Diesel engines

11.3.3 Diesel engines

telemetry, the need for periodic inspections could

be eliminated because only those vehicles that Another development for future consideration is reported problems would have to be tested. The

the further implementation of OBD for diesel

Conclusion, web resources and developments 263

Figure 11.4 Model based calibration of an OBD system

engines. As diesel engine technology becomes Hardware-in-loop (HIL) simulation plays a part more sophisticated, so does the requirement for

in rapid development of any hardware. New hard- OBD. In addition, emission legislation is driving

ware can be tested and validated under a number more sophisticated requirements for after treat-

of simulated conditions and its performance veri- ment of exhaust gas. All of these sub-systems are to

fied before it even goes near any prototype vehicle.

be subjected to checking via the OBD system and The following tasks can be performed with this present their own specific challenges. For example,

technology.

the monitoring of exhaust after treatment systems ● Full automation of testing for OBD

(particulate filters and catalysts) in addition to

functionality.

more complex EGR and air management systems. ● Testing parameter extremes.

● Testing of experimental designs.

● Regression testing of new designs of software Rate based monitoring will be more significant for

11.3.4 Rate based monitoring

and hardware.

future systems which allows in-use performance ● Automatic documentation of results. ratio information to be logged. It is a standardised

method of measuring monitoring frequency and

11.3.6 Comment

filters out the affect of short trips, infrequent jour- neys etc. as factors which could affect the OBD

What with the possibility of navigation systems logging and reactions. It is an essential part of the

reporting where we are, speed and traffic light evaluation where driving habits or patterns are not

cameras everywhere and monitoring systems known and it ensures that monitors run efficiently

informing the authorities about the condition of in use and detect faults in a timely and appropriate

our vehicles, whatever will be next?! manner. It is defined as:

Minimum frequency ⫽ N/D

11.4 Software

Where N ⫽ number of times a monitor has run,

D ⫽ number of times vehicle has been operated.

11.4.1 Introduction

Many web sites have information you can down-

11.3.5 Model based development

load. Some also include simulation programs,

A significant factor in the development of any demonstration programs and/or electronic books. future system will be the implementation of the

This section outlines a small selection of those latest technologies with respect to hardware and

available.

software development. Model based development and calibration of the system will dramatically

11.4.2 Automotive technology –

reduce the testing time by reducing the number of

Electronics

test iterations required. This technique is quite common for developing engine specific calibra-

This simulation program is created by the author tions for ECUs during the engine development

of this book. It is a great teaching aid and covers phase (Figure 11.4).

some complex topics in an easy to understand

264 Advanced automotive fault diagnosis

Figure 11.5 A screenshot from the AT program

way (Figure 11.5). It is even possible to set faults An ideal way of learning about automotive elec- in the system and then, using built in test equip-

tronic systems.

ment, carry out diagnostic tests! Available as shareware from: www.automotive- From the ‘Help File’:

technology.co.uk

Click on the key button in the toolbar to open the ‘Controls’ window (if it is not already visible). Now click on the key button in this window to

11.4.3 Other programs

start the engine. You can also right click the Just two programs have been selected here for screen and choose to start the engine from there.

the reader to consider further – they are both Don’t forget to check that the car is not in gear –

highly recommended as sources of information or else it won’t start!

relating to diagnostics and/or ways of learning Next choose from the ‘Run’ menu the electronic

more about automotive systems. system you would like to operate or work with. I suggest ‘Engine Management’ is the best place

PicoTech www.picotech.com

to start. The software, used extensively in this book, to In common with all of the other simulation win-

show automotive waveforms is a great source of dows you will use, you can set or control the

information (Figure 11.6). A free demo version operating inputs to the system. For engine

can be downloaded or requested on CD. management control, these are engine speed,

engine load, temperature and so on. The system will react and control the outputs in just the same

Auto Solve www.auto-solve.com

way as a real vehicle. Be warned the unregistered This is an e-book presentation on CD that is a version runs out of fuel!

very useful source of information and diagnostic

Conclusion, web resources and developments 265

Figure 11.6 A screenshot from the additional information pages built into the scope program

methods (Figure 11.7). It even includes some repair. It is often the case that it may be perceived useful flow charts and lists of codes.

that no faults can be found or fixed without spe- cialised manufacturer equipment which is only available at dealers.

This is not the case! The fundamental prin- ciples of diagnostics in conjunction with an Modern motor vehicles are highly sophisticated

11.5 Summary

applied, logical thought process are the most pow- machines that incorporate the latest developments

erful tools that you have. Any specialist equip- in electrical, electronics, software and mechanical

ment will still only be as good as the person using engineering. They are a marvel of modern engin-

it. Modern vehicle systems are certainly sophisti- eering practice and truly show how all these tech-

cated but the fundamental principles apply. An nologies can be integrated and harmonised for

ECU is only monitoring voltages from its sensors. maximum benefit to the end user.

