Administration. Fire procedure Toilets Breaks Mobile telephones please turn off

Transcription

1 Administration Fire procedure Toilets Breaks Mobile telephones please turn off

2 Agenda Technology development ECM logic Terminology Ignition system analysis Engine management systems Sensor identification and testing Closed loop fuelling

3 Today s Petrol Engines Inputs Outputs Cam sensor (CKP) Crank sensor (CMP) Air flow sensors (AMM/MAF) Engine coolant sensor (ECT) Throttle position switch (TPS) Heated oxygen sensors (HEGO) Accelerator position (APP) Map sensor (MAP) Knock sensor (KS) Exhaust gas temperature Fuel temperature sensor EGR position sensor Ignition coil(s) Idle speed control valve (ISCV) Throttle motor Injectors (petrol or diesel) Fuel pump Exhaust gas recirculation valve (egr) Turbocharger control Swirl flaps VVT control Variable induction control A BIG INCREASE IN ELECTRONICS!

4 Today s Diesel Engines Inputs Outputs Cam sensor Electronic injectors Crank sensor EGR valves Air mass meter Additive systems Map sensor Inlet metering valves Rail pressure sensor Pressure regulator Throttle position Swirl flaps Fuel temperature Glow plugs EGT EGR position DPFE sensor

5 Petrols and Diesels All controlled by a computer!

6 Communications

7 ECM Logic No codes Codes, no descriptions Codes and descriptions

8 P System Code Type Sub System Setting Conditions P = Powertrain 0 = Generic 1 = Fuel or air = Variable B = Body 1 = Enhanced 2 = Fuel or air C = Chassis 2 = Generic 3 = Misfire U = Network 3 = Either 4 = Emission control 5 = Vehicle or Idle speed 6 = ECU or output circuit 7 = Transmission 8 = Transmission 9 = SAE Reserved 0 = SAE Reserved

9 Electrical Fundamentals, Sensors and Testing

10 What Testing Can We Do? ELECTRONIC Resistance Voltage (DC & AC) Duty cycle/pulse width Current Frequency MECHANICAL Compression Fuel pressure Vacuum/pressure Back pressure Timing Scanner gives direction: Fault codes & live data

11 Electrical Fundamentals The physical pathway for current flow is called an electrical circuit

12 Electrical Fundamentals Voltage Voltage is an electrical force or pressure, which causes current to flow through an electrical conductor: Measured in units of volts (V)

13 Electrical Fundamentals Current Current is the flow of electrons through a conductor Measured in units of amperes or "amps" (A)

14 Electrical Fundamentals Resistance Resistance is the opposition offered to the flow of an electrical current by a substance through which it is passing Measured in units of ohms ( ) Symbol for calculations is (R)

15 Resistance Is Futile! Resistance testing requires the component to be taken out of circuit Resistance varies with temperature Resistance testing is not live testing in a normal operating environment

16 How Do We Test Circuits? Resistance has limited use Use volt drop Use current A V

17 Ohms Law A relationship exists between the voltage, current and resistance within the circuit, and this relationship is called Ohms Law Ohms law states: That one Volt is required to pass one Amp through a one Ohm resistance, providing that the temperature remains constant An easy way to calculate Ohms law, within a circuit, is to use the diagram to the side A V X R Current with a constant voltage = Higher resistance - lower amps Lower resistance - higher amps

18 A heated rear screen has a resistance of 0.5 Ohms Using Ohms Law, calculate the total current flow within the circuit, assuming a battery voltage of 12V Example? V 12 Volts 0.5 Ohms = 24 Amps A R

19 Watts Law When electricity flows in a circuit, the electrical energy is converted into thermal energy (heat), radiant energy (light) or mechanical energy (movement) The amount of work done by electricity in a time unit (i.e. one second) is called electrical power This is measured in Watts (W) A A W V X V R

20 Voltage 12v 12v BATTERY

21 Voltage <0.5v 12v BATTERY

22 Voltage 12v 12v BATTERY Bad Earth

23 Volt Drop Testing (Path of least resistance) RESISTANCE 0.5v 3.4v LOW RESISTANCE More voltage gets through the circuit HIGH RESISTANCE More voltage gets through the meter

