larryh

The HVB temp doesn't fall very fast. I charged the HVB from 1:30 am to 3:30 am this morning. The HVB temperature is now 90 F. Its only down 10 F from yesterday afternoon.

Today I monitored the Grille Shutters. Normally, when I have monitored them in the past, they have been completely closed. Today, they opened up to 94% after the engine coolant temperature reached 180 F. It was 85 F outside. They closed again while driving the final half mile to my home in EV mode--it looks like when EV+ mode turned on. I will have to monitor them in the Winter. But hopefully, they remain closed when it is cold outside. The HVB temperature reached 100 F today. I used the AC for 40 minutes during the trip set to 78 F. It used 1.04 kWh of electricity. Most of the time it used about 1.4 kW of power. That amounts to about 0.11 gallons of gas (assuming the ICE is 35% efficient and the motor is 80% efficient in generating electricity) or a 16% reduction in MPG.

I examined the efficiency of the ICE in generating electricity for my weekend commute the other day. I looked at two sections where the ICE was charging the HVB while traveling at 65 mph along relatively level sections of the freeway. I plotted ICE power vs. power supplied to the HVB (the electrical power generated by the motor). The results are as follows: y = -0.7365x + 11.21 , R^2 = 0.7406 y = -0.7821x + 13.499, R^2 = 0.8133 y is the power (in kW) supplied to the HVB battery. y is negative if power is being applied to the HVB. x is the power (in kW) output from the ICE. R^2 is a measure of how well the equations above fit the data. 1.0 is a perfect fit. 0.0 means no correlation. That implies the efficiency of the motor in generating electric using power from the ICE is between 73.6% and 78.2%. If the ICE were not generating any power for the HVB, then the power required from the ICE to propel the car at 65 MPH for the above equations would be: 11.21/0.7365 = 15.2 kW, 13.499/0.7821 = 17.3 kW.

When you put the car in neutral, you are still losing energy due to aerodynamic drag, rolling resistance, and internal frictions. The loss is far greater at higher speeds than slower speeds. To conserve as much energy as possible, you might want to reduce your speed some as soon as possible using regenerative braking to capture as much of the kinematic energy as possible before it is lost due to aerodynamic drag, rolling resistance, and internal frictions.

I repeated the same experiment, this time the stops were from 55 mph and I used Low to brake in all but the last case. Unfortunately, Google Earth is not perfect either (the altitudes are off by a few feet), so the percentages may be off by 5%. Initial Deceleration Regen Energy Regen Energy Regen Energy Regen Regen Electrical Speed (mph/sec) Input to Output from from Altitude stored Energy used (mph) Motor Motor Difference in HVB by Accessories 53.3 2.2 79% 79% 6% 65% 2% 52.8 2.1 80% 80% 4% 69% 2% 53.1 2.2 83% 83% 6% 68% 2% 53.5 2.3 83% 79% 2% 67% 1% 52.7 1.7 50% 50% 2% 62% 2% It looks like if you brake near the max charge limit, you capture about 80% of the potential/kinetic energy available for regen. The HVB stores about 70% of that. If you brake slower, you will get less regen as evidenced by the last row (presumably because it takes longer to stop and hence there is more opportunity to lose energy due to rolling resistance, aerodynamic drag, friction, etc.). Something is wrong with the HVB energy measurements during that stop. You can't store more energy in the HVB than is supplied to it--the percentage should be less than 50%. From this and the previous post, if you want more regen, you need to stop faster, up to the 35 kW charge limit for the HVB. However, I don't know a good way to implement that observation. There is no way to accurately guess how far before the stop you need to start applying the brakes at the maximum charge limit so that you arrive exactly at the stop sign. In addition, if you wait to brake, you are using additional energy from the HVB to maintain speed. It looks like the best option is to brake immediately at the max regen limit to slow down to around 30-40 mph, and then you can brake more slowly until you reach the stop sign.

