Saturday, June 19, 2021

Mercedes GL450 100k miles

 


I bought a 2013 Mercedes GL450 back in 2018.  It had 64k miles at the time.  It is a fantastic trip vehicle and we have used it for many long road trips.  It hit 100k miles the other day.

As I said this is a fantastic road trip vehicle.  We have taken it on numerous long road trips from 500 miles to 1800 miles each way.  I have made several trips over 1700 miles in 2 days and with me behind the wheel the whole time.  This has the lowest driver fatigue of any vehicle I have ever owned.  For a large SUV it actually handles pretty well.  The fuel economy is not bad either for an SUV this size.  It has done 21MPG on road trips and I generally get about 17MPG in town.  The twin-turbo 4.7L V8 has a nice wide powerband and good power.  I have towed a car on a trailer up steep hills out West with little effort.  


The utility of this vehicle is also very good.  It can tow 7500lbs and has great interior space.  The air suspension keeps it level at all times too.

The vehicle did have one annoying sound that was very intermittent when we bought it.  Accelerating from a stop while turning left cold the clunking sound would intermittently happen.  It was under warranty so we took it to the dealer.  They replaced a bunch of parts at 80k miles and it seemed to go away for a while.  At about 95k miles it came back and was much worse.  Finally we had the left front axle replaced and it was fixed.  One of the CV joints was bad causing this noise.  

The factory equipment tires do not last long at all.  There were not many tire choices for this vehicle either.  It has higher load and higher recommended pressure than most tires this size.  The first set I replaced I used the factory Continental tires at 76k miles.  They were down to the wear bars by 96k.  Now there are better tire options so I upgraded to Michelin tires.



Sunday, June 6, 2021

Energy Efficiency

 It's interesting to see how big of an effect mindset can be on society. Here I will share a few of my thoughts on the subject of energy efficiencies and management.  I do believe in reducing or eliminating waste.  As an engineer, it is my job.  If we focus on waste elimination we will positively impact costs as well as reduce energy needs.  If we just rethink how we acquire and use energy, I believe there are substantial wastes that can be reduced or eliminated.

The views expressed below are just my personal thoughts on opportunities for more efficient use of energy.


Transportation

Personal commuting

Commuting is the task of moving people (and related cargo) from one place to another.  I see this is a bit different from driving but it certainly includes that. I will focus on energy here rather than get into autonomous commuting.  A typical petroleum powered vehicle is less that 40% efficient use of fuel energy for propelling the vehicle.  At least 60% goes to waste, mostly in the form of heat.  Then when we want to decelerate (brake) we dump all that kinetic energy into even more waste heat. That is very significant energy waste.  Also consider how much time is spent idling at a stop.  Integrate this waste over a typical drive cycle and very little of the total energy consumed is used for propelling the car.  Extremely wasteful.  Hybrid powertrains can really help especially in city traffic.  However a hybrid still lugs around a very heavy inefficient powertrain that requires significant maintenance.  I believe that the best powertrain for nearly all commuters is pure electric.  Here are some of my reasons:
  • Nearly zero maintenance.  No oil/filter changes, no coolant flush, no trans service, no spark plugs, etc.  This is beyond the schedule maintenance as the electric powertrain is far simpler with less moving parts to maintain or fail.
  • Longer service life.  While engines and transmissions have improved in durability, they still pale in comparison to an electric powertrain.  There is of course the battery which is the biggest challenge for electric vehicle durability.  However, battery technology continues to improve and with the increased focus more recently, I believe we can solve this problem and have energy storage that lasts for decades soon.
  • Regenerative braking.  Instead of just wasting the kinetic energy slowing the vehicle down with brakes, a well design electric car recovers most of it, storing it back in the batter to be used on the next acceleration.  This is a huge deal!  Not only does this drastically reduce brake wear and dust pollution, it saves energy.  You get to recover a portion of the kinetic energy and use it to accelerate back to speed. This is a clear win-win no brainier.  
  • No idling, ever.  Electric vehicles do not use propulsion motors to power anything but moving the vehicle.  All accessories are electric so they can run independent from an engine.  No more wasteful idling ever.
  • No need to waste a trip to "refuel".  Unlike petroleum, electricity is already available at our homes, businesses, hotels, stores, etc.  Because of this you don't have to make a special trip, or add a wasteful stop in your commute to refuel.  Instead, the vast majority of daily commuters can simply plug in at home, work, the store, restaurants, etc.  You don't need a special charging place but rather just charge at the places you already go.  No sitting and waiting to refuel.  The refueling happens wherever you stop. This is a big paradigm shift I don't feel many people really grasp.  When electric cars are discussed, people always go right to lack of charging stations as the reason they are not ready for an electric car.  Those should only be needed for long distance drives.  You should never need this for our daily commuting.  I think people get stuck in current mindsets and struggle to adapt to this new approach.  I believe we will get over this. If we all went to electric vehicles we would not need anywhere near the dedicated charging stations that we have gas stations.  We would only need them along interstate highways.  In town any building can have charging ports at parking spaces but even these would not get near the use that gas stations do today.  All hotels, restaurants, work places, grocery stores, etc., can have charging stations and some already do today. Inductive charging is coming too.  This will allow wireless charging like some cellular phones have today.  Just pull into a parking spot and charging will happen automatically.
  • Ability to heat and cool the vehicle while it is parked and even while sitting in the garage.  Instead of hoping into a cold or hot car, or having to start and warm up the car (more waste) you can run the heated seats and HVAC before you even get in the car.  You can even do it (for short periods) while it is in the garage with the doors closed.  This actually help maintain your range as well since you can do this while it is plugged in and not use the battery.  Another benefit is safety since you can warm the windows and prevent fogging before you drive away.

