Volvo Engine Diesel 4 (VED4) | VEA

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Introduction

The Volvo Engine Architecture (VEA) was a family of modular petrol I3, petrol I4 and diesel I4 engines that commenced production in May 2013 at Volvo’s plant in Skövde, Sweden. Volvo marketed its VEA engines using the ‘Drive-E’ designation.

The four-cylinder VEA range consisted of two basic engines – the VED4 common rail diesel engine and the VEP4 direct-injection petrol engine – that were developed to power vehicles underpinned by Volvo’s SPA (Scalable Platform Architecture) and CMA (C-platform Modular Architecture) platforms. As such, the VEA engines effectively replaced eight engine architectures for three platforms. According to Volvo, VEA reduced the number of unique parts by 60 percent, thereby improving manufacturing efficiency and quality assurance.

All versions of the VEA were manufactured on the same production line. For this, the production line had to be re-modelled for cylinder block processing and thirty machining cells were replaced or converted at a cost of about 500,000,000 SEK. In total, around 2,000,000,000 SEK was invested in the Skövde plant for production of the VEA engines.

VEP4 and VED4 (1969 cc) commonalities

The 1969 cc VED4 and VEP4 engines had the following commonalities:

• A high-pressure die-cast aluminium crankcase and bedplate with nodular cast iron bearings – the bearings had a 60 mm diameter for the T6, T5, D5 and D4 engines, and a 53 mm diameter for the T4, T3, D3 and D2 engines. The cylinders had 82.0 mm bores – spaced at 91.0 mm intervals – and a stroke of 93.2 mm for a capacity of 1969 cc. Within the cylinder bores, VEA engines had cast iron liners that were sprayed with eutectic aluminium to develop a strong bond to the block, improve heat transfer and reduce distortion under load;
  The crankshaft and connecting rods were machined from a forged blank. Furthermore, the crankshaft had reinforcing cast iron bearings;
• For the pistons, the top piston ring had a Physical Vapour Deposition-coating (PVC) to reduce friction and the piston pins had a Diamond-like Carbon (DLC) coating. Within the cylinder block, oil jets sprayed the undersides of the piston to reduce operating temperatures. For VEA engines, different machining of the piston top was used to achieve different compression ratios;
• Double overhead camshafts. A belt in front of the engine drove the exhaust camshaft with a timing belt pulley, while the intake camshaft was driven by the exhaust camshaft via gears in the rear of the engine;
• BorgWarner turbochargers;
• A one-piece aluminium housing for the counter-rotating balance shafts which operated on needle bearings. Please note, however, that the VED4 D3 and D2 engines did not have balancer shafts because its shorter pistons, lighter connecting rods and smaller piston pins reduced reciprocating masses by 20 per cent and, in turn, vibration. Similarly, the  1498 cc VEP4 engines also omitted balance shafts;
• A chain-driven variable oil pump (pressure ranged from 1.5 to 4.5 bar) in which pressure was controlled by a solenoid actuator.

To reduce friction, the VEA engines introduced an improved surface treatment for the cylinder bores and crankshaft, and thinner 0W20 synthetic engine oil. The VEA engines were also designed to support ‘electrification’ in that components such as an Integrated Starter Generator (ISG) could be connected easily. The compact dimensions of the VEA engine also mean that an electric motor can be fitted in the front or rear of the vehicle, with a battery pack positioned in the centre of the car. For an example of such an application, please see Volvo VEP4 T8 Twin Engine.

Unique features of VED4 engine

Relative to the VEP4 petrol engines, the VED4 engines had the following unique properties:

• For VED4 engines, the gravity die-cast cylinder head was made from A319 T7 aluminium alloy and forced air quenching was used to minimise residual material stress – this produced a stronger microstructure with dendrite arm spacing of less than 17 micrometres (µm). The cylinder head had transverse cooling where the coolant cores and the support structure for the fire deck were designed to cope with a peak firing pressure of 190 bar;
• The double overhead camshafts were made from fabricated steel to reduce weight and provide hardness for the rolling contact with the roller finger followers which had hydraulic lash adjusters and actuated the four valves per cylinder;
• The timing belt was 28 mm wide (compared to 23 mm for the VEP4) and provided drive for the high pressure fuel pump and water pump;
• The belt-driven high pressure fuel pump generated pressure of up to 2500 bar and fuel was injected into the cylinders by eight-hole solenoid injectors;
• The pistons had a 25.2 cc bowl and the cylinders contained side-mounted glow plugs;
• Cooling system/thermal management: the outer cooling system differed for petrol and diesel engines because diesel engines have higher heat rejection at full load and lower heat rejection at part load and during warm-up. As such, VED4 engines had a mechanical water pump and pneumatic flow control valves could reduce coolant flow after start-up for faster warm-up. Heat transfer to the air conditioning system is achieved through a separate electric pump; and,
• To reduce emissions, the VED4 engines had Lean NOx Trap (LNT) and Diesel Particulate Filter (DPF).

Volvo’s VED4 engines featured i-ART (intelligent Accuracy Refinement Technology), a closed-loop fuel quality control system that was developed by Denso. Whereas conventional diesel injection systems had a single pressure sensor in the fuel rail which was used to control the injection pump, i-ART had a combined fuel pressure and temperature sensor, and a micro-processor, at the top of each injector. Using this information, i-ART enabled the injectors to deliver the optimum fuel and with timing at a precision of 10 microseconds (1/100,000 second) – this provided more precise combustion, lower noise and avoided knock (i.e. uncontrolled detonation). i-ART could also compensate for variations due to production and aging of the system. According to Volvo, i-ART could improve fuel efficiency by up to 2 per cent. While Volvo was the first European car manufacturer to introduce i-Art technology, Toyota first introduced i-ART in 2012 in its Brazil-market Toyota Hilux vehicles that were powered by 1KD-FTV engines.

As per the table below, turbocharging differs between VED4 engines. For example,

• D4 engines have series-sequential two-stage turbocharging (a small turbo and a large turbo); and,
• D5 engines have series-sequential two-stage turbocharging which included a VNT turbocharger.

PowerPulse for diesel engines

In 2016, Volvo introduced ‘PowerPulse’ for its VED4 engines in the Volvo S90 and Volvo V90. For PowerPulse, air would be drawn in from the air filter via a compressor and stored in a pressurised, two-litre air tank. When the driver sought to accelerate quickly from rest or at low speeds, this pressurised air would be delivered into the exhaust manifold to supply the turbocharger – this had the effect of delivering a ‘quick and responsive ‘pulse’ of power.’ Furthermore, the air in the pressurised tank would be automatically topped up so that PowerPulse was available on demand. At the time of its release, Volvo was the only manufacturer to use such a system.

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