Emissions Tuning Fundamentals: Low Cost Measurement Equipment

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Low Cost Measurement Equipment

10.51

00:00	Whether you're in an area with strict compliance rules or not, the relatively inexpensive tools we're going to discuss in this module can help make great improvements in the optimisation of your calibrations and mechanical components.
00:12	There are many benefits of an optimised calibration, for example, if you're able to reduce fuel contamination of the engine oil from overfueling, you can increase the lifespan of your oil as well as the internal engine components and turbochargers too.
00:25	Not to mention the cost saving of the fuel itself.
00:28	Earlier in the course I talked about atmospheric conditions and their impact on emissions.
00:33	Now, it's time to talk about an inexpensive way to measure those conditions.
00:37	Commonly called a weather station, these devices aren't anywhere near as complicated or costly as the name sounds.
00:43	For under $50 USD, you can get a unit which measures ambient temperature, pressure and relative humidity.
00:50	The next step up at about $100 USD has those features plus you get a unit which has external sensors for wind speed and direction to help decide if wind is going to be a big factor.
01:01	Beyond that, Kestrel and Eltronics are some examples of companies offering more expensive racing focused weather stations.
01:08	These add water grains as a measurement which can assist emissions efforts as well as tuning for optimal power and achieving a specific elapsed time at the drag strip.
01:17	In our experience, water grains, which we learned earlier is a measurement of air humidity, absolutely has a significant impact on engine operation but with that said, it's not critical data to create a successful emissions calibration.
01:31	With that in mind, if the more expensive system is worth it to you, great but don't feel like you can't succeed without it.
01:38	Speaking of less expensive options, if you don't have access to a weather station, getting weather data from the closest public weather station via a phone app like Weather Underground is the next best thing.
01:48	Just keep in mind that weather can vary significantly across a short distance so having a weather station with you is always preferred.
01:56	If you want to take it a step further, recently a company called Connection Concepts released a weather station designed for vehicle installation which streams data over the CAN bus.
02:06	This offers the convenience of data logging ambient data alongside your engine data as well as the ability to make actual tuning adjustments based on this data.
02:15	The next low cost measurement tool is one you may already be very familiar with, a wideband air fuel ratio sensor.
02:22	Most modern gas engine vehicles have widebands fitted from the factory these days which saves money and install time.
02:29	Some diesel engines will have them as well but before trusting data gathered from an O2 sensor in a gas or diesel engine, make sure it reads accurately over the full range that you'll be using and is in good working order.
02:41	This can be done by comparing the data to a known or trusted wideband sensor.
02:46	Often these factory wideband sensors tend to be very accurate at or close to stoich but less so as the air fuel ratio moves richer.
02:55	Precisely the sort of area we'd be expecting to be running in under high load for example.
02:59	So, care is required with the data these sensors provide.
03:03	If a vehicle doesn't come with a wideband, you can of course fit an aftermarket kit.
03:08	If you're going to add an aftermarket wideband sensor, we'd strongly recommend selecting one that transmits data via CAN as this avoids the concern of an analogue voltage being skewed by a ground offset, hence rendering the data potentially useless.
03:23	Most good CAN based wideband kits are around $500 or less at the time of recording and they're easily some of the best money you can spend.
03:32	I say this because while a wideband sensor doesn't measure emissions directly, choosing appropriate air fuel ratio targets and making sure that the engine is operating on these targets is possibly the most important aspect of emissions tuning.
03:46	In terms of wideband placement, factory fitted units are generally already in a good spot for accuracy.
03:52	Just be careful not to overheat them if you're increasing exhaust temperatures from stock.
03:57	When choosing a location to place an aftermarket wideband sensor, pre catalytic converter and post turbo if fitted is going to be the best option.
04:04	Placement post turbo reduces the exhaust heat and pressure present and gives you a reading of what's coming out of the combustion chamber before the cat goes to work on it.
04:14	Tuning for optimal emissions is in many ways an extension of typical tune optimisation and ensuring the sensor is in excellent condition is of course vital.
04:24	While an engine may operate happily at wide open throttle between an air fuel ratio of perhaps 11 .6 and 12.6 to 1, emissions can vary drastically across that range.
04:35	In order to tune with a high level of precision, we need precise measurement tools and that may be as simple as replacing the sensor used for emissions tuning more often.
04:44	If the wideband allows for free air calibration, we'd definitely recommend performing that prior to each tuning session versus perhaps once a week or maybe even once a month.
04:53	Next, exhaust temperature probes can be a useful addition to your suite of sensors.
04:58	K type thermocouples and the associated signal amplifier are again around the $500 USD mark.
05:05	If you monitor exhaust temperature on a stock vehicle at the exhaust manifold flange, near the turbo, pre and post catalytic converter, then you know what the OEM has deemed safe and acceptable.
