30-0006 Function description Electronic accelerator (EA) Block diagram Overvoltage protection EA control relay, Models 124, 202 (power supply) Idle speed control Base, Models (ISC) 129,140, 124.034/036 ASR/EBR data Power supply Pedal A/C compressor cut-in characteristic signal maps (engine 120 only) Vehicle speed Accelerator pedal/idle limiter (engine speed contact switch 120 only) Idle speed identifier Starting off torque Specified value limiter (engine 120 requirement, throttle only) valve Load value limitation (engine EA actuator Specified value 120 only) Specified value selection potentiometer Actual value potentiometer Idle speed safety contact Position Data bus Synchronous safety controller (CAN) contact ABS/ASR control Specified value requirement for ASR/EA control mode Speed signal Front left and rear right wheel Speedometer hall sensor (Model 124, engine 104 HFM-SFI) Rear wheel speed signal Output stages Monitoring system Fault memory LH-SFI or HFM-SFI control Idle speed signal Safety fuel shut-off EA actuator Actuator motor Coupling Throttle valve Test coupling for diagnosis (pulse signal for HHT or pulse counter)
Rear wheel speed signal Control (LH-SFI, HFM-SI) Starter lock-out/reverse lamp switch Starter lock-out/reverse lamp switch (AT) A/C compressor control, air conditioner, Models 124, 202 Cut-in signal CC switch Function selection Stop lamp switch Signal, switch off CC EA control Clutch pedal switch (MT) Signal, switch off CC Maintain idle speed function > 2km/h Diode matrix (Model 140 with engine 119, 120 LH-SFI only) Idle speed increase Function Data bus (CAN) DI/KSS control ABS/ASR control LH-SFI, HFM-SFI control 5-speed automatic transmission control Diagnostic ( only)
The following functions are integrated in the EA control : Idle speed control Cruise control Electrical/electronic throttle control (electronic accelerator) In conjunction with the mechanical components, all control processes as well as the mechanical positioning movements are performed by components of the electrics/ electronics. The EA control receives unfused voltage when the ignition is switched on from the base or overvoltage protection relay. The cruise control switch receives unfused voltage from terminal 15 (ignition). Using the control input signals (refer to block diagram), the output signal which the position controller, monitoring system and the data bus (CAN) receive is calculated in the "specified value selection" control. The specified value signal is compared with the actual value signal in the "position controller" control. In the event of deviations, the throttle valve position is adapted to the specified value (accelerator pedal position). ASR control If the specified value input (deflection of the accelerator pedal) is greater than the drive moment which can be transmitted to the road, this means the wheels will spin (slip). This slip is detected by the ABS/ASR control and signalled to the EA control as a signal (throttle valve reduction) via the data bus (CAN). In order to achieve an immediate reduction in torque, this signal is transmitted simultaneously to the DI control and the ignition timing is briefly retarded. The drive moment is reduced in the event of excess throttle opening until the slip at the drive wheel falls below a set value. In the event of excessive drive moment at the driving wheels (ASR control) the helical spring in the spring capsule of the actuator permits adjustment of the throttle valve contrary to the throttle pedal position. EBR control The EBR (engine braking regulation) is effective under the following conditions: Vehicle speed > 20 km/h to 120 km/h. No ASR control Opening angle of the throttle valve < 20 (set by the driver's foot). In so doing, the output stage for the actuator motor is actuated via the "approval/ disconnection " system which is downstream of the monitoring system. At the same time, the output stage is also actuated by the safety relay. Only if the signal is available from both systems is the actuator motor actuated and thus the position of the throttle valve determined.
