Vgt

The algorithm adopted and implemented by a control systems designer lies at the heart of the control systems solution. A good Figure 8.11 A multivariable compensator for EGR and speed In a diesel engine system behaviour. The outputs from the real system are compared with the computed outputs from the model. Certain types of deviation provide evidence of a fault. During development, an engine component (such as the intake system) may be represented implicitly (as lookup tables) or explicitly as...

W

Similarly Friction power FMEP*Vs*N 20 Brake power BMEP*Vs *N 120 To give total engine power, these figures have to be summed up over the cylinders (or, if all cylinders are identical, multiplied by the number of cylinders). The delivered or brake torque is derived from brake power using (kNm, for kW power and N rpm) (6.104) Specific fuel consumption can be calculated from the fuel mass flow rate divided by power. Thus brake s.f.c. given by B.s.f.c. Fuel flow rate...

542 Moving componentspistons

While in the cooling of cylinder liners and cylinder heads the relative motion between the coolant and the metal surface is imposed solely by the coolant pump, in piston cooling there may be additional relative velocities due to the acceleration of the piston. Indeed, with a 'cocktail shaker' type of piston, these velocities are the dominant ones. Investigations into piston cooling have to be carried out either on an engine or on a rig with reciprocating motion of the piston. Ricardo's rig...

D

M mass in the cylinder u internal energy per unit mass < j> equivalence ratio R gas constant for the equilibrium gas mixture The apparent heat release rate is determined by multiplying this calculated fuel burning rate by the heating value of the fuel. Usually the heat release rate is presented as a normalized quantity where the rate is divided by the product of the total mass of fuel injected and the heating value. This makes the area under the normalized curve equal to 1, and simplifies...

Michael Plint PhD CEng FIMechE and Tony Martyr

Michael Plint founded the company Plint & Partners and for the following 30 years was deeply involved with engine testing and the developing of test equipment. He held positions of visiting Professor at Austrian and American universities. Michael Plint died in November 1998. Tony Martyr has worked extensively with marine and automotive engines. He is currently Operations Manager with Ricardo Test Automation. He is co-author with Michael Plint on a standard work on engine testing.

411 Basic combustion theory

Combustion is the chemical reaction that converts the energy contained in the fuel to the internal energy of product gases. The internal combustion engine serves as a mechanism to convert this internal energy into useful work. This section discusses the basic chemical reactions that relate to diesel combustion and how the reactions associated with chemical equilibrium and chemical kinetics influence combustion. A brief discussion of hydrocarbon combustion is also included. Although diesel...

0 5 10 15 20

Figure 2.52 Engine mass flow characteristic superimposed on compressor map when one of two engines is driving propeller Frequently, two medium speed engines will be used geared together driving a propeller. The requirement can arise, if one engine fails, of driving the propeller with one engine only. If the engine turbocharger combination has been matched for optimum performance when producing half of the maximum power required by the propeller, then the match will be unsuitable for operation...

231 Compressor and turbine efficiency

The work output from (or input to) a turbomachine can be found from the first law of thermodynamics. From this law the steady Figure 2.11 A large turbocharger with axial turbine but inboard bearings (M.A.N.) Figure 2.11 A large turbocharger with axial turbine but inboard bearings (M.A.N.) flow energy equation may be derived. A turbomachine has one inlet and one outlet port. The steady flow energy equation becomes Q - W m (h2 + KE2 +PE2) (h, + KE, + PE,) (2.1) where Q heat transfer rate (+ ve to...

424 Diesel fuel quality issues

Diesel fuel contaminants can be divided into three general categories (1) those originating as foreign materials and introduced into the fuel such as dust, dirt, rust, and water (2) Those produced in the fuel through biological activity of bacteria, yeast, and fungi and (3) those produced by fuel degradation such as gums and sediments. This latter category relates to fuel stability and is discussed as a separate section. Dust, dirt, and rust can be controlled by rigorously enforced standards...

