in Compression Ratio for Diesel Engines

2015-26-002501/14/2015

In diesel systems, compression ratio(CR) is one of the key parameters which plays an important role in its performance. The volume of air that is sucked into the cylinder and which will be further compressed in compression stroke depends on the swept volume due to the piston movement from Top Dead centre (TDC) to Bottom Dead Centre (BDC) within the cylinder. The increase in CR through increase in the swept volume without changing either cylinder or piston sizes and without altering the TDC position will be very useful. The author proposes two schemes based on variable ConRod (Connecting Rod) and Movable Crank Pin approaches to realize the increase in CR. The author also touches upon the scope of varying the CR in these schemes.

Mandagaddi, Sireesha

Improvement of the Startability with Reverse Stroke Intake Devices for a Motorcycle Engine

2014-32-010711/11/2014

This paper proposes a novel engine starter system composed of a small-power electric motor and a simple mechanical valve train. The system makes it possible to design more efficient starters than conventional systems, and it is especially effective to restart engines equipped with idling stop systems. Recently, several idling stop systems, having intelligent start-up functions and highly-efficient generate capabilities have been proposed for motorcycles. One of challenges of the idling stop systems is the downsizing of electric motors for starting-up. However, there are many limitations to downsize the electric motors in the conventional idling stop systems, since the systems utilize the forward-rotational torque of the electric motors to compress the air-fuel mixture gas in the cylinders. Our studies exceeded the limitations of downsizing the electric motors by mainly using the engine combustion energy instead of the electric energy to go over the first compression top dead center

Masuda, Takahiro, Sakai, Kouji, Yamaguchi, Yuki, Kaku, Jun-ichi, Nagasaka, Hirobumi

Valve Spring Compression Testing System

2014-36-023009/30/2014

The compression springs of the valves of automotive engines are key elements in the dynamic behavior of the engine. Its wear is slow, gradual and progressive; so the driver of the vehicle eventually get used to the decrease in the engine performance. The compressive force losses cause the valves to close slower than expected and, consequently, the engines lose their efficiency. Professionals in the area of automotive maintenance apply empirical tests with varying criteria to evaluate and to determine the life cycle end at which the springs must be replaced. This article describes the development of a workbench for compression springs based on existing models on the market and the main premise is the low cost. Correspondent loads involved were determined and the components were modeled in CAD, allowing to develop a robust device able to handle the loads generated by the compression spring. The load is applied by means of a lever and the spring deflection is measured by a digital caliper

Vandresen, Marcelo, Lencina, Diovani C., Fernandes, Carolina P., Silva, Luana N., Feliciano, Lucas D. P., Cazangi, Humberto R.

Power Cylinder Blow-by: Problem Solving

J2798_201408 (Historical)08/05/2014

This document describes methodologies to determine the causes blow-by oil consumption caused by the power cylinder.

Piston and Ring Standards Committee

Augmenting Light Weighting Horizon in Automotive

2014-28-002304/28/2014

Better ride and comfort, enhanced safety, reliability and durability, lower running cost as well as cost of ownership continue to be challenges for automotive OEMs. Higher fuel efficiency is considered as USP not only for lower running cost but also is hygiene factor from sustainability point of view. This has necessitated the need for Augmenting Light weighting horizon in automotive OEMs. Augmenting this leads to invention of innovative materials and processes for emerging cost competitive market. This paper focuses on technology efforts towards augmenting light weighting Horizon in Automotive. Light weighting concepts being explored by OEMs with the help of automotive component manufacturers from Powertrain - Engines & Transmission, Chassis and Suspension are discussed. The Innovative concepts and case studies covered include Hollow Crankshaft and Camshafts, PM gears, composite / bimetallic brake drum, steering knuckle & leaf spring, hollow Anti Roll Bar (ARB) & Front Axle Beams (FAB

Raghvendra, G, Shende, Deodatta, Pathak, Udayan

Improving actuation speed and controllability

13OFHD1107_0311/07/2013

With high-speed hydraulic proportional valves, the performance of existing cam phasing systems can be improved or the actuation mechanisms can be applied directly to engine valve actuation. High-performance actuation mechanisms are key enablers for achieving higher efficiency and better performance in many systems. Common actuation mechanisms include electromagnets, piezoelectrics, motors with screws, and linear motors. In each mechanism, when linear on/off motion is considered, the actuator's entire mass must be accelerated each cycle. Researchers from Purdue University have developed a concept actuation system where the primary mass is always moving and the linear motion is caused by momentarily coupling the two masses to move together. Piezoelectric actuators have a very fast response, a high-frequency bandwidth, reaching an upper limit of 25 kHz, and relatively high force capacity. However, their stroke lengths are small; they also require high driving voltages, and the material is

