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29 Sep2017
Insist on even 0.1 dB down, Chery Engine Set New NVH Record

The auto NVH generally refers to the Noise, Vibration and Harshness, one significant indicator to show the auto makers’ manufacture level as always, and in close connection with the user’s experience on quality. Chery keeps its leading position in terms of the vehicle NVH. Chery’s G3 high-performance engine-1.6TGDI was off the assembly line this June, whose NVH is as good as the international mainstream auto brands, even better than them, such that the China-made auto climbs up to new tranquil level, showcasing Chery’s profound technological accumulation in all-round fashion.

(Noise Comparison in Front Cabin between Chery and Foreign-made Auto Brands)

What about the significance of NVH for the user’s driving or riding experience? The statistics show that there are about 1/3 faults relating to the NVH. In such context, there are lots of auto-makers investing nearly 20% of their R&D expense in NVH. As Chery follows positive R&D approach, it never waits for the problem to emerge. Instead Chery sets the R&D goal that the NVH level of our G3 engine must be better than that of the international mainstream brands engines as early as defining the product development stage. Chery strictly follows the R&D control process to solve all the possible NVH problems from both the source and the route.

The engine’s structure is the very source mentioned above to start with, Chery goes through detailed CAE simulation analysis and rounds of test and calibration, which optimizes the engine structure in great depth as follows: engine valve chamber cover, cylinder block, exhaust system, intake manifold, timing cover and oil pan etc. Chery persists in the principle of working hard for 100% optimization even if it is merely 0.1 dB down. Thanks to such constantly perfecting attitude, we have achieved evident effect in terms of NVH. For instance, thanks to our unremitting endeavor on optimizing the vibration on oil pan, its weight goes down by 18%, and its radiation noise down by about 1 dB.

(Chery’s G3 high-performance engine)

Apart from the engine structure, Chery focuses on the material, software control and the like details to search for breakthrough points to optimize the NVH. Chery follows the design philosophy of low NVH via adopting low NVH parts in great quantity as follows: tranquil timing chain, noise-reducing high-pressure oil pump and fuel rail injector, high-precision idler, generator and integrated exhaust manifold design on cylinder cover with excellent noise performance etc. In terms of the electronically controlled engine calibration, Chery takes targeted measures in great details to bring down the noise. To fight against the noise from the high-pressure common rail system, Chery takes noise-control measures from the hardware and software at the same time, which has effectively improved the noise level at idling speed. In connection with the noise from the supercharging system, Chery, by virtue of its experience on systematic R&D accumulated for long, makes detailed planning and analysis on its general layout, sizing, internal design parameters and silencer design etc. which ensures the best optimized NVH performance. To better the user experience, Chery takes noise absorbing and isolating measures to reduce the vibration and noise on the parts vulnerable to radiation noise regardless of the cost. For instance, we set independent acoustic hoods for the fuel rail and oil pump, glass fiber within the heat shield of the preheating catalytic converter, and de-vibrating modular for the heat shields of the chamber cover and supercharger.

(Advanced NVH Lab of Chery)

What’s behind R&D strength on the powerful product performance is the HR team and test verification system. As early as 2002, Chery established the NVH technological team, Chery’s NVH lab enjoys a complete range of functions in the industry in China, which covers the complete process on auto NVH and all NVH performance tests, laying solid foundation for the products’ high performance.

Chery’s NVH technological accumulation for years has been transformed into one marketing merit, and one core merit for the products. Chery 2.0 products represented by ARRIZO5 and TIGGO7 have led China in terms of NVH, and some performance indicators are even better than some international mainstream brands, which is accredited by the authority. TIGGO7 SUV scored 81.31, the highest score, and gained the “golden medal evaluation” during the China Eco-Car Assessment Programme (C-ECAP) announced by China Automotive Technology & Research Center this April. In terms of the interior noise, one of the five evaluation indicators, TIGGO7’s noise test at constant speed of 60km/hour scored 56 dB, leading the others within the same category. TIGGO7’s body crack is smaller than 1 mm by virtue of its precision manufacturing process. Therefore, its NVH is in parallel with the international mainstream auto brands. The G3 engine will be gradually applied in the autos, and the Chery products’ quality and strength will be further enhanced, helping Chery to step forward in going global.