The problem with today's technology and equipment is that most people do NOT READ the instructions! Whether it is because they feel that they don't need to or that it is beneath their level of intelligence, we all need to realize that the manufacturers wouldn't bother to write them and chop down millions of trees in the process of printing them if they were not necessary.
Most equipment comes with instructions and they are normally provided to assist in the use and care and maintenance of the equipment being used. Floor jacks for instance use hydraulic oil to operate, if the oil and the seals aren't checked regularly by following the maintenance instructions then the jack could fail during use and potentially cause a serious accident (once the jack has lifted the vehicle to the required height then axle stands should be used to support the vehicle for safety anyway.)
The same thing goes when using diagnostic equipment, although personal accident is a less likely occurrence in this regard, misuse could cause extensive (and expensive) damage to the equipment and because of misuse the likelihood of a warranty claim being possible is significantly reduced.
The bottom line is ALWAYS read the instructions and familiarize yourself with the operation of equipment before you use it.
Engine analyzers are designed to assist the technician to diagnose problems in a range of vehicle systems such as emissions, fuel, compression/power performance, charging and starting. The analyzer checks the systems and provides information through visual and printed data that indicate likely problems, probable cause and explanations, test recommendations, component repair/replacement and anticipated performance improvements.
The analyzers are built around a computer platform and driven by CD-ROM software. Most analyzers are designed to enable upgrades and optional capabilities to be installed as service requirements change and grow.
Purpose
Today's automotive industry is subject to many regulations and requirements. Growing environmental demands and requirements for high performance, maximum energy efficiency. Most of the major car manufacturers and other renowned companies and institutions use dynamometers in their development, quality assurance and research of vehicle performance.
A dynamometer or "dyno" for short is a device used to measure power and torque produced by an engine. It is said to be created by the "Father of Computing" Charles Babbage.
In general, dynamometers are useful in the development and refinement of modern day engine technology. The concept is to use a dyno to measure and compare power transfer at different points on a vehicle, thus allowing the engine or drive train to be modified to get more efficient power transfer.
For example, if an engine dyno shows that a particular engine achieves 400 N·m (300 lbf·ft) of torque, and a chassis dynamo shows only 350 N·m (260 lbf·ft), one would know to look to the drive train for the major improvements.
Dynamometers are typically very expensive pieces of equipment, reserved for certain fields that rely on them for a particular purpose.
Types
There are two types of dynos:
- Engine dynamometer
This type is normally fixed in a special frame that allows engines to be mounted on to it and can be directly coupled to the engine flywheel. An engine dynamometer measures power and torque directly from the engine's crankshaft (or flywheel), when the engine is removed from the vehicle. These dynos do not account for power losses in the drive train, such as the gearbox, transmission or differential etc.
- Chassis dynamometer
This type is sometimes known as a "rolling road" and the vehicle can be driven onto the rollers and then fixed to the ground with special anchors to ensure that the vehicle does not jump off of the rollers during testing. A chassis dynamometer measures power from the engine through the wheels. The vehicle is driven in gear which turns the rollers and the output is measured. These dynos can be fixed or portable.
In both cases the objective is to be able to measure power and torque output.
General workings
The dynamometer applies various loads on the engine and measures the engine's ability to move the load. Modern dynamometers are normally connected to a computer which uses math to calculate the output of the engine. The engine is run from idle to its maximum RPM and the output is measured and plotted on a graph. Nearly all aspects of engine operation are measured during a dyno run.
Pressure testers
There are a range of pressure testers used in the automotive industry. Each of them are used to provide information about the potential condition of various systems and components.
All gauges consist of a measurement scale from which a reading is taken. Depending on the type of fitting on the gauge, it is normally fitted to the vehicle component via a pipe or tube. In order to take the reading correctly, the instructions provided with the gauge should be followed. Most describe the specific operational circumstances that the reading should be taken in, in order to interpret the condition on the item being tested.
Most gauges are designed to read "zero" at atmospheric pressure (14.7lbs/sq inch or 1 Bar at sea level) as a base measurement.
Some types and applications:
- Vacuum gauges:
These gauges are not regarded by many as a pressure gauge, but in fact they are because the measure "negative" pressure below atmospheric pressure. They are normally used to determine an engines general operational condition. Depending on the reading a number of engine faults can be identified.
- Compression gauges:
These gauges are used to measure the compression pressures inside an engine cylinder and can identify overall condition and pressure leakage situations that could be caused by a range of engine faults.
- Cooling system pressure gauges:
These are used to identify faults in cooling systems and components like pressure caps.