111Historical

Although the history of the diesel engine extends back into the closing years of the 19th century when Dr Rudolf Diesel began his pioneering work on air blast injected stationary engines, and in spite of the dominant position it now holds in many applications, e.g. marine propulsion and land transport, both road and rail, it is today the subject of intensive development and capable of improvements. These will guarantee the diesel engine an assured place as the most efficient liquid fuel burning...

J [ J [L J U Gd4

Since the swinging form is not in fact a straight line this frequency should be divided by 0.92 to give a reasonable approximation of frequency with which to start the Holzer Tabulation. It will normally be necessary to make some adjustment to the assumed frequency until the total torque at the end of the system becomes satisfactorily near to zero. Table 10.5 gives the Holzer Table corresponding to the system shown in Figure 10.34 for the -node mode of vibration. 10.3.2.7 Estimation of...

Info

Figure 10.10 Balance of 180 crank two-cylinder engine bearings which if spaced a distance Lc apart results in a constant rotating load equal to a MRL L being applied at a crankshaft angular velocity 0) radian sec. This unbalanced rotating couple is transmitted through the bearings to the crankcase and its mountings leading to engine vibration. To eliminate this rotating couple balance weights must be fitted to oppose it. If two balance weights are fitted on the two end webs as shown in Figure...

Bdc

Figure 1.6 Gas exchange period. p-V diagrams (a) Two-stroke (asymmetrical timing) (b) Four-stroke. (Benson and Whitehouse) loop which may contribute positive or negative loop work to the work associated with the power loop. Figures 1.6a and b are typical p-V diagrams of the open or gas exchange period for two-stroke and four-stroke engines. In both types of engine the cyclic integral expression leads to the so-called indicated mean effective pressure

65 Turbomachinery and charge air coolers

Compressors and turbines are normally represented in engine models by their characteristic curves, which can come in several forms relating mass flow and efficiency to pressure ratio across them, inlet temperature and rotational speed. Usually they are expressed in terms of 'non-dimensional' parameters as this limits the variation between curves for different types, but it is not essential that they be in this form. Compressors and turbines are treated elsewhere in considerable detail, so the...

007

Where T is the static temperature at exit for adiabatic compression. From eqn (6.33), for flow brought to rest adiabatically For a compressor between two control vl umes. P, , 7't, are pressure and temperature in the inlet volume, P2, Ti2 the pressure and temperature in the exit volume as velocity in each volume is assumed to be zero. Returning to eqns (6.47, 6.50) then gives the power absorption of the compressor, the 't' subscript being dropped as total equals static in the CVs. The torque...

573Piston design

The following types of cooling are possible. This type has a deep arch undercrown shape to transmit heat to the skirt and hence to the liner. This can either be used uncooled or with jet cooling from the top of the connecting rod, or alternatively from a fixed jet attached to the crankcase. Cooling is by means of a chamber which is partly filled with oil. As the piston is reciprocated, high relative velocities between the cooling oil and the metal surfaces are effected. The oil level is...

1

(a) Symmetrical cam, (b) Asymmetrical cam, (c) Back-kick cam. Figure 11.29 Plunger-and-barrel assembly with leakage-return duct (b) 1 Leakage-return duct, 2 Ring shaped barrel groove. Figure 11.29 Plunger-and-barrel assembly with leakage-return duct (b) 1 Leakage-return duct, 2 Ring shaped barrel groove. certain engine types, special plungers are used which have a special starting groove. This starting groove is machined into the plunger's top edge and is effective only when the plunger is in...

80 100

Figure 5.3 Heat flux factor band for indirect injection engine cylinder heads be carried out as a part of engine performance cycle calculations, although in this case it is more convenient to calculate a mean heat flow rather than the local values. The original studies in this area were those by Nusselt2 and Eichelberg3 whose formulae provided the basis for later work, but formulae by Annand4 and by Woschni5 are now more generally used. For simplicity, the heat flux factor approach which was...

