China Light-duty Vehicle Test Cycle

The China Light-duty Vehicle Test Cycle (China Automotive Test Cycle, or CLTC) is China's official test standard for measuring fuel consumption and exhaust emissions in light-duty vehicles (vehicles with a maximum permissible gross vehicle weight not exceeding 3.5 tonnes, including passenger cars and light commercial vehicles). With the rapid growth of the Chinese automotive industry and the widespread adoption of traffic big data, the CLTC has completely superseded the European NEDC cycle that was previously used for years. Developed from hundreds of millions of kilometres of real-world driving data across typical Chinese cities, it accurately reflects local driving behaviours, speed variations, and idling durations across urban, suburban, and highway conditions, delivering fuel economy, driving range, and emissions figures that closely mirror real-world driving.

Core Technical Architecture and Drive Cycle Characteristics

The CLTC technical framework is built upon extensive real-world driving data mining, combined typical driving phases, and dynamic speed-time profiles across diverse speed ranges:

Multi-Scenario Dynamic Segmentation and Local Traffic Characteristics: 

The CLTC test comprises three distinct driving phases: CLTC-A (urban low-speed, low-load), CLTC-P (suburban medium-speed, medium-load), and CLTC-R (highway high-load). The complete cycle runs for 1,800 seconds across a total test distance of approximately 14.5 km. Compared to the outdated NEDC standard, the CLTC incorporates significantly more stop-and-go traffic, frequent braking, low-speed crawling, and prolonged idling typical of Chinese city driving. This results in a lower overall average speed alongside more aggressive and frequent acceleration and deceleration cycles.

Adaptability for Multi-Energy Powertrain Testing:

Beyond fuel consumption and emissions homologation for conventional internal combustion engine vehicles (ICEVs), the CLTC serves as the sole statutory benchmark in China for evaluating the combined driving range of new energy vehicles (NEVs), including battery electric vehicles (EVs), plug-in hybrid electric vehicles (PHEVs), and extended-range electric vehicles (EREVs). By accurately simulating real-world regenerative braking patterns as well as thermal loads from climate extremes and air-conditioning systems, it sets stringent dynamic benchmarks for electric drivetrain efficiency and battery management systems (BMS).

Safety Guidelines and Physical Constraints

Prohibiting Blindly Trusting Laboratory CLTC Range Ratings Without Accounting for Extreme Climate Loads:

The official CLTC range represents ideal laboratory figures achieved under controlled ambient temperatures and standardised rolling resistances. Drivers must never rely strictly on nominal full-charge CLTC ratings when planning long-distance road trips while running high-power cabin heating in sub-zero winter or full-blast air conditioning in scorching heat. Real-world range drops substantially due to cold-weather battery capacity degradation and heavy auxiliary loads from PTC heaters or heat pumps; always factor in sufficient charging margins. 

Prohibiting Ignoring Real-World Efficiency Degradation After Modifying Tyres or Aerodynamics from Factory CLTC Specs: 

CLTC homologation benchmarks apply strictly to vehicles in their stock factory aerodynamic and mechanical rolling configurations. Violating basic vehicle physics—such as fitting aftermarket oversized or ultra-wide tyres, roof racks, or heavy off-road body kits—substantially worsens rolling resistance and aerodynamic drag. These modifications disrupt the factory-optimised energy balance, leading to real-world fuel or power consumption that is markedly higher than official published figures.