Advanced Vehicle Technology Episode 1 Part 10 docx

Clutch/brakes (CV-A, CV-B, CV-C, CV-D/BV-E, BV-F and BV-G) (Fig. 5.39) The clutch valves control the engagement and disengagement of the multiplate clutches and brakes. These valves are variable pressure reduction valves which are actu- ated by the appropriate solenoid valves, electronic pressure regulator valves, traction valves and shift valves and are responsible for producing the desired clutch pressure variations during each gear shift phase. Clutch valves CV-B, CV-C and CV-F are influenced by modulation pressure which resists the partial closure of the clutch valves, hence it permits relatively high fluid pressure to reach these multiplate clutches and brake when large transmission torque is being transmitted. Retaining valves (RV-E and RV-G) (Fig. 5.39) In addition to the electronic pressure regulator valve which actuates the clutch valves, the retaining valves RV-E and RV-G modify the opening and closing phases of the clutch valves in such a way as to cause a progressive build-up or a rapid collapse of operating multiplate clutch/brake fluid pressure during engagement or disengagement respectively. Traction/coasting valve (T/C-V) (Fig. 5.39) The traction coasting valve T/C-V cuts out the regulat- ing action of the traction valve TV (5±4) and shifts the traction valve TV (4±5) into the shut-off posi- tion when required. Traction valve (TV) (4±5) (Fig. 5.39) The traction valve TV (4±5) controls the main system fluid pres- sure to the multiplate-clutch MPC-B via the trac- tion valve TV (5±4) and clutch valve CV-B and hence blocks the fluid pressure reaching the multi- plate clutch CV-B when there is a upshift from fourth to fifth gear. Traction valve (TV) (5±4) (Fig. 5.39) The traction valve TV (5±4) is another form of clutch valve, its function being to supply system pressure to the multiplate clutch MPC-B via clutch valve CV-B when there is a downshift from fifth to fourth gear. Converter pressure valve (CPV) (Fig. 5.39) The converter pressure valve `CPV' supplies the torque converter with a reduced system pressure to match the driving demands, that is, driving torque under varying driving conditions, it also serves as a pres- sure limiting valve to prevent excessive pressure build-up in the torque converter if the system pressure should become unduly high. The valve in addition vents the chamber formed on the drive- plate side of the lock-up clutch when the torque converter pressure control valve is actuated. Converter pressure control valve (CPCV) (Fig. 5.39) The converter pressure control valve `CPCV' is actuated by the electronic pressure reg- ulation valve `EPRV-4', its purpose being to pre- vent the converter pressure valve `CPV' from supplying reduced system pressure to the chamber formed between the drive-plate and lock-up clutch and to vent this space. As a result the fluid pressure on the torque converter side of the lock-up clutch is able to clamp the latter to the drive-plate. Converter lock-up clutch valve (CLCV) (Fig. 5.39) The converter lock-up clutch valve `CLCV' is actuated with the converter pressure control valve `CPCV' by the electronic pressure regulation valve `EPRV-4'. The converter lock-up clutch valve `CLCV' when actuated changes the direction of input flow at reduced system pressure from the drive-plate to the turbine wheel side of the lock-up clutch. Simultaneously the converter pres- sure valve `CPV' is actuated, this shifts the valve so that the space between the drive-plate and lock-up clutch face is vented. As a result the lock-up clutch is forced hard against the drive-plate thus locking out the torque converter function and replacing it with direct mechanical drive via the lock-up clutch. Lubrication pressure valve (LPV) (Fig. 5.39) The lubrication pressure valve `LPV' supplies fluid lubricant at a suitable reduced system pressure to the internal rubbing parts of the transmission gear train. 