267Matching the fourstroke vehicle engine

Turbocharger matching for many industrial and marine duties is relatively straightforward due to the limited speed and load ranges required. Matching the turbocharger to an automotive engine is considerably more difficult due to the wide speed and load variations encountered. Although the power required to propel a vehicle increases repidly with speed, a torque curve that rises as speed falls reduces the number of gearbox ratios and gear changes required. Such a torque curve is said to have...

Oxford Auckland Boston Johannesburg Melbourne New Delhi

Linacre House, Jordan Hill, Oxford 0X2 8DP 225 Wildwood Avenue, Woburn, MA 01801-2041 A division of Reed Educational and Professional Publishing Ltd A member of the Reed Elsevier pic group First published 1984 Second edition 1999 Chapter 6 Reed Educational and Professional Publishing Ltd and A.E. Joyce (System Studios) Ltd 1999 Section 11.3 Robert Bosch Corp. 1999 Section 11.4 Caterpillar Inc. 1999 All other chapters Reed Educational and Professional Publishing Ltd 1999 All rights reserved. No...

252 Charge air cooling and engine performance

For a fixed power output, intercooling will reduce charge temperature and hence thermal loading. Efficiency will also improve slightly since to achieve the same mass of air trapped in the cylinder, the boost pressure need not be as high and air-fuel, ratio can increase. Naturally if the thermal loading is reduced, reduction of the heat lost to coolant will also aid thermal efficiency, although marginally. However, the additional cost of the intercooling equipment must be offset by a higher...

251 Charge cooling principles

The principle reason for turbocharging is to increase the power output of an engine without increasing its size. This is achieved by raising the inlet manifold pressure, hence increasing the mass of fresh air drawn into the cylinders during the intake stroke and allowing more fuel to be burnt. However, from the basic laws of thermodynamics we know that it is impossible to compress air without raising its temperature (unless the compressor is cooled). Equation (2.27) is plotted in Figure 2.39...

360

Figure 2.35 Comparison of exhaust pressure diagrams on a four-cylinder, two-stroke engine, pulse and pulse converter turbocharging scavenging process of another, is reduced. For example, Figure 2.36 shows a substantial inlet to exhaust manifold pressure difference during the valve overlap period of this medium speed engine. The modular pulse converter concept developed by SEMT's even closer in concept to a constant pressure system, but avoids the use of a large-volume manifold. The exhaust port...

4000

Figure 9.11 Effect of manifold branch lengths on volumetric efficiency over speed range The directed port is arranged to cause the air to enter the cylinder at a shallow angle more or less symmetrically about the inlet valve stem and roughly normal to the radius joining the inlet valve and cylinder centrelines. The directed port is more readily used for a twin inlet valve head than the helical port. Figure 9.12 shows semi-diagrammatically one form for a single inlet valve. Although the detailed...

Diagram Time-area Scavenging

Figure 9.20 Uniflow scavenging opposed piston The two pistons may be connected together as follows (1) via their crankshafts and gearing, e.g. Fairbanks Morse (2) by means of two side rods from the exhaust piston to two crankshaft throws, or even eccentrics, immediately adjacent to that for the scavenge piston as is done in the Doxford engines (3) by means of the pistons working on a piston rod to operate a rocker arm at each end of the cylinder, the other end of each 'dog-legged' rocker arm...

How To Calculate Crankshaft Web Thikness

Crankshaft Web

I.e. the length of soild shaft of journal diameter D having the same stiffness as the crank unit from centre to centre of the bearings. After the evaluation of these formulae, if the values are within 10 of one another a mean of the two values is adopted. If greater than 10 difference is found the longer length is adopted. Where longer journal lengths exist, such as the centre main bearing at times and the front and rear bearings, the appropriate extra length is added to the equivalent length...