Kinematic Modeling and Analysis of a Cam Based CVT

2013-01-137104/08/2013

Continuously variable transmission (CVT) offers many advantages to vehicle performance over traditional transmission technologies. A novel cam based CVT was proposed in US patent # 4,603,240, by J. Klovstad and J. Fortune [1], which has a cam input to drive an angle dependent, clutch actuated output shaft. Based on the patented CVT, a kinematic simulation, utilizing three dimensional CAD software was performed, creating a visualization and analysis model to ascertain system performance and feasibility. This article describes the mechanism created, limitation of the modeling software and the approach utilized to overcome these limitations. The resultant motion is then analyzed to ascertain the performance of the mechanism and determine the viability of the design concept. Key improvements to the system are proposed to the design, based on system performance through this analysis.

Hickman, Gregory Fitzpatrick, Gu, Randy, Chang, Yin-Ping

A Study on the Dynamic Characteristics of a Single-body Hydraulic Lash Adjuster under Aeration

2013-01-172304/08/2013

To accurately simulate valve behavior in an engine employing a Hydraulic Lash Adjuster (HLA), it is necessary to reflect in the simulation model the dynamic characteristics of the HLA when feeding aerated engine oil. Traditionally HLA behavior was measured by agitating oil to aerate it inside an actual engine. With this technique, however, the aeration rate cannot be controlled to allow an examination of the relationship between aeration rate and HLA behavior. This study aims to establish a technique for obtaining HLA dynamic characteristics when oil contains air. We created an aeration device that allows free control of the oil aeration rate and, by applying excitation input to the plunger, revealed the relationship between oil aeration rate and the changes in HLA stiffness. Because of the small clearance between the HLA plunger and its housing, it is difficult for air to escape from low-temperature oil inside the HLA high-pressure chamber, which greatly affects HLA behavior.

Yoshii, Kenta, Kawano, Masaru, Yanagisawa, Nagao

Dynamic Analysis of a Valvetrain System

2012-36-012610/02/2012

The mathematical modeling of the dynamics of a mechanical system is a powerful tool for the engineer predicts the behavior of the system. In the design of intake and exhaust valvetrains of diesel engine, the dynamic analysis of the system is essential for the proper sizing of the components. Through dynamic analysis of a 1D model using the Simulink software, this paper will describe the behavior of a valvetrain system that uses an exhaust rocker with hydraulic lifter.

Tomoyose, Rodrigo

Recycling of Used Up Crankshaft Grinding Wheels

2012-01-106004/16/2012

For sustainability in automobile manufacturing, recycle, reuse, and repair of used up cutting tools is now an established process. Although many types of tools were designed for one time use and then throw, an increasing awareness of the impact on the natural resources have made manufacturers to put some of these back to use or sell it back to suppliers who have put up a mechanism to extract the elements e.g. Tungsten and use it for manufacturing of new tools. There are many ways in which cutting tools can be recycled. Be it by reshaping a used up throwaway type tool [1], by redesigning of a tool holder for the use of unused cutting edges [2] or reusing short length drills that are used in making of long oil holes in crank case, cylinder head, cam shaft or connecting rods [3]. This paper demonstrates successful use of used up crankshaft grinding wheels. These used up grinding wheels can be reformed and used for grinding of many other automobile parts that require a new grinding wheel

Datar, Surendra

An Efficient Multi-Body Approach Modeling Elastohydrodynamic Friction in Drive Systems

2012-01-091704/16/2012

Chain drives are used in powertrains for the kinematic coupling of the cam shaft, the ancillary units and the balancing shafts with the crank shaft. Advantages of chain drives are their high load carrying capacity along with increased durability whilst simultaneously being maintenance-free. A crucial issue in the drive is the optimization in regard of friction, further improving efficiency, reducing exhaust emission and abrasive wear. Modeling friction in drive systems requires precise description of the whole system dynamics. High-frequency oscillations occurring in the chain strands cause numerical problems in the friction computation. As a remedy, regularized friction curves are often used, being however not able to correctly determine all friction configurations and requiring a tradeoff between accuracy and computational efficiency. Another challenge is the sensitivity of the coefficient of friction to many factors among which are kinematic and kinetic quantities, lubricant

