What is the principle of the China VI engine?

[SophieRose]

China VI engine works on the same principle as other engines. China VI refers to the vehicle emission standard and has no relation to the working principle of the engine. The working principle of all engines is the conversion of other forms of energy into mechanical energy, with the automotive engine specifically converting chemical energy into mechanical energy. Working principle of automotive engine: By burning fuel in the cylinder, kinetic energy is generated, driving the piston inside the engine cylinder to reciprocate. This motion is transmitted to the connecting rod attached to the piston and the crankshaft connected to the connecting rod, causing them to perform reciprocating circular motion around the crankshaft center, thereby outputting power. A four-stroke gasoline engine mixes air and gasoline in a certain proportion to form a good mixture, which is drawn into the cylinder during the intake stroke. The mixture is then compressed, ignited, and burned to produce thermal energy. The high-temperature and high-pressure gas acts on the top of the piston, pushing it to perform reciprocating linear motion, and mechanical energy is output externally through the connecting rod and crankshaft flywheel mechanism. A four-stroke gasoline engine completes one working cycle during the intake stroke, compression stroke, power stroke, and exhaust stroke. Compared with China V, China VI has added DPF and DOC treatment technologies. When the engine is working, it reduces the particulate matter and nitrogen oxide components in the emissions, making it more environmentally friendly.

[DeStephen]

The core of China VI engines lies in triple-method emission reduction. Firstly, combustion optimization: utilizing high-pressure direct injection technology to achieve finer fuel atomization and more uniform air-fuel mixing, ensuring cleaner combustion with minimal soot. Secondly, upgraded aftertreatment systems – notice that large section of the exhaust pipe? It houses a Diesel Particulate Filter (DPF) capturing over 90% of carbon soot. This is followed by Selective Catalytic Reduction (SCR) using urea to break down nitrogen oxides into harmless nitrogen and water, plus an oxidation catalyst for unburned gases. Thirdly, an onboard diagnostic brain with sensors monitors emissions in real-time, triggering alerts if levels exceed standards. This integrated approach makes exhaust cleaner than the air we breathe.

[Jude]

In simple terms, it's about controlling at the source first and then purifying at the tail end. The engine itself employs thermal management technology, such as twin-scroll turbocharging for more efficient air intake, paired with ultra-high-pressure fuel injection above 350Bar, ensuring complete combustion of gasoline and naturally reducing carbon deposits. The exhaust side is where the real action happens. I've seen DPF filters dismantled in repair shops—their honeycomb structure is densely packed, trapping particles even one-twentieth the size of a human hair. The SCR system works in tandem with urea solution, which decomposes into ammonia at high temperatures, converting toxic nitrogen oxides into water vapor in the catalytic converter. Environmental temperature and pressure sensors installed on the vehicle autonomously adjust the operating state, so even cold starts in winter won't lead to excessive emissions.

[OCali]

The essence lies in the coordinated operation between the combustion chamber and the aftertreatment system. The intake system is upgraded with a low-inertia turbocharger, paired with precise EGR (Exhaust Gas Recirculation) to lower combustion temperatures and reduce nitrogen oxide formation. The aftertreatment process follows a three-step sequence: for diesel vehicles, the DOC (Diesel Oxidation Catalyst) first treats carbon monoxide, then the DPF (Diesel Particulate Filter) traps particulate matter, and finally, the SCR (Selective Catalytic Reduction) injects urea to break down nitrogen oxides. Gasoline vehicles primarily rely on an enhanced three-way catalyst paired with an actively regenerating GPF (Gasoline Particulate Filter). The vehicle is equipped with 15 sensors to monitor emissions. If the OBD light on the dashboard illuminates, it indicates an issue with the exhaust treatment system, necessitating prompt maintenance.

[DeMolly]

A comprehensive overhaul from the fuel tank to the exhaust pipe. The fuel supply system employs piezoelectric injectors with precision control at the 0.1 millisecond level, coupled with multi-stage injection strategies to ensure complete gasoline vaporization. The exhaust manifold is integrated into the cylinder head to accelerate warm-up, reducing cold-start emissions by 70%. The key lies in the aftertreatment section: gasoline vehicles feature precious metal-coated three-way catalytic converters and actively regenerating GPFs in their exhaust pipes, trapping 99% of particulates like filters; diesel vehicles utilize a DOC+DPF+SCR trio. The system monitors exhaust composition every 0.1 seconds, with urea pumps automatically adjusting injection volume based on nitrogen oxide concentration, achieving precision comparable to medical infusion devices.

[LaZachary]

The implementation principle is precise control plus catalytic magic. Inside the engine, the Miller cycle delays the closing of the intake valve, reducing the compression ratio to mitigate knocking and save fuel. The post-processing system showcases the real high-tech: the DPF filter core is made of cordierite or silicon carbide, capable of withstanding the 600°C high temperature during regeneration; the SCR catalyst's vanadium-based coating acts like a converter, magically transforming ammonia and nitrogen oxides into harmless substances. The vehicle is equipped with nitrogen oxide sensors that provide real-time feedback data to the ECU. If the sensors detect excessive emissions, the system directly limits speed to protect the environment. However, installing these devices increases the vehicle's weight by approximately 50 kilograms.