Ford Motor Company powertrain new Ford Mondeo car upgraded, using 2.0GTDI turbocharged direct injection gasoline engine exhaust gas and a direct shift dual clutch transmission, in order to facilitate the readers to understand the new engine, in this brief introduction to its engine, we want to help.
A mechanical system
FIG 1
The engine (FIG. 1) using the inline 4 cylinder arrangement, with integral BorgWarner turbocharger (BWTS) an exhaust manifold, dual variable valve timing mechanism, an improved cylinder block cooling water (first cooling gas ring), aluminum oil cooling , a cast iron crankshaft and balance shaft.
Second, the fuel injection system
In the past fuel injection system, the injector in the intake manifold injector, the fuel is injected into an intake port, injection come into contact with the fuel injector and a port surface, which causes the fuel to condense element surfaces, thereby forming a wall film, film loss occurs wall. Direct injection systems with little impediment to the flow of fuel, so that the loss of wall film is relatively low, a positive influence on the combustion of fuel and emissions. For intake manifold injection supercharged engine, a major problem is how to reduce the tendency of engine knock. High-temperature exhaust gas is reduced additional fuel injection, although this measure reduces the temperature, but will lead to increased fuel consumption and exhaust gas is too thick, and therefore produce very high emissions. The temperature of the combustion chamber is reduced by the fuel injection, compared to a similar intake manifold injection supercharged engine, thus increasing the geometric compression ratio and engine efficiency. Since the fuel injection system can control the angle of the intake cam, an intake cam angle changed by selectively, it can influence the actual compression ratio of the combustion chamber. Close to full load operating point when the excess air suction intake pipe is pushed back. If knocking tendency to fall again, the compression ratio can continue to increase, which further increase the efficiency at part load. GDI highest percentage fuel savings of up to 20, and there is a large potential for development.
1. Structures
Fuel injection systems using no return in the form of an oil systemBy the low pressure fuel pump, the high-pressure fuel pump, oil pressure sensor, and a tubing injector (Figure 2).
FIG. 2
(1) a low pressure system
FIG. 3
FIG logic low voltage control system shown in Fig. Pump Control Module (the FPDM) of the battery voltage supplied by the GEM, PCM transmission transmits a high frequency signal to a low frequency signal FPDM, FPDM oil feed pump (FP), a low-pressure closed-loop control by the fuel pressure sensor. An oil passage provided with a check valve, which is opened when the hydraulic pressure generated in the oil pump reaches 125 kPa. A standard low-pressure fuel pressure range is 380 ~ 620 kPa, when the engine is idling, hydraulic stability in the 320 ~ 340 kPa. Overvoltage protection valve opens at 830 ~ 930 kPa, the relief valve is used to remove fuel vapor tubing.
(2) a high pressure system (FIG. 4)
Figure 4
① high-pressure pump (FIG. 5)
Figure 5
[123 ] is a single high-pressure oil pump, driven by an exhaust camshaft, with the metering valve into the oil, the oil pressure of the oil pump 15 MPa. The main high-pressure pump includes a piston, the oil inlet metering valve (the IMV), the high pressure chamber, the hydraulic pressure limiting valve, and a pneumatic pressure buffer the pressure limiting valve (FIG. 6).
FIG. 6
a. A pressure limiting valve (FIG. 7)
7
when the oil pressure reaches 20 MPa, the pressure limiting valve opens the relief.
b. A pressure buffer (FIG. 8)
Figure 8
A pressure damper damping pulse vibrations generated by the low-pressure line in the high-pressure pump, thus ensuring the high pressure chamber when the engine speed is relatively high also have good oil-filled effect. Pressure buffer layer 2 by the membrane composition, an air cushion between the two layers in the separator.
c. Inlet metering valve
Figure 9
is provided on the high pressure pump into the oil metering valve (the IMV), to ensure that the pressure of the fuel rail into which the hydraulic pressure is consistent with the desired, closed-loop control (FIG. 9, FIG. 10) by a rail pressure sensor.
10
Further, the adaptive power control function comprises IMV, the IMV switching noise and idle current can be reduced consumption. Reduction of negative ground IMV duty control voltage, thereby reducing the current IMV, IMV in an open inoperative state. If the rail pressure decay, IMV work under control of the PCM. Adaptive control in the engine operating condition is idling Moreover, hydraulic pressure is kept constant.
IMV time-controlled energization exceeds 3 s duration will result in damage to the IMV, so do not use an external power supply.
is a part of the fuel metering valve of a high pressure pump, can not be replaced individually, when the valve fails, the entire high pressure pump must be replaced as a whole. The fuel metering valve in an open state when power is lost, can not produce high-pressure fuel. After the failure of IMV high pressure pump does not work you can still pump oil, but oil will be lower than normal.
② oil pressure sensor
After disconnecting the rail pressure sensor, in an open loop IMV failure mode, the PCM IMV no longer controls, the rail pressure pre set pressure.
