Prius Reliability

Well, here in Winnipeg, Duffy's Taxi operates over 100 Prius as taxi's. Overall they claim *much* better reliability than the typical Ford Crown Vic Police Interceptor.

 

the hybrid tech is much like the maytag man. actual lifespan data has yet to be generated in the real world, of course.

oil pressure is brought up and the engine crank is spun before spark is applied to ease the strain. the prius doesn't seem to have major engine issues resulting in significant lifespan decreases, unless you don't take care of it.

 

Consult Consumer Reports' reliability ratings. The Prius is "much better than average" overall (all years), and "much better than average" in almost every category for every year. Specifically the two engine categories are MBTA for every year. The Prius has been around since 2001, long enough to have a lot of real-world data.

 

You shouldn't lump all hybrid cars into the same heap. The technology varies a lot from one manufacturer to another, and presumably the reliability does so as well.

As the others have stated, the Prius is very reliable. It has all of the normal reliability of a Toyota, plus the mechanical simplicity of HSD. The HSD replaces much of the mechanical mess of a normal car with sophisticated electronics and software. It's expensive to develop, but not likely to fail once the development bugs are out of the system.

To add to galaxee's comments, the Prius doesn't use a normal starter motor. Instead it has a big high-voltage motor that can easily spin the engine at speed. When the engine needs to start, the smaller electric motor (MG1) spins up the engine until it reaches running speed. Once the oil pressure is up, spark and fuel are started and the engine simply runs. There isn't really a starting cycle in the normal sense.

The Atkinson cycle engine on the Prius is basically an Otto cycle engine with different valve timing. Reliablity is about the same, except the Atkinson engine runs with a little more compression. This is offset by the easy life of a Prius engine. RPMs are limited, and the engine never has to idle for extended periods. Mostly the engine runs at an optimum speed or not at all. It's an easy life.

Regenerative braking does the same thing for the brakes. Most Prius brakes die a slow death from rust, not from use.

Tom

 

CR also rates the Prius as among those whose owners are most likely to buy the same car.

Another source of real-world data, and another that confirms the car's excellent reliability, is TrueDelta.

 

The Prius was rated the most reliable family sedan two years ago (I think it was Consumer Reports).

Baring poor design, which we can pretty much discount by now (the current Prius engine has been used for 5 years now with no problems reported), any engines life expectancy is directly related to the power output. The Atkinson design puts out less power than an equivalent Otto cycle engine, so should last much longer. The Prius could be considered a high compression engine, but because of the valve timing is actually a low compression engine with a long exhaust stroke.

While the Prius is more complex than many "ordinary" cars, most of the complexity is in electronics, and electronics is very reliable these days. The Prius "transmission" is actually much simpler than most cars. Try rebuilding an automatic transmission some time.

 

I've only been to the dealer once in 75,000+ miles. I got a "check Engine" which turned out to be the pump for the inverter coolant, hybrid related, and fixed under waranty, no hassle. The original tires lasted over 67,000 miles and still had legal tread when I took them off. I thought our Subarus were the gold standard for reliability, but so far, the Prius is looking better than our beloved Subarus. As an aside, my wife's 117,000 mile Outback has been in the shop for over a week to fix an elusive oil leak. She is driving my Prius, and I am commuting 90 miles a day in my 88,000 mile Impreza. What bothers me, is that she is starting to like the Prius, and can't be bothered to get her keys out to open the front door (house), and rings the door bell to get in after work. Talk about spoiled!

 

One measure of reliability is the number of parts. In the case of the Prius, there are half a dozen control computers that provide intelligent actuation of engine, transmission, body and battery systems. The next effect appears to be a reduction in the number of parts and more feedback on vehicle performance. Often diagnosis comes from codes set by the control computers when they notice a problem. So we have fewer mechanical parts that are operated by control computers with the ability to tweak the car and keep it running. It seems to be more reliable and that is shown in the Consumer Reports data.

Since it is part of the normal operational scenario, the start/stop cycles have been optimized and tuned. For example, there is no 'starter gear' nor 'starter only' motor. This is a seamless part of the vehicle.

The 76 hp engine has the same engine block and many of the same parts as the 108 hp Otto version. This means there is less stress on the moving parts and that tends to improve reliability. It is also computer controlled including the throttle. You can stop on the accelerator but it won't blow itself apart.

GOOD LUCK!
Bob Wilson

 

Due to the aforementioned valve timing the engine runs with approximately normal compression ratio (effectively) but a higher expansion ratio than is usual. This is one of the factors contributing to it's higher than usual efficiency.