Electronic Diesel Injection control BS III Prepared by

Electronic Diesel Injection control - BS III Prepared by Prof S. D. Gandhi 12/6/2020 1

Electronic Diesel control - BS III 12/6/2020 2

1 Emission Norms Pollutant CO BS-I g/KWh 4. 5 HC 1. 1 0. 66 NOx 8 7 5 PM <85 kw, 0. 612 >85 kw, 0. 360 0. 15 0. 1 12/6/2020 BS-II g/KWh 4 BS-III g/KWh 2. 1 3

2 Important modifications on vehicle • Important modifications done to meet BS-III A) Engine: - Cylinder block with piston cooling nozzles - Modified cylinder head to accommodate claw type injectors - Wider piston bowl with reduced clearance volume - Waste gate type turbocharger - Superior cylinder head gasket to withstand higher combustion pressure - Stronger crankshaft with induction hardened fillets - Modified water pump with increased flow rate - Intercooled air intake - Larger diameter engine fan 12/6/2020 continued. . 4

2 Important modifications on vehicle B) Fuel Injection: - Electronically controlled distributor type fuel injection pump - 1 st cylinder injector with needle lift sensor - Solenoid controlled hydraulic timer device - Fuel water separator cum hand primer C) Transmission: - New light weight clutch housing - Changed gear ratios - Changed rear axle crown wheel and tail pinion ratios 12/6/2020 5

2 Important modifications on vehicle D) Electrical: - Electronic control unit (ECU) - Sensors at various locations for feedback / signals to ECU - Load dump protected alternator, horn E) Driving Controls: - Accelerator pedal module with potentiometer - Clutch pedal switch - Brake pedal switch - ‘CHECK ENGINE’ diagnostic lamp 12/6/2020 6

3 ELECTRONIC DIESEL CONTROL (EDC) The Electronic Diesel Control includes CEU, Sensors, Actuators and electronically controlled FIP. The microcontroller inside the ECU continuously evaluates the signal from sensors. Electronic Control Unit performs certain calculations based on algorithms and function groups to control vehicle operations like fuel injection, timing, governing, emission control, error identification, self test and safety checks with the help of actuators in the engine / vehicle system based on closed loop feedback received from sensors. 12/6/2020 7

3. EDC SYSTEM BLOCK DIAGRAM ECU SENSORS Coolant Temp. Fuel Quantity Air Temperature Engine Shut Actuators Fuel Injection Pump Off Boost Pressure Injection Begins Vehicle Speed Fuel Quantity Injection Begin Micro processor Engine Speed Starting Control Diagnosis Set point Generators Diagnostic Display Accelerator Sensor Speed Selection Lever 12/6/2020 MAPS (Database) 8

4. Advantages of Electronic Diesel Control • Driving Comfort Low idle Governor Stability Better Low End Torque Lesser Gear Shifting Frequency Active Surge Dampner Lower Noise Levels • Performance Higher Power and Torque Higher Grade ability Optimum Operation in Diverse Terrains and Altitudes Provision to Limit the vehicle Speed to desired level Lesser turn around time Lower fuel consumption. 12/6/2020 9

4 Advantages of Electronic Diesel Control • Error Detection Faster and precise error detection through diagnostic tester. Diagnostic lamp on dashboard to warn about critical errors. ECU and sensor inputs enable high low end torque and low idling governor stability. Variable fuel delivery quantity is attained to sustain desired engine idling speed for various load conditions on the engine making fuel delivery characteristics independent of mechanical characteristics of FIP governor. This results in lesser gear shifting frequency for a wider range of speed and load conditions. EDC optimizes fuel consumption depending on driver demand, engine speed and ambient conditions. 12/6/2020 10

4 Advantages of Electronic Diesel Control • Atmospheric pressure sensor compensates for the loss of volumetric efficiency at higher altitude by varying fuel delivery quantity. • Required fuel quantity for injection begin is electronically controlled depending upon coolant temperature for better cold starting. • Solenoid controlled timer advance enables timer advance at any engine speed depending on requirements. 12/6/2020 11