I redid these computations using more accurate Google Earth altitudes. The first column is the initial speed when the brakes were applied. Each time I came to a full stop. The deceleration shows how quickly I stopped. The next two columns show the percentage of available regen energy reaching the motor and the percentage of the regen energy being converted by the motor to electrical energy. The fifth column shows the percentage of the total regen energy which is potential energy from the gravitational potential difference due to a change in altitude from the beginning of braking to when I stop. The rest of the regen energy is kinematic energy from stopping the car. The sixth column is the percentage of regen energy stored in the battery. Part of that regen energy is used by accessories and is thus not available to be stored in the HVB. This is shown in the last column. Initial Deceleration Regen Energy Regen Energy Regen Energy Regen Regen Electrical Speed (mph/sec) Input to Output from from Altitude stored Energy used (mph) Motor Motor Difference in HVB by Accessories 14.5 1.7 82% 80% 0% 55% 21% 30.9 0.6 44% 35% 45% 22% 31% 29.2 1.4 82% 75% 27% 57% 15% 29.8 1.5 73% 72% 14% 67% 8% 43.5 1.5 72% 70% 25% 63% 5% 52.9 1.6 65% 63% 10% 58% 5% 26.8 1.1 59% 50% 4% 36% 15% 26.1 1.1 69% 67% 43% 55% 9% 46.5 2.2 76% 74% 4% 61% 4% 16.3 1.1 52% 51% 44% 41% 18% The percentage of regen energy converted to electrical energy by the motor varies from 50% to 80%, depending on the rate of deceleration and initial speed among other factors. The percentage of regen energy actually stored in the HVB varied from 22% to 67%, depending on the total amount available from the motor and the amount used by accessories.

You have expensive electric rates. There is no way to separate gas miles from electric miles. You don't know how many of the miles resulted from the combustion of gas and how many were from plug-in energy. The car does not track that information for you. If you want to compare gas cost per mile to electric cost per mile you will need do separate sets of trips: one set exclusively in EV mode and the other set when the HVB is depleted. Your trips are very short. They should be able to be done completely in EV mode.

Now that I have more accurate elevation data from Google Earth, I tried using grade assist on this hill again. The descent is 316 feet (96 meters) over 0.67 miles or an average grade of 9%. Assuming the car weighs 1875 kg, the potential energy difference is 9.81*96*1875 J or 0.49 kWh. The speed at the top of the hill was 27 mph or 12 meters per second. I stopped at the bottom of the hill, so the difference in kinetic energy was 0.5*1875*12*12 J, or 0.04 kWh. The total energy available for regen was 0.53 kWh. The total electricity generated by the motor was 0.32 kWh. The regen efficiency was thus 60%.

Using Google Earth I can get precise elevation data. The change in elevation was 183 feet over 0.77 miles, or a grade of 4.5%. The actual regen efficiency was only 31%. The fuel consumed to go back up the hill was 0.040 gallons. The amount of energy added to the HVB was 0.082 kWh. MPGe at 55 mph is typically 145. So I can go an additional 0.35 miles from the energy stored during regen. The MPG is then (2*0.77 + 0.35)/.04 = 47 MPG. Normally at 55 mph, I get 53 MPG. The ICE produced 0.415 kWh of energy to climb the hill. So the ICE efficiency was about 31%. In order for the car to get better MPG with hills than without hills, the regen efficiency has to be significantly better than 31%. A steeper downhill would help.

Looking at a 2% grade hill for about 0.8 miles, I see a regen efficiency of about 50%--it is difficult to tell since GPS altitude is not very accurate. However, the ICE efficiency appears to be 31% for the uphill climb. If the ICE efficiency for the climb drops from 35% to 31% and regen is only 50%, then the mileage is going to be worse with the hill than if there were no hill. The MPG was 45 with the hill vs 53 without the hill.

Actually, you may get better MPG on a hilly route. Assume the car is traveling at 65 mph, the car and contents weigh 1875 kg, and that there is a 2 mile long uphill and 2 mile long downhill at 5% grade. The elevation change is then 2*5280*5% = 528 feet or 161 meters. The potential energy difference between the top and bottom of the hill is 9.81*161*1875 = 2.96e6 J, or 0.82 kWh. If we assume that the car is about 75% efficient in regen, then the car will capture about 0.62 kWh of that potential energy when going downhill. At 65 mph, the MPGe is about 118, so that 0.62 kWh of energy from regen will power the car for about 2.2 miles in EV mode. The ICE will be on for only the first 2 miles. At 65 mph, the car normally gets about 44 MPG. So it will consume 2/44 = 0.0455 gallons of gas for the first two miles if the road were level. However, the ICE must provide an additional 0.82 kWh of energy to get up the hill. Assuming the ICE is 35% efficient, it will use 0.82 / 33.705 / 0.35 = 0.0695 additional gallons of gas to get up the hill. The total fuel consumption will then be 0.1150 gallons. On that 0.1150 gallons, the car will have traveled 2 miles up the hill, 2 miles down the hill, and then 2.2 miles in EV mode. So the overall MPG is 53.6, which exceeds the normal 44 MPG that the car gets going 65 mph on a level road. I would have to make actual measurements of the regen efficiency on such a downhill to verify my assumptions. 75% may be too high. In your case, you are saving the accumulated charge in the HVB until slower speeds. That should produce even greater MPG. Note that during the downhill, the car will be generating power at the rate of 0.62 / (2/65) = 20 kW for 1.8 minutes. Using hills for regen seems to be much more efficient than having the ICE run the generator directly to generate electricity. With hill regen, the ICE is on 1.8 minutes generating an additional 20 kW of power to climb the hill. Then it is off 1.8 minutes during the descent down the hill while regen is taking place. Then the car goes in EV mode for about 2.2 miles. If the ICE runs the generator directly, it would supply an additional 20 kW of power for 1.8 minutes, and then run in EV mode for about 2.2 miles. The ICE does not get the additional 1.8 minutes of rest during the descent down the hill. The ICE is on significantly longer when directly running the generator vs. hill regen. They basically accomplish the same thing, but when the ICE powers the generator directly, the ICE runs for a significantly larger fraction of the time. That is why hill regen is much more effective. So find the hilliest possible route for your commute.

