Volvo FH

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Volvo FH series
Volvo FH version 2
Manufacturer	Volvo Trucks Corporation
Parent company	Volvo AB
Production	1993-present
Assembly	Gothenburg (Sweden), Ghent (Belgium), Brisbane ( Australia), Durban (South Africa), Bangalore (India),Curitiba (Brazil)
Predecessor	F series
Class	Heavy truck
Body style(s)	COE Day cab Sleeper cab Globetrotter High cab
Engine(s)	Inline 6 turbocharged intercooled Volvo D12A(12.1 L)1993-1998 D12C (12.1 L)1998-2001 D12D (12.1 L)2001-2005 D12F (12,1 L)2004-2006 EGR D13A,B(12.7 L)2005-present D16A,B(16.1 L)1993-2001 D16C,E(16.1 L)2006-present Cummins ISX600(14.91 L)1998-2006 (Australia)
Transmission(s)	14 speed synchro manual SR1900 (1993-1998) SR(O)2400 (1993-1998) VT2514(OD) (1998-present) VT2814(OD) (2006-present) 16 speed synchro manual (ZF) ZT1816 12 speed semi-automatic (I-shift) V2512AT (2007-present) V(O)2812AT (2007-present) VO3112AT (2008-present) 6 speed automatic (Powertronic) VT1706PT VT1906PT
Electric range	24 V

The Volvo FH is a heavy truck range produced by Swedish Volvo Truck Corporation. Introduced in late 1993 as FH12 and FH16, production still continues with the now the second generation of FH range model lineup. FH stands for Forward control High cab where numbers denominate engine capacity in litres. The FH range is one of the most successful truck series ever having sold more than 400,000 units worldwide.^[1]

Contents 1 History 2 First Generation (1993-1998) 2.1 Design and Technology 2.1.1 Cab 2.1.2 D12 Engine 2.1.3 VEB 2.2 Version 98 (1998-2002) 2.2.1 Electronics 2.2.2 D12 facelift 2.2.3 Gearbox 3 Version 2 (2002-Current) 3.1 New Cab 3.2 Turbo Compound and I-shift 3.3 FH16 Intelligent Power 4 References

[edit] History

In late 1993 Volvo had unveiled its replacement for the legendary F cabover series in production for almost 25 years.^[2] The development of FH in what it appeared to be a clean sheet of paper design took seven long years. The development of all new design 12 litre engine with its overhead camshaft and electronic unit injectors technology took Volvo among the world's leading engine design ranks.

[edit] First Generation (1993-1998)

There were two models, FH12 and FH16 which shared common cabs and chassis and the FH12 immediately won "Truck of the year" award in 1994. The 16 litre engine, gearboxes and the driveline were carried over from previous generation albeit with many improvements and the host of additional features including all new Volvo engine management and its diagnostics for the D12A engine.

[edit] Design and Technology

[edit] Cab

The cab produced at Umea from hot dip galvanized, high tensile steel allowed for greater strength at thinner panels and box sections while reducing overall weight. The new FH cab was a logical progression from , for its days spacious but boxy F series cab to more aerodynamically efficient, with much improved ergononics and much better seating unit while reducing overall weight of the cab by almost 30%.^[3] The cabin was exccesively tested in wind tunel facility to confirm shape aerodynamics properties to reduce air-drag thus improving fuel efficiency. The cab featured more sharply raked windscreen while wedge shaped sides rounded into front panel at much wider radius corners and the rear vison mirrors were also streamlined.The cabin was subject to the toughest cab impact test where procedure involved placing a 15 tonne static weight on the roof and one tonne pendulum striking at the cab rear wall and at the windscreen pillars , at the end of which the cab doors must be able to be opened.^[4] In 1995 Volvo FH series became first heavy duty truck to be fitted with a SRS airbag to further improve passive safety.^[5]

[edit] D12 Engine

From the design angle the new D12A engine was the one of the largest engine project from Volvo Trucks since 1950 -ties at the time . The basic design was still based on direct injection in-line six diesel engine around 12 litres displacement but with entirely different fuel and valve systems when compared with previous Volvo engines. Built at the purpose built facility at Skövde on fully automated line where the bulk of the engine assembly is done by robots and the final engine "dressing is carried out manually. The D12A was designed as a "world engine" to be able to meet latest demands in high power output,low fuel consumption and lower emissions with its single OHC camshaft design, four valves per cylinder and one centrally located electronic unit injector, integrated engine compression brake and two-piece, steel and aluminium pistons. The engine design left the door open for future upgrades in both power output and emission technologies.

[edit] VEB

VEB The Volvo Engine Brake is a compression type engine brake first introduced on D12A and since used on later designed OHC engines from 9 to 16 litre displacement. The brake operates on a principle were exhaust valve cam followers acts on secondary cam profile when engine brake is activated. Engine oil pressure is used to eliminate extra valve clearance thus this action forces the follower against secondary lobes and unseating exhaust valves temporarily to achieve so-called compression bleeding as employed by similar systems from Jacobs, Cummins and Mack however Volvo system has an extra cam lobe thus giving two openings of the exhaust valves and is designed to work in conjunction with an exhaust brake so two of the engine's four strokes are used to raise engine braking effect - Exhaust and Compression strokes.

