Sean Bennett Diesel engines, trucks, and off-road equipment

April 10, 2017


Filed under: — techrite @ 1:18 pm

December 4th 2018    THE SHENZHEN PROJECT

China has a well documented smog pollution problem caused by the combustion of automotive and solid fossil fuels in, or close to, its urban centers. This problem was tackled using a number of initiatives, one of which was the selection of Shenzhen (population 12.9 million) in 2009 to transition to a 100% all-electric bus fleet. Though there was much sceptism at the time, this goal has now been accomplished and the currently city operates 16,359 all-electric buses. To put this number in perspective, the New York City (population 8.6 million) MTA operates a total of 5,725 buses (40% diesel, 40% CNG, and 20% hybrid). For its next challenge,  Shenzhen is in the process of implementing an all-electric taxi fleet, to be followed by all light duty commercial vehicles operating in the city.

AUTONOMOUS TRUCKS    December 2017

If you do much driving in California, Nevada, British Columbia, or Ontario, chances are you have already come across a prototype of an autonomous truck (AT). The word autonomous literally means free of external controls. When the term autonomous truck is used, it refers to a driverless truck. Sort of. At the moment of writing, there are five classifications of autonomy and only one describes a truck than can be operated 100% without a driver in the cab. The first four categories might better be described as semi-autonomous and that’s mostly what is currently observed on our roads today. The five categories of autonomy are:

  • Level one: specific actions are ‘driverless’ such as accelerating, steering, or accident avoidance+ but a human driver is in control.
  • Level two: most of the over-the-road operation of the truck is driverless, but a driver must be present and alert in the driver’s seat to assume control when prompted (by the vehicle electronics) or+ required.
  • Level three: the truck electronics make some decisions such as navigating a route, steering, braking, and even parking, but the driver is still ultimately responsible for the vehicle.
  • Level four: the truck is able to drive itself on a highway and undertake most running and emergency responses without human intervention. A driver is present and may be alerted to assume control by the electronics when a running condition not programmed into its computer is encountered.
  • Level five: the truck can navigate from point A to point B with no driver.

The most obvious indication that a truck is using some level of autonomous technology can be seen by the array of cameras and lidar antennae mounted over the cab roof and on the front bumper.  LIDAR is an acronym for light detection and ranging and the technology is one key to enabling autonomous vehicle operation. The combination of photo inputs and lidar laser processing is to map the vehicle’s surroundings by feeding the data to a computer. There is no doubt that the technology can map the truck’s surroundings better than a human driver. After all, it’s equipped with not just a pair of eyes and couple of mirrors, but with cameras mounted over every critical point of the chassis. However, the major challenge for autonomous technology is that the human brain can process many more decision-making channels in an instant than can a computer.

Accident Avoidance

The autonomous vehicle may be able to identify the difference between a plastic bag blowing across the road and a child crossing in front of it, but the response outcome will be determined by how its computer has been programmed.  While the response of a human driver might factor in countless variables such as the road surface conditions, the type of load in the trailer (liquid/ livestock/ cargo shift), other vehicles in the vicinity, pedestrians, etc, all in a fraction of a second prior to responding, the autonomous computer is limited to its programming. That said, U.S. Department of Transportation studies have shown that over 90% of commercial truck crashes are due to driver error. Advocates of autonomous vehicles state that even today’s (2017) semi-autonomous technology would substantially reduce that figure … and that as it becomes further advanced, serious truck accidents could be all but eliminated.

Why ATs are inevitable

Automation is changing the way we conduct business and industry analysts suggest that close to 50% of all jobs in the United States are under some level of threat. The prospect of eliminating truck drivers excites fleet operators, who forecast that up to $500 billion dollars annually can be saved in a trucking landscape not limited by driver hours of service (HOS) regulations, the costs of driver pay, and the liabilities of driver errors.  How fast the industry progresses to AT Level 5 will depend on how the technology is introduced onto our highways: a truck-car accident fatality on an Interstate today merits no more than a mention on a local news stream but one involving an AT commands nationwide coverage in the news environment of today.

VMRS   April 2017
ATA’s Vehicle Maintenance Reporting Standards (VMRS) is coding architecture that sets a universal language for fleets, OEMs, industry suppliers, operators, and anyone responsible for spec’ing and maintaining trucks. VRMS was developed by the ATA in 1970 to be a shorthand of maintenance reporting, and has helped reduce long-winded written communications, and inconsistencies over the industry. The system accommodates maintenance reporting through the spectrum of current data logging whether hard paper or online/electronic data based.