Mass Transit

City bussed and local trains can and all go electric.  The same comments for cars apply here.  The use cycle is of course much larger as busses operate all day long.  They do spend a significant amount of time idling at stops.  They also make short acceleration/deceleration cycles constantly.  Here the savings switching to electric is big.  Not to mention the emissions from petroleum powered vehicles in some of the more confined inner cities, tunnels, and drop-off zones in large venues can be a problem. Then there is the noise reduction as well.

Delivery, garbage, mail, etc.

All of these vehicles have even more start-stop and idling periods than the mass transit category above.  Same concepts apply but with even bigger energy savings.


Where does battery electric maybe not make sense?  

I believe there are several categories where hybrid powertrains are likely the best instead of pure battery electric:
  • Sports cars.  While you can make very high-performing electric sports cars, many drivers would miss having the engine as part of this experience.  The Porsche 918, Ferrari LaFerrari, and McLaren P1 were some earlier examples showcasing what hybrid powertrains can do for performance.  These applications do not need much energy storage since the car depends mostly on the engine to supply most the power, only using hybrid to enhance performance and braking.  This approach should make it's way across most sports cars, not just these supercars.  It can be enhanced to provide better active torque vectoring and traction control too. This is a small market share and collectively does not add up to much energy waste in the big picture.
  • Long-haul trucks.  Hybrid makes the most sense here to give the truck a long range and keep the weight reasonable.  The hybrid power can be used to downsize the engine to optimize it for Brake Specific Fuel Consumption (BSFC) while at steady speeds under typical loads.  Use hybrid power to add acceleration and hill climbing power and for regenerative braking.  It could even be possible to make smart mountain passes where trucks going up can take power harvested from trucks going down.  This would improve safety by keeping the brakes cooler as well.  

What about the waste and environmental impact of all those batteries?

Many electric car opponents discuss the cost, energy use, and waste of the batteries for electric vehicles.  It is certainly true that there is a real cost and we need to manage how we handle batteries at the end-of-life.  Todays batteries are hazardous waste.  However, these batteries are getting better and lasting much longer than they once did.  We can also develop recycling programs to recover the materials from the expired batteries.  Of course that is not cheap either.  Energy storage is an engineering problem to solve and as demand increases, the motivation to solve this will also increase research and development. With a world of smart people working on this, I believe we will see breakthrough invention and innovation make step-change improvements as well as continuous improvements in this area.  New electric energy storage can be relatively easily retrofitted to existing electric cars too.  I believe if you buy an electric car now, by the time you need to replace your battery there will be cheaper and better options available than there are today.  These better options can also increase the range of the vehicle, and potentially the charging rate.

Electric Power

Our traditional mindset has a grid with large centralized power generation facilities generating the electricity and distributing it with weather prone ugly powerlines.  It seems most still look at this mindset when applying solar power.  Why?  Instead of making large solar power projects that cover acres of land and then having to send it over these powerlines, why not generate it at the point of use?  Every roof can be used to generate solar power.  Picture every large building having an optimized solar grip on the roof.  Not enough space?  OK, cover the parking lots too. Everyone would get nice shady parking and no land is wasted.  Parking lots are not exactly a view anyone will miss.  

Homes are starting to get more solar power and this makers sense, especially in places like the desert where sun is abundant and air conditioning is one of the highest power consumers that happens to coincide with the most solar power generation.  This can also be used to charge the electric car in your garage.  

I see a continuing need for the power grid but only to fill in the gaps where/when solar cannot be generated, and to move power around from producers and consumers.  Every building can be both a producer and a consumer.  

I think there are places for wind power generation.  Like solar, you are dependent on mother nature to provide the right conditions.  In both cases, alternative power will be needed at times.  I believe natural gas cogen plants can fill this need well in cases where the power is needed for longer periods.  Nuclear power can also be used here.

