Cubic Automotive Test Systems - The Full-flow Dilution Constant Volume Sampling System

Introduction

The Gasboard-9802 full-flow dilution constant volume sampling (CVS) system is designed for the measurement of diluted emissions from vehicles and engines. It has a complete and technologically advanced hardware configuration and software platform. When used in conjunction with a high-precision gas and particle online analyzer, it meets cold-start emissions test requirements under normal laboratory conditions for major mobile source emission standards, including the upcoming Euro 7 standard.

Why You Need Gasboard-9802 CVS

The Constant Volume Sampling (CVS) system is widely used for emissions and fuel economy measurements of vehicle and engine exhaust gases. In the CVS method, the system has an exhaust gas inlet directly connected to the vehicle tailpipe and a dilution air inlet. Exhaust gases are diluted with air by using critical flow venturi (CFV-CVS) to maintain a constant total flow rate (air + exhaust) under all running conditions for mass emission measurement.

The CVS system procedure offers clear advantages for certification testing. In the sample transport line, dilution of exhaust gas eliminates or reduces water condensation risk. Exhaust stabilization reduces temperature and pressure fluctuations, simplifying the sampling process. The total flow rate is precisely measured and controlled, allowing easy calculation of mass per kilometer or emission rates.

Therefore, the CVS method has been adopted by most countries for regulatory exhaust emission testing, including Euro 4/5/6, upcoming Euro 7, US 40 CFR Part 1065, and other standards. The system supports various test cycles such as New European Drive Cycle (NEDC), World Light Vehicle Test Cycle (WLTC) and additional protocols.

Principle

In the CVS system, engine exhaust gas is mixed with dilution air to achieve a constant flow rate of diluted exhaust gas. The system extracts a portion of the mixed diluted exhaust gas for:

· Air bag sampling analysis

· Continuous online gas component analysis

· Filter paper sampling analysis

· Continuous online particulate matter analysis

The functional components of the Gasboard-9802 mainly include dilution air filtration device, dilution channel, dilution exhaust heat exchange device, venturi tube combination, negative pressure fan, air bag sampling system, particle sampling system and main control system.

Features

· With a wide range of diluted exhaust flow options, it accommodates the testing of engines and vehicles powered by various fuels and with different displacements.

· Integrated with a high-performance heat exchanger and a venturi tube, it ensures precise control of diluted exhaust flow, guaranteeing system accuracy and stability.

· Combined with the constant temperature control function of the heat exchanger and the air bag cabinet, it effectively prevents the condensation of diluted exhaust.

· Equipped with a high-performance dilution air filter, it can meet the requirements for emission testing at ultra-low emission levels.

Benefits

· High Detection Accuracy: System error is less than 2% of reading, complying with Euro 6/7 standard.

· Maximum Adaptability: A variety of total exhaust flow levels are available for different displacement engines.

· Easy Serviceability: Modular design facilitates fast integration, minimal maintenance and easy upgrades.

· Compact Design: The compact design ensures equipment installation in high adaptation with other facilities such as engine and dynamometer on site.

Specifications

CVS Flow Rate: 1~12 m3/min; 3~24m3/min; 9~60 m3/min; 30~150m3/min

CVS Temperature Control: 40±5°C

Air Bag Sampling Flow Rate: 3L/min, 6L/min, 9L/min

CVS Configuration: Up to 8 gas bags configurable

Particle Sampling Flow: 35~65L/min

Environmental Conditions: Ambient temperature: 5~35°C; Relative humidity:<80%RH; Atmospheric pressure: 80~102 kPa

Certification Test

Complies with the latest emission regulations

EU: Euro 5/6, Euro 7

China: China 6, China 7

Applications

Engine manufacturers

Automotive manufacturers

Universities and research institutes

Authorized testing institutions