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> Alfa Romeo 145 Press Release
Rich T
post 13th April 2004 15:56
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I was messing about on the web today and found that carsource.co.uk has lists of press releases about the 145/6, product recalls etc etc.

The bit pasted below seemed the most interesting to me, and answers those eternal questions about what's different on the facelifted model...

QUOTE(Press Release - Alfa Romeo 145)
BETTER VALUE 145 AND 146 TWIN SPARK

Alfa Romeo's sporting 145 and 146 hatchbacks now offer a revised exterior, changes to the interior and a new set of extra features. At the same time, reduced prices (for 146 versions) offer customers even better value.

Constituting almost 25% of overall Alfa Romeo (GB) sales last year, the 145 and 146 Twin Spark range with its Junior, Cloverleaf and Ti versions, has made a substantial contribution to the brand's success throughout Europe.

Exterior modifications to the revised range include:
  • New radiator grille
  • New shape body coloured bumpers with black inserts for 1.8 versions (1.6, Ti and Cloverleaf have body coloured inserts)
  • New round foglamps
  • Revised colour range

Interior changes comprise:
  • Chrome door handles, instrument bezels and handbrake button

Junior versions have now been replaced by the 145 and 146 1.6 TS 16v, both of which retain the Junior sporty look but lose the badge.

The 1.8 TS and 2.0 TS (Cloverleaf and Ti) versions complete the model line-up.

Driver, passenger and side airbags are now standard on all 145 and 146 versions.

The 1.6 TS gains a sunroof and single CD tuner in lieu of the radio/cassette as standard equipment. The 1.8 TS now has air conditioning and single CD tuner as standard, while headlamp washers and leather upholstery become available as optional extras. The 2.0 Cloverleaf and Ti versions benefit from the standardisation of air conditioning and new style alloy wheels, while retaining the standard 10 disc CD Autochanger.


Prices

These revised models are now more competitive than ever, as there has been no increase in price for the 145, and 146 prices have been reduced.


Engines

The 145 and 146 Alfa Romeo Twin Spark 16-valve engines belong to the same mechanical 'family' as the widely acclaimed units which made their UK debut in the Alfa Romeo 156 sports saloon in 1.8 and 2.0 guise, the 2.0 litre version also powering the GTV and Spider sportscars.

These engines are cleaner, quieter, livelier and more fuel-efficient than their predecessors. The Twin Spark is a classic power plant, with four cylinders in-line beneath a cylinder head featuring two camshafts controlling four valves per cylinder, that are inclined into each combustion chamber.

Improved flexibility and mid-range torque derived from variable valve timing, and variable geometry intake systems (1.8 and 2.0 versions) together with four valves per cylinder and Twin Spark ignition, make for effective fuel management and flexible power delivery.

These mechanical features combine with structural oil sumps which increase engine rigidity to minimise vibration, and individual cylinder knock control to optimise power and reduce fuel consumption.

The engines all meet EC Stage 2 exhaust emissions and noise standards. Low maintenance requirements are met by the incorporation of hydraulic tappets, automatic timing belt tensioners and longlife spark plugs.

Valves are angled at 46 to one another, and a second, smaller spark plug, (there are two spark plugs per cylinder), is sited at the back of the combustion chamber.

Piston cooling is assisted by oil jets, and the ignition is a phased sequential type with individual integrated coils per cylinder.

Twin Spark ignition, as its name suggests, employs two spark plugs, but they are of different sizes and perform different roles. The larger one is sited centrally and fires the compressed charge at the beginning of the power phase; the smaller one also sparks 360 later at the end of the exhaust phase, reducing harmful emissions and protecting the catalytic converter by ensuring that no unburnt fuel should reach it. Since each cylinder has its own direct-ignition coil, the spark plug leads are arranged so that the output from each coil is directed to two different cylinders.

The twin overhead camshafts are designed to have their relative timings altered so as to vary the amount of overlap between exhaust and intake phases.