5.10.8 Operating description of the electro/ hydraulic control unit To simplify the various solenoid valve, clutch and brake engagement sequences for each gear ratio Table 5.6 has been included. Neutral and park position (Fig. 5.39) With the selector lever in neutral or park position, fluid is delivered from the oil-pump to the selector position valve `SPV', modulation pressure valve `MOD-V', pressure reduction valves `PRV-1' and `PRV-2', shift valve `SV-1', traction/coasting valve `(T/C)V' and clutch valve `CV-G'. Regulating fluid pressure is supplied to the torque converter `TC' via the converter pressure valve `CPV' and to the lubrica- tion system by way of the lubrication pressure valve `LPV'. At the same time regulated constant fluid 172 pressure (5 bar) is supplied to the solenoid valves `MV1, MV2 and MV3' via the pressure reduction valve `PRV-1', and the electronic pressure regulat- ing valves `EPRV-(1±4)' via the pressure reduction valve `PRV-2'. In addition controlling modulation pressure is relayed to the spring chamber of clutch valves `CV-B, CV-C and CV-D' and brake valve `CV-F' via the modulation pressure valve `MOD- PV'. Neutral and parking position has the follow- ing multiplate clutch solenoid valves and electronic pressure regulator valves activated: 1 multiplate brake `MPB-G'. 2 solenoid valves `MV1 and MV3'. 3 electronic pressure regulating valves `EPRV-1 and EPRV-2'. First gear (Fig. 5.41) Engagement of first gear is obtained by applying the one way clutch `OWC' and multiplate clutch and multiplate brake `MPC-B and MPB-G' respectively. This is achieved in the following manner: 1 Moving selector position valve `SPV' into D drive range. Fluid pressure from the selector position valve `SPV' then passes via the traction valves `TV (4±5) and TV (5±4)' respectively to clutch valve `CV-B', it therefore permits fluid pressure to apply the multiplate clutch `MPC-B'. 2 Energizing solenoid valves `MV1 and MV2' opens both valves. Solenoid valve `MV1' applies a reduced constant fluid pressure to the left-hand side of shift valves `SV-1 and SV-3'. Shift valve `SV-1' shifts over to the right-hand side against the tension of the return spring blocking the fluid pressure passage leading to clutch valve `CV-D', however shift valve `SV-3' cannot move over since a similar reduced constant pressure is intro- duced to the spring end of the valve via solenoid valve `MV2'. Solenoid valve `MV2' applies reduced constant pressure to the left-hand side of shift valve `SV-2' and the right-hand side of shift valve `SV-3'; this pushes the shift valve `SV-2' to the right and so prevents shift valve `SV-3' also being pushed to the right by fluid pressure from solenoid valve `MV1' as pre- viously mentioned. 3 Electronic pressure regulator valve `EPRV-1' supplies a variable regulated fluid pressure to the modulation pressure valve `MOD-PV', this pressure being continuously adjusted by the elec- tronic transmission control unit `ETCU' to suit the operating conditions. Electronic pressure regulating valve `EPRV-3 supplies a variable controlling fluid pressure to brake and retaining valves `BV-G and RV-G' respectively, enabling fluid pressure to apply the multiplate brake `MPB-G'. Second gear (Fig. 5.42) Engagement of second gear is obtained by applying multiplate clutch `MPC-B' and the multiplate brakes `MPB-E and MPB-G'. This is achieved in the following manner with the selector position valve in the D drive range: 1 Multiplate clutch and brake `MPC-B and MPB-G' respectively applied as for first gear. 2 Solenoid valves `MV1 and MV2' are energized, thus opening both valves. Fluid pressure from `MV1' is applied to the left-hand side of both `SV-1 and SV-3'; however, only valve SV-1 shifts over to the right-hand side. At the same time fluid pressure from solenoid valve `MV2' shifts valve `SV-2' over against the return-spring tension and also pressurizes the spring end of shift valve `SV-3'. This prevents shift valve `SV-3' moving over to the right-hand side when fluid pressure from solenoid valve `MV-1' is simultaneously applied at the opposite end. 3 The electronic pressure regulating valves `EPRV-1 and EPRV-3' have their controlling current reduced, thereby causing an increase in line pressure to the modulation valve MOD-PV and to both brake and retaining valves `BV-G and RV-B' respectively. Consequently line pres- sure continues to apply the multiplate brake `MPB-G'. 