Vehicle Emission Matters

Talk – Tuesday 9th February 2016, ‘Vehicle Emission Matters’
Ivan Farrow
Reducing vehicle emissions has exercised the brains of vehicle and test engineers since the late 60’s. During this period the permitted levels have been reduced by 99% as technology has developed. Ivan provided a basic introduction to vehicle emissions and how they were, and are, tested in the laboratory and on the road. He examined the difficulties and variabilities encountered, as well as reviewing the difference between official laboratory tests and real-world emissions and fuel consumption, touching on the Volkswagen cheating admission in the process.
To ease the audience into the detailed technicalities he commenced with a walk-through of his career and how his aspirations were adjusted by factors mainly out of his control. He was always interested in how things worked and how to fix them, becoming obsessed with a 1934 Morgan three-wheeler at the age of fifteen and became the most enthusiastic member of the MTW club in the area. This provided an excellent pre-apprenticeship in automotive problem solving!
However he decided that the Motor Industry might be just a passing fancy and, looking for a long-term career, obtained a “thick sandwich” apprenticeship with AEI and Nottingham University.
Always looking for a good deal, he saw an opportunity to get a pilot’s licence and hence become an airline pilot via the University Air Squadron. He was very frustrated when he was rejected because his legs were too long to safely eject from a Chipmunk.
AEI saw him experiencing “the trades”, quality control, large foundry operations, testing, installation on site and turbine development but became largely irrelevant when GEC and AEI merged. This reduced job opportunities so much that a career move seemed appropriate. His chief engineer advised him not to move, as steam turbine engineering was a far more reliable career than automotive! Fortunately he did not agree.
Ford Research Centre proved a much more attractive position than the British Leyland job offer and gave him 23 years of interesting employment. Unfortunately the engine development engineer position that he accepted at Ford was transferred, in a reorganisation, to Test Operations taking him out of the “front line” and into a supporting but important role from which he was never able to escape.
He changed jobs within the Engine and Emissions department roughly every two years until a management cull was introduced resulting in a stalling in his progress.
The expertise gained allowed him to present papers alongside VW engineers at International Symposia and he always felt that VW were the world experts at understanding the emissions game. He was also required to sit on international standards committees.
Trouble shooting test concerns provided some very interesting problems at external test sites, usually at short notice. “Get out to Australia ASAP (1st class, if necessary) and find out why we are blowing up expensive prototype engines while the manufacturers aren’t” was one assignment. Within an hour of arriving in Perth he found that the manufacturers were cooling the engines with water whereas Dunton used the vehicle-specified anti- freeze. The difference in heat transfer rate caused the overheating. He was delighted to spend the rest of the week allocated to this problem enjoying the delights of Perth!
Another assignment could have caused an international incident. During the Fiesta development a foreign manufacturer was obtaining unbelievably low fuel consumption figures at the country’s national laboratory (using a Fiesta competitor car) that Dunton could not match when they tested it on their equipment. This time it was a much shorter flight to find that they had an aeration problem in their fuel measurement pipe work. He was not able to inform them or write any report in case the country in question thought that the UK was accusing them of cheating. However it solved a major problem for the Fiesta Programme Manager.
Looking for a new challenge in a long-term secure job he was able to move directly to be Head of Vehicle Emissions at Warren Spring Laboratory. A Civil Service job working in many “Green” areas including the national air pollution survey couldn’t be more secure, he thought. Unfortunately, in the month between accepting the job and joining the Laboratory the Government’s large vehicle emission contract was cancelled!
There was much analysis to be done of a 200-car survey to show differences between fuel and vehicle technology as well as chassis and road testing in both cold and hot start conditions.
Rather than remaining on a “sinking ship” he was able to move to a job managing Ricardo Engine Test Operations. They had always been a target employer for him (as a world-class engine developer) and his experience at Ford matched their requirements. He loved the area and the job seemed secure so he made a rather rapid decision (for him) to move his family to a house that he is still enjoying.
Shortly after moving in, and landed with a big mortgage, the finger of fate dashed his aspirations when the MD who had employed him was removed overnight and the replacement reorganised the horizontal structure and replaced it with a vertical one without an Engine Test Operations!
The opportunities for suitable work, locally, were virtually none existent so he chose to “get on his bike” and very soon obtained a position with Land Rover in the Electronics development department.
This was virtually a very well paid apprenticeship in practical electronics that provided a totally new range of experiences. He was surprised to be selected for this position as a mechanical engineer but possibly his previous vacation work there and enthusiasm for the brand helped. He had owned two Land Rovers previously one of which was a very early model and other had been used for a Geological Expedition to the Western Desert of Egypt. (11000 miles in 11 weeks)
This is one of the OBD Misfire detection tests!
