VW Polo Teardown (Part 2)
1.2-liter Turbocharged Direct Injection (TDI) diesel engine and suspensions
As reported earlier in "VW Polo Teardown (Part 1) Engine compartment and driver's seat area" (No. 1354 posted on December 2, 2014), the VW Polo teardown was performed on November 5 and 6, 2014. It was co-organized by the Saitama Industrial Development Corporation and Japan Auto Parts Industries Association. This second report focuses on the 1.2-liter TDI diesel engine and front/rear suspensions.
The 1.2-liter TDI diesel engine employs a variable nozzle turbocharger with an air-cooled intercooler to deliver high torques from low engine speed ranges. The engine uses common-rail type direct fuel injection, electronically controlled swirl control, electronically controlled exhaust gas recirculation (EGR), and oxidation catalyst with diesel particulate filter (DPF) to meet Euro 5 emission standards for cars in Europe. The VW Polo has strut type suspension in the front and the torsion beam type suspension in the rear. These suspensions have been used for years on the VW Golf and Polo. They are reputed for use on front-wheel drive vehicles in C and smaller segments around the world. The vehicle used for the teardown event was the 2012 British model of the VW Polo fitted with a 1.2-liter diesel engine and not sold in Japan.
Past teardown reports:
Main specifications of VW Polo (2012 British model)
|Vehicle||VW Polo 2012 British model (right-hand drive)|
|Dimensions||Length: 3,970mm, Width: 1,682mm, Height: 1,462mm, Wheelbase: 2,470mm|
|Fuel efficiency (NEDC)||Combined: 26.3, Urban: 21.7, Extra-urban: 30.3 (km/liter)|
|Diesel engine||1.2-liter inline 3-cylinder (intercooled direct-injection turbo engine),
compliant with Euro 5 emission standard,
DOHC 12-valve, compression ratio: 16.5,
maximum output: 55kW (75PS)/ 4200rpm, maximum torque: 180Nm/ 2000rpm
|Transmission||5-speed manual transmission|
|Price||GBP 13,634 (London, U.K.)|
|Plant name||Uitenhage plant, South Africa|
Source: Compiled by MarkLines based on "2014 Vehicle Teardown Study Group Data" issued by the Saitama Industrial Development Corporation and Next Generation Automobile Industry
1.2-liter TDI diesel engine
In order to meet the Euro 5 emission standard, the engine supplies highly pressurized fuel to the common rail for precisely controlled direct injection. It employs swirl, EGR and other controls. It also employs variable nozzle turbocharger and an air-cooled intercooler to generate high torques in low to high engine speed ranges. A balance shaft is used to improve the engine's quietness.
|Low emissions||Common rail system and direct fuel injection (solenoid type injectors)|
|Electronically-controlled swirl control valve|
|Electronically-controlled EGR valve|
|High torques in low ranges||Variable nozzle turbocharger|
|High-stiffness cylinder block|
Engine compartment layout and engine assembly
Air intake system
Front and rear suspensions
The VW Polo has the strut type suspension in the front and the torsion beam type suspension in the rear.
The 1974 first-generation Golf was the first VW model that adopted this combination. These suspensions have been improved and used on the Golf and the Polo since then. The rear suspension on the Golf was changed to the multi-link type starting with the 5th-generation model. The torsion beam type is re-adopted on the lower grades of the 7th-generation Golf. The Golf was not the world's first vehicle that used the specific front and rear suspension combination. However, other automakers started to use the same combination for their front-wheel drive vehicles because of Golf's superb performance and cabin spaciousness. The same combination is used today in many C segment and smaller vehicles.
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