24 Volt Drop Positive 0.5v ECU BATTERY

25 Volt Drop Negative 0.5v ECU BATTERY

26 Voltage ECM Output SENSOR ECU 0.25 TO 4.75V BATTERY Note: If 5v NO circuit exists

27 Typical sensor cicuit SENSOR ECU Measuring Point Inside ECU BATTERY +ve

28 0.2 v Typical Sensor Circuit 0.2 v ECU measures voltage here 0.2 v SENSOR ECU BATTERY +ve

29 volts FAULT CODE CTS VOLTAGE HIGH PCM SIGNAL TEMP SENSOR 1-4 v +ve

30 Current can tell us: Current Testing There is a circuit current can only flow if there is a circuit How much current is flowing What work is being done by the component Current ramping is an advanced technique used with oscilloscopes

31 Jargon Busting Analogue (AC wave form output) Digital (square wave form output) Frequency Pulse width (Modulated) Duty cycle (Modulated) The ECM uses all of these signals to control and monitor sensors and actuators

32 Analogue Waveform

33 Digital Waveform

34 Digital Square Waveform Frequency 1 sec period Voltage does not change due to frequency increase Voltage must peak to input voltage and switch to 0v for ECU to acknowledge an on/ off signal

35 Variable Pulse Width (PWM) Off time Total time, one cycle = 100% On time Duty Cycle 30%

36 PWM & Duty Cycle Pulse width alters the current being used. Pulse widths can be measured with duty cycle. Current Pulse

37 Basic System Layout Inputs Outputs

38 Fuel Pump What tests can I do Failure effects Different types What is it used for Current Volt drop Pressure Actuator tests (Scanner) Non start Incorrect fuelling Surging Misleading DTCs No Proving sufficient flow and pressure to the fuel rail

39 Fuel Pump Analysis Any motor can be tested for current flow. The waveform can tell us a great deal about the circuit.

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42 Fuel Pump Analysis Find a convenient point in the circuit and simply clamp one of the wires.

43 Inbuilt Tuition

44 Fuel Pump Testing Fuel pump speed analysis

45 Fuel Pump Testing Dead segments in pump

46 Basic System Layout Inputs Outputs

47 Ignition Coil What tests? What tests can I do Failure effects Different types What is it used for Primary voltage Secondary voltage (kv) Resistance Primary current Non start Misfire MIL Wasted spark Direct Distributor less To send sufficient voltage to the spark plug to ignite the fuel air mixture at the right time

48 Coil Principles + 12v HT The ignition coil is a step-up transformer that converts supply voltage to the high voltage required to jump across a spark plug gap. Switched Earth

49 Conventional System Direct connection to plug COP System Terminal 15 Ignition Supply Terminal 1 Coil Control Primary Secondary ECU/ Ignition AMP Removing the points and condenser

50 Common Supply Double Ended Coil System 1342 Firing Order TDC Power TDC Exhaust

51 Double Ended Coil System 1342 Firing Order TDC Exhaust TDC Power

52 Ignition Coils There are a few combinations of coil but all operate in exactly the same way as each other. Coil Pack, Cartridge and Coil On Plug.

53 Ionization Detection of an engine misfire can take between 20 and 90 seconds for the ECM to detect and respond Possible damage to the catalyst if a prolonged misfire occurs The misfire may also be caused by an injector or an air leak on a manifold By using an ionization trace a misfire can be detected immediately This is done by an additional amplifier built into the coil pack which puts a small voltage to the spark plug which in normal circumstances would not earth out to the electrode. High tension voltage creates the ionization field which is plasma, when combustion has taken place then the voltage will track across the ion particles in the plasma field and discharges to earth, the ECM now knows that combustion has taken place. This very accurate control and the ECM can use this trace for cylinder recognition so the ECM does not require a cam sensor signal Also because the ionization can accurately detect the combustion gas quality, it can detect pre detonation as well Theoretical diagram only Low volt Ion circuit Voltage stored in the low volt ion circuit discharges when ion particles are present (combustion) 12v