During this period he was staying in his caravan during the week and commuting to Solihull weekly.
Consequently when he heard that Daewoo were opening a research centre in Worthing he could not believe his luck. After been rejected by the Personnel Department twice he approached the MD and was instantly recruited.
He was prepared to do anything but soon found out that he was the only employee with engine knowledge – a very valuable bonus. Tasks included the design of an £18m engine and emission facility, diesel engine programme, new valve train development to avoid valve bounce, Cold climate testing in Sweden, trouble shooting, etc.
Trouble shooting was always interesting.
Out of the blue he was asked at short notice to fly to Korea (via the US where he had to evaluate some electronic testing kit) in order to investigate why a new car was suffering a lack of power in hot conditions during acceleration. As soon as he arrived he was hustled into a conference room full of chief engineers and vice presidents who demanded to know how he was going to fix the problem! Fortunately he had anticipated this question. He had discovered that the engine breathed air from within the bonnet, which got so hot that the ECU drastically reduced the ignition advance to protect the engine, consequently reducing the power. A minor revision to the intake duct to take engine air from the wheel arch solved the problem. It appeared that the Korean culture restricted subordinates from advising their bosses but a “so called expert” could work miracles. At least he got a full day in Hawaii en route!
Daewoo seemed to be the answer to his dreams until it emerged that their empire was built on straw and after a few years were absorbed by General Motors. The Worthing operation was closed down leaving only a very large hole in the ground designed to hold the equipment for the engine and emission tests facilities!
Once more he “got on his bike” to work away from home in Basildon and Millbrook Testing Ground. Companies he worked for included Ford New Holland Tractors on their engine development, Jaguar on exhaust systems, Iran Khodro developing Iranian built Hillman Hunters for better handling, integration of air conditioning, improved emissions etc.
He was then selected to engineer the transition of the Foggy Petronas FP1 to a fully homologated road bike. This was the most interesting, wide-ranging and most rewarding job of his whole career. The bike had been designed as a no-compromise racing bike and as a result had many challenges. The engine exhaust emerged from the rear engine at 800 degrees C to pass immediately under the carbon fibre seat that would soften at between 100 and 200 degrees C needing state- of-the-art insulation. The water pump was far too small as were the radiators, all requiring total redesign.
The exhaust system and silencer needed to be optimised for the conflicting requirements of noise, power, torque and styling. Extensive testing and development in wind tunnels, at tracks in the UK and Italy was necessary.
These were interesting and exciting at times, including:-
 Total engine failure at 140mph in the Ford wind tunnel
 Tyre failure at 150mph on the Nardo track
 Sudden hailstorm at 120mph at Nardo
 Clutch failures on the comparator Ducati under race start conditions
 When testing was complete150 examples were manufactured ready to be sold to the public in order that the race
bike could legally race in the World Super Bike class. However before they were sold Petronas abandoned their objective of becoming a major motorcycle manufacturer and stored them, probably in Malaysia, although when Ivan last saw them 75 were in Basildon, Essex.
 One day someone will discover the “barn find” of the century worth £3+ million in parts alone!! Diesel Emissions
In order to throw some light on the press coverage of the Volkswagen Cheating Scandal Ivan had to expand on:
how complex and variable emission testing is
how emission drive cycles do not represent real world conditions
how engineers can reduce emissions
how engineers optimise test and vehicle conditions for best emissions within the regulations the pressures on engineering decisions
the difference between chassis dyno testing and “real world” testing.
Ivan set the scene by giving some history of emission levels and technology time-lines, referring to the diagram below:
He identified the major routes to low emissions:
 Improve combustion to give low engine-out emissions
 Add vehicle exhaust treatment to reduce tail pipe emissions with cost packaging and weight compromises
A. Catalysts
B. SCR – Selective Catalyst Reduction
C. EGR – Exhaust gas recirculation
D. Particulate traps
E. NOx traps
He also identified the very many interactive factors that affect engine-out emissions: Combustion air and burn rate –
Pressure, Atmospheric, Altitude, Inlet restriction, Turbo/supercharger, Humidity, Water injection
Movement, Turbulence , Tumble, Temperature, Intercooler Fuel Chemistry
Ignition/injection –
Position of spark/injections, Timing of spark/injections, Intensity/fuel pressure, Burn rate, Detonation “pinking”
Injector Position –
In cylinder, In port, In manifold, Combined, Pressure, Spray patterns, Number of injections, Size of fuel
Emission Testing
He covered all the major aspects of measuring emissions – in an emissions laboratory, including why a Constant Volume Sampling system is universally used to provide dilute exhaust samples: essential for accurate analysis.
