Alfa 159 1.8 MPI 140 CV!!!

[blueyes]

Lo so che vende... per ora! E' una bella macchina, ma la 159 le dimezzerà il mercato.

ma cosa stai dicendo????

ma hai idea di che macchine sono???

ti rendi conto che non c'entrano NIENTE l'una con l'altra?

[Paco]

madbobo, croma e Sportwagon nn sono concorrenti, come non lo sono serie 3 e mondeo, una è generalista e l'latra no, che ne sai poi che vendicchia per 1 anno se è uscita da 9 mesi??

[fuzz77]

cmq che polmone che deve essere co sto motore del cacchio!!

già il 1.9 soffriva un pò anche se ricco di coppia ai bassi....questo li dentro muore!!! e poi e preso pari pari dalla produzione gm....bleah!!!

[davbs]

Lo so che vende... per ora! E' una bella macchina, ma la 159 le dimezzerà il mercato.

l'utente medio di Croma non ha nulla in comune, o molto poco, a mio avviso...

[Abarth03]

l'utente medio di Croma non ha nulla in comune, o molto poco, a mio avviso...

Sono due utenti completamente diversi.

Perfino in ambito aziendale, cioè di benefit, sono pronto a scommettere che la 159 viene data a figure professionali più in alto rispetto a quelle a cui viene data la Croma.

[simonepietro]

e poi e preso pari pari dalla produzione gm....bleah!!!

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deriva direttamente dal 1.6 twin port e rispetto al 1.8 gen 2 ne riprende buona parte delle misure interne tanto che le modifiche paiono minime , alleggerimento pistoni,(220 g contro 230g) aumento del piston pin(18mm a 19mm) aumento alzata valvole, nuovi profili degli alberi a camme e alleggerimento basamento, il tutto pesa 118 kg contro i 121 kg del vecchio , ma sopratutto la parte innovativa è il doppio variatore di fase dcvcp. Intervento del gruppo fiat?

Difficile stabilirlo dato che anche in documenti dettagliati non viene citata:

1 Introduction

The new 1.8 l engine is based on the 1.6 l

Twinport engine presented by Opel in 2003,

that offers an excellent cost-benefit ratio to

customers through its innovative high exhaust

gas recirculation (EGR) concept [1].

With the new 1.8 l engine variant, this customer

advantage was expanded to include

an improved power characteristic. Thus excellent

power performances combined

with reduced fuel consumption were the

top priorities of the product development

program.

With a power output of 57 kW/l, the engine

occupies a top position in this displacement

segment. Furthermore, it was

possible to offer 90 % of the maximum

torque in a broad range of 2200-6200 rpm.

The specific fuel consumption at the standard

2000 rpm/2 bar was reduced to 364

g/kWh.

The development targets were mainly

reached by optimizing the charge cycle using

of two continuously variable cam

phasers (DCVCP), a new design of the combustion

system, the cam profiles and the

complete intake and exhaust system.

The modular system of the engine family

permitted the adaptation of the cam

phasers without affecting the basic structure

of the engine. The main dimensions of

the 1.8 l engine were maintained from the

previous generation and thus all variants

of this engine family are produced on a

modified manufacturing system in the existing

engine plant, Table 1. In the future,

the engine will be offered in many applications

of Opel. In less than 30 months, from

the first concept engine to start of production,

the engine concept could be realized

and the development targets could be safely

reached by using state-of-the-art simulation,

test rig and rapid prototyping technology.

By Gunnar Böhler,

Uwe Dieter Grebe,

Torsten Löhnert,

Manfred Pöpperl and

Klaus Steffens

Der neue 1,8-l-Vierzylinder-Ottomotor

für Opel-Automobile

You will find the figures mentioned in this article in the German issue on page 242.

The New 1.8 l

Four-Cylinder

Spark Ignition Engine

for Opel Automobiles

2 Development Targets

The new 1.8 l engine was improved in all

relevant criteria compared to the previous

model. The most important development

targets have been summarized as follows:

increase of the brake mean effective

pressure in the entire speed range

fuel consumption reduction in the

MVEG cycle by 4 %

fuel consumption reduction in customer

use more than 4 %

emission limits according to Euro 4, potential

for Euro 5

total engine weight less than 120kg (DIN

70020)

maintaining the main geometric dimensions

low noise emissions

running smoothness

potential for further development.