Filippi, Markus, Ulbrich, Heinz

Modeling of Variable Valve Timing on High Performance Engine using Power-Oriented Graphs Method

2011-24-015009/11/2011

Engine efficiency is one of the key aspects to reduce CO2 emissions. In order to improve the emission maintaining high performance capabilities several devices are introduced in the system; variable valve timing technology allows more flexibility for modern engines to meet peak performance, fuel economy and low emissions targets [7] while providing good driveability. This paper describes the Lamborghini continuously-variable cam phaser model using a graphical technique, called Power Oriented Graphs (POG), this uses an energetic approach for representing the physical systems. The generally accepted approach is to calibrate an engine on a dynamometer and to adjust the operation of the engine to meet performance targets. With the current build and test approach, these adjustments may not be made until well into the development program, and this calibration is a costly and time consuming step in the engine development process: the main purpose of this works is showing how was described the

Corvino, Cristian, Calabretta, Michele, Zanasi, Roberto

Test Component Specifications

J1802/1_201105 (Historical)05/16/2011

This SAE Recommended Practice contains the reference information for SAE J1802.

Truck and Bus Foundation Brake Committee

Flexible Multi-body Dynamic Analysis of Multi-Cylinder Engine Valve Train

2011-26-008601/19/2011

In this paper, valve spring parameters are optimized based on an iterative logic with constraint on space availability, stress limit, stiffness and natural frequency of the system. The optimized valve spring configuration is used in the push rod type valve train and the valve train dynamics for different engine speed is studied using commercially available multi-body dynamic ADMAS software. The valve train components such as cam, tappet, push rod, rocker arm, valve retainers and valve are modelled as rigid bodies and the valve springs (inner and outer valve springs) are modelled as flexible bodies. Each coil of the springs is modelled as separate flexible body and contact between these coils are established. A comparative valve train dynamics analysis is also carried out with the existing and optimized valve spring combinations. It is observed that valve jump engine speed with respect to optimized valve spring is enhanced to considerable amount when compared to the existing valve

Prabakar, R. S., Mangalaramanan, S. P.

Novel Design of the Integrated Electric Parking Brake System

2010-01-170710/10/2010

A new design of integrated Electric Parking Brake system, called iEPB and integrated in the brake caliper, is introduced in this paper. It consists of an electrically operated brake unit and a hydraulically pressed unit independently, and uses a special self-locking mechanism instead of a screw device to increase the efficiency and the working speed. With all conventional EPB system's advantages, it also provides a stronger brake performance and a faster reaction time. In this paper, we describe the working principle of this new design at first, and then introduce the arrangement of the testing system, followed by a discussion of experimental data. The testing results prove the feasibility of this design. The conclusion paragraph summarizes the key points about the design of the iEPB system.

Liao, Yan-Sin, Huang, Chien-Tai, Chen, Chien-Tzu, Cheng, Shou-Yi, Chen, Bo-Ruei, Huang, Fu-Yen

Valvetrain Friction - Modeling, Analysis and Measurement of a High Performance Engine Valvetrain System

2010-01-149205/05/2010

Engine efficiency is one of the key aspects to reduce CO₂ emissions. Lamborghini S.p.A. has focused attention on the engine friction modeling, analysis and measurement to understand and control the phenomena. To reduce friction it is necessary to improve understanding of the behavior of the engine components and to pay attention to detail at every tribological contact. The valve train can make a significant contribution to whole engine friction especially at low engine speed and this is particularly true for a high speed sports car engine. Direct acting valve trains are often used for this type of engine to minimize the moved mass and so enable high speed operation. However the sliding contact between the cam and tappet results in higher friction loss than the roller finger follower valve train used on many modern passenger car engines. In addition, the high maximum engine speed demands a large valve spring force to maintain contact between cam and tappet. The large spring force can

