larryh

In this plot, I have removed the plug-in EV miles from the commute. These are the results I would expect to obtain if I made the trip entirely in hybrid mode and did not charge the HVB before each commute, i.e. I drove a Fusion Hybrid rather than a Fusion Energi. In the summer, at 75 F, I would average 46 MPG. In the winter, at 0 F, I would average 35 MPG. This time, it requires 46 / 35 = 1.3 times as much energy in the winter vs. the summer. This is far more than I would have expected due to the affects of increased air density and increased tire rolling resistance alone in the winter. I would have expected the increase to be more like 15% rather than 30%. I suspect the reason for the much higher than expected energy consumption in the winter is again significantly increased internal friction due to cold drivetrain components.

The following plot shows MPGe vs. Temperature for a longer 60 mile commute. I start out with a fully charged battery and after that is consumed the car enters hybrid mode. In the summer, at 75F, I average around 68 MPGe. In the winter, at 0 F, I average 44 MPGe. So it takes 68 / 44 = 1.55 times as much energy in the winter vs. the summer for my commute. The main reason for the large difference in MPGe for summer vs. winter is that I get less plug-in EV miles during the commute. Plug-in EV miles are approximately 2.8 times more efficient than ICE miles. In the winter, I have a larger proportion of less efficient ICE miles in the commute, which negatively impacts MPGe.

To summarize my previous posts, it requires 1.76 kWh of plug-in energy for my 8 mile EV commute to work at 75 F vs. 2.41 kWh at 0 F, or a difference of 0.65 kWh. I estimate that about 0.43 kWh of that difference is due to increased internal friction associated with cold drivetrain components (more viscous transmission fluid, stiffer bearings, more friction between gears, etc.). This increases plug-in energy consumption by 0.43 / 1.76 = 25% . The remaining 0.23 kWh is associated with denser air (aerodynamic drag) and tire rolling resistance. This increases plug-in energy consumption by 0.23 / 1.76 = 13%. Without the ICE running, it takes a very long time for the drivetrain components to warm up. In a typical winter commute, the transmission fluid temperature starts at garage temperature (about 20 F) and only warms up to 50 F by the end of the commute. At 50 F, there still is substantial increased internal friction. If the ICE were running, the drivetrain components would heat up much more quickly from the waste heat generated by the ICE and the effects of a cold drivetrain would be less pronounced. Whenever you read information about the effects of cold weather on mileage, they rarely mention increased internal friction. Yet, at least in my case, this is the factor that has, by far, the greatest impact on mileage in the winter. Now if rather than an engine block heater, they made a heater for the transmission instead. That would be far more useful for improving EV mileage in the winter.

I estimate about 1.4 kWh of my commute to work is used to supply kinetic energy (for acceleration) to the car. Thus during the summer, of the 2.51 kWh used to propel the car, 2.51 - 1.4 = 1.11 kWh is used to overcome friction. Of the 1.4 kWh used to supply kinetic energy, I get 0.75 kWh back during regen, i.e. 55%. During the winter, of the 2.84 kWh used to propel the car, 2.84 - 1.4 = 1.44 kWh is used to overcome friction. Of the 1.4 kWh used to supply kinetic energy, I get 0.43 kWh back during regen, i.e. 30%. The analysis in Post 348 is incorrect. The plug-in energy consumed at 75 F is 1.76 kWh and at 0 F it is 2.42 kWh. Thus 2.42 kWh / 1.76 kWh = 1.38 times as much plug-in energy is consumed in the winter vs. the summer, i.e. 38% more plug-in energy. At 0 F, the energy to overcome friction is 1.44 kWh / 1.11 kWh = 1.3 times the amount at 75 F. So 30% of the 38% total additional plug-in energy results from increased friction. The remaining 8% is due to less efficient regen (mostly from increased friction in the transmission). Note that ICE cars do not have regen and are inherently much less efficient. The effects of colder weather impact them less than a PHEV. Not including regen, the increase in energy consumption is 2.84 kWh / 2.51 kWh = 1.13, i.e. 13% more. Including regen, the increase in energy consumed is 2.41 kWh / 1.76 kWh = 1.38, i.e. 38% more. Cold weather has a much greater impact on PHEVs.

I believe this chart explains much of the energy losses at colder temperatures. It shows the power from the HVB required to propel the car at 30 mph vs. Transmission Fluid Temperature (TFT). The outside temperature is 30 F. It takes 1.5 times as much power to propel the car when the car is cold (TFT is 30 F) vs. when the car is warmed up (TFT is 110). When it is cold out, it is going to take many miles for the car to warm up (TFT to reach 110 F). It will take much longer when running in EV mode without the help of the ICE to warm things up. Pure EVs don't have an eCVT like the Energi. In cold weather when running in EV mode, I suspect the eCVT is a useless appendage that wastes a significant amount of energy. Pure EVs will probably not see as much of a dramatic reduction in mileage that I observe in the chart in post 346 above. Regen during cold temperatures works just as well as it does at warmer temperatures (provided the HVB is not too cold). The reason for significantly less regen in post 347 is the eCVT (and the rest of the car's transmission system) is siphoning away energy that would otherwise be available for regen.