54 Coil On Plug Adapter

55 Built-in Tuition Guidance

56 Ignition Coil Signal

57 Inputs Basic System Layout Outputs

58 Fuel Injectors What tests can I do Failure effects Different types What is it used for Duty cycle Pulse width Current Non start Black smoke Misfire Mechanical - Ve switch + Ve switch Injects the right amount of fuel Into the engine Fuel pressure drop Poor performance Actuator test (scanner)

59 Fuel Injector Why do we need it? The fuel injector supplies fuel to the engine when switched by the ECU. Can be located in the inlet manifold (MPI) or in the cylinder head (DI) What happens if it fails? Misfire/hesitation Lean/rich mixture No start/cutting out

60 Testing Injectors Noid lights do not tell if injector has fired Current Pressure drop (with scanner) ASNU Exhaust gas analysis

61 Built-in Tuition Guidance

62 Fuel Injector Current Ramp Battery voltage due to no ground being supplied by ECU Current ramping is still present as injector needs it to remain open against spring & fuel pressure The windings reached their saturation point. Enough energy is stored to overcome pintle spring & fuel pressure No ground means no current is flowing as injector is not energised The injector is now energised, meaning current flows into the injector windings The ECU removes the ground supply, this causes the magnetic field which has built up in the windings to be released. This is known as Electro-Motive Force (EMF) This deflection in the voltage on the falling edge is where a diode in the ecu is regulating the rate current diminishes from the circuit. Preventing pintle bounce and seat damage. ECU Provides ground to injector

63 Injector Voltage (Request) Injector (Amps)

64 Good waveform Bad waveform

65 Piezo Injector Driver Signal

66 Piezo Injector Amps Trace

67 Inputs Basic System Layout Outputs

68 Crankshaft Sensor What is it used for? What tests can I do Failure effects Different types What is it used for? AC voltage Resistance Oscilloscope Scanner (engine speed) Non start Misfire Hall effect Ac generator Magnetic Engine speed TDC reverence Misfire detection

69 CKP Crank Position Sensor Crankshaft position sensor (what's it for) Engine position (ref cylinder 1 TDC) Engine speed Used for misfire detection Accurate engine timing in conjunction with cam sensor

70 Live Data, CKP

71 Built-in Tuition Guidance

72 CKP Crank Position Sensor Crankshaft position sensor Permanent magnet sensor (generator)

73 Onboard Misfire Detection Crank sensor output (Waveform) 0v The speed of crankshaft rotation affects the size and shape of the waveform

74 Onboard Misfire Detection the crank slows for compression Slow Fast and accelerates on power

75 Onboard Misfire Detection so when a misfire occurs Misfire Event Slow Fast Slow Fast Slow Slow Fast the crank does not accelerate as expected

76 Case Study

77 Inputs Basic System Layout Outputs

78 Cam Position Sensor What tests can I do Failure effects Different types What is it used for? AC volts Non start Hall effect Cylinder reference Resistance (inductive only) DC volts Misfire Frequency Inductive (AC) Misfire detection Engine position Oscilloscope

79 Hall Effect Sensor Magnet Plate

80 Digital Cam Sensor Testing

81 Analogue CMP Sensor Testing

82 Built-in Tuition Guidance

83 Inputs Basic System Layout Outputs

84 Manifold Pressure Sensor What tests can I do Failure effects Different types What is it used for Volts No idle Analogue Sense engine load Frequency Erratic Idle Digital Turbo control Vacuum Poor performance Black smoke

85 Built-in Tuition Guidance

86 Map Sensor Signal

87 Inputs Basic System Layout Outputs

88 Coolant Temp Sensor Coolant temp sensor (why is it needed?) Identifies cold and hot engines Cold start enrichment Hot soak starting Emissions control Faulty component will cause: Possible not start Poor running High fuel consumption High emissions Misleading fault codes