If, when the accelerator pedal is released or Information is continuously exchanged during a downshift (e.g. manual) slip occurs between the ABS/ASR, LH-SFI or HFM-SFI, at the drive wheels, this is also detected by EA control s and the DI/KSS ignition the ABS/ASR control. The throttle control and the Diagnostic ( valve is briefly opened (approx. 450 ms) so only) via the data bus (CAN). The data bus that no further slip occurs at the rear wheels. is also checked by the monitoring system. This increases directional stability. When the ignition is switched on, the EA system and the integrated idle speed control is operative. The control detects the Accelerator pedal operated accelerator pedal position via the specified By operating the accelerator pedal, the value potentiometer in the EA actuator, on control movement is transmitted to the the engine 120 the actuator for the right specified value potentiometer in the actuator cylinder bank, located on the left. The via the floor-type accelerator pedal, bowden position of the throttle valve is signalled by cable and throttle linkage. Depending on the the actual value potentiometer in the EA accelerator pedal position, an appropriate actuator. voltage signal is input to the EA control by the specified value potentiometer. When the accelerator pedal is not operated, the position of the throttle valve is also determined as a function of the instantaneous coolant temperature before starting. Accelerator pedal not operated When the accelerator pedal is not operated, the idle safety contact is "closed" and the synchronous safety contact is "open". Both safety contacts and their signals are continuously checked by the monitoring system in the EA control. The control of the LH-SFI or HFM-SFI injection is actuated by the output signal of the monitoring system. As a result the actuation of the injection valves is guaranteed over the entire speed range via the safety fuel shut- off. In the absence of a signal, e.g. when both safety contacts are detected as open (mechanical or high contact resistance at the contact), the LH-SFI or HFM-SFI control actuates the injection valves so that an engine speed of only approx. 1200 rpm is reached with the quantity of fuel. The slip signal at the drive wheels is signalled to the EA control via the data bus (CAN). In ASR mode, the torque is reduced by closing the throttle until no further slip occurs. In EBR mode the torque is increased by briefly opening the throttle (approx. 450 ms) until no further slip occurs. Overall, the throttle valve can be adjusted between idle and full throttle or closed in the direction of idle by ASR or briefly opened slightly by EBR using the EA system. The opening angle for idle control is limited by the EA control over the entire adjustment range of the throttle valve (idle to full throttle stop).
Throttle control The throttle linkage is connected to the throttle by means of a loose connection via the drive lever and the internal spring capsule. On the engine 120, the EA actuator is "not" connected to the throttle linkage or the left cylinder bank (located on the right of the engine). The throttle valve is adjusted here only by means of electric/electronic actuation. Emergency running system (refer to chapter on Individual Functions) Fault memory (refer to chapter on Individual Functions) Cruise control (CC) The following signals are processed in the cruise control section of the EA control for the parameters of cruise control control: Pushbutton switch Speed of left front and rear wheel (Model 124, engine 104 HFM-SI, left front wheel and hall sensor signal, speedometer) Throttle valve position Selector lever position Stop lamp switch Clutch switch (MT only) The cruise control function can only be activated by operating the switch (S40) at a speed above 40 km/h. The cruise control switches off if the brake or clutch pedal are operated.
To maintain directional stability, the speed signal from the left rear wheel is measured in addition to the speed signal of the left front wheel. On Model 124, engine 104, signal of the left front wheel and the hall sensor signal from the speedometer. When the cruise control is switched off, the return of the throttle valve to the specified value of the accelerator pedal is monitored by the safety circuit in the electronic accelerator control. If, for example, when the stop lamp switch is 2 defective, the vehicle decelerates > 1.5 m/s, the deceleration is recorded by the computer and the actuator closes the throttle valve at the highest speed possible. If ASR detects drive slip during cruise control mode, the reduction of engine output (lower speed) has priority over cruise control mode. If ASR operates for more than 0.5 ms, cruise control is switched off. In this case the system has to be reactivated via the switch if further cruise control mode is required. Monitoring and limp-home systems If the max. differential speed between the left front wheel and the left rear wheel (EA) is exceeded for more than 0.5 s, the cruise control is switched off by the CC/ISC control. The synchronous safety