5. Do’s & Don’ts for EDC system • Additional electrical tappings should not be taken from OE (original equipment) wiring harness for the electrical connections as this will severely affect the performance of the ECU and Sensors. Always use separate provision provided for tapping any additional electrical connections for accessories. • Care should be taken while washing the vehicle. Do not splash water directly on the ECU, accelerator pedal sensors and other EDC components. • Diagnostic connector located in the fuse box (Dconnector) should not be left open after use. Always cover the fuse box with fuse box cover. • Reverse polarity protection: care needs to be taken while removing the battery connection and reconnecting the terminals in correct polarity. 12/6/2020 12

5. Do’s & Don’ts for EDC system • Only specified alternator and horn fitted with load dump device should be used in case of replacement. Normal alternator, horn etc will affect the ECU functioning. • Check the battery condition weekly and keep the battery in a healthy condition. • Never perform any welding operation on the vehicle without all battery connections to ECU disconnected. • Ensure proper connection of ECU positive cable directly from battery positive. • Ensure proper connectivity of ECU/ Sensor connectors with wiring Harness. Any loose connections in the circuit will result in malfunctioning of the engine. 12/6/2020 13

5. Do’s & Don’ts for EDC system • Fuses with correct specifications should be used. • Consecutive clamp support for electrical cables of sensors should not be more than 250 mm apart. Loosely hung wirings may damage electrical connection to sensors. • Never use adulterated fuel. Use recommended fuel meeting BS III specifications. • Drain water from Fuel- water separator regularly as per maintenance schedule. 12/6/2020 14

6. Electronic Diesel Control : Components The components of Electronic Diesel Control can be classified into four major categories. The details of each component, their specifications are mentioned below. • Fuel injection pump • Actuators • Electronic control unit (ECU) • Sensors 12/6/2020 15

Working Principle of CRDI Engines The common-rail injection system comprises basically three parts. 1. A high-pressure pump 2. A unit injector, which includes a control plunger above the needle valve and control – spring and a solenoid – operated injector control –valve mounted horizontally on top of the unit injector. 3. A common –rail accumulator, which is plumbed in between the high –pressure pump and the unit injector. with this system of fuel injection, the pressures generated and injected are de-coupled, that is they are not interconnected. 12/6/2020 16

Working Principle of CRDI Engines The pressure produced by the high pressure pump is transferred to the common- rail accumulator which stores the discharged fuel and maintains a constant fuel pressure in the common rail line of up to 1350 bar. This pressure is continuously available at the injector, in contrast to the conventional jerk injection pump, which needs to repeatedly rebuild pressure for each injection cycle. The injection pressure generated is therefore independent of engine speed, and the quantity of fuel injected does not rely on a timed position of any one of the pumping plungers. Radial plungers are adopted for care and inline plunger pumps are preferred for commercial vehicles to generate the high pressure for the common rail. 12/6/2020 17

Working Principle of CRDI Engines The system’s pressure is controlled by means of a pressure sensor. The unit injector control- valve solenoid is activated by an electrical pulse supplied by the electronic control unit. The instant the solenoid is energized and the time it is applied determines the beginning and the duration of injection. Note the two factors determining the quantity of fuel injected per cycle is the constant pressure generated and the opening duration of the nozzle needle valve. Pilot injection, second and possibly a third stage of injection can be achieved by repeatedly activating the solenoid control-valve, whereas the injection rate can be modified by controlling the nozzle needle movement. 12/6/2020 18

Electronic control unit The electronic control unit is the brains of this fuel injection system. It contains a memory element, engine control microprocessor and a solenoid drive element. The engine control microprocessor receives and processes information signaled from the various sensors which monitor the engine variables such as crankshaft position, engine speed and load, boost pressure and temperature, coolant temperature, accelerator pedal position, common -rail pressure etc. This data is then compared to the pre-stored memory. It is then computed and resulting outcome is used to predict the necessary injection timing and the quantity of fuel delivered to the cylinder each power stroke for the prevailing operating conditions at any one time. 12/6/2020 19

Electronic control unit This information is then converted into electrical signals, which are then sent to the solenoid drive circuit; accordingly electrical pulses are relayed to each injector control solenoid in turn to activate the respective injectors. 12/6/2020 20

Sensors used in CRDI System Sensors • Accelerator pedal • Brake pedal • Clutch pedal • Coolant temperature • Boost pressure • Air temperature • Engine speed • Vehicle speed • Injection 12/6/2020 21