③ injector
11
This engine uses a 7-hole injector (FIG. 11), the state of fuel atomization in shape and angle can be adjusted, to a fuelA spray angle injected into the combustion precisely calculated, so the injector orifice eccentrically employed. Precision fuel injection at an angle to prevent any fuel injector spray opening, seven conical mist can adapt individual condition of the combustion chamber, resulting in such a state of fuel atomization gas mixture formed in the combustion chamber is more advantageous.
When the PCM generating a magnetic field to the coil is energized, the needle against the force of the spring so that the valve is lifted from the valve seat to open the fuel injection hole. Due to the pressure difference between the rail and the pressure in the combustion chamber, the fuel will be injected into the combustion chamber. When de-energized, the valve needle by the spring force of the back pressure valve, the fuel injection end. Since the injection timing of the direct injection engine occurs during the intake stroke, petrol and air mixing time is shorter, it requires direct injection engine fuel injection duration as short as possible.
injection amount
depends on the opening time of the fuel rail and the injector pressure , PCM control of fuel injection by a square wave control signal. PCM to issue digital control signal, the amplifier circuit via the digital control signal into an analog control voltage signal is passed to the injector, the initial DC converter control signal into a voltage 65 V, the high acceleration voltage to 65 V for injection an opening is necessary. When the injector needle fully open, only a lower voltage than the opening of the valve can be maintained needle.
orifice design requires precise eccentricity correction injector when the injector is mounted, must pay attention to the installation location. Plastic plug must be inserted into each injector slot on the rail, the retaining clip must be installed in the correct position. On each injector and the rail on each holder has a retaining clip, the retaining clip for fixing a fuel injector, which ensures that the combustion chamber and the cylinder head on the injector openings fit precisely .
2. Operating modes
(1) the homogeneous mode (FIG. 12)
12
When the engine is when the normal operating temperature, gas mixture generated in the homogeneous operating mode. In this mode, fuel injectionAccording to the theory and exit of fresh air amount ratio 14.7: 1 accurate calculation of the fuel injection in the intake stroke, so that there is sufficient time so that all the remaining steam mixed uniformly mixed. In the homogeneous mode of operation, equivalent to a large extent the combustion intake manifold fuel injection combustion mode.
(2) catalytic converter heating operating mode (FIG. 13)
13
When the engine temperature when low, the catalytic converter heating operating mode can be used to provide a fast secondary injection of heated catalytic converters. Like the first injection from the homogeneous operating mode the intake stroke starts, the second time occurs at the compression stroke injection when the intake valve closing quickly, thus formed around the oil core of a concentrated around the ignition plug. The ignition timing is delayed, so that a combustion heat as much as possible can enter the exhaust pipe, to reach the three-way catalyst.
Third, the exhaust gas turbocharger system
14
The engine uses the exhaust exhaust manifold integral with a turbocharger system (FIG. 14), the specific configuration shown in Figure 15.
FIG 15a
FIG. 15b
(1) by intermediate pressure control solenoid valve
exhaust gas turbocharger boost pressure by a pressure control system of the solenoid valve, the maximum boost pressure of 120 kPa, the engine control unit by adjusting the duty signal boost pressure. Vacuum pressure control actuator duty ratio of the energization voltage boost depends on the pressure and the solenoid valve. When the duty ratio of 80% to 90%: exhaust throttle fully open; when the duty ratio is 20%, the exhaust damper is fully closed.
(2) Press damper
return damper is a mechanical device, controlled by a pressure difference, is to prevent the turbine in a case where the throttle valve is abruptly closed speed of the turbocharger decreases. Because of the sudden closing the throttle will result in the space between the throttle valve and a turbocharger wheelBack pressure, turbocharger impellers and therefore will be lead to strong braking, braked large turbocharger boost pressure loss, and when the next need to produce a supercharging effect power losses. With return valve, can be prevented if the sudden closure of the throttle when the back pressure.
return damper will open at a pressure difference between both sides of the supercharging pressure and the intake manifold when more than 24 kPa.
(3) an air flow meter (the MAF)
for metered air flow meter of the intake air amount of the engine, the PCM signal calculated by the fuel injection time, the fuel pressure, ignition timing, turbo boost pressure, engine load and shift control TCM. If the MAF fails, the system will be used as an alternative to the MAP sensor signal is used to calculate the intake air amount signal. MAF supply voltage for the battery, the voltage signal is 0 ~ 5 V.
PCM metered flow of air through the monitoring signal frequency, the frequency of the signal with increasing air flow rate and improved. If signal failure, PCM will use a fixed value of 25 deg.] C in place of the signal.
(4) MAPT sensor
MAPT located at the outlet of the cold, PCM, and by the air pressure and temperature sensor measurements after pressurization. If the sensor fails MAPT, the PCM to obtain the air pressure information can not be pressurized, the PCM is no longer controlled supercharging system in this failure mode, the boost solenoid will remain in a state of not working.
When the duty ratio of the boost control solenoid MAPT PCM failure ground control valve 98 is constant percentage, which limits the maximum boost pressure of the turbocharger.
(5) the intake manifold pressure (MAP) sensor
the MAP sensor is located into the upper manifold, the sensor MAFT (air flow and the intake air temperature sensor) together, for calculating the air flow rate.
(Wong Sin)