3 Concept Definition

For the gasoline engines from Opel, the applicable

technology is carefully selected

based upon the displacement and the vehicle

segment, Figure 1.

While the reduction of the fuel consumption

was clearly the top development

priority for the 1.6 l Twinport engine, the

optimization of the full-load behaviour was

added as another development focus for

the new 1.8 l engine.

The largest potential solutions to fulfil

these complex requirements are through

the use of the DCVCP concept and/or the

gasoline direct injection. Due to the more

favourable cost-benefit ratio, the DCVCP

concept was selected for this price-sensitive

market segment.

4 Design

The design concept of the new 1.8 l engine,

Figure 2, is based on the 1.6 l Twinport engine.

New subsystems as cam phasers, an

oil-water heat exchanger, piston spray

nozzles, an intake manifold with variable

runner length, a new exhaust manifold as

well as a standardized oil pan module were

integrated. The base engine was adjusted

to higher load.

Within the virtual development process,

all components were optimized to the required

package, the structural strength, the

vibration behaviour and the thermal behaviour.

The layout of the subsystems and the

entire engine system were executed before

the prototype phase based on a complex calculation

of the charge cycle and a detailed

flow simulation. The number of prototypes

and development phases were clearly reduced

through the use of these tools.

4.1 Cylinder Block

The cylinder block is based on the proven

hollow-frame concept of Generation 3. On

the exhaust side, the oil cooler was installed,

in the area of the main oil gallery

the piston spray nozzles and in the front

area the direct VCP oil supply.

In connection with the block development,

in spite of the increased loads, the

weight was reduced by 20 % compared to

the 1.8 l engine of the second generation,

COVER STORY 1.8 l Four-Cylinder Spark Ignition Engine

Engine Type 1,8 l 4V 1,8 l 4V

Generation 2 Generation 3

Displacement cm3 1796

Bore distance mm 86

Bore mm 80.5

Stroke mm 88.2

Stroke-bore ratio 1,1

Conrod length mm 129,75

Conrod mass g 440 421

Stroke / conrod ratio 0,314

Crankshaft bearing – diameter/width mm 43 / 17

Main bearing – diam/width mm 55 / 19

Piston pin diameter mm 18 19

Piston mass g 230 220

Inlet valve diameter mm 31,2

Exhaust valve diameter mm 27,5

Valve stroke, inlet / exhaust mm/mm 8,5 / 8 9,0 / 8,5

Cam phasing inlet / exhaust °CA fixed 60/45

Compression ratio 10,5

Rated torque at engine speed Nm 165 -170* 175

min-1 3800/4600* 3800

Rated power at engine speed kW 90-92* 103

min-1 6000 6300

Engine management Siemens Siemens

Simtec 71 Simtec 75

Fuel quality RON 91/ 95 / 98

Exhaust gas aftertreatment Close-coupled three-way catalyst

Emission standards EU IV

Engine mass (DIN 70020) kg 121 118

* depending upon the vehicle application

1 Introduction

Table1: Technical data of the 1.8 l engines

4 Design

Figure 2: Total engine view

4

and at the same time the stiffness of the engine-

and-transmission unit was optimized.

The grey cast iron block, at only 27 kg including

the bearing cap, will form the basis

of all future high-performance variants of

the Family 1 engine.

4.2 Crankshaft Drive

When designing the cranktrain components,

the focus was set on increasing the

strength. These requirements were met by

a new crankshaft design, a modified steel

conrod with floating piston pin bearing

and a new piston design. In spite of these

stiffening measures, the oscillating masses

were maintained. Piston cooling compensates

the high temperature profile that is

the result of the increased engine performance

and the geometry of the new lightweight

piston.

Regarding the cast crankshaft, a weight

saving of 6 % was reached, while the very

good bending qualities and the torsional

stiffness of the second generation are

maintained. The degree of balancing of the

rotating mass was improved by 60 %.