VRMS coding accommodates all equipment used by fleet operators whether over-the-road or within service facilities. This includes:

  • highway tractors
  • straight trucks
  • trailers
  • forklift trucks
  • general shop equipment.

VRMS codes are universal across the trucking industry regardless of whether a problem or a component is being referenced. There are codes for:

  • the reason a service procedure is undertaken
  • the nature of the work performed
  • identification of the exact nature of a component failure

A 9-digit VRMS code assigned to every critical component on a vehicle. For example, a diesel particulate filter (DPF) is coded as 043-006-017, and this is consistent regardless of the vehicle or component manufacturer.  This is especially useful for determining the operational life of components and classifying recall data.  In addition, VMRS streamlines work order ‘hard copy’ reporting by providing technicians with a universal and abbreviated language for describing service repairs.

VMRS provides a framework for determining the effectiveness of a fleet maintenance program and can help identify issues concerning its effectiveness. Some fleets have used it for:

• Determining the appropriate frequency of PMIs
• Calculating the longevity of components
• Forecasting the labor hours apportioned to PMIs

VMRS can help fleets budget, distribute labor, control inventory, manage warranty, monitor productivity, and track equipment performance. It has become essential for fleet technicians to use, and understand, the role of VRMS in the modern fleet service facility.

Fairness of CSA violations enforcement

May 15th, 2014

Recent data printed in the ATA’s iTech Newsletter correlated the number of CSA (compliance safety accountability) violations to inspections on a state-by-state basis and the analysis has raised a few eyebrows. Although an objective of CSA’s Behavioral Analysis and Safety Improvement Categories (known as BASIC) was to level the playing field for operators, the data indicates that inspections can be significantly more robust in some states, prompting questions about the way inspections are administered. There is no doubt that the autonomy of state highway traffic agencies empowers enforcement officers to target specific driver behaviors and out-of-service (OOS) categories, while being more lenient on others. In the iTech article, one carrier operated its fleet in one state for just 7% its accumulated haulage miles, but logged more than 60% of its total violations in that state.

Heading the list of robust enforcers was Rhode Island in which the violation-to-inspection ratio was 3.58:1. Included among the toughest states to operate in, at around 3.00 violations or more per inspection were Connecticut, Virginia, Wisconsin, and Texas. On the other end of the spectrum, the states in which carriers were least likely to be cited at 1.00 violation or less per inspection were California, Montana, Mississippi, and Tennessee.

The result of the data culled from CSA inspections data has led some fleets to educate their drivers on the political elements of truck inspections that prevail in the state(s) they operate in … this is nothing new, most seasoned truck drivers can immediately identify those states which tend to more aggressively enforce speed limits. The troubling issue is that fleets and drivers developing an understanding of the priorities of the jurisdiction in which they operate to minimize citations, defeats that initial CSA objective of leveling the playing field coast to coast.

The real key to fair play when it comes to CSA violations is the right combination of training and experience of those performing inspections. As much as possible, judgement calls should be eliminated: in the current inspection environment, a brake hose with minor evident surface rub could be classified as a chafed OOS condition by an inexperienced inspector. In other words, the language and specifications of a failure condition should be precise. Only then will CSA achieve real credibility within the trucking community.

Maintenance versus OOS Standards

April 15th, 2014

I write textbooks for aspiring truck technicians, so I cannot avoid making some references to the technical standards we work to in the industry. If the decision were mine alone, I’d indicate in text where the appropriate standard could be found and leave it to the student to research and obtain the most up-to-date information. The major reason I’d rather not insert too many maintenance  specifications in a textbook, is that both maintenance and out-of-service (OOS) standards are prone to change with more frequency than five year textbook revision cycles.

Since the introduction of Compliance Safety Accountability (CSA) in 2010, it has become increasingly important that truck drivers and repair technicians understand the difference between a maintenance and an OOS standard. Although I emphasize these definitions in textbooks, I decided to make this a blog subject because there is so much general confusion, especially among truck drivers. With the introduction of CSA, drivers, technicians, and fleets can be held accountable for safety violations … and because an objective of CSA is to remove the worst offenders from our roads, understanding what constitutes a safety citation is crucial if you want to remain an operator.

Maintenance standards are what all truck technicians should work to on a daily basis. They are published by manufacturers of equipment, so to locate the maintenance standards required of foundation brake components the technician would reference Bendix or Haldex service literature, available online at no cost.

OOS standards are published annually on April 1st available: a hard copy of these standards can be purchased for around $40. CVSA OOS standards are enforced throughout the NAFTA geographic region. The important thing to understand about OOS specifications is that they are NOT maintenance standards: an OOS standard identifies the point at which a component has deteriorated sufficiently that the rig has become DANGEROUS to operate. The CVSA will issue a citation for an OOS breach and this will be logged to the CSA database.