Calabretta, Michele, Cacciatore, Diego, Carden, Phil

A Systematic Approach for Design of Engine Crankcase Through Stress Optimization

2010-01-050004/12/2010

The cylinder block for the power train has always been a classic example of concurrent engineering in which disciplines like NVH, Durability, thermal management and lubrication system layout contribute interactively for concept design. Since the concept design is based on engineering judgment and is an estimated design, the design iterations for optimization are inevitable. This paper aims at outlining a systematic approach for design of crankcase for fatigue which would eliminate design iterations for durability. This allows a larger scope for design improvement at the concept stage as the design specifications are not matured at this stage. A process of stress optimization is adopted which gives accurate dimensional input to design. The approach is illustrated with a case study where an existing crankcase was optimized for fatigue and significant weight reduction was achieved. The precondition for the approach is that there should not be any major change in concept design

Londhe, Abhijit, Sen, Aparajita

MARCH 2010 AUTOMOTIVE DESIGN

AUTODES031003/01/2010

Jaguar's green technology Jaguar is synonymous with sporting elegance and refinement-and now also high tech materials and green endeavour. Ian Adcock gets the inside story from the all new XJ's engineering design team Spotlight on Phil Hodgkinson Phil Hodgkinson talks with Ian Adcock about Jaguar Land Rover's future engineering strategy EcoBoost set to cut fuel consumption by 20% Ford's EcoBoost is about more than cutting engine capacity and adding direct injection, turbocharging and twin variable camshafts. Automotive Design reveals the technology behind the headlines

Power Cylinder Friction: Mechanisms

J2904_201001 (Historical)

01/14/2010

This document covers the mechanisms from the power cylinder which contribute to the mechanical friction of an internal combustion engine. It will not discuss in detail the influence of other engine components or engine driven accessories on friction.

Piston and Ring Standards Committee

Study on Similarity of Pumping Flow in Engine Crankcase

2009-32-005111/03/2009

For the prediction of pumping loss in the engine crankcase at the early stage of engine design, a similarity law of the pumping loss on parallel cylinders with the phase difference of 180 degrees has been derived from the sum of the power loss due to the drag force of airflow through the cylinder bulkhead holes and the inertia force of fluid. It has been found that the mean effective pressure in the crankcase is in proportion to the square of the mean flow velocity at the bulkhead holes. Then, in order to validate the similarity law, by using a prototype engine with inline four cylinders, the pumping loss was estimated by subtracting the frictional loss with special pistons that had air holes, from the power loss in which the area of the bulkhead holes and engine speed were changed. The experimental results of the pumping loss were normalized by the similarity law. As a consequence, it has been shown that the pumping loss obeys the law. Thus, the similarity law is valid for pumping

Arisawa, Hidenori, Nishimura, Motohiko, Watanabe, Hiroyuki, Ueshima, Atsushi, Arima, Kazuki, Yamasaki, Akiyuki

PRISM Residual Stress Analysis on Camshafts

2009-01-042004/20/2009

PRISM is a new residual stress measurement system that uses hole drilling combined with electronic speckle pattern interferometry. Since it doesn’t require the application of strain gages, measurements can be performed without much preparation effort. The instrument evaluates a continuous surface area around the hole rather than three or six locations as with strain gages. Stress depth profiles with a dozen depth increments or more can be obtained within about half an hour. PRISM measurements captured the basic differences between the two types of stress profiles existing in the camshafts examined, which are in agreement with x-ray diffraction (XRD) measurements also performed. Thus PRISM is an option for quick stress testing of camshafts. Not all details of the XRD measurements were detected, though, specifically the very thin surface compressive layer (<30μm) could not be identified.

Rickert, Theo, Fix, Robert

Composite Assembled Cam Shafts

2008-32-007509/09/2008

Development of composite assembled cam shafts for small engines offers up to 20 to 40% lower weight compared to traditional as cast cam shafts. This is achieved via utilizing precision steel tube with net shape PM cam lobes and drive gear elements. This weight saving, in addition to reducing overall weight of the valve train, reduces inertia and hence offers potential improvements in fuel efficiency and reduced emissions. Combining the latest heat shrink assembly technology with PM lobes and drive elements offers optimum cost-performance.

