System Outputs
System Outputs
Main Relay Operation
Upon receiving the wake up signal from the ignition switch, KL15 supplying power to fuse 34, the EMS2000 provides a switched ground signal via Pin 97 to the Main Relay. This energizes the Main Relay, providing operating power to the EMS2000. Output of the Main Relay is monitored so that if the relay is energized and the power is not received by the EMS2000 a fault code is set.
EDR
An electronic throttle actuator (EDR) is used to adjust engine load based on throttle position requests received by the EMS2000 from the accelerator pedal position sensor. A DC-Motor electrically positions the throttle plate from idle to full load. The feedback of the position of the throttle plate and the position of the DC-Motor is achieved via 2 potentiometers, which are integrated in the throttle body:
- The MINI COOPER throttle body is 52 mm internal diameter.
- The MINI COOPER S throttle body is 57 mm internal diameter.
The EDR is operated by the EMS2000 for opening and closing of the throttle based on accelerator pedal position, DSC intervention and Cruise Control function. The EDR is a DC motor operating a gear driven throttle plate.
A variable duty cycle fixed frequency signal is sent to the EDR motor by the EMS2000. The EMS2000 switches polarity on the signal to the EDR motor at the rate of 600 Hz. (600 times per second) to maintain throttle position. Position and movement of the throttle plates is confirmed through the dual feedback potentiometers control functions.
The EMS2000 also provides power and ground for the feed back potentiometers.
Idle Speed Control
Idle Speed is controlled by the EMS2000 and EDR without the aid of an idle speed motor. For smooth driveability of the vehicle, the engine speed should remain constant when at idle no matter what the varying loads may be on the engine. The driver should not detect a fluctuation in engine idle speed under the following conditions:
- Engine cold start (increase in idle speed setting).
- Switching of different electrical loads (e.g. headlights, HRW or HFS).
- Turning the steering wheel to full lock (increased load from the Electro Hydraulic Power Steering (EHPS pump)).
- Air Conditioning Compressor engagement.
When there is a rapid change in electrical power demand on the alternator ie. front and rear heated windshield on with air conditioning fully on, there will be a corresponding rapid increase in the mechanical loading that the alternator exerts upon the engine. This in turn will have a significant effect on the engine idle speed stability. There is a delay between the electrical demand being made on the alternator and the mechanical demand being made on the engine. During this period of time the alternator transmits a signal to the EMS2000 to inform the control unit of the change in electrical load. The signal is PWM and allows the EMS2000 to control the throttle demand at idle to prevent flares and dips in the engine speed due to alternator loading or unloading.
The target idle speed setting for all MINI models is 750 rpm.
Idle Speed "Jack" Feature
As part of the vehicle power balancing strategy there is a feature to increase the engine idle speed to a set point when the EMS2000 system voltage reaches a certain threshold. The engine speed will remain at this point for a period of time before returning to the normal set point when the system voltage has recovered.
EML Warning LED
If the EMS2000 detects an engine safety related fault (but is not emissions related) in the EMS2000 itself, the EML warning light will illuminate in the IKE to show there is a fault with the drive by wire system. (This could be caused by a faulty throttle motor, gearbox or a sticking throttle flap.) The Warning Led is amber in color and is activated through a CAN Bus message to the IKE.
Fuel Pump Relay and Inertia Switch
Fuel Pump Relay:
The Fuel Pump Relay is a normally open contact relay used to control the fuel pump. The pump is initially energized when the ignition is switched on to position 2. It will remain energized for a set time to pressurize the fuel system. The fuel pump relay will remain energized if the engine running flag is detected otherwise it will be switched off after the time delay has elapsed. The relay is switched to off immediately if the engine stop flag is detected and is switched off after a time delay if the ignition key off is detected. The relay gets its B+ feed from the ignition switch through fuse 20 and is energized when the EMS2000 provides a ground on pin 105.
An inertia switch is installed in the B+ line to the relay between the fuse and the fuel pump relay. In the event of an impact greater than 14G the switch will open interrupting power to the relay The inertia switch has to be reset manually once it has been triggered.
O2 Sensor Heating
The oxygen sensor conductivity is efficient when it is hot (250° - 300° C). For this reason, the sensors contain heating elements. These "heated" sensors reduce warm up time, and retain the heat during low engine speed when the exhaust temperature is cooler. OBD II requires monitoring of the oxygen sensor heating function and heating elements for operation.
The two oxygen sensor heating circuits receive operating voltage from the Main Relay when KL15 is switched "ON". Each of the sensor heaters is controlled through separate final stage transistors.
The sensor heaters are controlled with a pulse width modulated ground during a cold start. This allows the sensors to be brought up to operating temperature without the possibility of thermal shock. The duty cycle is then varied to maintain the heating of the sensors.
When the engine is decelerating (closed throttle), the EMS2000 increases the duty cycle of the heating elements to compensate for the decreased exhaust temperature.
Shift Interlock Relay (ECVT Model Only)
Shift Interlock Relay:
This relay is used to drive the shift lock system on automatic transmission equipped vehicles. The shift lock system is a safety feature to prevent unexpected drive away of the vehicle by locking the gear lever in Park unless the brake pedal is depressed.
Gearbox Interface Unit
All of the control methods associated with the transmission are run as part of the EMS2000 software. The EMS2000 receives inputs from the main sensors of this system, communicates with the gearbox interface unit (GIU) to control the transmission, accepts driver inputs and provides information to the driver via the instrument cluster.
The control of the transmission is integrated with the EMS2000 and a GIU enables this integration, acting as a slave/interpreter for the EMS2000.