Fleets do not appear to be doing a good job of educating drivers who seem to be overly aware of critical OOS specifications and much less aware that ‘safe’ operation means that OEM maintenance specifications be observed. Studies undertaken in 2013 indicated that 70% of OOS citations could have been avoided if the driver had properly followed the required pre-trip inspection, a task that takes no more than 10 minutes to perform on a typical tractor-trailer combination.  by the CVSA so the 2014 edition has just become


Understanding Truck Wheel-End Vibration

September 23rd, 2013

It is an unfortunate fact that some manufacturers of on-highway truck tires assert that their product does not require balancing on installation, with the result that we assume wheel ends to be in balance. It is also a fact that tires represent only a portion of the dynamic rotating mass of a truck or trailer axle-end assembly. Another less well known fact is that when an axle end is dynamically balanced, tire longevity can be doubled. For a number of years, we have had the technology to balance truck axle ends so you’d think it would be something of a no-brainer to make use of it … but changing mindsets in our industry is not an easy task, especially when the economic interests of major suppliers are at stake. When an axle end is out-of-balance, the tire (regarded in the industry as a consumable) assumes the most punishment, but the resonant effect imparted through the suspension, the frame, the cab right through to the driver’s seat … has other consequences. In other words, the overall effects impact on much more than the vehicle tires. Rolling resistance increases proportionally with the extent of out-of-balance meaning that there is a major hit on fuel economy: fuel is another consumable that should be foremost in the minds of anyone working in the trucking industry as we head for the 2017 Federal mandates. It helps to understand a little about wheel and suspension dynamics and that begins with understanding something about resonation.

Most of us learn that the speed of rotation is measured in revolutions per minute or rpm.  We also understand that frequency is measured in waves (nodes and antinodes) that we rate as hertz – mathematically the wave frequency per second. If a wheel is out of balance it has a tendency to hop … and if the hop frequency of wheel is measured at 10 times per second (10 hertz), then a resonant frequency of 600 times per minute (60 seconds) results. The severity of resonant frequency is amplified by the actual weight imbalance of the rotating mass of the wheel end because it is all unsprung weight – the greater that unsprung weight, the longer the distance between the peaks and valleys of the waves (nodes and antinodes) and the higher the potential for vibration damage … in addition to the fuel economy and driver discomfort we mentioned earlier. Yes, tire longevity is the most obvious casualty … but the vibration load imparted to the suspension whose role it is to dampen resonation also increases in proportion to its severity which we know as oscillation.

Springs support the vehicle load and all springs have a working operating range, the limits of which are known as jounce (most compressed condition) and rebound (least compressed condition). Some types of spring have a built-in damping action such as multi-leaf spring packs which use inter-leaf friction to suppress oscillation … because of this self-damping action, multi-leaf spring packs on truck suspensions seldom require shock absorbers. However, the most common truck suspension is the air suspension. Air springs have zero self-damping capacity … so they require something else to accomplish damping, usually shock absorbers. Shock absorbers dampen axle oscillation by using simple hydraulics to smooth the resonant nodes and antinodes and they are pretty good at doing this assuming a balanced axle end and normal road conditions. However, when the severity of the oscillation exceeds the shock’s ability to suppress the resulting resonation, the vibration conducts to the chassis … and coincidentally ends up destroying the shock absorber. Let’s take a closer look at how out-of-balance intensity is produced.

The heavy spot in a wheel end is subject to centrifugal force for most of its rotation and it contacts the road surface just once per revolution. This is the basis of rotational reverberation frequency. You can get an idea of this effect by striking a truck tire with a 4 pound shop hammer on one side while feeling the reaction on the other. Going back to a real world truck tire, a mere 6 ounces of static imbalance can multiply to a force of 60 pounds when the wheel is moving at 60 mph down a highway – that’s like striking the tire with a 60 pound hammer each time it rotates.    The average commercial truck tire is subject to approximately 600 revolutions per minute when run at 60 mph. And a standard tandem-drive truck coupled to a tandem axle trailer has a total of 10 wheels … and up to 18 tires!

As an industry, it’s about time we looked at the real cost of out-of-balance wheel ends. Doing that may require seeking advice from a sector that extends beyond those manufacturers whose commercial interests might be hurt by improving the status quo. Solving the problem has the potential to save millions in operating costs … there are currently available solutions, axle ends can be easily and cheaply balanced, so it’s contingent on us to use them.


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