These are the inputs; the outputs are voltages and It is clear that this level of technology pro-

currents which drive actuators (injector, idle speed duces the safest, quietest and most efficient road

control valves etc.), they are all the same and vehicles we have ever known. The disadvantage

applied logic can fix most problems. of this level of sophistication really becomes

Engines and chassis are also complicated sub- apparent when something goes wrong! Clearly,

systems of the vehicle but in all cases the laws of the more sophisticated the device, the more diffi-

physics apply, and all engines do the same thing cult it will be to repair, or understand in order to

in more or less the same way. They are just

266 Advanced automotive fault diagnosis

Figure 11.7 One section from the Auto-Solve CD

energy converters! The basic principles are still ● Never assume anything … check it yourself. valid; for example, the ignition still needs to be

● Be logical when diagnosing faults. advanced under cruise conditions when the mix-

● Most of all, have confidence in your ability. ture is weaker, whether this is done mechani-

Follow these rules, never be afraid to ask for help cally or electronically. Likewise, any electrical and learn from the experience. You will build up circuit not conducting a current – is broken –

a portfolio of useful experience and knowledge somewhere! that will help develop your career as a diagnostic There are always a few simple rules to follow. expert. There is nothing that quite beats the feel-

● Don’t overlook the obvious. ing of solving a problem, especially if you know ● Look for simple solutions first.

that it has puzzled other people before you – to ● Always get as much information as possible

the point that they have given up! up front.

Good Luck!

ABS, 174, 175, 180 ABS speed sensor, 40, 41 AC, 164, 165 Accuracy, 25, 26 Actuator, 49, 94, 240 Advance angle, 108, 135 Aerial, 221 Air bag, 241, 242, 243, 244, 245 Air conditioning, 214, 231, 234, 235, 237, 238,

239 Air-cooled system, 148 Air cored gauge, 227 Air flow meter, 40, 42, 89, 92, 124, 141 Air flow sensor, 38, 91 Air supply, 131, 137, 144, 147, 148 Air temperature, 135, 147 Alternator, 4, 58, 159, 164, 165, 166, 167, 168, 228 Ampere hour capacity, 156 Antifreeze, 150, 151 Anti-lock brakes see ABS Anti-roll bar, 192, 193 Automatic gearbox, 253, 254, 257 Automatic temperature control, 236 Auxiliaries, 209, 215 Auxiliary systems, 12, 214, 225

Back probing, 17 Battery, 58, 112, 155, 156, 157, 158, 159, 242 Battery charger, 157, 158 Battery rating, 155 Beam axles, 190 Beam setting, 209 Before top dead centre (BTDC), 101, 111, 114, 135 Belt tensioners, 241, 243, 244, 245 Bimetal, 227 Black box, 13, 14, 231, 240 Block diagram, 13, 19, 124, 175, 229, 243,

257, 258 Blower motors, 233 Bonding, 221 Boost charging, 157 (Booster) brake servo, 171 Brake, 169, 171, 172, 177 Brake adjusters, 170 Brake disk, 172 Brake fluid, 172 Brake lights, 202, 212, 213 Brake roller, 172, 173 Braking efficiency, 171, 172 Bypass filtration, 152

California Air Resources Board see CARB Calliper, 170 Camber, 184, 187 Camshaft drives, 99 Camshaft sensor, 42, 114 CAN, 31, 36, 37, 59, 60, 201, 202 CAN controller, 202 CAN diagnostics, 202 CAN-High, 59, 60, 202 CAN-Low, 59, 60, 202 CAN signals, 59, 202, 203 Capacitors, 197, 221 CARB, 62, 63, 74, 75

Carbon dioxide (CO 2 ), 34, 62

Carbon monoxide see CO Carburation, 104, 105 Carburettor, 103, 104, 106 Castor, 184, 185 Catalytic converter, 62, 121, 130, 146 Charging, 156, 157, 159, 163, 166, 167, 168, 220 Charging circuits, 166, 167 Chip, 199, 200 Choke, 104, 105, 106, 199 Circuit, 14, 166, 197, 199, 200, 204, 211, 229 Circuit testing, 66, 163, 168, 209, 215 Closed loop, 19, 46, 68, 92, 110, 111, 133 Closed loop control, 110, 133, 239 Clutch, 161, 247 CO, 34, 62, 73, 120, 130, 146, 262 Coil, 55, 56, 108, 114, 117 Cold cranking amps (CCA), 156 Colour codes, 15 Common rail (CR) diesel, 36, 51, 52, 129 Common rail, 51, 52, 129 Compression, 35, 59, 78, 98, 101, 132 Compression tester, 35, 101 Condensation, 234 Condenser, 234, 235 Constant current, 157 Constant energy, 55, 109, 111, 136 Constant velocity joints, 249 Constant voltage, 157, 165, 227 Constant voltage charging, 157, 164 Constantly variable TransaXle see CTX Constantly variable transmission, 254 Control maps, 136 Controller area network see CAN Coolant, 148, 149, 150 Coolant temperature, 44, 87, 111, 126, 135, 236 Cooling, 115, 148, 149, 150, 151