R

k cos 28 where k a> MRecip R So in a similar manner to that for the primary forces the total vertical secondary force for both banks k cos a cos 26 + cos 2(6 - 2a) which by manipulation becomes k(cos 3a + cos a) cos 2< p The total horizontal secondary force k(cos a - cos 3a) sin 2< j> Evaluating the bracketed terms in these expressions for V angles normally met with, the values tabulated in Table 7.1 are obtained. Figure 10.19 shows the full state of affairs for one crankthrow of a 60...

563Fuel injector

Blockage of the spray holes in the fuel injection nozzles is another problem which has its origin in excessive temperature, leading in this case to a partial thermal degradation of the fuel and to lacquer or to carbon formation. From development experience the following are critical temperatures for hole type nozzles 1. Maximum metal temperature at nozzle tip 280 C. 2. Corresponding maximum metal temperature at nozzle seat 230 C. 3. Smallest hole recommended for freedom from blocking by lacquer...

243 Principles of pulse turbocharging

The majority of turbocharged engines use the pulse, not the constant pressure turbocharging system. However, the pulse system that has been developed is not the pure impulse system described in section 2.4.1 which is impractical, but a system that tries to make some use of the available energy of pure pulse and constant pressure systems. The objective is to make the maximum use of the high pressure and temperature which exists in the cylinder when the exhaust valve opens, even at the expense of...

421 Hydrocarbon types

A carbon atom can form covalent bonds with other carbon atoms or with other atomic species. Each atomic species has its own preferred number of bonds that it requires to achieve a stable configuration. This preferred number of bonds is called the covalent valence of the element. Carbon atoms seek to form four bonds and hydrogen atoms one bond. Hydrocarbons are molecules that contain only hydrogen and carbon. The simplest hydrocarbon molecule, methane, is formed when four hydrogen atoms attach...

221 Ttarbochargers for automotive diesel engines

Turbochargers in this class are used for passenger car diesel engines rated at 45 kW upwards to larger special heavy truck and construction vehicles rated at up to 600 kW. The most important design factors are cost, reliability and performance. To keep cost low, the design must be simple, hence a single stage radial flow compressor, and a radial flow turbine are mounted on a common shaft with an inboard bearing system (.Figure 2.4). This arrangement simplifies the design of inlet and exhaust...

242 Principles of constant pressure turbocharging

With constant pressure turbocharging, the exhaust ports from all cylinders are connected to a single exhaust manifold whose volume is sufficiently large to ensure that its pressure is virtually constant. The unsteady exhaust flow processes at the cylinders are damped into a steady flow at the turbine. Only one turbocharger need be used, with a single entry from the exhaust manifold, but frequently several smaller units are fitted so that a reasonable boost pressure can be obtained in the event...

I

Figure 2.13 Axial flow turbine performance map by the user, for the following reason. For a given turbocharger, it is possible to link the compressor and turbine characteristics and plot the equilibrium running line on compressor and turbine maps. This comes from balancing the compressor and turbine power eqns (2.14 and 2.18), and imposing a common rotational speed, factors that are implicit in any experimental turbocharger test. This equilibrium line is shown in Figure 2.15 and runs across...

Cc2

This equation has two real roots so that a simple three-mass system has two principal modes of vibration, i.e. two natural frequencies. At the lower frequency or fundamental mode of vibration there is a single node in the system when one of the end masses, dependent on the actual system values, moves in one direction whilst the other two masses move in the opposite direction. This is usually called the I-node mode of vibration of the system (Figure 10.31b). At the higher frequency there are two...

342 The differentially supercharged diesel engine DDE

Dawson8 in the 1960s, though not strictly a compounded scheme, nevertheless provides an interesting comparison with the differential compound engine. Figure 3.11 shows a simplified layout. Again an epicyclic geartrain provides a differential connection between engine, compressor and output shaft. However, there is no power turbine, the engine exhaust passing directly to atmosphere. High boost pressure can nevertheless be accommodated by greatly reduced valve...

143 Dissociation and reaction kinetics

The equations of section 1.4.2 assume that the product composition is uniquely determined by the chemical composition of the fuel and the air-fuel ratio. In practice two effects occur which render these assumptions inaccurate, particularly at very high temperatures. Dissociation is the term used to describe the tendency of gases such as water vapour, H20, and carbon dioxide, C02 to undergo a partial decomposition process according to expressions such as The degree of dissociation is itself a...

