Index

1) Definitions and terms
2) Driving for MPG
3) Handling (for new owners)
4) Maintenance for MPG
5) Maintenance for Long Life

1997-2001 Model - NHW10 was first generation sold only in Japan but may be found in other Pacific countries.

2000-2003 Model - NHW11 second generation known as 'Prius I' in GreenHybrid.com mileage database. Also called 'Prius Classic.' It has a small rear spoiler that reduces drag at highway speeds.

2004-current Model - NHW20 third generation known as 'Prius II' in GreenHybrid.com mileage database. A hatchback without a rear spoiler.

ICE - internal combusion engine. On Prius, a 1500 cc, Atkinson engine with extended intake valve openinig to reduce compression ratio to 8:1 while expansion ratio remains 13:1.

MG1 - motor generator one built into the transmission provides engine starting, non-moving electricity and balances the engine torque in the electronicly controlled, constant velocity planetary gear (CVT).

MG2 - motor generatore two built inito the transmission providies forward traction, regenerative brakinig and reverse gear.

PSD - power split device is the planetary gear that couples the engine, MG1 and output drive train feeding the final reduction gears and MG2.

pulse and glide - a type of high mileage driving that involves accellerating to a target speed and then gently feathering the throttle to let the car coast down to a minimum speed with the ICE off. In one controlled test, an NHW20 and team of drivers achieved 110 MPG over a 14 mile loop.

stealth mode - to drive on electric only power. The NHW20 models can be modified with an electric vehicle mode switch. In all others, this is achieved by low speeds and gentle accellerator pressure.

transaxle - the combination transmission and differential in the front-wheel drive Prius. Attached to the side of the ICE, it houses MG1 and MG2 and has output shafts for the front wheels.

Try to preserve vehicle momentum instead of regenerative braking and startup: brake early and coast to 'stop lights' just as it turns green; modest speeds; follow but do not tailgate large profile vehicles.

In cold weather, use a 'warm-up' route at low speeds if possible before higher speeds. The 'warm-up' route is long enough if the engine 'auto-stops' at the last stop sign or liight. Warmer weather can use a shorter 'warm-up' route.

When approaching destination, use 1-2 mile electric only or 'stealth mode' to maximize trip MPG.

Try to 'chain' trips to minimize cooling between each destinataion.

Miniimize speeds into a headwind or try to follow large vehicles without tailgating.

Keep your weekend 'chore' MPG separate from your standard, weekly 'commute' MPG by topping off Monday morning and Friday evening.

Techniques that improve commute MPG need to be tracked as single variable changes.

Use cruse control, if comfortable with it, to minimze fuel wasting variations.

In summer, park where it will be shaded and in winter, in a sunny place.

Back in to park to drive off when you start.

The fuel tank has a flexible bladder to minimize gas fumes but this means: (1) it is not terribly accurate, (2) sometimes the calculated and displayed MPG can be off by more than 5 MPG.

The mechanical brakes are quite ordinary because the regenerative braking is handled in the transmission. Because of regenerative braking, your brake shoes tend to last 3-4 times longer than ordinary brakes.

The engine oil is just like any car and easy to change yourself or at discount places. Just insist that they not overfill it. Have them take out the excess until they do it RIGHT or you'll pay in lower mileage.

Get a tire gage and/or fill with nitrogren. Keep the tires as hard as possible, 42/40 works for most tires but always ask. The front tires need to be 2 psi harder for proper handling and best ABS operation.

The "B" mode is used for additional engine braking going down long, mountain grades. You have to press the button to move it into to "B" and can do this will driving. When done, just move it back to "D" for better MPG.

Keep tires at maximum with 2 PSI more in front than rear for better handling. Stock tires are often run at 42/40. Recheck pressure at least every month with a trusted tire gage. Reportedly nitrogen filled tires may not require monthly pressure checks.

Keep ICE oil at 3/4 between 'empty' and 'full' to minimize ICE splash energy losses. Synthetics are OK but we lack empiricial data comparing Toyota oil and 3d party synthetics.

Check transaxle oil early and replace if contaminated or discolored. There is an experiment with Amsoil ATF but no results yet. NHW11 uses "Type T" and the NHW20 uses "Type W".

In high humidity and corrosive areas, check the brakes frequently to avoid binding and uneven rotor wear problems.

Make sure after-market electrical devices can not drain the auxillary, 12 VDC battery from unexpected loads. Normally the cigarette lighter is "OFF" when the ignition is in lock position.

When jumping a dead 12 VDC battery, check and double check the polarity since a reverse connection can fry most of the expen$ive control computers instantly.

A Mazda Miata battery can replace the 12 VDC battery provided an adapter terminal kit is gotten for the smaller sized terminal, Japanese connector.

Keep the filters clean or replaced frequently.

Fleet reports indicate the NHW11 models may need to have steering assembly checked frequently.

In cold weather, an engine block heater can save nearly 100 ml. of gas due to faster warm-up.

Use 'rain-out' to minimize use of windshield wipers and keep rear view mirrors clear.

Check the throttle assembly every 50,000 miles for butterfly soot.

If you are down to your last key or key-fob, buy a replacement from Ebay and 'teach' the new key or key-fob to your car. If you lose the last key or key-fob, you'll have to replace the $1,600 hybrid vehicle control ECU.