While not new to Alfa Romeo, the variable valve timing system has been developed with the use of the latest electronic engine management system. The phase shift is actually less than in the past, (a matter of 25 rather than 30), but it moves to give full overlap at as little as 1800 rpm when maximum torque is required, and to eliminate overlap either at full power or at idling. Thus, these engines achieve notable efficiency.

and pull strongly throughout the RPM range, thanks to the precise metering of fuel and timing of ignition which are part of the responsibilities of the electronics - along with modulating engine 'knock', monitoring emissions, and governing the exhaust gas recirculation system. Over 90% of peak torque is available from between 2500 and 3000 rpm, depending on the version.

With laminar cast iron blocks, crankshafts with eight counterweights, and rolled, hardened crankpins together with crossflow aluminium alloy cylinder heads and variable valve timing, the 1.6 Twin Spark engine follows the highly successful design of the 1.8 and 2.0 litre versions. Porting is notably efficient from the smallest valve opening, and a cross-section of the intake ports reveals that they are rectangular on curved sections - a configuration that produces a maximum power increase of some 2 per cent.

The 1.8 litre Twin Spark 16V features twin overhead camshafts, four valves per cylinder, Twin Spark ignition and variable valve timing, but it also has variable geometry intake manifolding. Motor racing fans will recall when racing cars used intake ports of different lengths depending on whether they needed to maximise power or torque. More recently, F1 engines have used a telescopic system to adjust intake lengths to engine speed requirements.

On the new Twin Spark 1.8, the intake manifold contains a glassfibre-enriched nylon system of moving parts that channels the air into 380 mm or 560 mm ports according to the needs of the moment. This is 'intelligent variability' in the sense that it is not simply mechanical, but controlled by the same electronic unit that regulates the engine's ignition and fuel injection functions. The system exploits 'ram' effect and acoustic resonance phenomena to ensure that the cylinders are always appropriately filled.

Advantages are twofold. On the one hand, this system uprates power and torque output at intermediate RPM. At the same time it optimises the smoothness of the entire drivetrain to the benefit of driveability and overall engine efficiency (enhanced fuel economy).

Everything found on the 1.8 also appears on the 2.0 litre. In addition, this version features an engine block with a Vibrodine twin balancer shaft system that minimises the characteristic vibrations of a four-cylinder power unit. This innovation has enabled Alfa Romeo to reconcile strong performance (max power 155 bhp and an impressive 138 lb. ft of torque) with smooth running at all engine speeds.


Transmissions

Working in conjunction with these engines is a transverse gearbox which is quiet in operation, offers fast and precise gearchanging, and makes for an enjoyable drive.


Steering

Alfa Romeo's acclaimed high ratio steering rack, (2.1 turns lock to lock), as fitted to the GTV, Spider, 145 Cloverleaf and 146 Ti, is also specified on 1.8 T. Spark 16V versions. Hydraulically assisted and speed sensitive, it provides notably precise responses and a progressive feel.


Brakes

The braking system of the 2.0 litre versions is used by the 1.8 T. Spark 16V - that is to say 284 mm ventilated discs at the front and 240 mm discs at the rear, with vacuum servo assistance. All models in the 145 and 146 ranges are equipped with ABS anti-lock braking as standard equipment, and all versions have disc brakes all-round, ventilated at the front.


SAFETY, SECURITY AND THE ENVIRONMENT

With both the 145 and 146, Alfa Romeo's engineers and designers considered safety and security issues as an integral element of the fundamental design-engineering process. High levels of active and passive safety formed part of the initial design brief and have been scrupulously followed through to production.

Much of the unique Alfa Romeo character - zestful performance, precision handling, powerful standard equipment ABS anti-lock brakes (the latest generation Bosch 2E system), and a driver orientated facia - also has major benefits in active safety, or the avoidance of accidents.

Passive safety - those sub-systems of the car which come into play during an accident - was also an overriding concern. Thus, high levels of torsional stiffness in the bodyshell and deformable front and rear crumple zones to dissipate crash energy, are allied to safety cage reinforcements around the doors, roof rails, side sills and B-pillars, and high strength tubular steel impact bars are built into the doors. This ensures that both models meet the new EC side-impact regulations that have come into force this year.

The stiffened bodyshell has successfully passed the most demanding crash tests, including a 50 per cent offset impact against a rigid barrier; one of the most demanding from all viewpoints.

Driver, passenger and side airbags are standard on all the new 145 and 146 versions. The steering column features a telescopic lower section and a collapsible steering wheel.

