ELECTRICAL POWER STEERING ( EPS )

ELECTRIC POWER STEERING EPS BEKERJA BERDASARKAN KECEPATAN KENDARAAN DAN TENAGA PUTAR PENGEMUDI PADA STEERING WHEEL YANG SELANJUTNYA DIKONVERSIKAN SECARA KELISTRIKAN DAN DIKONTROL OLEH MIKRO KOMPUTER ( CONTROL MODULE ) EPS TIDAK LAGI MENGGUNAKAN POWER STEERING OIL PUMP TETAPI MENGGUNAKAN SEBUAH MOTOR DC YANG DIKONTROL SECARA ELECTRIC.

KELEBIHAN EPS Kehilangan tenaga mesin sangat kecil Konsumsi bahan bakar lebih irit Lebih ringan dan kompak Sistem power steering bekerja berdasarkan kecepatan kendaraan Mudah dalam pemeriksaan bila terjadi kerusakan Lebih aman

3-1.Lokasi Komponen -A pinion-assistant type EPS system is employed. -The EPS system is sensing vehicle speed. -The EPS system is controlled at all vehicle speed range. -By employing the pinion-assistant type, EPS motor is unified with steering gear box. -EPS control module is separated from the steering column assembly.

-Steering system yang baru dikembangkan The steering gearbox was newly developed. It has superior mounting rigidity that helps to realize a positive steering feel. Plus, the power-assistance unit is located outside the cabin so the cabin is relatively quiet.

KOMPONEN UTAMA EPS Steering wheel Steering column assy.(motor dan clutch) Rack and Pinion Power Steering Control Module (PSCM) Vehicle Speed Sensor (VSS) Noise suppressor

FUNGSI KOMPONEN PSCM : 1. Mengontrol arus listrik yang memutarkan motor berdasar- kan signal yang masuk. 2. Mengontrol tegangan clutch. 3. Fail safe function. VSS : Mendeteksi kecepatan kendaraan. NOISE SUPRESSOR : Mendeteksi putaran mesin CLUTCH : Menghubungkan/memutuskan pu- taran motor dengan gear reduksi.

3-2.Fungsi Komponen This table shows the function of each components. There is nothing different from the existing models.

TORQUE SENSOR Mendeteksi kuat puntiran steering wheel Mendeteksi arah putaran steering wheel

PRINSIP KERJA TORQUE SENSOR (new swift) Apabila steering wheel diputar searah jarum jam (sjj) maka slider akan bergerak naik Apabila steering wheel diputar berlawanan arah jarum jam (bjj), maka slider akan bergerak turun

3-3-1.Penjelasan Front suspension frame Steering gear case consists of input shaft, output shaft, torsion bar, torque sensor, worm gear & wheel and EPS motor. The steering gear case is supported by front suspension frame.

The torque sensor is a non-contact variable inductance type. When the steering wheel is turned, the torsion bar between input shaft and output shaft is twisted. This torsion creates an axial movement of the core (3). In right turning, the core goes up and the inductance of coil 1 (1) varies. In left turning, the core goes down and the inductance of coil 2 (2) varies. This variance of inductance is detected by the amplifier (4) of the torque sensor. The torque sensor outputs the voltage signals to EPS control module. The amplifier (4) consists of double circuits, one of which is main (5) and the other is sub (6). EPS control module calculates the steering torque and direction by using these two signals. The EPS control module calculates an average value of the voltages obtained by main and sub signals. The average value is used as steering torque. The steering direction is detected by comparing the average value with 2.5 volts. 3-3-2.Torque Sensor

3-3-4.Manual Stopper If some malfunction* occurs in EPS system, EPS system works as a manual steering, i.e. without power assistance. Also when the engine is at stop, the system works as a manual steering. [Manual Stopper Operation] When the steering wheel is turned, the torsion bar is twisted. As the power supply to the EPS motor is cut off, there is no power assistance. If the steering wheel is further turned, the driver’s force is directly transmitted to the output shaft (pinion shaft) via manual stopper part. Note*: In case of VSS malfunction, EPS provides a minimum power assistance.

3-3-3.EPS motor 5b EPS motor is equipped with a torque limiter. If an excessive torque input (impact torque) occurs at a tire, the torque limiter absorbs the impact to protect the EPS motor and gear. [Torque limiter operation] 1.An excessive torque (impact torque : 5a) is transmitted from a tire to worm gear (3). 2.The impact torque (5a) is transmitted to the boss (4e) which is spline-fitted to the worm gear (3). 3.If the impact torque(5a) exceeds the specified value (5b), a slip occurs between the boss (4e) and the friction plate (4d) which is fixed to the motor (1). The yellow zone in the graph shows the slip zone.

3-4.Detail Kontrol The terminal E52-17 sends power steering signal to ECM when the steering wheel is turned.

3-4.Detail Kontrol (cont.) EPS control module determines the basic assistant force by steering assistance control. EPS control module corrects the basic assistance force by adding inertia compensation, handle return and steering attenuation controls to improve the feeling of steering. According to the results of these controls and maximum current regulation, the EPS control module calculates the target current. Then the EPS control compares the target current and the measured value to adjust the current.

P/S CM BAGAN ALIRAN CONTROL TORQUE SENSOR BATTERY VEHICLE SPEED SENSOR NOISE SUPPRESSOR MOTOR CLUTCH OUTPUT DTC

FAIL SAFE FUNCTION Bila terjadi ketidak normalan pada DTC dari P/SCM maka akan menghentikan bekerjanya: Motor & Clutch (OFF), dan kemudi masih dapat bekerja secara manual

OPERASI P/SCM & LAMP.IND. EPS A. BILA TIDAK ADA KERUSAKAN Saat Ign.Switch di ON kan tanpa dilakukan grounding pd.Diagnostic Switch Terminal, mk lampu indikator EPS menyala selama 2 detik kemudian padam. B. BILA ADA KERUSAKAN Lampu ind.EPS menyala terus, kerusakan yang terjadi tersimpan dlm back up memory P/SCM. Bila Diagn.Sw.Terminal di ground kan mk lampu indikator EPS berkedip sesuai DTC

PROSEDUR MELIHAT DTC 1. Carilah monitor coupler 2. Hubungkan dg kabel antara term. A dan B pd m.coupler 3. Putar steering wheel ke kiri & ke kanan dan tarik rem parkir 4. Start mesin 5. Bila tdk ada kerusakan DTC 12 (normal) 6. Bila ada kerusakan pd 2 bag. atau lebih, DTC akan menunjukkan mulai dari kode angka terkecil dst ke angka yg lebih besar.

POSISI MONITOR COUPLER / DST

MONITOR COUPLER (DST=Data Swicth Terminal)

LAMPU INDIKATOR EPS

TABEL DTC