The following is a simplified analysis of why regenerative braking is less effective in the winter. The actual analysis is much more complicated. At 75 F, the total amount of energy required to propel the car for my commute is 2.51 kWh, the energy recaptured by regenerative braking is 0.75 kWh, and thus the net plug-in energy used is 2.51 - 0.75 = 1.76 kWh. At 0 F, the total amount of energy required to propel the car for my commute is 2.84 kWh, the energy recaptured by regenerative braking is 0.43 kWh, and thus the net plug-in energy used is 2.84 - 0.43 = 2.42 kWh. It requires 2.84 kWh / 2.51 kWh = 1.13 times more energy at 0 F to overcome increased friction. In the summer, 0.75 kWh / 2.51 kWh = 30% of the total energy used to propel the car is recaptured via regenerative braking. In the winter time, 13% more energy is required to overcome additional friction and is not available for regenerative braking. Thus of the 2.51 kWh of energy to propel the car in the summer, 13% * 2.51 kWh = 0.33 kWh is lost to additional friction and can no longer be used for regenerative braking. That leaves 0.75 kWh - 0.33 kWh = 0.42 kWh available for regenerative braking. So now only 0.42 kWh / 2.84 kWh = 15% of the energy is recaptured by regenerative braking in the winter. Whatever energy is lost to overcome additional friction is not available for regen. This greatly impacts the efficiency of regen and overall MPGe of my commutes.

kWh/mile is computed as the net plug-in energy consumed by the car divided by the total distance traveled. Thus the net plug-in energy consumed for my commute is kWh/mile times the number of miles traveled. The actual distance of my commute is 7.8 miles. So the net plug-in energy (NE) consumed for my commute is (see post 346 above): At 0 F, NE = 0.310 * 7.8 = 2.42 kWh, and at 75 F, NE = 0.225 * 7.8 = 1.76 kWh. If the percentage of energy recaptured by regenerative braking is R, then the total energy (TE) used to propel the car is TE = NE/(1-R). This is the net plug-in energy plus the energy recaptured through regenerative braking (see post 347 above): At 0 F, TE = 2.42 / (1-0.15) = 2.84 kWh, and at 75 F, TE = 1.76 / (1-0.30) = 2.51 kWh. In this case, the total energy used to propel the car is 2.84 / 2.51 = 1.13. That means it requires about 13% more energy to propel the car at 0 F vs. 75 F. This is due to increased air density, increased tire rolling resistance, and increased internal friction at 0 F vs 75 F. The energy recaptured through regenerative braking (RE) is R * TE: At 0 F, RE = 0.15*2.84 = 0.43 kWh, and at 75 F, RE = 0.30*2.51 = 0.75 kWh. Regenerative braking is significantly less effective at colder temperatures. Much of the kinetic energy that would otherwise be available for regen is lost due to increased friction from higher air density, increased tire rolling resistance, and increased internal frictions, among other factors. In addition, if the battery is cold, then it can't accept as much regen as when it is warm. Any regenerative braking above the maximum charge limit of the battery is lost and cannot be stored in the battery. It is because of the significant impact of cold temperatures on regenerative braking that the kWh/mi at 0 F is 1.38 times that at 75 F. 13% of the increase is due to increased friction required to propel the car at colder temperatures and the remaining 38% - 13% = 25% is due to less effective regenerative braking. During my city commute to and from work with many stop lights and a 55 mph speed limit, regenerative braking is critical to attaining good mileage. In the winter, the effectiveness of regenerative braking is cut in half. The very feature that makes EVs so efficient in the first place is rendered significantly less effective by cold weather.

The following chart shows the percentage of energy recaptured via regenerative braking vs. temperature during my 8 mile commute to work in EV mode. At 75 F, 30% of the total energy used to propel the car is recaptured via regenerative braking. At 0 F, 15% of the total energy is recaptured. Cold weather significantly impacts regenerative braking. In this case, the effectiveness of regenerative braking is halved at 0 F vs. 75 F.

The following plot shows the effect of temperature on my 8 mile commute to and from work in EV mode. I have plotted kWh/mile consumed by the car vs. temperature. At 75 F, I get about 0.225 kWh/mile (150 MPGe). At 0 F, I get about 0.310 kWh/mile (109 MPGe). It appears that it takes about 0.310 / 0.225 = 1.38 times more energy at 0 F vs. 75 F.