For the new 1.8 l engine, a new designed

crankshaft sensor system is used for the

first time. The anisotropic magnetoresistive

sensor (AMR) is integrated into a plastic

carrier and as a module it is pressed into

the cylinder block together with the crankshaft

seal made of PTFE. The corresponding

magnetized sensor disk is mounted between

the crankshaft and the flywheel.

The entire weight saving concerning the

cranktrain is 0.8 kg while maintaining the

mass moment of inertia.

4.3 Cylinder Head

When designing the cylinder head, special

attention was dedicated to the structural

strength and the cooling. The inlet and exhaust

port geometry was dimensioned by

simulating the charge cycle and the flow.

The new front camshaft bearing bridge

contains the control valves and the bores

for the cam phasers oil supply. In addition,

it provides the basis of the thrust bearing.

Due to adujusting the cylinder head cover

with the integrated oil separator the

bearing bridge contour, the sealing efficiency

could be improved.

4.4 Valve Train

Here, the friction-reducing concept of the

mechanical tappets with mass reduced

valves and springs was taken over from the

1.6 l of the third generation design. The hollow

cast camshafts were adjusted to the oil

supply of the phasers and the location of

the position sensors. The charge cycle calculation

provided the data to optimize the

cam profile and the valve lift.

4.5 Cam Drive and Cam Phasing

Maintaining the layout of the belt drive

and the toothed belt dimensions, the automatic

belt tensioner was adjusted to the increased

moments of inertia. The toothed

belt change interval of 150.000 km was

maintained.

The new 1.8 l engine is the first in the

market using a vane-type cam phaser out

of a thin-wall forming process. Low weight,

minimum space requirements and a wide

phasing authority characterize this concept.

The camshafts can be phased at the

inlet side by 60°CA and at the exhaust side

by 45 °CA, Figure 3.

Using de-throttling measures in the oil

circuit, additional software functions and

an optimized phasing and locking strategy,

the camshafts can be adjusted at ambient

temperatures up to -30 °C.

4.6 Oil Circuit

The large number of vehicle applications

required a new design of the oil pan. It was

achieved to develop a common die cast design

for all applications. Special attention

was dedicated to the dynamic behaviour of

the oil volume. The precasted oil suction

channel in connection with the plastic oil

scraper, which also covers the suction point

in the oil pan, provides an economic solution

as well as an optimum solution from

the functional point of view. According to

the requirements of the Vehicle Platforms,

it is possible to install different sensors.

The front-end module including the integrated

oil and water pumps as well as the

toothed belt protection and the fastening

points of the accessories is in principle carried

over from the 1.6 l Twinport engine.

The flow volume of the oil pump, however,

had to be optimized due to the additional

oil requirements for piston cooling and cam

phaser purposes. To improve the oil pressure

behaviour in the cylinder head, pressure

control is now performed indirectly.

The increased thermal load of the oil required

the integration of an oil-water heat

exchanger. This new module, consisting of

heat exchanger and oil filter, included an

additional water by-pass tube. It is part of

the engine inherent water circuit.

The module was integrated under space

saving considerations at the exhaust side of

the cylinder block. The weight is only 1.1 kg,

Figure 4. This design ensures a maximum

intercooling of the oil and a minimum loss

of pressure. During the cold-start phase,

however, this measure allows a faster heating

of the engine oil and an early reduction

of the internal engine friction.

The cam phasers are supplied with oil

through separate bores in the cylinder

block and head. The recirculation of the increased

amount of oil in the cylinder head

is permitted through additional pre-cast oil

return channels.

4.7 Water Circuit and Thermal

Management

The cooling principle of the parallel flowthrough

known from Generation 3 was

kept. Redesigning the water jackets of

cylinder head and block regarding water

distribution and fluid dynamics, improved

the heat transfer significantly, Figure 5.

The additional water supply of the oil

cooler, parallel to the water circuit of the

engine, was designed by extensive CFD

simulations so that a minimum of water is

needed to achieve maximum oil cooling.

The new thermostat housing is executed

as a weight reduced plastic construction.

All vehicle-related interfaces of the cooling

circuit are identical for all generation 3 engines.

By increasing the cooling water temperature

in the part-load range, thermal management

contributes to a minimization of

customer fuel consumption by reducing

the frictional mean effective pressure and

the wall-heat losses.