- Tire pressure gauges:
Probably the most common of all, these are normally part of an tire inflation device (although pencil types (shown left) of measurement only are available) and are used to ensure that the air pressure inside the vehicle tires is maintained at the recommended setting.
Scan tools are basically an interface device that is able to communicate with the on board control computer fitted in a vehicle. It has a special connection that fits into the vehicle wiring harness (or via an adapter plug on some vehicles).
The automotive industry introduced standards known as "on board diagnostics" standards ODBI and OBDII (OBDIII is currently under development). The scan tool is a software driven device that contains information about the particular vehicle it is fitted to and communicates with the various on board systems to determine status and condition.
The scan tool is normally used by a technician when a vehicle that is being serviced has a "check fault" indication via a mil lamp or check lamp on the vehicle dash. The scan tool is used to run diagnostic tests on the various vehicle systems and on completion of the tests, information is provided to the technician in relation to the probable cause of the fault.
Most manufacturers have proprietary brand scan tools for their vehicles, however the after market has produced several different of generic scan tools that when the appropriate software information is installed in the tool it is able to replicate the manufactures specific scan tool and provide technicians with the information they need to repair the vehicle.
Multimeters (DVOM)
Introduction
Multimeters or Digital Volt Ohm Meters (DVOM)'s as they are sometimes known are used extensively by technicians in the automotive industry as a basic electrical test tool. In fact, in the hands of a qualified operator the DVOM can be used to diagnose very complex problems in vehicle electrical systems, however the requirement of this practice is much reduced with the advent of "on-board" diagnostics and the use of scan tools.
There are several types available with an equally diverse range of prices to suit. The more substantial types have more functions and are generally more reliable. In some locations many meters are known more commonly by their "brand" name.
Description
The DVOM is an electronic measuring instrument that combines several functions in one unit. The most basic instruments include an ammeter, voltmeter, and ohmmeter.
Normally the meter has a central rotating selection switch which is used to select the electrical test function that the meter is going to be used for, and a set of input points that are used to connect the meter to the item/circuit being tested by test leads. Most meters also have a safety fuse fitted (of about 10 amps maximum) into them for operational safety and to prevent damage to the meter should it be connected to excessive electrical loads.
Features available in some units
Some of the features that these meters have are:
- A continuity tester that beeps when a circuit conducts.
- Digital output (as a number, rather than a scale reading) of the quantity under test.
- An amplifier to sense small voltages, currents and high resistance's.
- Measurements of inductance and capacitance. This is helpful to test components, and therefore much used by technicians that must build and repair equipment.
- Tests of diodes and transistors. This is popular with technicians who have to fix broken equipment.
- Scales and sockets for temperature measurement with standard thermocouples.
- An intermediate-frequency oscillator, a detector and an audio amplifier with a speaker, to diagnose and tune radio circuits. This used to be standard on some Russian models. It is an inexpensive compact substitute for an oscilloscope. It permits one to hear a signal, rather than see it.
- A slow oscilloscope. This is appearing in some high-end computer-controlled multimeters.
- A telephone test set.
- Automotive circuit tester.
- Record high and low voltage snapshots
Test light
A test light is normally used as a basic circuit testing tool to ensure that the circuit is carrying a voltage to enable an electrical component to operate. It is normally constructed in such a way that the tester is insulated from the user and has a small bulb in the circuit. One end of the tester has a "spike" probe that is able to pierce the insulation of cables and the other end has a small clip that is able to be clamped to a suitable return point for completion of the circuit.
Hydrometer
A hydrometer is an instrument used for determining the specific gravity of liquids. It is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or shot to make it float upright. The liquid is poured into a tall jar, and the hydrometer is gently lowered into the liquid until it floats freely.
The point where the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a paper scale inside the stem, so that the specific gravity (or density) can be read directly in grams per cubic centimeter.
In light liquids like kerosene, gasoline, and alcohol, the hydrometer must sink deeper to displace its weight of liquid than in heavy liquids like brine, milk, and acids. In fact, it is usual to have two separate instruments, one for heavy liquids, on which the mark 1.000 for water is near the top, and one for light liquids, on which the mark 1.000 is near the bottom of the stem.
The function of the hydrometer is based on Archimedes principle that a solid suspended in a liquid will be buoyed up by a force equal to the weight of the liquid displaced. Thus, the lower the density of the substance, the lower the hydrometer will sink.
In the automotive industry the common applications of a hydrometer are in battery testing for state of charge and coolant testing for coolant concentrate to water ratio. In each case the hydrometer is different because it has a particular scale on the float to suit the particular application.
