larryh

Engineering Test mode does not show all the DTCs. It could have been a communication error between the modules that caused the problem. That would show up as an OBD II DTC. You would need a scanner to read it.

The codes should be saved by the car for several weeks. The dealer should be able to access them.

To see OBD II DTCs, you need a scanner. For all other DTCs, you can use ET (Engineering Test) mode by holding down the left OK button on the steering wheel while starting the car. You can use the up/down arrows to scroll to the screen that shows DTCs. However, I am not aware of any source that provides their meanings.

When I measure the power on the electric meter for the 240 V charger when charging the HVB, it is usually a fairly steady 3.425 kW. The charger inside the car consumes a steady 3.324 kW of power. The car's electronics and fans consume the remaining 100 watts of power. The power consumed by the electronics and fans vary by a small amount.

For the first year that I have now owned the car, I drove 11,400 miles and spent a total of $627 on electricity and fuel. That includes the electricity to precondition the car during the many days it was below zero. The average MPGe over that time was 55, which also includes the electricity to precondition the car. I did not pay anything to have the car serviced.

For my recent 56.5 mile commute, MPG was 82.0. During the commute, accessories consumed 0.724 kWh of electricity. The ICE had to burn extra gas to provide this energy. If I assume the energy content of each gallon of gas is 33.705 kWh and that the car is 33% efficient in converting the energy from the combustion of gas to electricity, then the car burned 0.724/33.705/.33 = 0.065 gallons of gas to produce the energy required to power the accessories. Had the accessories consumed no power, MPG would have been 90.4. The hit on MPG by accessories was approximately 9.5%.

Maybe it would be worthwhile if they would thoroughly inspect/test the car and fix anything that is out of spec. That would include updating all the computer modules to the latest calibration and applying all TSBs.

If they provided a regular gas Fusion, then for me, at least, it would cost about $25 extra per week for fuel. I currently spend less than $5 / week on fuel. After two weeks, that leaves only $50 of the $100 left. The $100 cash wouldn't really cover the extra expenses and inconvenience for use of my car.

I would get regen by applying the brakes instead of from hill assist. I would expect very similar results.

I forgot to account for the kinetic energy of the car. I stopped at the bottom of the hill. That amounted to an additional 0.09 kWh of energy. I fixed my post above.

I used grade assist today to see how much energy I could capture in the HVB going down a hill. The hill was about 0.8 miles long with a descent of about 220 feet. I estimate the potential energy difference to be about 0.353 kWh (assuming the car and contents weigh 1900 kg). The car was traveling at about 40 mph at the top of the hill and I stopped at the bottom. The kinetic energy difference was about 0.09 kWh. The total energy generated by the motor was 0.355 kWh. So it converted 0.355 / 0.443 = 80% of the available kinetic and potential energy to electrical energy. The car reports the HVB charge increased by 0.308 kWh. Accessories required about 0.010 kWh of energy. Going back up the hill, the total energy output from the HVB was 0.710 kWh. Accessories required 0.008 kWh. The car reports the HVB energy decreased by 0.694 kWh. So it took twice as much energy to go back up the hill than was recovered going down the hill. The max power I observed to charge the HVB during the descent was -28.6 kW. The max power I observed coming from the HVB for the ascent was 32.3 kW.

The sensor for the car's engine temperature display is not really measuring the engine coolant temperature in EV mode. There is a separate cooling loop for climate control vs. the engine. The display is showing the temperature for the climate control loop. See the following post: http://www.fordfusionenergiforum.com/topic/1446-cold-weather-observations/?p=13029

