Car modification-modification of fuel injection system[汽车改装知识]

carThe fuel injection system is composed of a fuel delivery system, a sensor system, and an electronic control system. The working principle is very simple: the gasoline is pressurized with a gasoline pump, fromtankIt is sent to the high-pressure oil circuit and adjusted by the pressure regulator to maintain the oil pressure in the system at 2.5-3.0kg/cm2. At the same time, each sensor transmits the engine's air intake and operating status to the engine in the form of electronic signals Electronic control unit (ECU: Electronic Con-trol Unit), ECU analyzes the signal according to the signal, calculates the required fuel injection volume, and then transmits the fuel injection signal to the solenoid coil of the fuel injector. The fuel valve, gasoline is injected into theValveForwardIntake manifoldInto the cylinder with the opening of the intake valve.
It is generally believed that the best air-fuel ratio of the engine is 14.8:1 (under this ratio, the engine can be considered the most environmentally friendly and theoretically can achieve complete combustion), but at highRotating speed, In order to obtain higher engine power at high load, the air-fuel ratio should be increased to 12:1-13:1. The purpose of refitting the fuel supply system is to'increase the fuel supply in an appropriate amount when appropriate'.
The modification of the fuel supply system can be divided into two categories: hardware modification and software modification. Hardware modification is usually the modification of mechanical components to increase the fuel supply per unit time. The software modification is mainly to change the fuel supply computer program, because the original car manufacturer's supply The oil computer program is set in consideration of exhaust gas control, fuel consumption economy, operational stability, etc., so in terms of power output performance, it is impossible to achieve'performance first'. In the case of high speed and high load, Often there is the embarrassment of insufficient fuel supply. In this case, you must rely on changing the fuel supply computer program to achieve the effect of modification. Okay, let's take a look at the specific components that can be changed.car repairMaintenance net
1. Pressure regulator
Let's first look at the pressure regulator, which is responsible for providing a fixed pressure to the injector in the multi-point injection system. In theory, the greater the pressure, the more gasoline will be ejected during the same injection time, and the fastest way to change the oil pressure It is to install an adjustable pressure regulator. This type of pressure regulator has a vacuum tube. It can adjust the oil pressure by changing the vacuum in the intake manifold according to the load of the engine, so that the oil pressure of the engine is under low load. Lower, and the oil pressure rises at full load to meet the pressure and fuel injection volume required by the fuel injector.
2,Pressure regulating valve
The pressure regulating valve (the city's'fuel pressure regulating valve') is the fuel return device installed behind the pressure regulator. After installation, the fuel injection pressure of the fuel injector can be increased (generally 20%), so as to achieve the same In the case of fuel supply mode, the fuel injection volume can be increased by 5%-10%. The pressure regulating valve can increase the power output in the full speed range.Intake and exhaust system, Cars that require high fuel supply in the high-speed area are very helpful. The installation of an adjustment valve is still the least expensive of the fuel supply system modification parts, but after the installation, it will increase a certain amount of fuel consumption. This is also often said'Yes There will be gains and losses'.
3. Fuel injector
The caliber of the fuel injector determines the fuel injection volume per unit time, and changing to a larger caliber injector is the most direct way to increase the fuel injection volume, but the size of the replacement caliber depends on the degree of engine modification. Nozzle modification is not difficult. The biggest difficulty is to find a matching injector. Usually, the injectors of the same car series or the same series of engines can be matched with each other. The fuel injection volume brought by the modified injectors is increased. It is comprehensive, that is, the fuel injection amount will increase from low to high speed, which may cause excessive fuel supply at medium and low speeds, resulting in increased fuel consumption and poor operation. Usually, the engine is greatly affected. After the modification, the fuel injection time required at high speeds is longer than the intake time of the engine running one stroke, which causes the fuel injector to continuously inject fuel and cannot provide sufficient fuel. At this time, increase The nozzle caliber is the only choice.