• Operation Description
  • The exhaust stroke is used when exhaust brake shutter closes exhaust manifold after turbocharger opening as a result exhaust back pressure is raised creating braking effect.
  • The compression stroke is used next to utilise the back presssure in exhaust where at the piston's Bottom Dead Centre the exhaust valve are opened briefly and high pressure in exhaust manifold is than let in acting against the the piston moving upwards on it's compression stroke thus slowing it even more and increasing the engine braking effect.
  • At the end of the compression stroke just before piston's Top Dead Centre exhaust valves are open briefly again to release "bleed" compression thus again slowing the piston on its subsequent downwards movement and consequently achieving engine braking effect while also storing the pressure in the exhaust manifold again using the exhaust brake shutter ready for the next repeat of the cycle.

[edit] Version 98 (1998-2002)

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In conjuction with introduction of FM series in 1998 ^[6], Volvo had facelifted existing FH series with minor modifications to the cab but major upgrade to the electrical system,engine and gearbox. The so called TEA Truck Electronic Architecture introduced a technical solution to possibility of various electronic control units to work and communicate with one another. The systems have been linked using two data buses or data links which allowed control units to exchange relevant information over the data network.

[edit] Electronics

TEA is a computerized control and monitoring system which is used to control and coordinate the various functions of the vehicle main components. The control units communicate over what is known as CAN at two speeds SAEJ1587/1708 @9,600 bps and SAEJ1939 @ 250,000 bps where up to eight Electronic Control Units were used to control various functions. J1939 data link is used for mission critical rapid communication among ECUs and J1587/1808 is used for diagnostic and programming link as well as "slow" communication e.g. for back up purpose. The new instrument cluster included a LCD panel to show information or diagnostic messages from the systems broadcasted via J1708 data link.

[edit] D12 facelift

The original D12A engine was considered as a rather conservatively power rated and expectations of higher horsepower output from such an engine design was always at the mind of not only designer but customers alike. The D12C differs from earlier version substantially with completely redesigned engine head , timing gears and addition of bottom end of reinforcement with a stiffening subframe to cope with increased power output to 460 HP.

[edit] Gearbox

The gearboxes were based on previous SR1900 series and shared the same number of gears and gear change pattern. The SR2400 series gearbox was discontinued and replaced with the now same model shared across entire FH and FM range. Torque increase from 1900 Nm to 2500 Nm was due to changes to machining of the gears as well as use of the new type of narrower synchromesh mechanism allowing to increase gear width. The single control housing and the synchro mechanism reduced gearchange effort by about 50%.^[7] The control housing was also identical for left and right hand drive versions reducing overall production cost and assembly.

[edit] Version 2 (2002-Current)

In 2001 Volvo introduced the third generation of the FH and FM series with the cab and driveline given major makeover.^[8] with an investment cost of 600 million euros ^[9] Major changes included redesign of the cab to improve aerodynamics , the new automatic gearchange transmission I shift , new electronics system and the engine improvements.

[edit] New Cab

The changes to the cab included a new day cab , which is 150 mm longer with redesigned air intake and flat floor. New rear view mirrors were introduced to reduce blind spots and improve air flow , new headlights and front side marker lights, new split sunvisor and new wider front steps complemented the external modifications. The interior has been redesigned with more rounded edges around the dashboard , the new seats with integrated seatbelts and integrated telephone speaker and microphone with steering wheel controls for radio and inbuilt GSM phone were an option. As a standard equipment FH models also included FUPS (Front Underrun Protection System) to further enhance safety by preventing smaller vehicles from being "underrun" or wedged under front of the truck in a event of frontal collision.

[edit] Turbo Compound and I-shift

• D12D's further development of venerable D12C resulted in increased power output to 500 hp equipped with turbo compound technology which utilize more energy from exhaust gases after the turbocharger using an extra turbine to drive the engine crankshaft via hydraulic clutch and reduction gearing. The cooling system changes coincided with more advanced electronics for engine management system (EMS) with electronically controlled cooling fan which was now fully controlled by the Engine ECU (EECU) and as a result fuel consumption is also reduced.

• I-shift transmissions ^[10]is a concept of manual transmission with computerized gear change control Transmission Management System

(TMS) which contains two ECU's the transmission control unit (TECU) and the gear selector control unit (GECU). I-shift borrowed from old transmissions technologies like non synchronized main gears which allowed to reduce size and weight and a counter shaft brake to achieve more precise shift control while matching engine rpm to transmissions rpm e.g TECU request the EECU to correct engine rpm as to synchronize the rpm so smooth gear change can be made aka double clutching in "old days".The main advantage of the system is in safety and comfort of an automated gear changes while driver can concentrate on "just driving".

[edit] FH16 Intelligent Power

After delaying introduction of new 16 litre engine for 2 years ^[11] in 2003 Volvo had introduced what was at the time its most powerful truck ever built. ^[12] The D16C engine was available in two power outputs configurations 550 hp and 610 hp and it was a completely new design similar in the lines of D9 engine introduced a couple of years earlier for FM series. The notable design changes included timing gears being on the flywheel side of the engine (rear mounted), design which allows for increased airflow around the engine , more precise injection and valve operation, noise reduction and manufacturing cost due to flywheel casing being used to house timing gears as well. In 2005 Volvo had increased the available power of D16C to 660 hp ^[13] respectively making in it one of the most powerful production truck available.

[edit] References