The following plot shows the ratio of the actual energy consumed by my Level 1 and 2 chargers divided by the plug-in energy reported by MFM and shown on the car's trip odometers. The data is plotted for approximately each month of the year. I have a metered Level 2 Charger and use a Kill-A-Watt meter for the Level 1 Charger. So I can track of all the electricity used to charge the car. I also record all the plug-in energy recorded by the odometers in the car. In the winter time, the ratio is around 1.65. It requires a lot of energy to precondition the car--this is energy that is not recorded by the car's trip odometers. In the summer, the ratio falls to about 1.3. I don't precondition the car in the summer. The ratio in the summer is greater than one since charging the car is not 100% efficient. For the level 2 charger, efficiency is around 82%. For the level 1 charger, it is around 72%. In addition, the car uses energy to charge the 12 Volt battery occasionally, which is not recorded by the car's trip odometers. Finally, there are small vampire losses from the chargers themselves (2 - 3 watts). This data might be useful in assisting someone who is trying to estimate the actual amount of electricity consumed by the car from what the car reports on the odometer. But note that it is based on a mixture of charging with Level 1 and Level 2 chargers and Minnesota winters. You will have to compensate for any differences from these assumptions.

When you say the ICE is quieter in the FFE, is that during acceleration, driving at constant speed on the freeway, or under all conditions? I have the 2013 FFE. Using an SPL meter, I measure the noise in the car to be about 63 db at 70 mph on the freeway. The SPL meter does not notice any significant difference in noise levels when the ICE is on vs. when it is off. The noise is mostly road and wind noise. However, I can hear the difference when the ICE is on vs. when it is off. There is a low frequency background drone when the ICE on. However, it does not stand out much from the road noise. Perhaps during acceleration, the electric motor is able to assist the ICE more on the FFE (with a larger battery), so the ICE doesn't have to work as hard. Or perhaps, the ICE charges the HVB less often or faster in the FFE. When the ICE charges the HVB, the ICE has to work much harder and makes significantly more noise. Since the FFE HVB is much larger, the ICE doesn't charge the HVB as much (at least until you enter hybrid mode). I suspect that, in general, the FFE doesn't put as much load on the ICE as the FFH (using higher RPMs instead).

I have now had my 2013 FFE for two years and driven 23,000 miles. Looking through the data I have collected over this time, my best estimate of the SOH of the HVB is 96-97%. When new, the HVB should store 7.2 kWh of energy at 100% SOC. Lately, with the warming temperatures, mine stores about 6.95 kWh of energy. For my 60 mile commutes, I have been averaging 5.5 kWh of energy from the HVB until the ICE turns on. With the current outside temperatures, I would have expected about 5.7 kWh when new. The most plug-in energy I have ever output from the HVB was 6.0 kWh (the outside temperature would have to be warmer to do that). So degradation appears to be around 2% per year so far.

MPG is miles per gallon of gas. You aren't consuming gas while driving in EV mode, so the numerator (miles driven) keeps increasing while the denominator (gallons of gas consumed) remains the same, i.e. MPG increases.

The system sensors have many limitations. They are going to give false alarms or fail to detect various conditions. This if from the manual. Due to the nature of radar technology, there may be certain instances where vehicles do not provide a collision warning. These include: • Stationary vehicles or vehicles moving below 6 mph (10 km/h). • Pedestrians or objects in the roadway. • Oncoming vehicles in the same lane. • Severe weather conditions (see blocked sensor section). • Debris build-up on the grille near the headlamps (see blocked sensor section). • Small distance to vehicle ahead. • Steering wheel and pedal movements are large (very active driving style). Because the way radar works, if the relative motion between the car and the object is less than about 6 mph, the object will go undetected. The radar uses doppler (relative motion between the car and an object) to distinguish between the background and objects of interest. They would have to add a great deal more intelligence to the detection algorithms in order to be significantly more accurate.

Here is another video of showing the future of automated driving:

Should you be interested in learning more about GPS accuracy, you can visit Garmins web site: http://www8.garmin.com/aboutGPS/

Is remote start enabled in the car? You can try this checklist: The remote start system will not work if: • the ignition is on • the alarm system triggered • you disable the feature • the hood is open • the transmission is not in P • the vehicle battery voltage is too low • the service engine soon light is on. It won't work if the MIL is on.

ECM = Engine Control Module monitors driver inputs and controls engine related functions. PCM = Powertrain Control module interprets driver inputs and controls energy management, generator, and motor functions. The GPS and Instrument Panel Cluster faults will not illuminate the MIL. My guess is that the ABS module fault caused the MIL. All the faults that I listed above were retrievable months after the MIL turned off. If there are any DTCs, the dealer should be able to read them. I have no trouble finding them with ForScan.