Seatbelt pretensioners are standard on the height-adjustable front seatbelts. In an accident situation the pretensioners automatically recoil seatbelt slack in a few milliseconds so as to restrain front seat passengers properly.

The sporty front seats feature an anti-submarining cushion design, which prevents the driver or passenger from sliding beneath the seatbelt in a heavy impact.

A comprehensive on-board fire prevention system, (FPS), includes an inertia switch which cuts - in just a few thousandths of a second - the electric fuel pump, along with three fuel-flow stop valves. A tough flameproof fuel tank is positioned in a protected part of the car, and flame-retardant upholstery material is used in conjunction with the stringent requirements of US 302 safety regulation standards.

Environmental concerns are addressed through the use of three-way catalytic converters with heated lambda probes. The heated lambda probe ensures that the catalyst operates effectively, even immediately after a cold start, minimising pollution during the critical engine warm-up period. Engines are fitted with stainless steel exhaust manifolds and exhaust gas recirculation equipment, and the shape of the combustion chambers has been designed with optimum volumetric and thermal efficiency in mind. Twin spark plugs per cylinder also make for faster, more efficient combustion and cut polluting emissions.

Only fully recyclable materials are used in production and all factory processes are subjected to a regular ecological audit.

A prime security feature is the 'Alfa CODE' ignition key. This activates the on board immobiliser system through a transponder concealed in the key grip that sends a signal to an aerial coiled around the ignition switch. When the transponder emits a unique code, it is picked up by the aerial and activates the immobiliser control unit which 'freezes' the engine management computer, preventing the engine from being started without the correct key. In addition to the Alfa CODE immobiliser, all 145 and 146 versions are fitted with a sophisticated remote controlled alarm system offering both protection from forced opening of doors and, with an Ultrasonic facility, protection from glass being broken. As an additional deterrent, all windows are etched with the vehicle's identification number (VIN) and eight digit vehicle chassis number, prior to sale, and each vehicle is automatically registered with the NVSR. Alloy wheels are also fitted with anti-theft bolts.

Like all Alfa Romeos, 145 and 146 models come with a three year/60,000 miles mechanical warranty in addition to an eight year corrosion protection warranty and a three-year paint warranty.


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Fuel
post 14th September 2011 22:17
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Fuel exhuming old interesting posts!!!
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hazeyblue
post 15th September 2011 09:05
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Great find... cool.gif
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930Tech
post 15th September 2011 15:17
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QUOTE
the smaller one also sparks 360 later at the end of the exhaust phase


Do you think that was a mistake?
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Fuel
post 19th September 2011 23:02
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QUOTE(930Tech @ 15th September 2011 12:17) *
Do you think that was a mistake?


No Waynes, it is not a mistake!

Many cars do that in order to save one sensor! (sensor that would give the additional information of which cylinders are at the compression stroke instead of exhaust).
They put a sensor at the crankshaft and no matter in which cycle the cylinder is, if it is in the correct angle it ignites.




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930Tech
post 20th September 2011 04:28
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I took that as the second spark plug fires 360 degrees after the first.

That'd be at the same time the first plug is firing again dunno.gif
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Hybrd
post 20th September 2011 17:30
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4 stroke, so the the first plug would fire every 720 degrees, (2 full revolutions of the crank) smile.gif

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Cloverleaf76
post 20th September 2011 18:14
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I love that my car (registered 8/98 from memory) was born with about half the features they promise and a bunch of stuff from the older version too. Only in Naples...
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cesar86
post 20th September 2011 19:11
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Hmm so that's how the 2nd plug (in theory at least) burns any fuel remaining in the exhaust gases. Clever idea smile.gif

But i wonder if any slight change in ignition timing could lead the 2nd plug to cause a backfire at the intake, since it sparks a little before piston TDC in the exhaust stroke, and at that time the intake valve's already open and fuel mixture coming in (there's nearly 33 of overlap with variator on, in ph1 engines).



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Fuel
post 20th September 2011 22:47
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QUOTE(cesar86 @ 20th September 2011 16:11) *
Hmm so that's how the 2nd plug (in theory at least) burns any fuel remaining in the exhaust gases. Clever idea smile.gif

But i wonder if any slight change in ignition timing could lead the 2nd plug to cause a backfire at the intake, since it sparks a little before piston TDC in the exhaust stroke, and at that time the intake valve's already open and fuel mixture coming in (there's nearly 33 of overlap with variator on, in ph1 engines).


