Diesel Fuel Injection Pump 0 445 020 045 0445020045 Engine Auto Engine Part

Technical classification and core applications of oil pumps
According to the power source, control method and application scenario, oil pumps can be divided into three categories, and their technical characteristics and applicable scenarios are significantly different:
1. Mechanically driven oil pump (traditional fuel system)
Principle: driven by the engine camshaft or gear, relying on mechanical structures (such as plungers, eccentric wheels) to control fuel pressure and flow, and the pressure changes linearly with the engine speed.
Typical types:
Gear pump: a pair of gears mesh to generate negative pressure oil suction, simple structure, low cost, often used for low-pressure oil delivery (such as pre-supply from the fuel tank to the high-pressure pump, pressure ≤0.5MPa), but the flow pulsation is large.
Plunger pump: the plunger reciprocates in the cylinder to compress the fuel, and the pressure can reach 10-20MPa. It is widely used in traditional diesel engines (such as inline pumps, distribution pumps), but the pressure control accuracy is low (error ±5%).
Vane pump: The vanes on the rotor fit with the pump housing under the action of centrifugal force to form a sealed cavity, with stable flow, mostly used for low-pressure fuel supply in gasoline engines (pressure 0.3-0.5MPa).
Limitations: It is impossible to adjust the pressure independently of the engine speed, and it is difficult to meet the high-precision injection requirements (such as multiple injections). It has been gradually replaced by electronic control systems.

Electronically controlled high-pressure oil pump (core of common rail system)
In order to adapt to the "high pressure, precision, and flexibility" injection requirements of the common rail system, electronically controlled high-pressure oil pumps have become mainstream. Its core is to control the fuel pressure independently from the engine speed. The typical technical features are as follows:

Pressure level: The pressure of the diesel common rail oil pump has increased from 160MPa in the early stage to 200-300MPa (such as Bosch CP4.2 pump pressure 250MPa), and the gasoline direct injection (GDI) oil pump has been upgraded from 20MPa to 35-50MPa (such as Continental HDP5 pump).
Structural innovation:
Multi-plunger design: 2-4 plungers are used to work alternately (such as 3 plungers for Bosch CP3 pump), reducing flow pulsation, and pressure fluctuation ≤±2MPa.
Integrated control valve: built-in pressure control valve (PCV) and flow metering unit (FMU), real-time adjustment of fuel supply through ECU signal (response time ≤10ms), and realization of common rail pipe pressure closed-loop control (accuracy ±1MPa).
Applicable scenarios: diesel vehicles (heavy trucks, passenger cars), gasoline direct injection engines, which are standard for national VI and above emission regulations.

Special scenario oil pump
Hybrid dedicated oil pump: for the "frequent start-stop, partial load" working conditions of the hybrid system, a low-inertia drive motor (such as the electric high-pressure pump of Toyota THS system) is used to maintain high pressure (such as 35MPa) when the engine is stopped, and the response time is shortened to 5ms.
Alternative fuel pumps: Special pumps suitable for biodiesel, methanol, and hydrogen fuels need to solve the corrosion problem (such as using 316L stainless steel plungers) and low-viscosity seals (such as PTFE coatings). For example, Weichai's methanol engine pump pressure reaches 180MPa.