Howe, Ian, Haberberger, Thomas, Cerini, Richard

Technology for Cylinder Deactivation

2005-01-007704/11/2005

The paper deals with maintaining the efficiency of the engine at different loading conditions. In a 6 cylinder engine, when it is fully loaded it operates with maximum efficiency. But at partly loaded condition, its efficiency drops down. In this paper a 6 cylinder engine is converted into a 4 cylinder engine, so that the part load for 6 cylinder engine acts as a near full load for 4 cylinder engine. For this, the crankshaft is divided into a number of segments, so that it will be possible to disengage two of the cylinders from the other four cylinders. During this conversion, servo motor is used to vary the crank angle according to the number of cylinders, which in turn is controlled by ECU (Electronic Control Unit). Even though the cylinder deactivation can also be done by cutting down the fuel supply for one or two cylinders, still the deactivated cylinder produces frictional power loss. By adopting the method in this paper, this loss can be avoided and the engine will also run at

The Effect of Exhaust Variable Cam Phaser Transients on Equivalence Ratio Control in an SI 4 Stroke Engine

2005-01-076304/11/2005

It is a well established fact that variable camshaft phasing can be used to reduce engine out emissions during steady state operation. However, a transition in camshaft timing which often accompanies engine speed / load changes, can have a significant dynamic impact on volumetric efficiency. The change in volumetric efficiency can be highly unpredictable, and can last for several engine cycles following the endpoint of cam movement. Since precise control of catalyst feedgas equivalence ratio is crucial to meeting increasingly stringent automotive emission requirements, the steady state benefits of cam phasing can be overshadowed by the loss of A/F control during transient operation if the engine control algorithms are not properly designed and calibrated. This paper investigates the impact of exhaust variable cam phaser transients on equivalence ratio control, and the mechanism by which volumetric efficiency is affected.

INA EcoValve A Continuously Variable Valve Lift (CVVL) System

2004-01-139103/08/2004

Different mechanisms for Continuously Variable Valve Lift (CVVL) have been proposed and patented and partially implemented in mass production. The objective of this paper is to review the functional appeal of one possible solution, comprising the valve train itself and the control mechanism. This paper describes the operating principle of the valve train and the control mechanism and also shows examples for different arrangements to allow for various cylinder head architectures. The current state of development is outlined and an application on a modern inline four-cylinder engine is presented. Results of experimental investigations are shown to evaluate the functionality of the system. The potential of load control by means of Early Intake Valve Closing is discussed on the base of fired engine test bench results.

Himsel, Frank, Faria, Christof, Solfrank, Peter, Grau, Ulrich, Geiger, Uwe

Modal Analysis of Valve train Test Rig Support Structure

2001-01-387803/05/2001

Improvement of fuel economy is one of the most important development targets of modern passenger car engines. Modern solutions such as Direct Injection, Variable Valve Trains, or Cylinder Deactivation help to obtain this requirement. Each one of these techniques optimize the thermodynamic efficiency of the engine. However, the mechanical structure of combustion engines shows many areas of possible optimization regarding the mechanical efficiency. Engine friction affects the overall fuel consumption, mainly under low speed conditions combined with part load. Low speed/part load conditions are relevant for the real life fuel consumption of an engine, as well as friction improvements have significant effects on the fuel economy. The valve train drive produces the dominant friction portion under these conditions. Hence the friction optimization of this engine subsystem is one of the key issues regarding mechanical efficiency. The valve train friction consists mainly of friction produced by

Maas, Gerhard, Cavalca, Katia Lucchesi, Dias, Milton, Dedini, Franco Giuseppe, Mastaler, Alexandre

A Continuous Variable Valve Event and Lift Control Device (VEL) for Automotive Engines

2001-01-024403/05/2001

This paper describes a new variable valve control device called VEL (Variable Valve Event and Lift Control Device), which enables continuous control of both valve events (opening duration) and valve lifts, from the lowest lift or deactivation state (0) to a long event and high lift state. VEL is composed of two subsystems. One is a mechanical valve train system, which converts crankshaft rotation into output cam oscillation via a transmission mechanism involving a rocker arm. The valves are moved by the output cam oscillation. The other is an electric powered actuator system, which varies valve events and lifts according to driving conditions by controlling the angular positions of a control shaft. This control shaft has a eccentric control cam inserted into the fulcrum cylinder of the rocker arm, so as to change the state of the transmission mechanism and the output cam. In VEL, the combination of a unique transmission mechanism and state change mechanism, make it possible to gain a