Pulse converter turbocharging SEMTmodular system

Simple exhaust manifold Disadva'ydges Poor turbocharger acceleration (between pulse and constant pressure systems) Figure 2.26 showed exhaust, cylinder and inlet manifold pressures measured on a four-stroke engine in which the cylinders are connected in groups of three. The valve timing is typical of automotive engines (medium speed engines have longer valve overlap). The diagram represents the almost ideal case of pulse operation for several reasons. First, the exhaust pressure wave has built...

760

In many measurements of air flow it is convenient to balance The above is valid for small pressure differences such as the pressure drop across the inlet valve of a naturally aspirated diesel engine. Where higher pressures are involved a more complicated expression allowing for compressibility must be used. In the four-stroke engine the pressure drop across the inlet valve is created by the section generated by the descending piston in the case of the naturally aspirated version. When the...

69 Model results and engine performance

Using the methods outlined in the previous sub-sections it is possible to build a basic steady-state diesel engine model. While it would require enhancement or detailed performance analysis it would contain the main elements and be sufficiently accurate for preliminary investigations. The model would course require input routines to provide the data needed for the various calculations described and output routines to provide the results of the form indicated below. For steady-state operation it...

161 Closed period

1.6.1.1 Generalized calculation procedure The governing equations are the non-flow energy eqn (1.32a) together with the semi-perfect gas state eqn (1.33e), i.e. Non-flow energy equation n, Cvi i r+icvi Tdn +dQE+pdV-dnif CALVAL 0 in which the first two terms represent the change in internal energy of the cylinder charge, dQL the incremental heat loss from the cylinder, p dV the piston work, and dmf. CALVAL the fuel heat release. Equation of state in differential form pdV+Vdp tR0(dni) + tniR0-dT...

151 Closed period

It is evident that the sequence of events constituting the idealized cycles described in section 1.3 on air standard cycles, does not represent the processes which actually occur in the diesel engine. The compression process, instead of being reversible and adiabatic, with fixed index of compression y 1.4, will be irreversible due to frictional effects, non-adiabatic due to heat transfer from cylinder walls to gas (not pure air since the trapped charge will inevitably be slightly polluted by...

Charles A Beard CEng FIMechE MRAeS

Beard was a senior consultant with Ricardo Consulting Engineers and worked in design and development. Bernard Challen has updated the chapter. Original chapters by Charles A. Beard. Bernard Challen has updated this chapter. Chapter 11 Fuel injection systems Professor Michael Russell MSc CEng FIMechE Chief Research Engineer, Lucas Diesel Systems. Formerly Professor of Automobile Engineering at the Institute of Sound and Vibration Research, Southampton, he has published widely on...

References

B., Internal Combustion Engine Fundamentals, McGraw Hill (1988) 2 WATSON, N. and JANOTA, M. S Turbocharging the Internal Combustion Engine, Macmillan (1982) 3 FERGUSON, C. R., Internal Combustion Engines, Wiley & Sons (1985) 4 RAMOS, J. J., Internal Combustion Engine Modelling,, Hemisphere (1989) 5 NAT. U.S. BUREAU STANDARDS, JANEF Thermochemical Tables, NSRDS-NB537 (1971) 6 GORDON, S. and McBRIDE B.,'Computer Program for the Calculation of Complex Chemical Equilibrium...

262 Air flow characteristics of engine and turbocharger

The air flow rate through a turbocharged (non-aftercooled) diesel engine will be a function of the engine speed, compressor delivery air density and the pressure differential between intake and exhaust manifolds during the period of valve overlap. If the engine is run at constant speed, but steadily increasing load, then the mass flow rate will increase approximately with the increasing charge density. The air flow through the engine may be superimposed on a turbocharger compressor...

