Automotive Energy-Saving Technologies

1. Definition and Strategic Positioning

Automotive energy-saving technologies encompass innovations and applications engineered to reduce vehicle energy consumption and lower carbon emissions across the powertrain, driveline, vehicle lightweighting, and energy management systems. Their primary objective is to maximise energy efficiency without compromising performance or safety, serving as a critical pillar in achieving the automotive industry's "dual-carbon" goals. According to the "Technology Roadmap for Energy Saving and New Energy Vehicles 3.0", internal combustion engines will remain an essential power source over the next 5 to 15 years, with energy-saving technologies progressing towards diversified power sources, maximised energy efficiency, and intelligent control strategies.

2. Engine Energy-Saving Technologies

The internal combustion engine remains the primary contributor to overall vehicle energy consumption, offering the greatest potential for efficiency improvements. Key technologies include:

• Gasoline Direct Injection (GDI): Injects fuel directly into the combustion chamber for precise fuel metering, delivering 2% to 5% better fuel economy over conventional multi-point injection (MPI) systems.

• Exhaust Turbocharging: Harnesses exhaust gas energy to drive a turbine and force more air into the cylinders, enabling engine downsizing while yielding 4% to 10% in fuel savings.

• Variable Valve Timing (VVT) and Atkinson Cycle: Optimises valve timing and adjusts intake volume to achieve an expansion ratio higher than the compression ratio, reducing fuel consumption by 2% to 8%.

• Variable Cylinder Management (VCM): Deactivates specific cylinders under light-load conditions to raise the operating efficiency of the active cylinders, cutting fuel usage by 3% to 8%.

• Exhaust Gas Recirculation (EGR): Re-routes a portion of exhaust gases back into the combustion chamber to slow the burn rate, reduce pumping losses, and allow higher compression ratios for improved fuel efficiency.

Looking ahead, dedicated hybrid engines are targeted to achieve a peak thermal efficiency of up to 48%, setting a definitive benchmark for future energy-saving powertrains.

3. Drivetrain and Low-Resistance Technologies

Driveline parasitic losses and running resistance represent another major source of energy consumption. Key solutions include:

• High-Efficiency Transmissions: Upgrading from a conventional 4-speed automatic (4AT) to an 8-speed unit (8AT) reduces fuel consumption by 6% to 8%; Dual-Clutch Transmissions (DCT) eliminate torque converter churning losses to achieve 2% to 7.5% in savings; Continuously Variable Transmissions (CVT) keep the engine operating within its sweet spot, improving efficiency by 2% to 6%.

• Low Rolling Resistance Tyres and Aerodynamic Design: Tyre rolling resistance accounts for roughly 35% of total driving resistance, making low rolling resistance tyres vital for cutting drag; every 10% reduction in aerodynamic drag improves vehicle fuel economy by approximately 4%.

• Vehicle Lightweighting: Every 10% shed from a vehicle's kerb weight delivers a 6% to 8% improvement in fuel efficiency, with advanced materials such as carbon fibre unlocking further weight-saving potential.

• Regenerative Braking: Recovers kinetic energy during braking via an electric motor to recharge the battery, capturing up to 80% of otherwise wasted braking energy in hybrid and fully electric models.

4. Intelligent Vehicle Energy Management

With the transition of electrical and electronic architectures towards domain control, energy-saving strategies have evolved from component-level tweaks to vehicle-wide holistic management. Intelligent vehicle energy management systems integrate multi-source inputs (such as road speed, gradients, traffic conditions, and driver inputs) and leverage AI algorithms to dynamically coordinate the engine, electric motor, high-voltage battery, air-conditioning, and other auxiliaries, ensuring optimal efficiency across varying driving scenarios. In hybrid vehicles, this ensures seamless interaction between the engine and electric motor; predictive energy management also uses navigation and cloud-based data to proactively manage battery charge and regenerative braking profiles across undulating terrain, further unlocking efficiency gains.

5. Future Trends

The "Technology Roadmap for Energy Saving and New Energy Vehicles 3.0" sets clear targets for 2040: the average fuel consumption of new internal combustion passenger cars is projected to drop to 3.5L/100km, while fleet average carbon intensity will fall by 60% compared to 2024 levels. As the primary technological bridge, hybrid powertrains will see ongoing breakthroughs in dedicated hybrid engines, dedicated hybrid transmissions (DHT), and integrated system architectures, driving the complete hybridisation of internal combustion passenger vehicles by 2035. In parallel, automotive efficiency benchmarks are transitioning from straightforward fuel economy metrics to comprehensive lifecycle carbon emissions, aligning with the industry's overarching carbon neutrality roadmaps.