2011
MINI model was October 28, 2010 listing, the same year in November, began selling in Beijing and other places. The models equipped with N18 engine, called N18B16MO. Where N represents the gasoline engine generation BMW Group, represents inline 4-cylinder, turbocharged with 8 represents a direct injection system, B for gasoline, 16 represents the displacement of 1.6 L, M for medium power levels, the representative newly developed O . The engine displacement without increasing the premise, technical updates improved performance, especially the power output of the ride made improvements, which will eliminate the slow response of the user complaints turbocharged engine power. The following technical publication highlights The engine is described briefly.
(1) intake
In order to improve engine performance and to ensure smoothness in the output torque, N18 engine with separate vacuum valve and an electronic pneumatic system.
① electric valve Valvetronic
FIG 1
during engine operation, since the throttle section is way flow of the intake air amount is controlled, so that the cylinder in the intake stroke, the cylinder will produce additional negative pressure (FIG. 1A), and the smaller the throttle opening, the larger this negative pressure, which increases the engine in the power loss low-load area. N18 uses an electronic engine intake valve mechanism, and the intake throttle valve opening degree is generally kept at a maximum engine operation, the throttle effect is small, thereby reducing the negative pressure (FIG. 1b) of the cylinder intake stroke, effective reduce power loss when the engine intake stroke. And reducing the throttling effect causes the air flow rate increases, so the acceleration response of the engine more quickly.
FIG. 2
N18 electric valve mechanism of the engine is increased by a servo valve lift mechanism (FIG. 2 in a conventional intake valve mechanism ). DME engine control unit drives the servo motor based on the position of the accelerator pedal, the eccentric shaft gears rotate, changing the torsion spring is connected to the intermediate position of the push rod via a worm drive to controlThe opening and closing time of the intake valve, the intake air amount changes, eventually leading to the engine torque and power with the change of the accelerator pedal varies. Servo motor operating current up to 40 A, the regulator must take measures so as not to affect the normal operation of lights and various control units. When the electronic valve fails, the throttle will immediately replace its function.
FIG. 3
② TwinScroll turbocharger
Fig 4
the turbocharger the exhaust gas stream into two groups (FIG. 4), a set of 4 cylinders airflow, another group of cylinders 2,3 airflow. 2, each group of gas streams retardation 360deg; (crank phase). Such flow disturbances can be reduced, the inertia of airflow sufficient to give more aerodynamic. When the engine speed is greater than 700 r / min, then quickly established turbocharger boost pressure, engine speed is 1 600 r / min, the maximum boost pressure, so that overcome the deficiencies of low-emission vehicles starting power defect.
③ vacuum pneumatic system
Figure 5
In order to obtain a smooth torque output, N18 engine is equipped with separate vacuum pneumatic system (FIG. 5) by the DME according to the position of the accelerator pedal to control the supercharging pressure.
(2) a cooling system
① turbo cooling pump pressure
Figure 6
Since the highest speed of the turbine of up to 200,000 r / min, up to a maximum temperature of the turbine chamber 1 050 ℃, so that the working conditions of the turbocharger very bad. To this end, the turbocharger is connected not only with the engine lubricating system, but also integrated in the engine cooling circuit (FIG. 6). Also it includes a turbocharger cooling pump (FIG. 7), which can be discharged vortexAccumulated heat in the turbochargers, the turbine journal so as to prevent oil coking phenomenon occurs at. Heat may also be discharged in the turbocharger when the engine turned off.
FIG. 7
② friction wheel actuator
Figure 8 [123 ]
N18 by the engine crankshaft driving pulley tape back, and then to drive the pump (FIG. 8) by a friction wheel. This can reduce the lateral forces applied to the pump shaft, the pump housing may thus be made entirely of plastic. Such plastic housing structures may improve the flow and efficiency of the pump.
by means of a friction wheel actuator moves the support rod controls the driving of the pump (FIG. 9), when the friction wheel does not contact the tape will not driven pump.
Figure 9
(3) the crankcase ventilation
To meet the N18 engine intake boost mode, a special design of the valve chamber cover (10). The intake manifold vacuum or overpressure two different state, the pressure regulating valve and two-way valve by the valve cover to the leakage of the cylinder chamber gas delivery according to the crankcase.
10
(4) duplex catalytic converter
FIG. 11
N18 engine uses two separate coating layer different catalytic core (FIG. 11), the exhaust emissions of the engine 2 after treatment in the catalytic converter, enough to meet the emission Europe ⅴ standard.
(5) The lubrication system
FIG. 12
N18 engine characteristic curve is the control of the new oil pump (FIG. 12), according to the conditions and the oil pressure sensor signal to control the output pressure of the engine oil pump, and oil is optimized.
(Huang Yang)