3

Figure 2.17 Ideal limited pressure cycle-naturally aspirated that could be done is represented by the cross-hatched area 139-10-11. This work is done by the piston but could be recovered by a turbine in the exhaust. It will be called the piston pumping component of exhaust energy. The maximum possible energy available to drive a turbine will be sum of areas 5-8-9 and 13-9-10-11, but it is impossible to devise a practical system that will harness all this energy. To achieve this, the turbine...

20

Ambient & coolant temperature 20 C Figure 2.40 Intercooler effectiveness and density ratio, as a function of pressure ratio of the compressor temperature. The latter results in a drop in specific energy at the turbine, hence boost pressure will also reduce, but not enough to offset the density gain due to the lower charge temperature. Thus air flow increases and overall, the total turbine power does increse. The air-fuel ratio will be weakened, leading to a reduction of specific fuel...

731 Modelling the gasexchange process

The accuracy of simulating combustion processes depends on the initial conditions within the combustion chamber at intake valve closure. Residual gas left in the combustion chamber from the previous engine cycle effects the combustion process through its influence on the charge mass, charge temperature and dilution. These parameters, in turn, influence the ignition delay and the combustion rate, as mentioned previously. Three-dimensional computations of the flow field set up during the gas...

Qje Cpa[r03T017 225

Where 77 overall turbocharger efficiency. Thus the relationship between the inlet manifold pressure (p02) and exhaust manifold pressure (p03) is a function of the overall turbocharger efficiency (if), the turbine inlet temperature (T03) and, to a lesser extent, the air-fuel ratio (AFR). The air-fuel ratio at full load, will be governed by thermal loading or the onset of black smoke in the exhaust. The turbine inlet temperature will also be dependent on air-fuel ratio, the amount of cool...

163 Completion of calculation sequence

Completion of the open period calculations for a cycle leads to the trapped conditions, pt, Tt and charge composition which form the initial conditions for the next cycle (see section 1.6.1.2a). Since these conditions were an estimate for the first cycle, the computation has to be continued for several cycles (usually three) until the trapped conditions, and hence the cycle conditions as a whole, have stabilized. Cycle simulation is now universally adopted throughout industry as an invaluable...

Raymond Farnell and Duncan Riding

Raymond Farnell is Senior Noise Engineer at Perkins Technology. He has been responsible for the noise engine reduction of many engines, combining practical testing and development techniques. Duncan Riding is Section Manager at Perkins Technology. He has been involved with the development and refinement of many engines, working mainly from the finite element and analytical area. Chapter 21 Larger engine noise and vibration control Stanley Walker Stanley Walker is currently Principal Engineer,...

Plunger Beral Type Fuel Pump

Diesel Pump Plunger Control

Plunger stroke from opening of the inlet port to TDC. Use is made of symmetrical cams, eccentric cams, and cams (back-kick cam) which prevent the engine being started in the false direction of rotation (Figure 11.27) 11.3.3 Pump-and-barrel assemblies (pumping elements) Plunger-cmd-barrel assembly basic version. The pump plunger together with the pump barrel form the plunger-and-barrel assembly. This utilizes the overflow principle in conjunction with port and helix control. The pump plunger has...

Bosch

Figure 11.22 Fuel injection system 1 Fuel tank, 2 Fuel supply pump, 3 Fuel filter, 4 In-line fuel injection pump, 5 Timing device, 6 Governor, 7 Nozzle holder with nozzle, 8 Fuel return line, 9 Glow plug (GSK), 10 Battery, 11 Glow plug and starter switch, 12 Glow control unit (GZS). 'advance' direction as pump speed increases. In special cases, load-dependent control is provided. The diesel engine's load and speed control are determined by the injected fuel quantity (correct terms for fuel...

065

0.50 0.55 0.60 Turbocharger efficiency Figure 2.20 Effect of turbocharger efficiency on specific fuel consumption, constant pressure system (Ryti and Meier) air right through the system and to waste, since considerable mixing of air and combustion products takes place. The amount of 'excess air' required will depend on the scavenging efficiency of the system being used and many other factors. It is therefore impossible to quote general rules, but the amount will vary from 10 to about 40 (from...