He also showed how this very bulky apparatus was miniaturised to fit in a vehicle at Warren Spring Laboratory to enable ‘real world’ tests.
The Ford atmosphere emission test chamber was used to determine where the large variability in laboratory emissions results came from.
However one major conflict will always be the trade-off between NOx and particulates. This allows a range of different routes to meet the targets by altering the EGR rate and therefore the exhaust system components.
Laboratory Emission Measurements Constant-Volume Sampling
On-Road Emissions Testing
Laboratory Emission Measurements
Atmospheric Emission Test Chamber

Emission testing variability
Variability caused by Atmospheric Pressure
Emission testing variability
Variability caused by Humidity
Variability of historic emission results.
He covered how the chassis Dynamometer was set up to simulate road-loads and vehicle inertias
Objective – to simulate road loads
 Select equivalent inertia flywheels or electrical simulation
 Carry out run-down tests between two fixed speeds on track to determine overall drag  Fit vehicle to chassis dynamometer and adjust to get similar run-down times
 Run preconditioning cycle and soak for legislated time
Small Emission Lab
In order to achieve, repeatable and comparable results the initial Test Cycles were very simple and unrealistic.
Compare the above, legislated cycle with London Congested Traffic established while at Warren Spring Laboratory
Real World Congested Traffic Test Cycle
Legislated Test Cycles City Driving x4
How do engineers optimise test results legally – cheat?
 Reduce friction – Run-in Wheel bearings, Wheel
 Reduce Brake rubbing
 Charge battery
 Tape panel gaps in prototypes
 Use minimum soak period and highest soak
 Increase tyre pressures
 Use lowest tolerance speedometer during run-
down test Session 2015/16 No 2
 Squeeze into lowest inertia band by using the weight tolerance
 Calibrate engine for optimum on the test cycle
 Blue-printed engine
 High temperature and altitude set-up testing
 Run tests at optimum pressure, humidity, and
 The Legislation specifies test and vehicle
March 2016
How could VW have cheated?
Two programmes within the engine controller- one clean one dirty activated by Parameter measured within the controller that characterises the emission cycle
 Air/Water/Oil start temperature
 Time since last run
 Specific speed/load characteristics of cycle
 Throttle position sensor
 Wheel speed differential monitor switched off  etc
What might have caused VW to Cheat?
Powertrain Programme constraints would have been agreed years before based on engineering estimates that may have been optimistic?
Production job-one timing was immoveable without the enormous cost of delaying
Targets missed in any of the following?
 Fuel economy
 Emission regulations
 Performance
 Noise
 Cost
Emission equipment packaging not met for:-
 Catalyst size
 NOx / Particulate trap
 SCR – Insufficient urea capacity perhaps. Heavy trucks refill their urea tanks regularly but car manufacturers
have chosen to fill only at the yearly service. Perhaps this is not achievable if the emission targets are to be met
However a company of their standing should only have made this error once and should have corrected it by retrofitting the affected vehicles.
Optimistic Fuel consumption Results
The VW cheating controversy has been reported by the press at the same time as the falsely optimistic fuel consumption results. As a result the public have understandably linked them and assumed the motor companies are cheating again. However it can be seen from the chart previously shown that on-road fuel consumption (22 years ago), at the low speed that the chassis dyno results were recorded at, did not differ widely from on-road cycles.
Emission Analytics are a commercial company with modern techniques and equipment who sell their on-road testing capability to car magazines etc. and have published some of their data. This shows that fuel economy results are now 20+% optimistic but Ivan has not been able to scrutinize their methods so cannot comment on their accuracy.
However it does appear that downsizing of engines will produce better fuel economy under low power / low speed situations (like the Urban Drive Cycle) but not necessarily at the higher speeds that the public drive them at.
Considerable efforts have been and are being made, worldwide, into improving the accuracy and realism of the emission and fuel consumption drive cycles in the laboratory and there are pressures from many areas to carry out on-road tests too.
Bearing in mind the variation in results found when conditions are optimized in a laboratory using a simple test cycle Ivan cannot envisage anyway that these variations can be bettered on the road. However modern technology is a wonderful thing and he is looking forward to the future.
He identified the major routes to low emissions:
 Improve combustion to give low engine-out emissions
 Add vehicle exhaust treatment to reduce tail pipe emissions with cost packaging and weight compromises
 Catalysts
 SCR – Selective Catalyst Reduction  EGR – Exhaust gas recirculation
 Particulate traps  NOx traps
Finally he concluded by showing the chart below and a diagram showing how on-road emissions are measured.
On-Road Emissions Testing

Ivan Farrow