Electric energy storage can also be used to make better use of solar and wind energy.  

Hydroelectric power is one of the best power sources and we should of course continue to maintain and utilize our dams.  

I still believe there is a place for coal power, primarily as standby power.  This can be started for cases like the Texas deep freeze of 2021.  Keep this electric generation capacity available but use it as a last resort.  

Thermal Energy

We heat and cool our homes and other buildings.  We also convert energy to heat for things like hot water, drying our clothes, etc., and move heat for air conditioning  There are many inefficiencies here where we can make better use of the thermal energy and reduce the need of gas, coal, oil, and electricity.  Take for instance a typical home on a hot summer day.  We run the air conditioning to pump heat to the outside while we use other energy such as gas or electricity to heat the water and dry our clothes in a dryer.  Why do we take the air conditioned air from inside our home only to heat it to dry the clothes?  Why can't the dryer take the heat you are already pumping out of the house to heat the clothes in the dryer?  In fact, why can't it take the hot air from outside to start with already hotter air on warm days?  These things can easily be done actually.  To start with we need dryers that have both intake and exhaust pipes instead of just exhaust.  Then we can bring pre-conditioned air into it and optimize this energy.  

Today you can buy heat pump hot water heaters and these really make sense in certain hot climates.  Geothermal systems also make sense and can be used to also heat the hot water.  In the summer heating your hot water will actually save energy versus just cooling the house.  Hot water heat can and should be added to heat pump systems in hot climates.  You take the heat from where you don't want it (the house) and pump it to where you do (the hot water tank).

There are times when you can simply bring in outside air to heat or cool the home.  If you have a smart thermostat and air handling system, you can monitor the temperature and humidity inside and outside.  If conditions outside become more desirable, just pump that air into the building.  This also brings fresher healthier air into the house.  In some case you may want to add better filtration systems to the air coming in from outside but that is cheap and easy.  Active duct valves are also needed to make each room in the building comfortable.  This becomes especially important in multi-story buildings.  In buildings with a basement, you may be able to cool the top floor simply by bringing colder air from the basement and pumping it to the top floor.  This will make both spaces more comfortable.

In the winter we take warm air from inside our homes, heat it more in the clothes dryer, and then pump it all outside while our heating system runs trying to heat the house.  Often people will also run a humidifier to add humidity to the house.  Instead, you can simply us the hot humid air your just produced in the dryer.  You would still want to condense some of that humidity out and you may want to employ a heat exchanger for most the air as you can add too much humidity but the current state is very wasteful.    

Thanks goodness we are finally replacing wasteful incandescent and halogen light with LED.  This really makes sense in hot seasons and climates.  Back in the day we would run incandescent bulbs which used over 80% of the energy they consumed to produce heat, only to have to run the air conditioning more to pump all that waste heat back outside.  That is very wasteful.  

Sunday, January 17, 2021

Garage parking indicator

 I shopped around for various parking assistance devices for tight garages, or any garage really.  There are various types but most require that you park a specific vehicle in a specific way to work.  For instance, the old tennis ball on a string really only works for the vehicle you set it up for, parked the direction you set it up for.  I wanted a system that would allow me to park any of my vehicles either direction while minimizing the distance to the garage door.  This way you maximize the space at the front of the garage.

Years ago in another garage I built a simple system using standard garage door sensors, some LEDs, and an old cell phone charger.  It works but this time I wanted something a bit better.  I searched again on the internet for a kit or system I could just buy and install but to my surprise there really is not one like the system I made.  

Here are the components I made the system using.  

I mounted the alarm sensors 18" high and the distance away from the door opening that I wanted.  This was about right for most bumpers or license brackets to interrupt the beams.  I wired one power supply to the sensor that does not have the alarm relay (less terminals).  The other power supply supplies the main sensor and the LEDs.  The sensor has a normally open (NO) and normally closed (NC) contact which is used to switch between the green and red LED strips.  
Main sensor

Terminal block above main sensor. Wire pair on right is power supply.  Wires going up go to the LED strips. Wires heading down connect to the main sensor.

Front LED strips (wall with garage doors)

Back LED strips





My system spans both doors as in this case there are on the same wall.  Other garages stagger the doors so you may need 2 systems.  I had the aim the sensors a bit into the garage to get the performance I wanted.  I had also planned to add some reed switches and a relay to disable the LEDs when the doors were both closed but after I got it working I decided it was not necessary. The extra wires were for that.  There are many variations to this approach.  I like not having anything to trip over on the floor, or things hanging in the garage.  I like that I can pull the vehicles in either direction, and move vehicles to different stalls and it still works.  

These doors do have sensors already to prevent closing the doors on things.  However, those don't indicate if you are parked in the right spot or not.  You can only guess and try to close the door.  I also found the sensors are mounted much too low to prevent closing the door in your car.