4 The electronic pressure regulating valve `EPRV-2' has its controlling current reduced, thus pro- gressively closing the valve, consequently there will be an increase in fluid pressure acting on the right-hand side of both brake and retaining valves `BV-E and RV-E' respectively. As a result the brake valve `BV-E' opens to permit line pres- sure to actuate and apply the multiplate brake `MPB-E'. Third gear (Fig. 5.43) Engagement of third gear is obtained by applying the multiplate clutches `MPC-B and MPC-D' and the multiplate brake MPB-E. The shift from second to third gear is achieved in the following manner with the selector position valve in the D drive range: 1 Multiplate clutch `MPC-B' and multiplate brake `MPB-E' are applied as for second gear. 2 Solenoid valve `MV2' remains energized thus keeping the valve open as for first and second gear. 173 CLC TTCP S OWC MPB E MPC A MPC B MPC C MPB F MPB G MPC D RV-E RV-G BV-E BV-G RGV BV-D CV-B CV-C Y (T/C)V TV (5-4) CPV CLCV CPCV to LUB LPV NRV 174 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU GCPS 1 2 3 DNRP MV3 MV1 MV2 PRV-1 SV-1 SV-2 SV-3 1 MPV BV-F SPV P EPRV-1 TV (4-5) MOD-PV PRV-2 EPRV-2 EPRV-3 EPRV-4 Y NRV Fig. 5.41 Hydraulic/electronic transmission control system ± first gear 175 CLC TC P T S OWC MPB E MPC A MPC B MPC C MPB F MPB G RV-E BV-E RGV CV-C RV-G BV-G BV-D Y (T/C)V CPV CLCV CPCV LPV CV-B TV (5-4) MPC D NRV to LUB 176 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU 1 2 3 DNRP GCPS Y P SPV 2 MPV BV-F EPRV-4 EPRV-3 EPRV-2 EPRV-1 PRV-2 MOD-PV TV (4-5) MV3 MV1 MV2 PRV-1 SV-1 SV-2 SV-3 PRV Fig. 5.42 Hydraulic/electronic transmission control system ± second gear 177 CLC TTCP S OWC MPB E MPC A MPC B MPC C MPB F MPB G MPC D RV-E RV-G BV-E BV-G RGV BV-D CV-B CV-C Y (T/C)V TV (5-4) CPV CLCV CPCV to LUB LPV PRV NRV 178 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU GCPS 1 2 3 DNRP MV3 MV1 MV2 PRV-1 SV-1 SV-2 SV-3 1 MPV BV-F SPV P EPRV-1 TV (4-5) MOD-PV PRV-2 EPRV-2 EPRV-3 EPRV-4 Y 3 PRV NRV Fig. 5.43 Hydraulic/electronic transmission control system ± third gear 179 CLC TTCP S OWC MPB E MPC A MPC B MPC C MPB F MPB G MPC D RV-E RV-G BV-E BV-G RGV BV-D CV-B CV-C (T/C)V TV (5-4) CPV CLCV CPCV LPV Y BV-F to LUB PRV NRV 180 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU GCPS 1 2 3 DNRP MV3 MV1 MV2 PRV-1 SV-1 SV-2 SV-3 1 MPV BV-F SPV P EPRV-1 TV (4-5) MOD-PV PRV-2 EPRV-2 EPRV-3 EPRV-4 Y 4 Fig. 5.44 Hydraulic/electronic transmission control system ± fourth gear 181 [...]... splitter gear ratio, or to the central third gear 5 .11 .1 Description of transmission system (Fig 5.48) The system being described is broadly based on the ZF Man Tip Matic/ZF AS Tronic 12 speed twin countershaft three speed constant mesh gearbox 18 7 Output Power flow path Input R 1 2 3 4 5 6 R L 1 H L 2 H L 7 H Low range 3 4 5 6 8 9 10 H L L H High range 11 L 12 H Floating mainshaft Countershaft Output shaft... Transmission program EPRV-4 CLC T TC P MPB MPC MPC MPC MPB MPB MPC E S A B C F G D OWC RV-E BV-E RV-G BV-G 18 4 CPV BV-D RGV NRV CLCV CV-B (T/C)V CPCV Y CV-C to Lub LPV TV (5-4) PRV PRV BV-F TV (4-5) SV-3 MPV MOD-PV SV-2 R PRV-2 SPV SV -1 185 EPRV -1 PRV -1 P MV1 MV2 EPRV-2 NRV Y MV3 ETCU GCPS EPRV-3 1 2 3 D N R P FIQ (torque) Fig 5.46 TVP (acceleration) Hydraulic/electronic transmission control system ±...CLC T TC P MPB MPC MPC MPC MPB MPB MPC E S A B C F G D OWC RV-E RV-G BV-E BV-G 18 2 CPV BV-D RGV NRV CLCV CV-B (T/C)V CPCV Y CV-C to LUB TV (5-4) LPV PRV PRV BV-F TV (4-5) SV-3 MPV MOD-PV SV-2 5 PRV-2 SPV SV -1 183 EPRV -1 PRV -1 P MV1 MV2 EPRV-2 NRV Y MV3 ETCU GCPS 1 2 3 D N EPRV-3 R P FIQ (torque) Fig 5.45 TVP (acceleration) Hydraulic/electronic transmission control system... L Constant mesh 1- R shift solenoid control valves 1- R shift power cylinder H 1- R selector fork Exhaust valve 1C 2C 2–3 shift power cylinder 3C EVO IVC Splitter shift solenoid control valves IVC EVO HS L LS IVO Splitter shift power cylinder EVC 3 2 3–2 selector fork H Low gear splitter engaged RC 1 R Selector rods Splitter fork Splitter selector rod Range fork Air reservoir tank 3–2 1- R selector forks... 