05:17	Keeping exhaust temperatures within a similar range will generally keep you out of trouble in terms of component reliability.
05:23	When it comes to performance and reliability tuning, often the focus is on avoiding excessive exhaust temperature only.
05:30	For clean emissions though, getting the exhaust up to temperature, specifically the catalytic converters during startup, is also critical.
05:37	We've talked a bit about how important the start and warm up portion of engine operation are to the total emissions output and the quicker you can safely get a catalyst hot enough to operate efficiently, the better.
05:49	Monitoring with EGT probes helps you verify the temperature impact of calibration or component changes independent of other factors.
05:57	You can take it a step further though by using the exhaust temperature data in conjunction with additional sensor data.
06:04	For example, some changes that get the cap warmed up faster may have unintended consequences that an opacity meter or 5 gas analyser would alert you to.
06:13	But before we get into those additional devices in the next module, it's worth mentioning another of the many uses for exhaust temperature data.
06:21	NOx emissions are generally caused by high combustion temperatures so an EGT probe placed right by the exhaust port can be helpful in determining when you've gone too far.
06:31	Again, if you can combine this with a 5 gas analyser, you get the benefit of both pieces of data, then you can see how they correlate and you'll know how to tune your combustion temperatures to stay below the point at which NOx generation becomes unacceptable.
06:45	One thing we haven't yet discussed is how to record this data.
06:48	While you can keep track of passing or failing scan tool results, mileage and date, as well weather conditions by simply typing them into a spreadsheet, wideband sensors and EGT probes offer a lot of data if you have the means to record it.
07:02	Options to record this data range from relatively inexpensive to very costly.
07:07	As CAN based data transmission has become more common, there are more modules available which can amplify K type EGT probe signals and pass the data over CAN in addition to CAN based wideband systems.
07:18	This allows you to record and display data from a number of modules in one place and in some cases even integrate with dyno software.
07:27	Since the subject of data logging devices and analysis could be its own course, which HPA does offer in case you haven't already taken it, we'll keep the logger discussion here to a very simple overview.
07:38	When choosing a logging system, it's important to purchase something that meets not only your current needs but your future needs too if possible.
07:45	For example if you need to sample 3 analog sources and 3 EGT probes on a 4 cylinder as your first project, you may want to go for something that would also suit a 5 to 8 cylinder engine with 2 banks in the future.
07:58	This is a case where the saying buy once, cry once may make sense and you can avoid having to replace your logger in the future.
08:06	Also keep in mind that central logging of all of the data in one place is ideal and we'll be discussing additional devices that you may want to incorporate in coming modules.
08:16	Some loggers will record data from wired sensors, CAN modules and also pole the OBD2 interface.
08:22	Having engine data like engine and vehicle speed as well as throttle position alongside your other data really helps correlate engine conditions to emissions outcomes.
08:32	In short, this is an area where investment is worthwhile.
08:35	A good logger can be used for so many different types of projects related to calibration or component R&D, racing, diagnostics and more.
08:44	In addition to making sure the logger has the inputs needed, it's also important to make sure it can log at a reasonable frequency.
08:51	20Hz is enough for thermocouples, basic OBD2 data and widebands in most cases but in some situations higher frequency sampling is beneficial.
09:01	If you want to record logger data without using your laptop, the logger will either need have sufficient onboard memory or allow for external logging onto an SD card or other storage device.
09:12	Outside of these specs, the quality of the analysis software is just as important as the hardware.
09:17	Being able to extract key conditions from a data set, perform quick comparisons before and after making calibration or component changes and observing trends makes the data useful.
09:28	Some software has functionality that makes these tasks easy and efficient while other offerings simply don't.
09:35	Less expensive loggers can still tick the boxes for the number of inputs and the sampling rate but the biggest difference is in the reliability, quality of the features and efficiency of the analysis software.
09:46	One workaround for the less expensive systems is exporting the data into a format that you can analyse in a more capable piece of software such as MegaLogViewer HD which is a well known, respected and very powerful universal analysis package.
10:00	Let's run back through some of the key points before we move on.
10:03	Monitoring ambient conditions like temperature, pressure and humidity using an inexpensive weather station or a weather app can enhance emissions tuning accuracy.
10:13	Wideband air fuel ratio sensors, especially CAN based models are essential for reliable emissions tuning and should be calibrated regularly.
10:21	Exhaust gas temperature probes provide valuable data for maintaining engine reliability and optimising catalyst performance, particularly during cold start.
10:30	Datalogging systems that integrate wideband, EGT and engine data improve analysis efficiency and allow for more informed calibration decisions.
10:40	While starting with budget friendly tools is acceptable, investing in scalable, higher quality equipment early can save time and money in the long run.