13 Air standard cycles

It will be clear from the foregoing sections that the real processes in the diesel engine cylinder, particularly those of fuel preparation, combustion and gas exchange are extremely complex and require sophisticated computational techniques which are discussed in a number of specialist texts.',2-3 Air standard cycles which are discussed in most elementary textbooks, provide a useful basis for comparing actual engine performance expressed in terms of indicated mean effective pressure (pjnd, eqn...

341 The differential compound engine DCE

This concept, intended specifically for heavy vehicle applications constitutes an attempt to combine the thermodynamic advantages of compounding as described in section 3.3 with the characteristics of an integrated engine-transmission system of the continuously variable type5-7. Like most of the latter it employs a fully floating epicyclic gear train in which the engine is connected to the annulus or ring gear, while the sungear and planet carrier drive, respectively, the supercharging...

414 Combustion system design

Designing diesel engines to produce their maximum power without excessive smoke or other pollutants requires careful matching of the combustion chamber geometry, the in-cylinder air motion, and the fuel injection. A large number of successful designs have been developed that involve very different approaches. Diesel engines can be divided into direct injection (DI) engines and indirect injection (IDI) engines. Direct injection engines have the fuel injected directly into the main chamber above...

415 Analysis of cylinder pressure data

Much useful information about the diesel combustion process can be obtained by measurement and analysis of the cylinder pressure. Specifically, the indicated mean effective pressure and the apparent heat release rate can be computed. Other quantities such as the peak pressure and the peak rate of pressure rise are also useful as indicators of overall stress and noise levels, respectively. Accurate measurement of cylinder pressure requires three things a pressure transducer that can survive the...

112 Diesel fuel injection systemsLucas Diesel Systems

Toroidal Combustion Chamber

11.2.1 Compression ignition combustion processes In indirect injection engines, the fuel is introduced via pintle nozzles into an anti-chamber to the space above the piston, which is called a 'prechamber' or a 'swirl chamber', depending upon the intensity of rotary air motion in this chamber. A swirl chamber layout is shown below in Figure 11.1 together with a much magnified section through a pintle nozzle. In IDI engines, much of the energy to mix the fuel with the air comes from the air...

Fatigue By Fluctuating Load

Fatigue Fluctuating Load

Figure 10.43 Typical fatigue curve for aluminium alloys means that alternating loads and stresses varying sinusoidally with time are applied, the maximum cyclical tensile stress being equal to the maximum compressive stress. This alternating stress with time is indicated in Figure 10.44A . It will be noted that the mean cyclic stress is zero. In practice this state of affairs rarely occurs and other cases may be distinguished. It the mean stress is tensile as indicated in Figure 10.44B with a...

Crank Of Cvil Engg Digram

Which is then used in a modified formula for a better estimate for ft)2. Since R should be zero a new value for co would be This form of correction gives a quadratic iteration which gives rapid convergence if the first approximation is reasonably good. 10.3.2.2 Gas torque and harmonic components An internal combustion engine produces its instantaneous torques, and the resultant mean output torque, as a result of the instantaneous gas pressures acting on each piston throughout the cycle. The...

A

Figure 11.34 Constant-pressure valve 1 Valve holder, 2 Valve element, 3 Valve spring, 4 Filler piece, 5 Compression spring, 6 Spring seat, 7 Ball, 8 Restriction passage. a timing device (if required) for varying the start of delivery as a function of engine speed a fuel supply pump for delivering the fuel from the fuel tank, through the fuel filter and the fuel line, to the injection pump a number of high pressure fuel injection lines, corresponding to the number of engine cylinders, connecting...