I wonder how fast the ICE spins in deceleration fuel shutoff mode when providing negative torque to slow the car down. The generator must supply positive reaction torque in order for the ICE to transmit negative torque to the wheels to slow the car down. If the ICE is not spinning fast enough, the generator rpm will be negative. To supply positive torque, the generator will have to act as a generator to try and slow the rpm toward zero. But if the HVB is full, I don't think we want to do that. If the ICE is spinning fast enough, the generator rpm will be positive. Then the generator will have to act as a motor, consuming electricity from the HVB, to try and increase rpm for positive torque. I have not observed the generator actively supplying positive torque. I have only observed positive torque generated passively in EV mode due to friction and other forces. Ideally in EV mode, the generator is spinning freely with negative rpm. But friction and other forces in the generator result in a drag on this negative rpm trying to reduce it towards 0, resulting in positive torque. The resulting positive torque is more than I would expect and is purely a function of generator speed. It results in losses of 1.5 kW or more. I haven't quite figured out what is going on. The generator torque as a function of rpm is as follows, where y is the generator torque in Nm (positive) and x is the generator rpm (negative): y = -1.3x/2000, -2000 <= x; y = 2.5e-8x^2 – 0.0001x + 1, -2000 <= x <= -6000; y = x/6000 + 3.5, -6000 <= x It seems strange that torque is such a perfect piece-wise linear/parabolic function with round and non-arbitrary constants. It looks like the torque is being controlled by one of the control modules for some reason rather than spinning freely. This happens in EV mode in all gears.

That brings up an interesting question. How does the car implement deceleration fuel shutoff? From what I have read, the ICE is connected to the planet carrier via an overrunning, one-way clutch. So I'm not sure how the ICE could supply negative torque to slow the car down.

The following chart shows the power being supplied to the HVB during a 60 mile commute as a function of the car's speed. Negative power means the HVB is being charged. As you can see, during most of the trip, the HVB was being charged. A 240 V charger supplies about 3 kW of power to the HVB. The maximum power for charging the HVB is 35 kW during regenerative braking. So it did not matter whether the car was operating in positive or negative split mode, or whether the power flow screen said "Hybrid Drive" or "Charging HV Battery", during most of the trip the car was charging the HVB when the ICE was on. The motor supplied the majority of the electricity. If I compute the value for the MPGe threshold equation in the previous post, most of the time the threshold was below 140 MPGe, and a significant fraction of the time, indicative that it would be advantageous to charge the HVB.

I believe the answer to what happens in EV mode is here: http://www.google.com/patents/US20110263379 See paragraph 30. When the powertrain battery 12 is acting as a sole power source with the engine off, the torque input 18 and the carrier assembly are braked by an overrunning coupling 53. It states the planet carrier is braked.

Actually, if you go through the calculations, the MPGe threshold is: MPGe threshold = 33.705*v/(P*e), where v is the speed of the car, P is the power from the ICE in kW at the given speed when it is not charging the HVB, and e is the efficiency of the motor/generator. So plugging in the numbers from my previous post: MPGe threshold = 33.705 * 66 / (20*0.8) = 139, same as before, accounting for roundoff errors. This assumes the ICE is as efficient when generating the extra power to charge the HVB than when it is only generating enough power to drive the wheels. In general, that is not true, It may be more or less efficient when generating more power to charge the HVB.

Assume the car is going 66 mph on the freeway. At that speed, the ICE is producing about 20 kW of power and consuming gas at a rate of about 0.027 gallons/minute. So, the mileage is about 66/(60*.027) = 40.7 MPG. At that speed, the ICE should be running at a very efficient operating point. If we want to charge the HVB, the ICE will have to generate more power. The best we can hope for is that the ICE will be equally efficient when generating the additional power. Suppose the ICE generates 10% more power. If efficiency remains the same, it will use 10% more gas, i.e. 0.0297 gallons/minute. If the efficiency of generating and storing electricity is 80%, then after one hour, we will have stored 0.8*(10%*20) = 1.6 kWh of electricity. If we want the mileage of the car to be better if the car charges the HVB than when it doesn't, we need to exceed 40.7 MPG. We will have used 60*0.0297 = 1.782 gallons of gas after one hour. So we will need be able to travel 40.7*1.782 = 72.5 miles on that gas, i.e. we will have to go 72.53 - 66 = 6.53 miles with the ICE off using the energy stored in the HVB that was accumulated over the one hour the ICE was on. The equivalent gallons of gas for 1.6 kWh is 1.6/33.705 = 0.0475 gallons. We will need to get at least 6.53 / 0.0475 = 137 MPGe in EV mode going 66 mph to exceed an overall average of 40.7 MPG. The actual MPGe in EV mode going 66 mph is closer to 120 MPGe. The car cannot generate electricity and power the motor from the accumulated electricity efficiently enough to achieve higher mileage. At slower speeds, the situation will most likely improve. The ICE will be less likely to be operating at its most efficiency operating point, so charging the HVB would allow it to run at a more efficient operating point. In addition, MPGe increases significantly with decreasing speed.