That's not made to burn anything at exhaust gases, Cesar. There is nothing to burn there!
It's made this way just for a matter of simplicity!... the ignition system doesn't need to know in which stroke each cylinder is to ignites!
It simply ignites every 360 degrees!.... instead of each 720 degrees at the compression stroke.





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Fuel
post 20th September 2011 22:56
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QUOTE(Fuel @ 20th September 2011 19:47) *
That's not made to burn anything at exhaust gases, Cesar. There is nothing to burn there!
It's made this way just for a matter of simplicity!... the ignition system doesn't need to know in which stroke each cylinder is to ignites!
It simply ignites every 360 degrees!.... instead of each 720 degrees at the compression stroke.


The second spark is made right after the first one and has the purpose to burn some part of the mixture that would be trapped somewhere in the cylinder (probably at the angles).
I trully don't know how much of the Alfa Romeo Twin Spark technology in our engines is "pure marketing" or if it really works for something.

However, as the chamber was designed to work with the 2 spark plugs, probably it needs both to work properly!



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cesar86
post 21st September 2011 00:12
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Bit confusing 'cause the text says otherwise:
The larger one is sited centrally and fires the compressed charge at the beginning of the power phase; the smaller one also sparks 360 later at the end of the exhaust phase, reducing harmful emissions and protecting the catalytic converter by ensuring that no unburnt fuel should reach it.

I finally did some reading on the TS technology, most sources say both plugs fire at slightly different time in the 8V engines, and at exactly the same time in the 16V engines , and is meant to improve the efficiency in fuel mixture burning. Most of the time there's at least a very small amount of fuel left in the exhaust gases, specially when we hammer the gas pedal. And that's where the 2nd plug comes in, at least in theory it makes sense.

The use of two spark plugs depends specially on combustion chamber design. In our 16V engines it seems to work well (or seemed back in the 90s), but not necessarily other engines would benefit from that. And one of the aspects of chamber design is to ensure the force exerted over the piston (during combustion) is well spread over it's surface and not mainly concentrated in the center, which is the weakest section, and that depends on how the flame propagates through the compressed fuel mixture. So perhaps the TS technology also plays part in this, which would help extend piston lifetime, and perhaps other components lifetime, indirectly.

But now, considering combustion chamber and spark plug designs have greatly improved in the last years, nowadays would probably be pointless to use two spark plugs instead of one.

This post has been edited by cesar86: 21st September 2011 00:14


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Fuel
post 21st September 2011 03:12
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QUOTE(cesar86 @ 20th September 2011 21:12) *
Bit confusing 'cause the text says otherwise:
The larger one is sited centrally and fires the compressed charge at the beginning of the power phase; the smaller one also sparks 360 later at the end of the exhaust phase, reducing harmful emissions and protecting the catalytic converter by ensuring that no unburnt fuel should reach it.

I finally did some reading on the TS technology, most sources say both plugs fire at slightly different time in the 8V engines, and at exactly the same time in the 16V engines , and is meant to improve the efficiency in fuel mixture burning. Most of the time there's at least a very small amount of fuel left in the exhaust gases, specially when we hammer the gas pedal. And that's where the 2nd plug comes in, at least in theory it makes sense.


Yeah. You are right. At the 16v TS both plugs sparks at exactly the same time! But that exists just to make 2 flamme fronts, burning the mixture properly. (However, they can work on the delay of the two plugs as the chamber design requires it)

Even though when we hammer the gas pedal can be some small amount of fuel left in the exhaust gases, making the plug to sparkle at this stroke will not make this fuel (involved by burned gases) burn. It's just a waste of a spark, and makes the plug to live shorter! This solution is made ir order to make the ignition system simpler and cheaper.

To emphasize, IMHO the text is wrong!

This post has been edited by Fuel: 21st September 2011 03:14
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Oldmanmille
post 21st September 2011 07:10
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Im just pleased it all works whistle.gif

Too technical for this time of the morning but interesting nonetheless.....


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