89 Inputs Basic System Layout Outputs

90 Throttle Position Sensor What tests can I do Failure effects Different types What is it used for Voltage MIL on? Analogue Acceleration enrichment Frequency Digital Over-run fuel cut off Scanner Auto box kick-down

91 TPS Sensor TPS Signal Return 0.25V 0v - 4.5V 5v +

92 TPS

93 TPS Signals

94 Inputs Basic System Layout Outputs

95 Mass Air Flow Meter (MASS, MAF, AMM) What tests can I do Failure effects Different types What is it used for Output Volts Loss of power Analogue EGR control Volt drop Digital Fuel quantity control Frequency Turbo control

96 Live Data, AMM

97 What s The Difference? Diesel Petrol

98 Built-in Tuition Guidance

99 Digital AMM

100 MAF Sensor Testing Digital sensors give a square waveform which can be checked with an oscilloscope This is a variable frequency signal that can be measured with a graphing meter

101 Inputs Basic System Layout Outputs

102 Closed Loop Control To keep the catalytic converter happy the ECU controls fuelling (air fuel ratio) Fuelling can be altered to compensate for wear/ageing and other fuelling problems Correct fuelling is achieved by the ECU altering the injector on time

103 Heater Oxygen Sensor B1S1, Pre catalytic converter B1S2, Post catalytic converter What tests can I do Failure effects Different types What is it used for Voltage Current Frequency Incorrect fuelling Surging at cruise Zirconia Titania Wideband Fuel control Catalytic converter testing

104 Built-in Tuition Guidance

105 O2 Sensor Closed Loop By increasing and reducing the Injector Pulse Width, the PCM can satisfy two important functions: 1. Send measurements to the PCM so that it can maintain the A/F at a desired 14.7:1 ratio (stoichiometric) 2. Maintain an efficient Catalytic Converter.

106 Zirconia Sensor 1 Hertz

107 Inputs Basic System Layout Outputs

108 Post Cat Oxygen Sensor Pre Cat Sensor Post Cat Sensor Upstream Downstream

109 Knock Sensor What tests can I do Failure effects Different types What is it used for Oscilloscope Volt drop Loss of power Analogue Combustion cylinder knock

110 Knock Sensor Construction 1) Retaining bolt 2) Engine cylinder block 3) Electrical connections 4) Seismic mass 5) Piezoelectric element

111 Knock Sensor Piezoelectric Crystal Body Seismic Mass

112 Knock Sensor

113 Built-in Tuition Guidance

114 QUICK BREAK

115 Live VERUS Pro Demo

116 MODERN DAY DIAGNOSTICS What is the key to profitable vehicle diagnostics?

117 MODERN DAY DIAGNOSTICS What is the key to profitable vehicle diagnostics? Can we still apply the same tried and true diagnostics methods from before?

118 IT S ALL ABOUT SPEED AND EFFICIENCY! Average diagnostic charge is 20 per hook up Average charge per healthcheck is 10 The more you do the more money you make

119 IT S ALL ABOUT SPEED AND EFFICIENCY! % % % % Diagnostic Time

120 RETURN ON INVESTMENT Diagnostic Tool Return on Investment Input in blue coloured cells: How long will you, or have you had your tool? 24 Mth How many times do you hook up per week? 5 What is your diagnostic charge? 25 How many Health Checks per week? 5 What is your Health Check charge? 25 Total you have spent on subscription? How much did you pay for your tool? Income generated since you bought the tool 26,000 Total Profit for the 24 Months 21,198

121 RETURN ON INVESTMENT

122 VERUS PRO BENEFITS 1. JOB CARD: A permanent time, dated recorded history of the vehicle (with DTCs and additional notes or attachments) 2. KNOWN GOOD VALUES: History of scope comparisons 3. COMPONENT TEST METER: Shows you where and how to connect, tells you what the results should be and the possible causes 4. INFORMATION: Component locations and wiring diagrams 5. INTERNET ENABLED: For diagnostic forums and information

123 RETURN ON INVESTMENT

124 Thank You We hope tonight s presentation has been of interest to you, and that we have been able to answer some of those questions you always wanted to ask.