2

Secondary balance Figure 10.21 Balance of crankshaft for eight-cylinder 90 vee engine In the case of four-cycle engines having even numbers of cylinders there are at least several firing sequences which can be used for a given crank arrangement. In the case of the two-cycle engine, if equal firing intervals are to be maintained each firing order requires its own crankshaft arrangement. Taking, for example, a six-cylinder two-stroke engine, Figure 10.22 indicates three possible crankthrow...

32728

Vector sums for six-cylinder engine example given in Figure 10.34 (a) Vector sum for orders Nos. 1, 4, 7, 10, etc. (b) Vector sum J, 2-1, 3-1 5-1, 6-1, etc. (c) Vector sum for orders Nos. 1-1, 4-1, 7-1, etc. (d) Vector sum for orders Nos. 3, 6, 9, etc. 120 . The cylinder number and the amplitude corresponding to it is shown. It is found that more than one vector has the same angular oposition, so these have been arithmetically added making the diagram to the right. Then by taking cosine...

571 Cylinder head

Flake graphite cast iron or aluminium alloy are by far the most commonly used for the cylinder head, although steel is also employed, as is nodular cast iron and bronze. If it were not due to difficulties in casting, steel would probably be more widely used since it does offer possibilities of a better fatigue life under engine conditions. With steel it is essential that an inhibitor is added to the coolant since the oxide scale formed gives a serious barrier to heat transfer. In the author's...

264 Matching the marine engine

The required power versus speed characteristics of the marine engine is governed by the performance of the propeller, and will therefore depend on whether a fixed or variable pitch propeller is used. The characteristics of the fixed pitch propeller are such that the power requirement increases with the cube of the speed (the well-known 'propeller law'). Thus b.m.e.p. increases with speed squared. It happens that the output characteristics of the turbocharged engine are ideal for this...

244 Principles of pulse converter and other turbocharging systems

Pulse Converter Diesel Engine

Pulse converter turbocharging systems have been developed to improve the performance of those engines that suffer from low turbine efficiency with pulse turbocharging due to long windage periods and partial admission (multiple turbine entries) losses. They attempt to preserve the advantages of the pulse system, with its inherent high available energy and unsteady flow at the exhaust port, with steadier and more efficient flow at the turbine. A pulse converter system, in its simplest form, is...

21 Introduction

The purpose of supercharging is to increase the mass of air trapped in the cylinders of the engine, by raising air density. This allows more fuel to be burnt, increasing the power output of the engine, for a given swept volume of the cylinders. Thus the power to weight and volume ratios of the engine increase. Since more fuel is burnt to achieve the power increase, the efficiency of the engine cycle remains unchanged. A compressor is used to achieve the increase in air density. Two methods of...

P7100 8000

Inline Injection Pump

Figure 11.36 Inline injection pumps Size comparison (looking onto camshaft end) Figure 11.36 Inline injection pumps Size comparison (looking onto camshaft end) directly to the vertical lift of the roller tappet which results in the reciprocating plunger movement (Figure 11.37). The pump plunger's total lift cannot be varied, although the effective stroke, and with it the delivery quantity, can be changed by using the control rack to rotate the pump plunger. The plunger is forced up to TDC by...

Impacts

Hydraulic Pump Mechanism

Figure 11.11 Cross-section of DP rotary pump mechanism showing internally-lobed cam ring and two plungers in a common bore which pump via rollers each equipped with a shoe. The cam ring Is rotated to set injection timing The pumping mechanism has to be filled between each pumping stroke. The volume between the plungers and the central drilling in the rotor are connected alternately to the intermediate pressure supply to fill the pump and the high pressure outlets via separate ports in the...

Dr Rolf Reitz PhD FSAE

He is currently Wisconsin Distinguished Professor in the Mechanical Engineering department at the University of Wisconsin-Madison. Previously he was a research scientist at the Courant Institute of Mathematical Sciences in New York, Princeton University and a staff research engineer at the General Motors Research Laboratories. Dr Cecil C.J. French DSc Eng FEng FIMechE FIMarE A past President of IMechE and former director of Ricardo Consulting Engineers, now working as an independent consultant....