I am an new owner of a 2022 Prius LE. I have two operational questions concerning it. I have observed that when operating the vehicle in "B" (brake assist) driving mode if I turn on the radar controlled cruise control the indicator shows up on the dash but I cannot set the speed. It just won't. If I change the driving mode back to "D" then the speed will set. Is this normal SOP or is there a bug in the software? I can't locate in the owner's manual where it would talk about this. I have observed on the energy monitor screen on the dash when there is energy flowing from the battery to the electric motor and then to the wheels and there is no energy (arrow) coming from the ICE (internal combustion engine). I would like to know if the ICE is shut down completely or is it just at an idle. I have no engine speed indicator in the vehicle and the sound of the ICE is imperceptible when moving. I can hear the ICE start when parked and the battery needs charging. But when moving I can't tell. Anybody know? Thank you!
Yes, it’s normal. Owner’s Manual (PDF), page 333: ■ Dynamic radar cruise control with full-speed range can be set when ● The shift position is in D. [ . . . ] It could be either; the energy monitor screen shows an approximation of the major energy flows, not whether the engine is running. For a tachometer, you’d need to connect a diagnostic tool—or a device such as a ScanGauge display—to the DLC3 (OBD II) connector.
In 7 years - I've only used "B" mode twice. So - sorry, can't advise - but the book indicates that is probably norma.
Op's questions have been answered. But I can relate to this. I have not used "B" for a long time. I found out leaving enough space for the car in front of you, coasting in D provides enough regen braking to go down hill in most of my driving circumstances.
B mode does not offer the same benefits as it would in a full electric car in charging up the battery more. With hybrids the B mode is mostly for engine braking and slowing the car without using the brakes. In B mode when you leave off the gas- the gas engine revs up like downshifting a manual transmission car to slow it down with the engine. It is not something you want or need to use on a regular basis. To improve fuel economy, try using the pulse and glide technique as well as eco mode. Also light to moderate application of the brake pedal will engage regenerative braking putting energy back in your battery. Harder braking will apply the brake pads and dissipate the energy as friction and heat, rather than going to the battery. Use your energy guide to help coach you on understanding and improving your technique and efficiency.
Welcome to the chat room! Your ICE is completely off; in standby mode. NOT idling. Your car doesn't have a starter, like a conventional car. The series of electric motors in the transmission and electronic clutch performs this duty. Your 'red' energy monitor (arrows) is correct, whenever you see them, your ICE is on and active. Sometimes the red arrows doesn't show up when the engine first fires up for the day and is in warm-up mode; but the red arrows are accurate 99% of the time. You'll notice this in winter, when the engine is obviously running, yet no red indicator. After the ICE warm-up, the red arrows will always be there when the ICE is running. Hope this answers your questions. PS. The ICE doesn't always engage in B-mode; it's speed and how fast your picking up speed dependent. Whenever I'm crossing the Sierras; the car will regen first; If your still picking up too much speed, it'll then engage the ICE to slow the car even further. Dynamic cruise will disengage when you place the car into B-mode.
One more comment on "B" mode. The manual explains that it is meant to keep from completely filling the hybrid battery on long, steep descents. As a result, you regenerate less electricity and burn more fuel than if you left it in "D" and coasted or braked. "B" mode is the hybrid equivalent of downshifting in a gasser to avoid overheating the brakes.