GPS Altitude is not accurate enough to do very precise computations. Unfortunately, the result accuracy is very sensitive to accurate altitude. Will have to do measurements on level roads.

EV later mode is a charge sustaining mode. It attempts to maintain the battery within a predetermined range of state of charge based on when EV later mode was initiated. It does whatever is required to keep the state of charge within that range. It would be interesting to observe what the car does when it is at the top of the range and you are going down a long hill providing an opportunity for significant regen. I don't have any hilly routes that I regularly drive on to investigate what happens. You would probably get better mileage if you didn't have any hills to begin with. In general, you want the ICE to do all the hard work and reserve the HVB to power the motor for slower speeds. As indicated in many of my posts, regen based on potential energy (hills) or kinetic energy (regenerative braking) is about 80% efficient. It requires about twice the energy from the HVB going up a hill as you get from regen going down the hill. Unless you can make it entirely in EV mode, you would want to use the ICE to go up hills. In addition, you want to gather as much regen as possible on the down hills. And you want to use the regen energy (and plug-in energy) during slower speed driving. Which I believe is what you are doing. You could also try leaving the car in auto mode while going up the hills with the ICE on. In auto mode it made attempt to do more opportunistic charging of the HVB while going up the hill rather than in EV later mode. You will have to monitor the Engage screen to see if it is using the Motor to assist the ICE rather than to charge the HVB.

MPG is computed over the entire trip, not just non-EV miles. So gas used for trip 1 is 11.2/70.6 = 0.16 gallons. 120 V charging efficiency is about 72%.

During my commute this morning, I tried forcing the ICE to charge the HVB and then after it had finished charging, run in EV mode to use up the accumulated charge. I was traveling at 65 mph with cruise control on. I forced it to run in EV mode by temporarily reducing cruise control speed and then restoring it back to 65 mph. I did this for two cycles. The MPG over these two cycles was 41.7. Simply running with the ICE on the entire time on, the MPG in the past has been around 44. As predicted, this technique does not appear to improve mileage at 65 mph. For each cycle, the HVB charge ranged from 3.5 kW to 3.7 kW. The ICE was off for about 40 seconds each time. When charging the HVB, the instantaneous ICE MPG started at around 25 MPG and gradually increased to 42 MPG. ICE power started out at 30 kW and gradually reduced to 19 kW. The power supplied to the HVB was about 10 kW when the ICE output was 30 kW, and reduced to less than 1 kW when the ICE output was 19 kW. At 30 kW, the ICE consumed 0.0863 gallons for each kWh of mechanical energy produced (34% efficiency). At 19 kW, the ICE consumed 0.0832 gallons of gas for each kWh of mechanical energy produced (36% efficiency). The ICE was about 4% more efficient producing power at 19 kW. During the first cycle while the ICE was on, the ICE supplied 0.743 kWh of mechanical energy. The generator produced 0.141 kWh of mechanical energy and the motor consumed 0.317 kWh of electrical energy. This implies that 0.567 kWh of energy was required to propel the car. The HVB received 0.142 kWh of electrical energy (if no power was consumed by the accessories). Assuming the generator and motor are equally efficient, this also implies that they were 93% efficient in converting between mechanical and electrical energy.