Nakamura, Makoto, Hara, Seinosuke, Yamada, Yoshihiko, Takeda, Keisuke, Okamoto, Naoki, Hibi, Tsutomu, Takemura, Shinichi, Aoyama, Shunichi

Machining of Automobile Engine Cams Using Two Cutting Tools Controlled with Linear Servomotors

2001-01-097303/05/2001

A machine tool with four-control axis for machining of engine cams is presented and built to improve a machining efficiency in this study. A workpiece is fixed at a spindle chuck and placed between two cutting tools on the machine tool. Positions of the cutting direction of two cutting tools are controlled independently with two linear servomotors set on a linear rail guide. The linear servomotors are controlled with a PC, various products with non-circular cross sections can be then machined by the machine tool. Machining experiments shows that the machine tool is effective to reduce machining time and improve machining accuracy.

Automotive Engineering International 2001-01-01

AUTOJAN0101/01/2001

Ford's new four The largest engine development program in company history will lead to at least 200 applications, starting with the new Mondeo's Duratec HE and replacement of its existing cast-iron-block four-cylinders with higher aluminum content powerplants. GM Powertrain's new inline six for SUV's For the first time in nearly two decades, three new General Motors vehicles will feature an inline six-cylinder engine developed by GM Powertrain. Fuel-stratified injection from VW Though gasoline direct-injection technology is being introduced in the Lupo FSI, VW says it easily can be adapted for high-volume use in larger vehicles such as the Polo and Golf. LS6 for Z06 The latest high-performance Corvette engine features improved breathing, new pistons, an increased compression ratio, and a new high-profile camshaft. New diesel V8 for S-Class Mercedes-Benz engineers employed common-rail technology, twin turbochargers, and a water-cooled intercooler to achieve a 9.6 L/100 km fuel

Characterization of Combustion, Piston Temperatures, Fuel Sprays, and Fuel-Air Mixing in a DISI Optical Engine

2000-01-290010/16/2000

A transparent direct-injection spark-ignition engine incorporating a rapid-acting, drop-down cylinder has been built. The design enables access in less than a minute for cleaning windows. Combustion performance of the optical engine is characterized in terms of indicated pressure and coefficient of variation of indicated pressure as a function of injection timing. Piston temperatures are measured and a skip-fire routine is developed so that quartz piston top temperatures agree with a matching non-optical engine. Laser-induced fluorescence imaging of in-cylinder fuel injections highlights the effects of ambient pressure and fuel temperature on spray morphology. Measurements of gasoline vapor distribution provide statistics on heterogeneity of fuel distribution as a function of injection timing. Flame imaging records details of flame development which depend on the degree of fuel mixing.

Steeper, Richard R., Stevens, Eric J.

Vibrational and Sound Radiation Properties of a Double Layered Diesel Engine Gear Cover

1999-01-177305/17/1999

The introduction of a thin fluid layer between two layers of sheet metal offers a highly effective and economical alternative to the use of constrained viscoelastic damping layers in sheet metal structures. A diesel engine gear cover, which is constructed of two sheet metal sections spot welded together, takes advantage of fluid layer damping to produce superior vibration and sound radiation performance. In this paper, the bending of a double layered plate coupled through a thin fluid layer is modeled using a traveling wave approach which results in a impedance function that can be used to assess the vibration and sound radiation performance of practical double layered plate structures. Guided by this model, the influence of fluid layer thickness and inside-to-outside sheet thickness is studied.

Welsh, David A., Evensen, Harold A.

Cummins 4B Noise Reduction Anti-Backlash Camshaft Gear

1999-01-176105/17/1999

An anti-backlash camshaft gear has been developed for the Cummins B Series 4-cylinder diesel engines. This gear reduces the gear train impact to result in lower engine noise levels and improved engine sound quality. The greatest benefit is at the low idle condition, where an engine noise reduction of about 2 dB(A) has been observed. Noise reductions throughout the engine speed and load range are also significant. The first application of this noise reduction gear is for a light duty pickup truck.

Huang, Jeffrey C., Abram, Kwin R.