2 3 1 CA R CP S 3 Power piston Splitter Range shift power cylinder Gearbox Epicyclic single stage gearing range gear box R 1 2 Constant mesh three speed and reverse gear box Selector rod plunger & spring Constant mesh power cylinder Splitter shift power cylinder L Fig 5.47 3 H 1 2 3-2 Selector rod and fork Splitter selector rod and fork L R 1- R Selector rod and fork Range H selector rod and fork 1 and... control to 5 .11 .9 Constant mesh three speed and reverse gear shift (Figs 5.47 and 5.48) These gear shifts cover the middle section of the gearbox which involves the engagement and disengagement of the various central mainshaft constant mesh gears via a pair of sliding dog clutches There is a dog clutch for engagement and disengagement for gears 1- R and similarly a second dog clutch for gears 2±3 19 1 ... Twin countershaft 12 speed constant mesh gearbox with synchromesh two speed splitter and range changes 18 8 mounted on the mainshaft to obtain the high splitter gear ratio Power is now able to pass via the twin countershafts to each of the mainshaft constant mesh central gears by way of the constant mesh gears 1, 2, 3 and R load by the electronic diesel control unit `EDCU' which is part of the diesel... whereas vehicle speed or wheel speed is monitored by the wheel brake speed sensors These three factors are continuously being monitored, the information is then passed on to the electronic transmission control unit `ETCU' which processes it so that commands can be transferred in the form of electric current to the inlet and exhaust clutch actuator solenoid control valves 5 .11 .3 Constant mesh 1- 2-3 and... 5 .11 .5 Clutch engagement and disengagement (Fig 5.48) With the ignition switched on and the first gear selected the clutch will automatically and progressively take up the drive as the driver depresses the accelerator pedal The three basic factors which determine the smooth engagement of the transmission drive are vehicle load, which includes pulling away from a standstill and any road gradient, vehicle. .. the selector position valve `SPV' moved to reverse drive position `R' 1 Multiplate brake `MPB-G' applied as for neutral and park position 2 Solenoid valve `MV1' energized thus opening the valve Constant fluid pressure now moves shift valves `SV -1 and SV-3' over to the right-hand side 3 Electronic pressure regulating valve `EPRV -1' de-energized as for neutral position 4 Electronic pressure regulating . (5-4) CPV CLCV CPCV to LUB LPV NRV 17 4 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU GCPS 1 2 3 DNRP MV3 MV1 MV2 PRV -1 SV -1 SV-2 SV-3 1 MPV BV-F SPV P EPRV -1 TV (4-5) MOD-PV PRV-2 EPRV-2 EPRV-3 EPRV-4 Y NRV Fig. 5. 41 Hydraulic/electronic transmission control system ± first gear 17 5 CLC TC P T S OWC MPB E MPC A MPC B MPC C MPB F MPB G RV-E BV-E RGV CV-C RV-G BV-G BV-D Y (T/C)V CPV CLCV CPCV LPV CV-B TV. (5-4) CPV CLCV CPCV LPV Y BV-F to LUB PRV NRV 18 0 FIQ (torque) TVP (acceleration) SS engine/trans. Transmission program ETCU GCPS 1 2 3 DNRP MV3 MV1 MV2 PRV -1 SV -1 SV-2 SV-3 1 MPV BV-F SPV P EPRV -1 TV (4-5) MOD-PV PRV-2 EPRV-2 EPRV-3 EPRV-4 Y 4 Fig. 5.44 Hydraulic/electronic transmission control system ± fourth gear 18 1 CLC TTCP S OWC MPB E MPC A MPC B MPC C MPB F MPB G MPC D RV-E RV-G BV-E BV-G RGV BV-D CV-B CV-C Y (T/C)V TV. a low splitter gear ratio, or to the central third gear 18 7 R L H L H L H L H L H L H Input Power flow path Output R 1 2 3 4 5 6 7 8 9 10 11 12 Countershaft Input shaft Transmission multiplate brake Floating mainshaft Output shaft High range Low range L H 3 2 1 R A P S C P C A H Power piston Splitter Gearbox Range