contact must be bridged by means of the switching transistor in cruise control mode. Inadmissible acceleration is now detected by monitoring the speed and acceleration plausibilities, and the cruise control is switched off. When the cruise control is set, the position controller in the EA control receive an appropriate input signal. As a result the position of the throttle valve is specified, Maximum differential speed recorded by the actual value potentiometer up to 149 km/h 3 km/h of the throttle valve and signalled to the EA above 150 km/h 5 km/h control. If the driver requires a higher speed via the accelerator pedal, the cruise control remains inoperative. Fault memory (refer to chapter on individual functions) Cruise control/idle speed control (CC/ISC) Block diagram
Overvoltage protection relay Models 124, 202 (power supply) Base Models 129, 140 Voltage supply AC compressor cut-in signal CC/ISC control Cruise control Idle speed control Specified value selection LH-SFI or HFM-SFI control Idle speed signal Safety fuel shut-off CC switch Function selection Accelerate/Set Decelerate/Set Resume Off Position controller Data bus EA actuator Actuator motor Clutch Throttle valve ISC actuator Drive actual value potentiometer Throttle valve actual value potentiometer Idle speed contact Safety contact Monitoring system ABS/ETS control Speed signal Left front and rear wheel Output stage Fault memory Test coupling for diagnosis (pulse signal for HHT or pulse counter) Speedometer hall sensor (Model 124, engine 104 HFM-SFI) Speed signal Rear wheel LH-SFI/HFM-SFI control
Control (HFM- CC/ISC control Clutch pedal switch SFI) (MT) Switch off CC signal Maintain idle speed Starter lock-out/reverse function > 2m/h lamp switch Selector lever position Diode matrix detection (AT) (Model 140, engine 119, 120 LH-SFI only) A/C compressor control idle speed increase Models 124, 202 Cut-in signal Stop lamp switch Switch off CC signal Data bus (CAN) Function DI/KSS switch unit LH-SFI, HFM-SFI control 5-speed transmission automatic control Diagnostic ( only)
The following functions are integrated in the CC/ISC control Cruise control Idle speed control The Cruise control function can only be activated at a speed above 40 km/h by operating the switch. The cruise control switches off if the brake or clutch pedal are operated. To maintain vehicle stability, the speed signal from the rear axle and, in vehicles with electronic traction support (ETS), that of the left rear wheel is measured in addition to the speed signal of the left front wheel. If the differential speed between the front and rear wheel is too high, cruise control is switched off after 0.5 s. The position is fed back by the drive actual value potentiometer and the throttle valve actual value potentiometer. If the driver requires a higher speed via the accelerator pedal when the cruise control is switched on, the cruise control remains inoperative. The idle speed contact and the safety contact are located in the CC/ISC actuator. Normally the contact is always closed. The idle speed contact is closed when the accelerator pedal is not operated and opened when the throttle is opened. Normally (when driving) the safety contact is always closed. If it is "open", in the event of a fault, (e.g. due to an inadmissible throttle opening), the "safety fuel shut-off" is Maximum differential speed triggered up to 149 km/h 3 km/h by the injection system control and above 150 km/h 5 km/h the engine speed is limited to approx 1200 rpm. If, for example, a stop lamp switch is defective and the vehicle decelerates > 1.5 m/s2, the deceleration is recorded by the computer and the actuator closes the throttle valve at the highest positioning rate possible. When the cruise control is switched on, the control input signals (refer to block diagram) are used to calculate the output signal which the position controller, the monitoring system and the data bus (CAN) receive in the "specified value selection" control. In so doing, the output stage for the actuator motor is actuated via the approval/ disconnection system which is downstream of the monitoring system In cruise control mode the safety contact is bridged by means of the switching transistor. Inadmissible acceleration is detected by monitoring the speed and acceleration plausibilities and the cruise control is switched off. Fault memory (refer to chapter on individual functions) Idle speed control (refer to chapter on idle speed control) Idle speed control (ISC) Block diagram for ISC with separate control (engine 104, Model 140 only without EA or CC/ISC)
Data bus (CAN) DI/KSS switch unit ABS/ASR control LH-SFI, HFM-SFI control 5-speed transmission automatic control Diagnostic ( Base Power supply A/C compressor cut-in signal ISC actuator Drive drive actual value potentiometer Throttle valve actual value potentiometer Idle speed contact ABS control Rear axle speed signal Starter lock-out/reverse lamp switch Selector lever position detection (AT) ISC control Specified value selection Position controller Data bus Monitoring system LH-SFI control Idle speed signal EA actuator Actuator motor Clutch Throttle valve Clutch pedal switch (MT) Maintain idle speed function > 2 km/h Test coupling for Output Fault diagnosis Diode matrix stage memory (pulse signal for HHT or Idle speed increase pulse counter)