4.8 Intake Manifold Module

Out of an intensive concept study, a twostep

intake manifold with a rotary sleeveswitching

device was selected. The lateral

position of the throttle valve permits an optimum

port formation of the single manifold

runners in connection with a reduction

of the losses in the fresh air section from

the air filter to the intake valve, Figure 6.

The cross-section of the runner is constant

over the entire length. The manifold

length in the power mode is 40 % of the

torque mode. In order to minimize the flow

resistance at high speeds, a rotary sleeve

was used instead of a flap-switching device.

This solution guarantees the maximum

possible cross-sectional area in the

open position. Another advantage of the

rotary sleeve design is that a high tightness

can be reached in the closed position.

4.9 Exhaust Manifold

The four-into-one exhaust manifold was

performed as a deep-draw design with a

close-coupled catalyst. A reduced exhaust

gas backpressure and an optimization of

the exhaust emissions were achieved

through an even distribution of the exhaust

gas when flowing into the catalyst

and an even flow of the lambda sensor.

4.10 Engine Management

System

Corresponding to the new requirements of

the camshaft phasing and the thermal

COVER STORY 1.8 l Four-Cylinder Spark Ignition Engine

management, the Engine Management

System was modified in the form of a higher

computing power and additional sensors.

The layout of the engine-mounted PCB

control unit was redesigned in order to

make allowance for the different vehicle

applications and for future extensions of

functions.

5 Strategy Camshaft Phasing

5.1 Internal Residual Gas as a

Result of Camshaft Phasing

In addition to an improvement of the fullload

behaviour, camshaft phasing offers a

considerable potential to minimize the fuel

consumption by allowing internal exhaust

gas recirculation and the associated reduction

of the engine’s pumping losses.

By a controlled camshaft phasing, the

internal residual gas is recirculated in three

different ways into the combustion chamber:

inlet port recirculation

exhaust port recirculation

combustion chamber recirculation.

Which of the three ways is the optimum depends

on the set load point. In Figure 7 the

simulation result is represented for the partload

point bmep=2 bar, n=2000 rpm [2].

5.2 Phasing Strategy in the

Engine Map

Based on the simulation, the subsequent optimization

on the engine test stand and in

the vehicle, the strategies for the individual

map areas were calibrated according to the

criteria: fuel consumption, emission, driveability

and full-load behaviour, Figure 8. The

engine related results are represented in sections

6.2 and 6.3, Part Load and Full Load.

6 Development Results

6.1 Combustion /

Thermodynamics

The combustion system was designed for

the fuel qualities RON 91 to 98, in order to

ensure a worldwide use of the powertrain

without major modifications. According to

a corresponding study, the optimum compression

ratio is 10.5: 1.

The combustion system was developed

with the systems AVL Visioknock and Visioflame

regarding the combustion initiation,

the course of combustion and the antiknock

properties.

As an example Figure 9 illustrates the

ignition phase, i.e. the flame propagation a

short time after the ignition and the local

distribution of the knock-event probability

during a knocking combustion at full load.

Due to the adaption of the charge motion

and the cylinder-head cooling, a optimized

combustion can be reached that

avoids the formation of local areas with a

high number of knock events.

The even spatial distribution of the

knock-event probability with local peaks

documents the optimum design of the system

from a combustion point of view.

The quality of the combustion system is

confirmed by the analysis of the 50 %-Mass

fraction burned at full load, Figure 10.

The influence of the rotary sleeve position

of the variable intake manifold onto

the charge motion and thus onto the combustion

process is demonstrated in the area

of the switching point at n = 4200/min. The

reduced volumetric efficiency in the power

mode is compensated by an almost optimum

position of the 50 %-Mass fraction

burned. At higher speed the 50 %-Mass fraction

burned can, given a high volumetric

efficiency, be maintained around the optimum.

6.2 Part Load

Due to the application of intake and exhaust

cam phasers and the option of another

variable by positioning the manifold

rotary sleeve in torque or optimum position,

the total system became more complex.

The system was optimized through a

process simulation and corresponding experiments.