It appears that given the current speed of the car and current power requirements (based on acceleration), the car is free to operate the ICE at any rpm and torque it chooses. If the ICE does not produce enough power, it will come from the HVB. If the ICE produces excess power, it is used to charge the HVB. This is very different from normal cars where the rpm and torque of the engine are highly correlated with the current speed and acceleration. I have observed this behavior in the winter when the car is warming up. Regardless of speed or acceleration, the ICE operates at a constant 1500 rpm and within a limited torque range. The car is free to jump to any location (within reason) that it wants to on the Engine Map that I have previously posted. For a given power output, it can choose to operate anywhere on the appropriate line of constant power (the curved lines shown on the Engine Map). So it is free to choose the most efficient operating point given the current demands of the car, something not possible with normal cars. Also, the current drive ratio of the car is determined as follows: E / W = (M+G)/3.55/W = (10.394*W+G)/3.55/W = 2.91 + G/(3.55*W), where the variables are defined as in the previous posts. So when the generator rpm is positive, the drive ratio is greater than 2.91 (low gear). When the generator rpm is negative, the drive ratio is less than 2.91 (high gear).

No. I have only used hill assist to go down hills at a constant speed. I have not generally applied the brakes with hill assist.

A schematic for the HF35 Powersplit Transaxle used in the Energi can be found here in this series of charts: http://www1.eere.energy.gov/vehiclesandfuels/pdfs/merit_review_2010/power_electronics/apearravt024_poet_2010_p.pdf

I suspect that the Positive and Negative Split modes of operation are equally efficient and there is no overwhelming reason to choose one over the other. In Positive Split Mode, the generator is consuming mechanical power and producing electrical power. The motor then converts that electrical power back to mechanical power. The generator steals power from the ICE powering the wheels, but the electric motor adds that power back to the wheels. If the generator and motor were 100% efficient, then the wheels are effectively receiving all the power the ICE is producing. In Negative Split mode, the roles of the generator and motor are reversed. Now the motor takes power from the ICE powering the wheels and generates electricity. The generator then converts the electrical power back to mechanical power which effectively adds the power back to the wheels. Again, if the generator and motor were 100% efficient, then the wheels are effectively receiving all the power the ICE is producing. In either case, the motor or generator generating electricity can generate more electricity than the motor or generator that is consuming it, and the excess power can be used to charge the HVB. So I'm not sure why in the MFT power flow screen, Positive Split mode is labeled as "Charging HV Battery" and Negative Split mode is labeled as "Hybrid Drive". Either mode can charge the HVB.

The most accurate data that I have indicates that m = 2.5432 and k = 2.53. So the equation involving RPMs is: 0.9948*M + G = 3.53*E

The following plot shows a clear relationship between generator speed (rpm) vs. the car's speed (mph). When the car travels at increasingly slower speeds, the generator speed increases in the positive direction. High positive rotation of the generator corresponds to low gear ratios for the ICE to power the wheels. When the car is traveling at increasingly higher speeds, the generator speed increases in the negative direction. High negative rotation of the generator corresponds to high gear ratios for the ICE to power the wheels. So we see a continuous shift in the gear ratio from low ratios to a high ratios with increasing speed. Every once in a while at the higher speeds, the car decides to charge the HVB and shifts to a lower gear ratio as evidenced by the cluster of markers corresponding to generator rpm near or above 0 around 65 mph. Otherwise, at 65 mph the car runs in "overdrive" with the generator rpm around -1500.