2. Core breakthrough direction of oil pump technology

1. Ultra-high pressure and pressure stability control
Breakthrough in pressure limit: By optimizing the plunger pair (gap ≤ 0.001mm) and pump body strength (forged with 42CrMo4 alloy steel), the diesel oil pump pressure sprints to 300-400MPa (such as DENSO's 300MPa pump has been mass-produced), and the gasoline GDI oil pump breaks through 80MPa (Bosch HDP8).
Pulsation suppression technology:
Using a symmetrical double-plunger arrangement (such as Continental's 2-plunger pump), flow pulsation is reduced by 60%;
The common rail pipe has a built-in pressure storage chamber (volume ≥50mL) and a damping hole, and the pressure fluctuation is controlled within ±0.5MPa to ensure the consistency of the injector spray.
2. Electronic control accuracy and energy efficiency optimization
Closed-loop control upgrade: ECU uses real-time feedback from the common rail pressure sensor (sampling frequency 1kHz) and combines fuzzy PID algorithm to adjust the PCV valve opening, and the pressure control accuracy is increased from ±3MPa to ±0.5MPa (such as Weichai WP13H engine).
Low power consumption design:
Adopt variable displacement technology: When partially loaded, the oil supply is reduced by eccentric wheel offset (mechanical pump) or plunger stroke shortening (electronically controlled pump), and the power consumption is reduced by 30% (such as the "on-demand oil supply" mode of Bosch CP5 pump);
The electric oil pump adopts permanent magnet synchronous motor (efficiency ≥ 95%) to replace the traditional DC motor (efficiency 70-80%), such as the electric high-pressure pump of BYD DM-i system.
3. Innovation of materials and manufacturing process
Wear-resistant and corrosion-resistant materials:
Plunger pair: adopt tungsten carbide (WC) based cemented carbide (hardness HRC ≥ 90), with titanium nitride (TiN) coating, the wear rate is reduced by 80%;
Pump body: use austempered ductile iron (ADI), the strength reaches 1200MPa, and the weight is 20% lighter than the steel pump body.
Precision manufacturing process:
Plunger hole processing: Honing + electrolytic polishing, surface roughness Ra≤0.02μm, to ensure sealing performance;
3D printing application: The pump body flow channel adopts laser selective melting (SLM) technology, and the flow resistance is reduced by 15% (such as the GDI oil pump of Porsche 911 GT3).

Intelligence and diagnostic technology
Real-time status monitoring: Built-in temperature, pressure, and vibration sensors transmit data through the CAN bus, and the ECU can identify faults such as "stuck, leak" (such as pressure deviation > 5MPa triggers an alarm).
Predictive maintenance: Combined with big data analysis, the life is predicted by the plunger wear (based on the pressure decay rate), and the replacement cycle is warned in advance (error <50 hours), such as Cummins' "Connected Diagnostics" system.

3. Future technology development trends
1. Higher pressure and full-domain adaptability
Goal: Diesel oil pumps break through 400MPa, gasoline GDI oil pumps reach 100MPa, and ultra-high pressure is used to achieve fuel atomization particle size <5μm (currently about 10μm at 200MPa), further reducing particulate matter (PM) emissions.
Adaptation to extreme working conditions: Develop -40℃ low-temperature start (viscosity adaptability) and plateau (altitude 5000m) pressure compensation technology to ensure pressure fluctuation ≤±1MPa.
2. Electrification and integration
All-electric oil pump: Replace mechanical drive, directly control the plunger through the motor (such as Bosch's eHighPressurePump), and increase the response speed to 1ms, adapting to the "no engine idling" scenario of autonomous driving.
System-level integration: The oil pump, high-pressure oil rail, and injector form a "three-in-one" module (such as Denso's "common rail assembly"), which is 40% smaller in size and 60% less in leakage points.
3. Alternative fuels and new energy synergy
Adaptation to e-fuel (synthetic fuel), hydrogen internal combustion engine: Develop chemically resistant pump materials (such as Hastelloy) and low friction seals (such as graphene coating), and the hydrogen fuel pump pressure must reach 70MPa or above (to ensure hydrogen atomization).

Hybrid system deep integration: Collaborate with the motor controller to reduce the power consumption of the oil pump during the energy recovery phase (such as the "intelligent energy supply" mode of the Ideal L series, the power consumption of the oil pump is reduced by 40%).

Carbon neutrality-oriented energy efficiency improvement
Goal: The total efficiency of the oil pump (mechanical efficiency + volumetric efficiency) is increased from the current 85% to 95%, which is achieved through fluid mechanics optimization (CFD simulation flow channel design) and magnetic suspension bearings (replacing mechanical bearings, friction loss is reduced to 0).

Lightweight: Use carbon fiber composite materials (such as the auxiliary oil pump of the BMW iX), reduce weight by 50%, and further reduce energy consumption.