The 5th Period of Chaichefang

2012-04-22 WenQian Zhang 中文版

  Headquartered in Beijing, chexun.com was established in 2008 as a professional automobile website. In 2011, chexun.com began to run Chaichefang column, which buys two hot-sell cars every month fully at its own expense per month, deconstruct them jointly with Tsinghua University and display to consumers what is behind their gorgeous appearance.

  The car models deconstructed in the 5th Period of Chaichefang are Shanghai Volkswagen Tiguan and Dongfeng Honda CR-V. Both of them are sports utility vehicles (hereinafter referred to as SUV) oriented at urban users. How are their internal processes? Are they cost effective? Chaichefang will answer these questions.

  Part 1 Deconstruction

  I. Front of Body Structure: Two cars have different structures.

  Front impact beam

  Tiguan score: 7.5 points

  CR-V score: 5.5 points

  The two cars have different front bumper structures. Behind Tiguan front bumper shell are foam plastic and then metal bar. CR-V front bumper shell is directly connected with the metal bar without a buffer layer.

 

Tiguan

CR-V

Foam plastic buffer layer

Available

Not available

Space between metal bar and ground

490mm

520mm

Metal bar thickness

2.63mm

2.29mm

Energy adsorbing box thickness

132mm

120mm

  II. Rear Part of Body Structure: Visually, Tiguan’s protective steel beam is thicker and heavier.

  Rear impact beam

  Tiguan score:5.5 points

  CR-V score:3.5 points

  The tail structures of both cars are basically identical. Behind the bumper shell, there is a metal beam and no buffer layer of foam plastic.

The 5th Period of Chaichefang

  At Tiguan’s tail is a metal beam with a steel plate thickness of 2.21mm.

The 5th Period of Chaichefang

  At CR-V tail is also a steel beam with a steel plate thickness of 1.6mm.

  The tail protection structures of both cars are very similar. If we insist on finding the difference, there are two: the first is material thickness and the second is the depth of energy absorbing box: it is 160mm in Tiguan and 47mm in CR-V.

  Conclusion: Tiguan’s energy absorbing box has a longer travel and looks safer. Besides, visually, Tiguan’s protection steel beam is thicker and heavier.

  III. Door of Body Structure: Both doors are delicate and CR-V is even better.

  Wheel fenders:

  Tiguan score:7.5 points

  CR-V score:6.5 points

  Front doors:

  Tiguan score:7.5 points

  CR-V score:5.5 points

  It can be seen from the table below that there are certain differences in their door structures. Tiguan doors are integral stamped pieces but the rear doors are made of single layer steel plate. CR-V’s doors use welded pieces for the upper part but all the four doors are made of dual layer steel plates. For the protective steel beams in doors, Tiguan adopts a profiled material, with the protection area larger than CR-V’s. CR-V adopts a sectional material, with a smaller protection area compared with Tiguan’s.

 

Tiguan

CR-V

Front door structure

Two layers of steel sheets

Two layers of steel sheets

Rear door structure

One layer of steel sheet + one layer of plastic plate

Two layers of steel sheets

Distance from front door beam to ground

580mm

680mm

Distance from rear door beam to ground

700mm

855mm

Steel beam form

Dual-box type special bar

Φ32mm circular steel tube

  There is a also slight difference in the reinforcement of door steel sheets. Tiguan (left in the picture below) uses no metal reinforcing bars but two non-metal sticking pieces to eliminate the vibration of door plate. CR-V (right in the picture below) uses a metal reinforcing bar above the protective steel beam.

The 5th Period of Chaichefang

  The door interior plates of both cars have a sticking layer on the back. The difference is that CR-V’s sticking layer is soft fabric (right in the picture below) with a smaller coverage area while Tiguan uses a sticking layer (left in the picture below) with a larger area. But its material is very hard, very greatly different from commonly seen soundproof cotton

The 5th Period of Chaichefang

The 5th Period of Chaichefang

  Conclusion: Visually, both cars have a delicate workmanship, especially CR-V,whose workmanship is much finer than the Japanese series cars deconstructed in the previous periods of Chaichefang.

  IV. Roof of Body Structure: CR-V’s thermal insulation layer is thin.

  Roof

  Tiguan score:4 points

  CR-V score:9 points

  After removing the interior ceiling, under Tiguan (left in the picture below) roof steel panel was a layer of asphalt covered by a yellow composite sticking piece. Under CR-V (right in the picture below) roof steel panel were three reinforcing bars covering very large areas, 65 mm, 5mm and 22 mm, respectively. It was the first time for us to see reinforcing bars with so large an area since Chaichefang program started.

The 5th Period of Chaichefang

  The ceiling structures and materials of both cars are very approximate and the biggest difference is that there are two pieces of thermal insulation layer sticked on the back in CR-V (right in the picture below).