A Dual Material Approach for P/M Automotive Camshaft Timing Sprockets

1999-01-033603/01/1999

A novel approach to the manufacture of high-performance powder metallurgy (P/M) sprockets and gears has been developed. The result is advanced components with a unique combination of properties tailored to the current needs of the marketplace. This dual material or “Duplex” method allows for the selective application of dissimilar yet compatible P/M alloys in order to optimize properties and reduce costs. In the example described, expensive sinter-hardening or induction-hardening materials were used for the teeth of an automotive camshaft timing sprocket, while the core consists of a low density and low cost material. Key advantages of this approach are reduced weight and rotational inertia, increased sound dampening properties, lower cost, and a reduction in the size of the press required for compaction. The paper describes this development and contrasts the advantages to the current manufacturing methods for components of this type.

Geiman, Timothy, Cadle, Terry, Mandel, Joel, Landgraf, Carl

Misfire Pattern Recognition in High Performance SI 12-Cylinder Engine

98052102/23/1998

This paper presents an original procedure for misfire detection in a high-performance 12-cylinder engine, based on the analysis of the time periods between subsequent combustions. A detailed analysis of the misfire effects on the engine crank-shaft instantaneous speed is presented, then a misfire detection procedure is designed, based on the misfire pattern recognition. The capability of this methodology was then validated under the worst case condition of a random misfire in several tests performed with the vehicle running on a circular race-track, at low and high load, in different gear, under acceleration and during a normal urban cycle. The results obtained are very interesting because the misfire pattern recognition works well even during cut-off or gear shifts, avoiding false alarm due to the strong influence that these phenomena have on crank-shaft dynamics. In conclusion same considerations have been done about the procedure capability of detecting more than one misfire within

Moro, Davide, Azzoni, Piero, Minelli, Giorgio

Powder Metal Alloys with High Contact Fatigue Properties: Application to Cam Lobes and Bucket Tappet Shims

98033102/23/1998

Forged bearing steels and powder forged steels (e.g. AISI 52100, SAE 5160 and MPIF FL-4680) have been used to make cam lobes for assembled camshafts operating with roller followers. Application of powder metal (pressed and sintered) alloys to this and other components that operate under high rolling contact stress has been limited by relatively poor rolling contact fatigue (RCF) properties. This paper introduces developmental sintered steel alloys with high RCF strength. The density of these alloys is 7.4-7.6 Mg/m3 and the macrohardness is 500-800 HV. Endurance limits are in the range 1,700-2,280 MPa. The RCF endurance limit at 200 million stress cycles was determined using a testing rig. Camshafts for a 4.6 L V8 engine and a 4.0 L V6 engine have been assembled. These engines have a single overhead camshaft with end pivot rocker with roller follower (type 2 valve-train). The maximum static normal contact stress on the lobe is approximately 1,200 and 1,500 MPa for the V6 and V8 engines

Blanchard, Pierre, Trasorras, Juan R. L., Dempsey, Andrew J., Maulik, Paritosh

Design Considerations for Overhead Valve Train in Small High Speed 4-Cycle Engines

97847610/27/1997

Ryobi Outdoor Products (ROP) in Arizona, one of the subsidiaries of Ryobi Group of companies, developed 26.2cc OHV engine for string trimmers. (2) The outline of the valve train of this engine was presented at the SAE conference at Indianapolis 1996.(3) This paper describes methodologies and theoretical considerations by which such a unique valve train was developed. The theoretical consideration includes how optimize the valve train design to minimize the moving mass as a total system. Methodology for optimizing the design of each component of valve train is also presented. A review of how the theoretical optimization was translated into the final production engine design is given. The experimental effort to optimize cylinder head design to make the overall optimized design theory reality is described.

Kurihara, Katsumi, Conley, James G.

Flow Visualization and Analyses of Two-Stroke Loop Scavenging Diesel

97273909/08/1997

This paper analyzed and studied the in-cylinder flow in two engines. Both are two-stroke loop scavenging 8-cylinder in-line engines. One cylinder diameter is 150mm and the other is 160mm. For researching its loop scavenging performance, one cylinder of both engines is examined. The upper section of the cylinder above the ports is cut off and replaced by a glass one, and the cylinder head is replaced by a plexiglass plate. Then they are mounted on the test bench. A metal screen is put in the glass cylinders. Threads are tied at the screen cross points. The direction of flow in cylinder can be visualized when the air flows. A kind of instrument, named Hot Ball Anemometer, is applied to measure the air flowing speed. The diesel's loop scavenging performance can be realized and satisfactory results obtained.

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