Predictive efficient drive

3376 Views 7 Replies 2 Participants Last post by StatCoder, Sep 26, 2020

StatCoder

Discussion Starter · Apr 19, 2020 (Edited)

Predictive efficient drive*1, 2, 3
*1:Vehicles with hybrid system
*2:This function can only be used in the mainland U.S.A. It cannot be used in other states and territories, including Alaska and Hawaii.
*3:Refer to the “OWNER’S MANUAL”.

The system operates based on the driving situation and traffic information to enhance fuel economy.
The predictive efficient drive function can be turned on/off. (P.117)

Predictive deceleration support
The system automatically stores and registers support points where the driver always decelerates or stops based on pedal operation and the vehicle speed of the driver.
The registered points are shown on the map as icons for use as predictive deceleration support points.
When the position of the vehicle approaches the registered point, the icon changes to an emphasized icon.
Depending on the system or driving situation, the engine brake amount increases after releasing the accelerator pedal.
As a result, the battery charge amount can be increased when decelerating or stopping the vehicle to enhance fuel economy.

■ Predictive deceleration support Example: 7-inch display
Reference operation range
●When the vehicle approaches to predictive deceleration support points registered in the navigation system, the “Reference operation range” of the ECO Accelerator Guidance (P.104) on the multi-information display will be turned off to encourage the driver to reduce excessive acceleration.
●The engine braking force will be increased according to the driving conditions to more efficiently charge the hybrid battery (traction battery) after the accelerator pedal is released.

Predictive SOC control
The system reads the road and traffic conditions ahead to efficiently control the charging and discharging of the hybrid battery according to the actual driving situation.
The capacity of the hybrid battery is limited. When it is fully charged, regeneration cannot occur, and when the battery is depleted, it may be forcibly charged by the engine. The system predicts these situations to adjust the battery charge level in advance, effectively utilizing the battery.
●The system operates when starting route guidance and the position of the vehicle is along the guided route. (The system does not operate in parking lots, etc.)
●When multiple destinations are set, the system will continue to operate to the last destination.

■ Predictive SOC control
The following types of control are performed based on data such as road and traffic information during route guidance by the navigation system to help ensure that the vehicle efficiently uses electricity.
●When there is a long downhill slope along the route, the system reduces the hybrid battery (traction battery) level before reaching the slope to help ensure charging capacity for regenerative braking while traveling downhill.
●When traffic congestion is predicted along the route, the system helps ensure a certain battery level before reaching congested roads to reduce the frequency of starting the engine to charge the hybrid battery (traction battery) due to low battery levels.

This system seems to have two separate components.

The deceleration support stores nav points where the driver always decelerates or stops and shows them on the nav display. It increases engine braking when the accelerator is released to increase battery charge to be used for acceleration. So, it's trying to predict whether you are lifting your foot off the accelerator because you are coasting or whether you are slowing/stopping.

The SOC control uses route guidance to reduce charge level before long downhill slopes and increase charge level before reaching traffic congestion. I would assume this might not work if you just use Waze or Google Maps for navigation. It says "based on data such as road and traffic information during route guidance" so, perhaps, it doesn't always need your destination and can make some decisions based on the road you are traveling on. The battery only has a capacity to power about a half-mile of EV-only driving so it shouldn't need information about your route more than a mile or two ahead, right?

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lloyd123

· #2 · Apr 19, 2020

StatCoder said:
The battery only has a capacity to power about a half-mile of EV-only driving so it shouldn't need information about your route more than a mile or two ahead, right?

Maybe I'm misunderstanding what you mean by the "EV-only" part but I think that the system can use this extra battery charge garnered by the PED to also help power the Highlander by supplementing the gas engine use thus reducing load on the gas engine and improving fuel efficiency - not just in electric only mode. Possibly could be done either before a long downhill stretch to help make room for the upcoming charge or after the long downhill stretch depending on up coming terrain.

I already have a number of these deceleration green icons on my map where I always use the brakes around town.

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StatCoder

Discussion Starter · #3 · Apr 19, 2020 (Edited)

I’m just wondering how much it needs to have your route entered into the stock nav. I use Google Maps so presumably the NAV will not know my route. Can it still predict that I’m coming up on a long downhill or coming up on traffic?

I guess I’m trying to quantify how much it really needs to predict if the battery can’t store that much charge. If 100% EV gets you a half mile then does 50% EV get you a mile? It probably doesn’t need to know my route to make a guess as to what road I’ll be on a mile from now. In other words, will you get better gas mileage if you always enter your destination into the nav?

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lloyd123

· #4 · Apr 19, 2020

StatCoder said:
I’m just wondering how much it needs to have your route entered into the stock nav. I use Google Maps so presumably the NAV will not know my route. Can it still predict that I’m coming up on a long downhill or coming up on traffic?

I guess I’m trying to quantify how much it really needs to predict if the battery can’t store that much charge. If 100% EV gets you a half mile then does 50% EV get you a mile? It probably doesn’t need to know my route to make a guess as to what road I’ll be on a mile from now. In other words, will you get better gas mileage if you always enter your destination into the nav?

This explanation of the Lexus PED - I assume the same as the one in the Highlander - says it requires the driver set a destination in the navigation syytem.

Lexus UX250h to feature Predictive Efficient Drive

The sophisticated control system requires the driver to enter a destination. Then, using navigation data on the route ahead, plus satellite traffic information, it activates a predictive eco drive algorithm to mix gasoline engine operation with the hybrid’s electric drive for maximum efficiency. The computer continuously analyzes the route, looking for opportunities to maximize regenerative braking; where it sees them, it switches to electric drive operation at the appropriate time.

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lloyd123

· #5 · Apr 19, 2020

Also found this that says it will predict up to six miles ahead

2019 Lexus UX Explained – Video

Predictive State of Charge (SOC) control for the hybrid battery is a world-first technology that functions on both downhill roads and in congested traffic. Operating when the UX is following guidance from the navigation system, it will predict the route for a distance of up to about six miles (10km) ahead.

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StatCoder

Discussion Starter · #6 · Apr 19, 2020

That clears it up quite a bit. I'm in the habit of putting every trip into Google Maps to avoid the occasional bad traffic jam caused by a crash or construction. It's too bad that SOC system can't get route information from Apple or Google Maps to make things a little more efficient.

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lloyd123

· #7 · May 3, 2020

So in order to optimize your fuel economy it would make sense to always input your destination even if it's a place you've been to a million times and could drive to blindfolded - just turn off the audio navigation prompts to avoid that aggravation.

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StatCoder

Discussion Starter · #8 · Sep 26, 2020 (Edited)

Of the 8 bars of battery level, mine seems to hardly ever get 2 or 6. This makes a lot of sense from a battery life standpoint as these batteries last longer if they are not charged or discharged fully. I’m skeptical that the PED system would be able to do much for fuel efficiency using only half of the battery capacity to store energy. My impression is that this capability really only is useful for plug-in hybrids with much larger batteries and EV ranges of more than a couple miles.

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