Generation 4 Prius Plug-In Hybrid-EV Conversion

[NAVITEL]

Greetings to everybody,

When transitioning from electric vehicle (EV) mode to hybrid vehicle (HV) mode, it has been consistently observed that there is a rapid decrease in EV miles by around 0.2 to 0.5 miles, despite the engine activating promptly. This outcome is unexpected, as one would anticipate the preservation or even a gain in EV miles during this transition.

 

In essence, my understanding was that once the HV mode is engaged, the electric vehicle (EV) miles remain fixed. However, I have seen a little decrease in EV range, and while the engine does partially replenish the lost EV range (about 0.3 miles), it never returns to the initial level achieved upon activating the HV mode.

I am inquiring about the normalcy of my present situation. Despite the lower temperatures, I am now able to get a full charge of around 43 miles.

I would want to express my gratitude in advance for any input that I may get.

[TechnoTrailblazer]

Greetings,  

This phenomenon may be considered typical and expected due to the operational characteristics of the Toyota hybrid system. Even while the engine is operating, the system relies on electricity from the battery to sustain the gear ratios required for propelling the vehicle. This phenomenon is seen in all Toyota hybrid vehicles.
In the event that the traction battery is completely depleted, leaving it devoid of any energy, the vehicle will be rendered inoperable. When transitioning from electric vehicle (EV) mode to hybrid electric vehicle (HEV) mode, there is a little decrease in the average electric vehicle range.
There is no cause for concern.
Take pleasure in your automobile.

[KOOLCAR]

I have not seen this phenomenon occurring in any of the Prius vehicles that I have owned. I will exercise vigilance during future instances of operating my automobile in electric vehicle (EV) mode, particularly inside urban areas. I am interested in knowing whether other individuals who own a Prius have seen this phenomenon.

[Rudy7831]

Is it accurate to say that when the button is pressed to transition from electric vehicle (EV) mode to hybrid vehicle (HV) mode, there is an instantaneous decrease in the estimated range? The presence of the aforementioned feature is not observable on my Prius PHEV.

Upon observation, it is noted that when the engine is in an inactive state and has reached a low temperature, the act of transitioning to high voltage (HV) mode often results in an instantaneous engine start. However, it seems that the engine does not actively provide power to propel the vehicle, but rather engages in a gradual warming process. When the accelerator is depressed, the predominant operational mode of the vehicle seems to be electric, as shown by the auditory and tactile sensations, with little or negligible engine reaction.

During this time frame, it is observed that the electric vehicle (EV) range experiences a decline similar to that experienced in EV mode. However, after a brief period of one to two minutes, once the engine has reached an optimal operating temperature, it exhibits a significantly enhanced response. Consequently, when the accelerator is engaged, the engine promptly reacts to the driver's demand. Over a duration determined by the prevailing speed and conditions, the vehicle gradually replenishes the battery, thereby restoring the charge level and EV range to approximately the same level as prior to the transition to the hybrid (Hv) mode.

The rationale for this practise may be attributed to the dual purpose of engine warming and catalytic converter heating. The engine requires warming to facilitate optimal performance, while the catalytic converter necessitates a high temperature for efficient operation and pollution control. The Prius vehicle prioritises the use of its battery over the engine in order to decrease emissions during the first warming phase.

In instances when the engine has been operating in hybrid vehicle (HV) mode over the course of the trip, resulting in elevated temperatures throughout the system, transitioning from electric vehicle (EV) mode to HV mode prompts a quick response from the engine. Consequently, the delay and subsequent decrease in EV range often seen during this transition are not observed.

However, it should be noted that even while operating in HV mode, the estimated electric vehicle (EV) range may fluctuate by several miles or more due to factors such as speed and driving conditions. Especially at lower speeds when the power need is insufficient to engage the engine, the vehicle will continue to function only on the electric motor for an extended duration, relying on the battery for power. Eventually, when the speed or power demand prompts the engine to activate, it will recharge the battery to restore its charge level.

[NAVITEL]

Thank you for your insightful response. I have seen that my observations align well with your analysis. However, I am puzzled about the marginal decrease in electric vehicle (EV) mileage. The decline in altitude is not abrupt; rather, it exhibits a steady reduction of around 0.3 to 0.4 miles over a duration of approximately 30 to 40 seconds. However, it is worth noting that under certain situations, as you previously said, a significant portion of the "losses" may be recovered.

The provided explanation about the observed phenomenon seems to be very insightful. It may be inferred that the Prius Brain has superior knowledge and understanding compared to human cognition.

There does not seem to be any discernible issues present.The battery consistently maintains its charge level without experiencing unexpected reductions, consistently displaying the same electric vehicle (EV) range as seen on the previous day.

I highly regard your perspective and express gratitude once again. I am open to receiving more insightful input from you and really appreciate it.

[NAVITEL]

I would like to express my gratitude to TechnoTrailblazer   for providing a coherent explanation. I am eagerly anticipating BhxTrev's insights on this matter. It is my belief that a little decrease in electric vehicle (EV) mileage is to be expected, contingent upon prevailing circumstances. Furthermore, the engine makes every effort to recover from this minor decrease. In general, it may be argued that using the battery's energy for a duration of at least 30 seconds, even during periods of engine inefficiency, yields a little increase in overall efficiency.

[NAVITEL]

It is accurate to state that the VW Golf GTE has the capability to override the computer system, so allowing the user to fully preserve the electric vehicle (EV) miles. Conversely, the Prius PHEV consistently prioritises actions that optimise overall efficiency with respect to the EV miles.

I anticipate that my assertions may be subject to correction by others in relation to this matter.

[KOOLCAR]

Based on my assessment, I have not identified any apparent issues.The battery consistently maintains its charge level without experiencing unexpected reductions, consistently displaying the same electric vehicle (EV) range as shown on the previous day.

No, the situation seems to be within the expected range, and the claimed electric vehicle (EV) range of 43 miles is commendable. In comparison, my Prius, which is a few years older, has an estimated range of around 36 miles.

It is important to note that as we transition into the Autumn season and temperatures begin to decline, the indicated range of electric vehicles (EVs) will progressively diminish. One should not be taken aback if the range diminishes to the 30s, and during the coldest period of the year, maybe even the 20s, contingent upon the weather and driving circumstances.

 

[nickoyster4]

Apologies for the misunderstanding, but I misinterpreted the title of this discussion topic. As my Prius lacks a plug-in feature, it is inherently incapable of providing any kind of input. It is likely that my age is a contributing factor.

[NAVITEL]

Yes, everything is satisfactory. Thank you. Indeed, I have experienced a single winter season in the United Kingdom with my just acquired Prius PHEV. The estimated range of the vehicle decreased to around 35 to 36 miles, however it should be noted that I like to travel at a slower pace.

This morning, I completed a 2-mile trip to Morrisons using the electric vehicle (EV) mode. However, I switched to the hybrid vehicle (HV) mode for the last 1/4 mile when ascending a hill. Upon activation of the engine, the electric vehicle (EV) range experienced a decrease of about 0.6 miles. However, upon reaching the parking destination, the engine successfully replenished the EV range to its previous level and subsequently deactivated (entering EV mode).

There likely exists an efficiency rationale behind this design choice, whereby the programming of the system enables the utilisation of a small portion of electrical energy from the Battery during instances when the engine is activated.