The new diesels of PSA - Ford - Jaguar 2.7 V6
by François Dovat
(© François Dovat)
The first baby born of the technical cooperation of the two groups was named HDi 1.4 by Peugeot-Citroen and Duratorq TDCi 1.4 by Ford. A 1.6 version as well as a 2.0 derived of the PSA DW 10 were presented in February 2003. A 2.7 liters V6 follows and will soon be in production, first for the Jaguar S-Type.
Already available on the C3, 206, 307, Xsara and Fiesta, 37 applications of this engine (together with version 1.6) are envisaged. Production numbers should somewhere between 2500 to 6000 units per day in the Douvrin and Trémery factories lately equipped. According to the variants of cylinder heads (8 or 16 valves) and turbocharging equipments, the powers of the 1.4 are staggered between 60 and 92 hp with a torque reaching 200 Nm. All the connections engine-vehicle are standardized, whatever the version is.
In spite of the structural stiffness necessary to resist to a firing pressure of 160 bars, pledge of a high efficiency, the engine weighs 98 kg only, which is 50 kg less than the former XUD9 with Ricardo Comet swirl chambers. Cylinder head, block and bedplate are cast out of light alloy with insertion of thin dry liners and cast iron bearing webs during the high pressure die casting process. To save weight the cams are set on a tube and the filters - airflow meter - intake manifold - valve-cover - fuel filter unit is made out of composite material, as is a silencer at exit of the compressor, the water pump casing, the water inlet and outlet casings and the suction filter of the oil pump.
The precision of the timing and volume pre-injected by the common rail equipment has been further improved; the injectors having now 6 holes of 118 microns diameter, which allows an extremely fine pulverization.
An oxidation catalyst is placed on the front side of the engine, directly at the turbine outlet in order to benefit of the highest temperatures, the intake being at the rear engine side
With a stroke of 82 mm and a bore of 73.7 mm, the mean piston speed does not exceed 11 m/sec at 4000 rpm. A hefty torque back-up of 27% is due to a mean effective pressure of 18 bars at 1750 rpm against 14.2 bars at 4000 rpm (16 V version).
The 16 valves version of 1560 cc was presented in February 2003. Due to a bore of 75 mm and a stroke lengthened to 88.3, a power of 110 hp and a torque of 235 Nm are obtained (even 260 Nm with "overboost", meaning a masterly torque back-up of 35% and nothing less than 21 bars bmep). The weight also is increased to 120 kg.
The Bosch common rail injection equipment works up to 1600 bars and is now capable of 2 pilot injections, 2 main injections and 2 post-injections, thanks to a more powerful calculator and to even more accurate injectors. A Garrett turbocharger with variable geometry turbine inlet was developed especially for this engine, which is, of course, outfitted with an intercooler.
The press release insists on the fact that it is not only a version of the 1.4 with increased cubic capacity. The combustion chamber was redesigned to decrease the "swirl" (i.e. whirling turbulence) and the angle of pulverization of the fuel spray has been widened.
According to the vehicles and countries, this engine will be equipped with a soot filter. Together with a more powerful process of regeneration, the new fuel additive is said to improve reliability and durability.
The production of this version should reach the figure of 1.1 million annual units as of 2005 and it will be carried out with the Citroen plant of Trémery – which was already the largest factory of automotive diesels in the world before the launch of this new engines line.
The cylinder heads comprise a separate camshaft(s) bearings unit. The cylinders are siamesed for an optimal stiffness (here on the 1.4 8V version).
The bearing caps out of cast iron are integrated in the bedplate and are fastened by 4 studs each, a concept which provide an outstanding rigidity.
Toroidal combustion chambers in the pistons, crankshaft with 8 counterweights, levers with rollers followers on stationary hydraulic lifters and vacuum pump at the camshaft end with. The 2 camshafts of the 16 valves cylinder head are connected by a short chain (8V version shown here).
This one is an improved version of the famous HDi DW10 of 85 x 88 mm bore and stroke in a cast iron cylinder block, topped by the 4 valves/cylinder head with twin camshafts which was already available on the 2.2 liters DW12 version.
To ensure a better protection in the event of frontal shock, the engineers of Ford and PSA managed to reduce the width and the height of the engine, respectively of 4 and 1.5 - 2 cm. The Siemens injection equipment with piezoelectric injectors makes it possible to largely enhance the performances: the power is increased to 136 hp and the torque to 320 Nm, and even 340 Nm with "overboost".
Having profited from the joint attention of engineers of Ford and PSA, this engine should associate the proverbial smoothness of the HDI with the performance of the Mondeo's TDCi.
The 60-degree V6 diesel has a capacity of 2720 cc from 81 x 88 mm bore and stroke. Depending on application it will have an output of up to 207 hp and 440 Nm. Its specific power of 76 hp/liter and 20.3 bars of mean effective pressure plainly demonstrate that recent progress on small automotive diesels has really been tremendous.
The cylinder block is cast in compacted graphite iron (CGI) and will be the first to use of this material in volume engine production. As a result of the outstanding strength and durability of CGI, less material is needed than for a conventional cast iron block, ensuring reduced engine weight. The bearings cups are an integral part of an aluminum ladder frame which forms a rigid structure. This frame is fastened on each bearing plane by 4 vertical main bolts together with 2 horizontal cross side bolts.
The cast aluminum pistons with toroidal combustion chambers are cooled by an oil jet spraying in two internal wave-shaped channels to help cool each piston crown. Friction is reduced through PTFE (polytetrafluoroethylene) coating.
The connecting rod big ends are fracture-split.
In the aluminum heads, 4 valves per cylinder are actuated by twin camshafts and roller levers pivoting on motionless hydraulic lifters. Six out of the twelve intake ports are closed under low load operation to increase swirl. A single long toothed belt drives the four hollow camshafts. The common rail high pressure pump is then driven by the rear end of one of the exhaust camshaft.
The latest common-rail technology works under 1650 bars and includes multiple pilot injections, closed loop control and piezo-electric injectors. The diameter of their holes is 145 microns, about the thickness of a hair. Advanced control strategies also contribute to lessen emissions at source under all operating conditions through an optimized and efficient combustion process. An exhaust gas recirculation system (EGR), the port deactivation and electronically controlled turbines inlet vanes on each cylinder bank's turbocharger further reduce emissions. Besides, the latter system also improves the transient response. The V6 is Euro 4 capable and in association with a particle filter, soot emissions will be reduced to an almost undetectable level. Of course, an intercooler (of the air-air type) is outfitted.
The ECU high capacity processor continuously controls the engine’s operating parameters together with transmission and braking controller. It gathers information from 23 sensors and orders 20 actuators. It also monitors the oil level, temperature, quality, and uses a complex algorithm to assess the oil duty cycle and inform the driver.
The volume production of CGI necessitated the development (over the last eight years) of new manufacturing technology and machine tools but the end result is the lightest engine of his category at 202 kg (DIN 70020).
The V6 diesel will be built at Dagenham, GB, in Ford brand new facility which has been open in July 2003. The initial production volume will be up to 150,000 units yearly and this outstanding engine will be available first in 2004 on the Jaguar S-Type and later on in some unspecified Peugeot-Citroen (probably the 607 and C5, at least) and Ford cars.
"Jaguar engineers were involved from the very beginning of the V6 diesel programme within the main project team of Ford Motor Company and PSA Peugeot - Citroen to help define the base engine specification and technologies necessary to deliver the high standards of power, refinement and drivability expected of a Jaguar," says the joint press release.