All inputs and outputs of the ECVT control system pass through the EMS2000 and the GIU The EMS2000 monitors the speed of the transmission output shaft and communicates with the GIU to select the correct gear ratio to suit the current driving conditions. The GIU drives the park, reverse, neutral, drive and sport LED module to display the selected gear next to the gear selector lever and the EMS drives the instrument cluster display.
Shift Interlock Relay (ECVT Model Only)
This relay is used to drive the shift lock system on automatic transmission equipped vehicles. The shift lock system is a safety feature to prevent unexpected drive away of the vehicle by locking the gear lever in Park unless the brake pedal is depressed.
Shift Interlock Relay:
Gearbox Interface Unit
All of the control methods associated with the transmission are run as part of the EMS2000 software. The EMS2000 receives inputs from the main sensors of this system, communicates with the gearbox interface unit (GIU) to control the transmission, accepts driver inputs and provides information to the driver via the instrument cluster.
The control of the transmission is integrated with the EMS2000 and a GIU enables this integration, acting as a slave/interpreter for the EMS2000.
All inputs and outputs of the ECVT control system pass through the EMS2000 and the GIU The EMS2000 monitors the speed of the transmission output shaft and communicates with the GIU to select the correct gear ratio to suit the current driving conditions. The GIU drives the park, reverse, neutral, drive and sport LED module to display the selected gear next to the gear selector lever and the EMS drives the instrument cluster display.
A/C Compressor Control
While the ignition is turned on, the BC1 outputs a compressor on/off request to the EMS2000 every 10 (+/-) 0.1 seconds. When the ignition switch is first turned to position 2, the request is set to compressor off. When the engine is running and the AC switch is pressed, the BC1 illuminates the indicator LED in the switch and changes the request to compressor on.
When it detects the request has changed to compressor ON, the EMS2000 energizes the compressor clutch relay, located in the engine bay fuse box, to supply battery power to the compressor clutch.
After receiving a compressor ON request, the EMS2000 outputs a compressor clutch status message to the BC1 to advise if the request was granted or not. If the compressor ON request was granted, the BC1 keeps the indicator LED in the AC switch illuminated. If the compressor ON request was refused, the BC1 flashes the LED at 0.5 Hz and repeats the compressor ON request until it is granted or cancelled by:
- Pressing the AC switch again, which changes the request back to compressor OFF.
- Selecting the blower off, which changes the request back to compressor OFF.
- Selecting the ignition switch to 0.
Once the compressor ON request is granted the LED in the switch remains illuminated until the request is cancelled or the engine stops, even if one of the grant conditions no longer exists. If one of the grant conditions no longer exists, the EMS2000 de-energizes the compressor clutch relay, to disengage the compressor clutch, until the grant condition is restored.
Hard acceleration can cause the compressor clutch to be disengaged. After three occurrences in a single ignition cycle the EMS2000 disregards further hard acceleration occurrences and leaves the compressor clutch engaged. The air conditioning will be automatically suspended if:
- The engine speed is above 6016 rpm.
- The evaporator temperature falls below 2° C - to prevent freezing.
- The coolant temperature goes above 118° C - to protect the engine.
- The AC system pressure goes above 30 Bar to protect the system.
- The AC system pressure goes below 1.6 Bar - to protect the system.
- The accelerator pedal is fully depressed (continuous full pedal demand) for more than 5 seconds.
- The accelerator pedal is depressed rapidly (instantaneous full pedal demand) for more than 2 seconds.
- The engine speed is below 500 rpm (engine stall).
The system will revert back to normal operation once the reason for suspension has been removed.
Note:
During cranking the AC compressor will be disengaged.
On IHKA systems compressor requests are handled via the CAN Bus from the IHKA.
Engine Coolant Fan
The Engine Coolant Fan is controlled by the EMS2000 through a relay and relay pack at two different speeds, Low and High.
In addition to maintaining coolant temperature, the fan is used to cool the A/C refrigerant and where applicable, the ECVT gearbox oil.
The cooling fan operates on Low speed when the AC is switched on and the system pressure reaches 8 bar. Should the AC system pressure rise above 18 bar, the fan will automatically run on High speed.
For the engine coolant system the fan operates on Low speed at 105° C. When the temperature drops to 101° C the fan will switch off. High speed is switched on at 112° C and will remain on until the system coolant temperature drops by 4° C at which point the system will revert to Low speed fan.
The engine coolant fan is operated through two relays, a Low speed relay and a High speed relay. The Low speed relay is mounted in the engine compartment fuse box and is energized any time fan operation is needed (Both Low and High speed). The High speed relay is mounted on the fan housing in the relay pack. The relay pack contains the High speed relay and a voltage reducing resistor.
When Low speed fan operation is needed the EMS2000 energizes the Low speed relay. Voltage flows from the Low speed relay to the relay pack, through the voltage dropping resistor, enabling Low speed fan operation.
When High speed fan operation is needed, the EMS2000 energizes the High speed fan relay in the relay pack mounted on the fan housing. (The low speed relay remains energized). The fan is now run at full battery voltage and achieves high speed operation.
A diode is installed in the relay pack to prevent voltage feedback through the resistor.
IKE
The IKE communicates with the EMS2000 over the CAN Bus. Information concerning Low Fuel Levels are passed to the EMS2000 for evaluation of misfires. The IKE also transfers requests for the A/C compressor from the IHKS/IHKA to the EMS2000. Any vehicle system not on the CAN Bus that communicates with the EMS2000 does so through the IKE.
OBDII Plug
The OBDII connection to the EMS2000 is through the D-Bus. This allows communication with the DISplus and emission related powertrain components.