The 5th Period of Chaichefang

The 5th Period of Chaichefang

  Using asphalt and composite material, Tiguan can insulate partial heat for the car. Comparatively, CR-V’s roof thermal insulation layer is evidently inferior to Tiguan.

  When we removed Tiguan’s ceiling, someone shouted: it is paper. It was true that the composite thermal insulation layer in Tiguan roof looked not different from corrugated board but was only felt harder by hand. Not long ago, someone unexpectedly found corrugated board in a Japanese car roof, which aroused a shock on the Internet. In fact, there is a great difference between the corrugated board for packaging boxes and the composite material used in Tiguan.

  Conclusion: The thermal insulation layer in Tiguan is easy to cause misunderstanding and CR-V’s thermal insulation layer is thin.

  V. Floor of Body Structure: CR-V is much better than Tiguan.

  Interior floor

  Tiguan score: 5.5 points

  CR-V score: 6 points

  Tiguan’s interior floor is composed of floor mat and a soundproof layer (left in the picture below). The floor mat feels good but the soundproof layer texture is very rough.

  CR-V’s interior floor is composed of floor mat and soundproof layer (right in the picture below). The soundproof layer is composed of polyurethane and rubber, which not only has a thickness far greater than Tiguan’s but the material texture is much finer.

The 5th Period of Chaichefang

The 5th Period of Chaichefang

  In terms of the flatness of interior roof, CR-V once again wins. The biggest difference is in the heave at the middle of rear row seats. The heave in Tiguan (left in the picture below) is as high as 180 mm, affecting the comfort of the three passengers on the rear row seats. There is almost no heave in CR-V (right in the picture below) and the floor is very flat.

The 5th Period of Chaichefang

The 5th Period of Chaichefang

  Besides, there is a great difference in the wiring harnesses hidden under the floor mats in the two cars. Tiguan’s wiring harnesses (left in the picture below) are wrapped by black adhesive tape intermittently, being suspect of material saving. CR-V’s harnesses (right in the picture below) are all set in an insulation pipe and there is a protection layer made of white plastic where they cross beams.

  Interior material flame retardancy

  Tiguan score: 5 points

  CR-V score: 5.5 points

The 5th Period of Chaichefang

The 5th Period of Chaichefang

  Conclusion: In terms of floor material, floor design and wire harness safety, CR-V is greatly superior.

  VI. Overview of Car Body Structure: Doubt about laser welding

  With respect to car body structure, both cars use many large pieces of steel plates and only a few of small pieces welded together, especially Tiguan, which use a great number of integral stamped pieces. Though CR-V is not comparable with Tiguan, it is much better than Qashqai also in Japanese series.

  The A, B and C column structure and thickness are listed in the table below.

  A, B and C columns

  Tiguan score: 5.5 points

  CR-V score: 5 points

 

 

Tiguan

CR-V

A column

Structure

Three-layer steel plates

Three-layer steel plates

Total thickness

3.6mm

4.6mm

B column

Structure

Three-layer steel plates

Three-layer steel plates

Total thickness

4.0mm

4.3mm

C column

Structure

Two-layer steel plates

Two-layer steel

Total thickness

1.8mm

1.4mm

  Tiguan adopted laser welding at its roof, door and sides. However, when the door frame sealing strips were removed, we saw many weld spots with defects at the four doors, with some even burned through. It could not be understandable that some places where laser welding was applied were also be electrically welded. Was such superfluous work required by process or a remedy measure for the defects of laser welding?

  In contrast, CR-V’s electric welding process is very good and there are 23-25 weld spots per meter in very regular order.

The 5th Period of Chaichefang

  Conclusion: Laser welding has a very good WOM but the manufacture should explain why there is burn-through.

Both Tiguan (lower) and CR-V use thick, heavy metal bars and Tiguan also has a buffer interlayer composed of foam plastic but CR-V does not have.

The 5th Period of Chaichefang

  At the front of CR-V’s metal bar, there is a 65mm projecting metal pillar. Viewing from its shape and position, it should be a design of energy absorbing box type but there is no beam at its top. It is unknown what the purpose of this design is and maybe, there was a beam here in the original design.

  According to China’s new car assessment program, in the collision test, Tiguan achieved a score of 48.2 points and a 5-star safety rating (tested in 2010) and CR-V achieved a score of 50.6 points and a 5-star + safety rating (tested in 2007).

  Conclusion: In terms of only the front structure, Tiguan’s front bumper which is of dual-bow variable cross section design in combination with a foam plastic buffer interlayer has a protection level obviously greater than CR-V. CR-V achieved a higher score according to China’s New Car Assessment Program because the assessment of complete car is not based only on front protection.

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