put on the market in summer 2009 Mercedes-Benz S400 HYBRID Mercedes – Benz’s first hybrid car, which is equipped with a 3.5 L V6 petrol engine with a compact hybrid module is enhanced. The model can generate 205 kW engine output power, the motor can produce 15 kW of power and 160 N? M starting torque, which causes the engine to achieve the overall power of 220 kW and 385 N? M of the maximum torque integrated. The car according to the new European driving cycle conditions overall fuel consumption (NEDC) is measured 7.9 L / 100 km, CO2 emissions of only 186 g / km. The use of hybrid drive technology enables the contradictions of power and environmental protection of the car be resolved, broken only small cars in order to achieve the conclusion of environmental protection. In this paper we will be the car’s hybrid system and main technical highlights are introduced.
First, the hybrid driving system overview
Benz S400 HYBRID hybrid vehicle is a motor (integrated starter and generator functions) as an auxiliary power of the engine driving the vehicle. At the start and acceleration conditions, the auxiliary motor, as compared to the same displacement of the vehicle, fuel consumption and CO2 emission improvements.
1. The composition of the hybrid system (FIG. 1)
FIG 1
Benz S400 HYBRID hybrid system components such as ( ) 1 shown in FIG. A motor directly connected to the engine, is used as a starter and generator, which provide power for starting a high-voltage battery. In this brief introduction to the effect of several high-voltage parts S400 HYBRID hybrid system.
(1) a high voltage battery (AlOO)
High voltage S400 HYBRID lithium ion battery technology, it is possible to store energy and to provide a high voltage DC power to the motor. During charging, use I / U charging mode, i.e. firstly charged at a constant current, and then charged at a constant voltage.
(2) a motor (A79)
can be used for the motor according to the working needs, respectivelyThe starter and a generator, the output power up to 15 kW, can produce up to 240 V AC voltage.
(3) DC / DC converter (N83 / 1)
DC / DC converter is a bi-directional DC voltage converter, whose role is to: stop the engine when the battery is 12 V power; auxiliary jump start the vehicle; high voltage battery power during support.
(4) Power electronic device (N129 / 1)
Power electronic device integrated AC / DC converter, which allows three-phase motor to operate on high voltage direct current onboard electrical system. For security design, the self-discharge which can be done within 1 s.
2. Function of the hybrid system
(1) the engine stop / start
at rest or when the vehicle speed below a minimum value, the engine will automatically shut down. When the accelerator pedal is depressed, releases the brake pedal or the high voltage battery power below a minimum value, the engine will automatically start.
(2) regenerative braking
The hybrid system is assigned to the braking torque and brakes the motor, when the motor as a generator, the excess braking torque into a high energy transmission voltage of the battery to charge. Motor
(3) boosting effect
The hybrid power system to provide support for the engine at the start or acceleration, when the engine is improved low speed torque assist.
Second, each of the vehicles to improve system
In order to achieve Benz S400 HYBRID hybrid technology, the major vehicle of this system are improved and upgraded.
The engine system 1.
Benz S400 HYBRID equipped with 3.5 L V6 engine is based on engine transformation from S350, adaptive valve timing. Transformation process, researchers use the advantages of the expansion phase of the Atkinson cycle is longer than the duration of the compression phase (the ultra-expansion ratio of an engine cycle increasing expansion engine), the intake and compression phase of the intake valve remains openTime is slightly longer, which aims to improve the thermal efficiency of the engine while reducing fuel consumption and reduce exhaust untreated.
In addition to optimizing torque and fuel consumption drive means (motor) by an additional motor, the control unit of the engine which, a cylinder head, a piston and fuel pumps member has been improved, so that the engine fuel consumption reduction At the same time, increased power 5 kW, reaches 205 kW, specific improvements include: an engine control unit to ME9.7 ME17.7, which is to meet the functional requirements of the hybrid; sporty engine cylinder head, the effect can be achieved better charging motion (tumbling motion); sporty engine piston, to some extent, reducing fuel consumption; using adjustable fuel pump, fuel consumption is reduced when the partial load.
2. The cooling system
In order to cool the power electronics and DC / DC converter, S400 HYBRID which is provided for cooling the engine cooling system low-temperature cooling circuit 2 independent elements (FIG. 2).
FIG. 2
As shown, when the ignition switch is turned on, power supply to the power supply 15 circulates through the electronic power electronics of the circulating pump relay K108 1 pump 1 (M13 / 8), M13 / 8 to work, build cryogenic cooling system pressure. Then, the engine control unit according to the temperature of the power electronics cooling system coolant to control the power of the electronic circulation pump relay power electronics circulation pump 2 (K108 / 1) 2 (M13 / 9) work, accurate to the cryogenic cooling system control.
3. A brake system
FIG. 3
S400 HYBRID brake system provided with a regenerative braking system (brake energy reproducing the RBS system) (FIG. 3), the hydraulic brake system by the motor regenerative braking achieved.
(1) a regenerative braking system works
As shown, driver’s braking intention is detected by the pedal angle sensor 3, and transferred to a regenerative braking system control unit N30/ 6. Continuously regenerative brake system control unit in communication with power electronics control unit, and issuing a braking torque request. The power supply unit transmits a signal to the electronic control unit controls the regenerative braking system, indicating how much regenerative braking torque may be absorbed. If the ABS system does not provide the correct requested braking torque or a regenerative braking system control unit issues a closing command, the regenerative braking system is closed.