I analyzed the OBD II data for my commute home the other day during regen. I observed the following for various stops taking into account the altitude difference between when the stop began and when it completed (gravitational potential energy), along with the initial speed (kinetic energy): Initial Speed Deceleration % Mechanical Energy % Energy Captured by Motor Rate Captured by Motor supplied to HVB 30 mph 0.6 mph/sec 50% 68% 30 mph 1.7 mph/sec 86% 92% 30 mph 1.6 mph/sec 83% 95% 43 mph 1.5 mph/sec 82% 96% 53 mph 1.7 mph/sec 70% 96% The faster you stop, without exceeding the maximum 35 kW regen limit, the more efficient the regen (probably because aerodynamic drag and rolling resistance have less opportunity to siphon off the potential/kinetic energy). You capture more of the potential/kinetic energy and the energy captured by the motor is converted more efficiently to electricity--motor efficiency is about 95% for the faster deceleration rates. With the slow deceleration, the efficiency of the motor was 68%. The overall efficiency of regen was about 79% for the faster stops from slower speeds. I'm not sure why the stop from 53 mph did not capture as much of the potential/kinetic energy as did the stops from slower speeds. I will have to examine more stops. Also, I am not sure how accurate my GPS altitude is.

I added an observation for 75 F: 10 F 57 F 75 F Plug-In Electricity Consumed from HVB 2.3 kWh 1.5 kWh 1.7 kWh Electricity supplied to HVB from regen -0.47 kWh -0.51 kWh -0.50 kWh Mechanical Energy output from Motor 2.28 kWh 1.56 kWh 1.74 kWh Mechanical Energy supplied to Motor for Regen -0.47 kWh -0.54 kWh -0.60 kWh The observation for 75 F was the reverse commute from work to home. There is an altitude change of 19 meters during the commute, downhilll to work and uphill back home. The difference in the gravitational potential is around 0.1 kWh. Thus it should take at least 0.2 kWh more energy to go home than to go to work. Taking this into account, the energy consumed for the commutes at 57 F and 75 F were very similar. Of course wind and traffic will affect the results. I have plotted MPGe vs. temperature for my commutes to work. I get the maximum MPGe at 68 F, which is roughly in the middle of 57F and 75F.

The only source I know of Ford specific DTC codes are scattered through this document: https://www.motorcraftservice.com/vdirs/diagnostics/pdf/OBDSM1402_HEV.pdf Another potential source is FORScan which can be downloaded from forscan.org. It works with ELM 327 scanners.

I would wait to see if the MIL turns off after three on/off cycles before going to the dealer. If it turns off, immediate service is not required.

I was greeted to a similar onslaught of error messages once when the car failed to charge the 12 V battery when the car was on and plugged into the charger, but the charger was turned off. The 12 V battery voltage fell below 6 V. ET mode showed several DTCs after the incident. A scanner revealed several comm failure DTCs. It looks like several of the modules are not communicating with each other.

Yes--we had a couple inches of rain here in St. Paul. It will finally be almost 80 tomorrow. Is should be much nicer here for the remainder of your visit.

The only long term data that I have retained vs. temperature is MPGe and Regen miles (post 84 and 197 in this thread). I would have to collect more detailed information to present the information above.

I will have to wait for it to warm up. It should be in the 70's this week. But, 1.5 kWh is about the least amount of energy I consume for the commute. For the 57 F commute, the HVB temperature ranges from 82.4 F to 86 F. For the 10 F commute, it ranged from 41 F to 55.4 F.

I compared the results for two of my 8 mile commutes to work in EV mode, one when it was about 10 F and the other when it was 57 F. 10 F 57 F Plug-In Electricity Consumed from HVB 2.3 kWh 1.5 kWh Electricity supplied to HVB from regen -0.47 kWh -0.51 kWh Mechanical Energy output from Motor 2.28 kWh 1.56 kWh Mechanical Energy supplied to Motor for Regen -0.47 kWh -0.54 kWh It required about 46% more energy to propel the car the when it was cold. Regen was about 8% less when it was cold. So the main driver of decreased mileage appears to be the increased energy required to move the car when it is cold.

The following is a more complete summary of the trip: The motor/generator consumed a net 5.10 kWh of energy from the HVB. Accessories consumed 0.72 kWh. That means 5.82 kWh of plug-in energy was used. The ICE produced 8.33 kWh of mechanical energy. It consumed 0.71 gallons of gas. That means the overall efficiency of the ICE for the trip was 8.33/(33.705*.71) = 35%. The motor/generator generated 1.63 kWh of electricity powered by the ICE. The motor/generator generated 1.39 kWh of electricity through regenerative braking. Overall, they generated 3.01 kWh of electricity during the trip. The motor/generator consumed 3.09 kWh of mechanical power from the ICE, and 2.4 kWh of kinetic energy during regenerative braking. The motor/generator consumed a total of 7.39 kWh of electricity and produced 7.39 kWh of mechanical power. It may look like 100% efficiency, but it was not. I didn't separate out the mechanical power consumed during EV mode, when the ICE was on, and during regenerative braking.