The MIL comes on for many reasons. Using ForScan I can read the DTCs from the OBD II connector. The following shows some of the DTCs that I have observed when the MIL light was on: Code: U0121 - Lost Communication With ABS Control Module Code: U0151 - Lost Communication With Restraints Control Module Code: U0155 - Lost Communication With Instrument Panel Cluster Control Module Code: U016A - Lost Communication With Global Positioning System Module Range/Performance Code: U0198 - Lost Communication With Telematic Control Module Code: U0100 - Lost Communication With ECM/PCM A These all resulted one time when I washed the car when it was about 20 F. Apparently the moisture condensed on the cold circuits in the car causing the car to loose communications with several of the modules. I have washed it several times since in the cold and have not had any further problems. I have also observed the MIL when the 12 V battery was low.

Because of the large measurement errors in GPS location, it takes a few seconds for the GPS device to recognize you are accelerating or stopping unless you provide it with the car's speed. When you are braking, it is going to continue to think you are traveling at constant speed until it has enough evidence to recognize that this is no longer the case. Similarly, when you are accelerating from a stop, it won't recognize that you have started accelerating until it has sufficient measurements to realize that you have started moving. Thus you see the large spikes in speed error when coming to a stop and when accelerating from a stop. I have no idea how long it should take the car to figure out recalibration for a change in tire size. However, I would be very wary of changing tire size on the car, I have no idea how many systems in the car may be impacted. In the very least, the odometer readings will be wrong.

The following plot shows the error in speed computed by GPS during my commute to work. The speed estimate provided by GPS is off by more than 10 mph at times. If speed is off, then GPS location is also off. For each second that passes while the GPS speed is off by 10 mph, location error will increase 15 feet. So after 5 seconds (the length of time it took GPS to correct the error), the GPS location error is off by 75 feet (in addition to the normal GPS location error). If GPS has access to speed information, i.e. tire rotation speed, then location is going to be far more accurate. You definitely want to provide the car's speed to the GPS location estimation algorithm.

The following chart shows smoothing of GPS data. Here 321 independent measurements were taken to come up with the final GPS location. The car is stationary. I only have the smoothed measurements, i.e. average of the previous measurements. So at measurement 20 on the plot, you see the relative GPS error based on averaging 20 independent measurements. The individual raw measurements jump all over the place. Initially, with less than 10 measurements, the location is off by more than 10 feet relative to the final calculated value. Because the individual measurements are very noisy, it takes many measurements to converge on an accurate estimate. Convergence is much faster if you know the car's speed, i.e. tire rotation speed. Without tire rotation speed, GPS smoothing is going to have to calculate both speed and position, which takes significantly longer to do than if you knew the exact speed of the car. If you are accelerating or braking, then smoothing takes all that much longer to come up with an accurate estimate. If you know the car's speed at all times, you can come up with a much more precise location much faster. Convergence will be much faster than what is shown in the chart below under all conditions: constant speed, acceleration, and braking, The plot only shows relative error, which is different from absolute accuracy. The dilution of precision of the measurements was 10, which implies absolute accuracy is only fair. The final estimated position was off by about 25 feet.

I have a Garmin GPS. They are not all that accurate. As I stated, accuracy is about 30 feet under ideal conditions. Many times, it is much worse. Differential GPS is better with accuracy around 10 feet. I have made many recordings of data from the OBD II connector in the car along with GPS data. The GPS data is very noisy. I only trust the distance traveled as measured by the car and not the GPS data for shorter distances.

GPS is not always accurate. To be accurate, GPS requires direct line of sight to the GPS satellites. If you drive the car through a forest, tall buildings, in a parking garage, etc., the signal quality from the GPS satellites will be poor and location accuracy will be degraded. You need to know the distance traveled, i.e. tire rotation, to maintain an accurate position for the car. The GPS position is going to 1000s of feet off. I think you will have more problems with location if they only relied on GPS position and did not use distance traveled from the tires. Using distance traveled from the tires will significantly improve position accuracy provided the tire information is correct. Even under the best conditions, GPS measurements are noisy and accuracy is maybe around 30 feet. The noisy measurements need to be smoothed with the help of distance traveled from the car. You wouldn't want to see you car jumping all over the road on the navigation display. Whoever installed the tires should haven been aware of these issues and should have taken corrective action so you did not experience any problems.

The HVB energy varies with temperature--see post 127. The BMS takes temperature into account, along with many other factors, to determine the energy in the HVB. SOC is computed as the current amount of energy in the HVB divided by the maximum energy that the HVB can store. The BMS can only estimate the current energy and the maximum energy that can be stored in the HVB. There is probably a 5% margin of error. As temperature changes, its going to come up with different estimates for the current and maximum energy, so the SOC is going to change. I have plotted HVB voltage vs. SOC vs temperature. I see no evidence that voltage varies with temperature at a given SOC. WIth increasing temperature, the HVB voltage increases as well as the energy in the HVB. The BMS takes this into account when computing SOC.