The main function element (2) of the regenerative braking system
① brake pedal (FIG. 4)
Figure 4 [123 ]
pedal angle sensor B37 / 1 using a Hall sensor measuring the angular position of the brake pedal, and transfers the information to the regenerative braking system control unit N30 / 6 in the form of two signal voltages. Actuating the stop lamp switch signal is transmitted mixing S9 / 3 regenerative brake pedal to the brake system control unit N30 / 6.
② pedal force simulator valve (FIG. 5)
Figure 5
the pedal force simulator pedal force for activating the valve Y113 analog functions, or in the case of failure to deactivate. In normal operation, the solenoid is energized, the valve bore is closed at this time the pedal force simulator valve Y113 as a rigid, self-supporting, and therefore when the brake operation, the driver can sense the simulated pedal reaction force.
③ RBS brake booster vacuum pump and a motor
can be used in an engine and an electric vacuum pump to provide a vacuum brake booster for the RBS. RBS RBS brake booster solenoid valve is operated brake actuator, which is controlled by a solenoid valve unit controls the regenerative braking system.
Figure 6
RBS brake booster (Fig. 6) comprises a vacuum sensor RBS, RBS may be measured brake booster vacuum chamber the degree of vacuum; a stroke sensor diaphragm RBS, RBS brake booster for recording the position of the diaphragm plate.
Figure 7
Electric trueVacuum pump (FIG. 7) by the regenerative braking system control unit N30 / 6 control, to maintain the vacuum in the brake booster, and maintaining the start / stop mode of the vacuum supply.
(3) regenerative braking mode of operation of the system
① regenerative braking mode
As shown in FIG. 3, the reproduction absorption torque during braking, the RBS solenoid valve is not activated, the requested brake torque generated by the motor. At this time, the motor as a generator, the generated braking energy into electrical energy, does not participate in the brake hydraulic brake. And when the regenerative braking system control unit actuates the pedal force simulator valve Y113, the pedal force of the pedal simulator of resistance, and therefore, although no working hydraulic brakes, the driver can still feel the brake pedal similar to the usual force feedback.
added hydraulic regenerative braking mode ②
In this mode, the regenerative braking system control unit actuating pedal force simulator valve Y113, the pedal force of a pedal simulator of resistance; the RBS solenoid valve A7 / 7y1 unit actuation control by the regenerative braking system, and therefore increase the brake pressure in the brake hydraulic pressure, regardless of the pedal position; free path 3 is not completed at this time, a part of the regenerative braking torque generated by the motor.
The hydraulic brake mode ③
If the braking torque can not be absorbed regenerative braking system, the regenerative braking system control unit actuates the pedal force simulator valve Y113, the pedal force simulator pedal simulation resistance; the RBS solenoid valve A7 / 7y1 regenerative braking system actuation control means. In this case, Y113 will enable a feature to increase the braking force of the hydraulic brake, this time 3 free travel has not ended.
④ hydraulically assisted
In case of an emergency braking or failure information, the regenerative braking system control unit is no longer actuated pedal force simulator valve Y113. At this time, the free end of travel 3, the brake booster A7 / 7 directly actuated by the brake pedal, and brake pressure is increased is generated using the traction system hydraulic unit A7 / 3 and the brake booster.
4. The automatic transmission system
Benz S400 HYB722.950 gear 7 mounted RID automatic transmission which for the hybrid drive has been improved. In addition to the new transmission control software also uses the transmission electric assist pump, and the torque converter and torque converter housing also improved.
(1) Power transmission auxiliary pump
Benz S400 HYBRID using electrohydraulic control by the automatic transmission and the oil pump shaft driven by the engine, when the engine is stopped, the oil supply is interrupted this causes all the control elements and actuators are unloaded into the standard state and the automatic transmission is no longer working. Thus, when the engine is started again, since the establishment of the hydraulic transmission is not timely, block D when engaged, causes the start operation delay, this situation may be improved by using the transmission power assisted pump.
Figure 8
The transmission power assisted pump integrated transmission sub oil pump control unit N89 (FIG. 8), located the following transmission bell housing. The pump performs two functions: ensure transmission oil is supplied to the hydraulic system when the engine is turned off; hot idling in the coasting downshift mode during the main pump support.
The air conditioning system
Figure 9
Benz S400 HYBRID air conditioning system also made some improvements for the hybrid driving system, the installation of a refrigeration compressor for holding an electric vehicle interior and cooling of the high-voltage battery cooling (FIG. 9) when the engine is turned off.
10
High voltage battery cooling operation process (FIG. 10): battery management system BMS control unit analyzes the sensor from the high voltage battery cell temperature data, calculate an instant high voltage battery temperature; when the temperature exceeds the standard range, a battery management control unit sets the high voltage battery temperature state of the transmission by an engine control unit N3 / 10 and the central gateway controlling unit N93 to the air conditioning control unit; air conditioning control high-voltage battery unit activates the cooling function by the engine control unit CAN ON battery management system bus control unit and the electric refrigerant compressor; air conditioning shut-off valve Y19 / 1 open, the refrigerant flowing through the battery management system integrated in the control unit of the evaporator, the heat radiated from the high-voltage battery.
6. The steering system
11
In order to achieve still providing adequate steering assist even when the engine stops automatically the separate power steering and engine to ensure that independent power steering. Benz S400 HYBRID from the power steering gear – rack steering adjustment itself, motor mechanism A91 / 1 (FIG. 11) of the steering pump hydraulically by electro-hydraulic power steering. With such an improved steering system, while also reducing fuel consumption.
(high cloud Chuyi Min)