Path: ...!feeds.phibee-telecom.net!2.eu.feeder.erje.net!feeder.erje.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Don Y Newsgroups: sci.electronics.design Subject: Re: Speed limiters Date: Sun, 7 Jul 2024 16:58:24 -0700 Organization: A noiseless patient Spider Lines: 42 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Injection-Date: Mon, 08 Jul 2024 01:58:27 +0200 (CEST) Injection-Info: dont-email.me; posting-host="1204b6b780de24b9cb690be0c57d3575"; logging-data="581961"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1948Julck4uMgOUX118vDIb" User-Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Cancel-Lock: sha1:IOva/mZbJVvKHdglz2NSS7W60Wc= In-Reply-To: Content-Language: en-US Bytes: 3098 On 7/7/2024 3:51 PM, KevinJ93 wrote: > On 7/7/24 9:57 AM, Don Y wrote: >> On 7/7/2024 9:08 AM, KevinJ93 wrote: >>> On 7/7/24 9:00 AM, Don Y wrote: >>> <....> >>>> Nothing for the cruise control touches the brakes.  It relies on the engine to >>>> slow the vehicle. >>>> >>>> There are newer "collision avoidance" systems that will actively brake >>>> if they sense you're approaching an object with which you may collide. >>>> >>>> Newer cruise controls will adaptively adjust speed to prevent you from >>>> creeping up the backside of the vehicle in front of you. >>> >>> <...> >>> >>> Many adaptive cruise control systems (but not all!) have full authority down >>> to zero-speed; they control the brakes as well as the throttle. >> >> This ---------^^^^^^^^^^^^^^^^^^^^^^^ is the difference between them and legacy >> "cruise control" systems.  It can only control the vehicle's speed to the same >> degree that a human can /with just the throttle/. >> >> In The West, it is not uncommon to find yourself driving through varying >> elevations (mountains).  Relying solely on the engine for braking often >> won't allow you to comply with the posted speed limits *or* "safe driving >> conditions". >> >> [OTOH, being overly reliant on the brake can lead to brake overheating and >> failure] > > My recent cars automatically increase engine RPM by changing gear to maximize > engine braking, in addition to using brakes if necessary. > > Some people find that disturbing to have the engine spinning at 4000-5000RPM > down steep hills. This is how we drive "manually" (manually forcing the automatic into a lower gear). But, it is distressing to have the car operating like this for a 20 mile stretch!