Function When the ignition is switched on, the idle speed control system is operative. Before starting, the position of the throttle valve for idle is specified via the actuator motor depending on the coolant temperature. Depending on the input signals shown, refer to block diagram, an output signal is transmitted to the specified value selection in the idle speed control. It evaluates the idle speed signal in conjunction with other adjacent signals. The position controller and the data bus (CAN) is actuated by the output signals. The signals are checked by the monitoring system and the output stage actuated via the approval/ disconnection system. The ISC control compares the actual and specified engine speed and determines the required position of the throttle valve via the actuator motor. The position of the throttle valve is recorded by the actual value potentiometer in the actuator and signalled to the ISC control. The adjustment range of the throttle valve for idle adjustment (e.g. opening angle) is limited to max. 10 by the control. Support of idle speed control by the ignition system If there is an engine speed control deviation, the idle speed control is supported by varying the ignition timing. Idle speeds with and without gear engagement vary. They are determined according to the selector lever position and the coolant temperature via the EA, CC/ISC or ISC control. increase or stabilization a) Speed stabilization on engines with A/C compressor When the A/C compressor cuts in, the EA, CC/ISC or ISC control receives a cut-in signal. The control processes the applied voltage and transmits an appropriate signal to the specified value selection. The cross-section of the opening becomes larger before the A/C compressor cuts in so that the idle speed remains almost constant in the process. b) Speed stabilization on vehicles with automatic transmission (AT) The signal is evaluated when the drive position is engaged. This results in a changeover of characteristics. This signal is then passed on to the specified value selection. In this way, the throttle valve is opened to a varying extent due to the characteristic in force when the accelerator pedal is deflected. A gentle progression is thus achieved for each selector lever position. c) Increasing engine speed to generate heat In order to bring the catalytic convertor more quickly to operating temperature, the speed is increased for approx. 20 seconds after each starting operation when coolant temperatures are below +20 C and a recognized idle speed signal and selector lever position P/N. Engine Temperature Time M 104 < + 20 C approx. 20 seconds 1100 100/rpm
M 120 +20 C - + 30 C approx. 20 seconds 850-50 + 100 n 1/min 1100 1000 900 800 700 600 Start ca. 20 Zeit t s Diagram applies to a coolant temperature of 20 C (simulated) and selector lever position P/N. Shown on engine 119 in Model 140. d) Speed increase on engines with diode matrix (Model 140, engine 119, 120 LH-SFI only) In order to achieve a higher charge current at idle speed, the engine speed is increased from 550 rpm to 650 rpm under certain conditions. The control receives a signal via the diode matrix when auxiliary appliances are switched on. The idle speed increase is activated when drive stage D, 3, 2 and 1 is engaged when P54-2845-13 V2 Diode matrix, speed increase (footwell right)
one or more of the following appliances are switched on: Dipped beam (except in the case of daydriving light) Blower on stage 3 or higher in the case of automatic heater control Heated rear window Automatic air conditioning Left and right auxiliary fans Front or rear seat heating on stage 2 The idle speed increase is switched off when dry stages P, R or N are engaged and a coolant temperature of 110 C. Charge current Generator speed Charge current 550/rpm 1595/rpm 47 A 650/rpm 1885/rpm 65 A 2180/rpm 6300/rpm 120 A e) Idle speed increase dependent on Detection and adaptation of mechanical battery voltage end stop of throttle valve (Models 129 and 202 with engine 104) The control detects and adapts the In order to increase the charge current of the end stop (idle speed stop) when the ignition generator, the idle speed is increased to is switched on. The time for this is approx. approx. 650 rpm under the following 45 s. operating conditions: The detection is effected by the throttle valve Battery voltage <12.3 V being drawn onto the end stop by the Selector lever position "D" actuator motor integrated in the actuator. Coolant temperature 40-110 C The throttle valve position is recorded by the If these conditions are met, the idle speed actual value potentiometer, transmitted to the remains at the increased level after control and stored there. exceeding 900 rpm when the engine speed reduces. The control then calculates from these values the position of the throttle valve for idle speed.