Parameter variations on the

test stand were considerably reduced by a

pre-selection of optima from the simula-

COVER STORY 1.8 l Four-Cylinder Spark Ignition Engine

7 Vehicle Application

Table 2: Technical data of a vehicle from the D-segment

Vehicle-Segment D-Segment

Vehicle curb weight kg 1300 1320

Acc. to 70/156/EEC

Engine 1.8 l Gen.2 1.8 l Gen.3

Transmission 5th speed

Transmission ratio

1st / 2nd / 3rd / 4th / 5th speed 3,727 /

2,136 /

1,414 /

1,121 /

0,892

Axle ratio 3.737

Tires 195 / 65 R15

Top speed km/h 205 213

Acceleration

0-100 km/h s 11.2 10.5

Fuel consumption acc. to

99/100/EEC

Total l/100km 7.6 7.3

CO2 emission g/km 182 175

tion by means of Design of Experiments

and an automatically performed test series.

Compared to a system with constant

cam timing, a potential fuel saving of up to

5 % is developed in the consumption map

with the use of continuously variable times

at the intake and exhaust sides.

By fine-tuning the parameters, a specific

fuel consumption figure of 364 g/kWh

was achieved for the representative partload

standard point (bmep = 26 bar / 2000

rpm), Figure 11.

6.3 Full Load

One of the main development targets was

the demonstration of a peak position concerning

the specific torque and power values

and to ensure the possibility of extension.

In the development process, the simulation

of the charge cycle essentially contributed

to the new design of the charge cycle

components and their harmonization

with the fully variable cam phasers in the

intake and exhaust tracks.

By using cam phasers, it was possible to

optimize the cam profile for filling at low

and medium speed ranges. This measure

would lead to a reduced volumetric efficiency

at higher engine speeds, but due to

the very good dynamic properties of the

two-step intake manifold, this consequence

is compensated.

6

The geometry of the four-into-one exhaust manifold with

close-coupled catalyst was adjusted by detail optimization to

the variable charge cycle components at the intake side.

Comparing the present engine to the previous one, the volumetric

efficiency was increased in the lower and medium speed

range by up to 11 % and up to 15 % at maximum speed. Special

attention may be dedicated to the almost constant course of

volumetric efficiency at high speeds, which demonstrates potential

for further power optimization, Figure 10.

The maximum torque (175 Nm/3800 rpm) and the maximum

power (103 kW/ 6300 rpm) could be increased by 6 or 14 % respectively.

Thus, an excellent weight-to-power ratio of 1.14

kg/kW was achieved.

The implemented measures for full load optimization ensure

a top position among comparable competitor’s engines, Figure

12.

7 Vehicle Application

In a direct vehicle comparison, better driving performances and

a reduced fuel consumption can be offered to the customer.

Table 2 shows an example of a comparison between the 1.8 l engine

Generation 2 and 3 in a vehicle of the D-segment.

8 Summary

The new 1.8 l engine was reengineered in all relevant areas. The

current version sets a standard for power range and customer

fuel consumption. At the same time, it offers the potential to

meet future demands of the market as well as legal requirements.

The lambda-1 concept permits the application of conventional

emission treatment methods and the use of several

fuels worldwide. The engine perfectly fits the modular concept

of the mid-size engine family, which reduces the processing and

assembly work accordingly and offers the necessary flexibility

in view of future developments.

[Zoppas]

Bè penso che croma soffrirà un pò con l'arrivo di 159 sw ma un pò di mercato in italia se lo saprà ritagliare ancora....mica è ancora moribonda una D generalista in italia almeno un annetto vendicchia.

[Zoppas]

Questo 1.8 non dovrebbe essere frutto della Joint Venture fra Fiat e Opel/GM? Io sapevo così e anche Taurus lo disse...

[bialbero]

ottima la 159 con lo stesso OPEL 1.8 da 140cv...bella mossa, si si, dove sta la vera alfa?

[simonepietro]

Questo 1.8 non dovrebbe essere frutto della Joint Venture fra Fiat e Opel/GM? Io sapevo così e anche Taurus lo disse...

si, ma non si riesce a capire se effettivamente il gruppo fiat ci ha messo le mani. Anche in articoli di stampa molto dettagliati e tecnici , come quelo che ho trasformato in documento di testo da un p.d.f ,non viene mai detto quale contributo la fiat abbia dato.