honda jazz hybrid fuel consumption

[dfconnolly]

Hi all Hybrid owners

I continue to run my spreadsheet inputting fuel amounts and mileages between fill ups.

A lot of my journeys are I suppose relatively short (less than 10 miles) and I have noticed that the true mpg has plummeted during winter weather. I'm now experiencing low 50's versus the top end 50's during the hottest weather in the summer.
Overall I have now completed 8849 miles on 731.2 litres of petrol which equates to an overall 55 mpg, I also observe that the digital display optimistically always over states by about 4 mpg so its only relatively indicative and in no way should it be considered as accurate.

I think it would be useful if all folk can indicate the typical length and driving style of their journeys when quoting hybrid mpg as well as time of year. I had my car serviced in September (1st one) and allied to the colder weather the mpg fell from my best summer high of 63.4 to Winter worst of 47.8 .............and I am very light footed in ECO mode!

I can't wait for the warmer weather to come along,.......... written as I'm looking at the snow falling with 6 inches already down and Hybrid snugly parked in the garage..................roll on Summer!

[eagle123]

I always take mpg figures with a pinch of salt, knowing that manufactures achieve these figures on a rolling road.

Real world figures may not match the ones quoted, and there various factors like driving style, short runs, weight too much clutter in the car, tyres being underinflated, and others not mentioned like even the wrong tyres,

[John Ratsey]

My Hybrid has averaged 58.1 mpg over 6800 miles. I try to be very light-footed and always use ECO mode and tend to potter along the motorways in the low 60s conscious that the Jazz's spacious and good visibility cabin isn't very aerodynamic. Equally, I try to avoid short journeys unless absolutely necessary.  I've got a long trip around Scotland scheduled for a month's time which contains a lot of the driving conditions where the hybrid system thrives.

John

[guest3880]

M.
Perhapsy sister in law has a honda jazz hybrid purchased new in september 2012.The car is driven carefully and has only done 700 miles so far but the fuel consumption is dissapointing at 42=43mpg= my own 2009 ex 1.4 i=shift which is briskly driven is returning as much.Perhaps the fuel consumption will improve as the miles mount?

[John Ratsey]

That is extraordinarily low for the hybrid and I would wonder whether the system is working properly. How is the mpg being measured (actual fuel and miles or computer (which is usually optimistic))?

We have another thread http://clubjazz.org/forum/index.php?topic=3019.msg20535#new which specifically discusses the hybrid fuel consumption.

John

[Alan]

Are you saying that this car has only done 700 miles in 7 months if so that is less than 2 tankfulls of petrol, I doubt if the engine has ever fully warmed up to obtain a proper working temperature let alone obtained maximum working efficiency, all factors that would affect fuel consumption.

[guest3880]

Although the car is not used very often, when it is used it does trips of 60 plus miles which include both A road and motorway running so I believe it will be properly warmed up.

[John Ratsey]

Is the mpg as indicated by the car's computer or calculated from fuel used?

If the latter then I would check the records of fuel bought and the calculation of mpg (note that an imperial gallon is 4.54609 litres - some calculators use the smaller US gallon which will give you more gallons).

The computer will give different mpg readouts for the A and B odometers. I reset my B odometer on each refill so I get a better indication of fuel consumption for the current driving conditions (my computer is typically 3mpg high).

The Jazz's high shape gives relatively poor aerodynamics so it's not ideal for motorway driving. Nonetheless, it should give 55 mpg at 70 mph unless there's also a 30 mph headwind.

I would suggest that the B odometer is reset at the start of the next 60 mile trip so the reported trip mpg can be observed. Depending on driving conditions it should be nearer 60 mpg than 50 mpg. If not, get Honda to check the car.

John

[culzean]

sister in law has a honda jazz hybrid purchased new in september 2012.The car is driven carefully and has only done 700 miles so far but the fuel consumption is dissapointing at 42=43mpg= my own 2009 ex 1.4 i=shift which is briskly driven is returning as much.Perhaps the fuel consumption will improve as the miles mount?

the first question you know is gonna be asked is ' if the car has only done 700 miles in 8 months why bother with a hybrid anyway' - I would only have hybrid if I was going to do plenty of miles and could justify the extra cost of car against fuel savings (or lived in or had to travel into a congestion zone regularly), same with people who buy a diesel and only do low mileage (which is really bad for modern diesels with particulate filters). 

another thing is, how does the battery keep it's charge if it is left for long periods without the engine running ?  it may spend most of it's time recharging the battery and that won't help MPG.

Doing local mileage is never going to give you great fuel consumption, and what I have found with the MPG indication is that it is really sensitive to changes in driving style/conditions for first 50 miles and then (as it averages the present rate of consumption over more miles on the trip computer) it doesn't change anywhere near as quickly, and when you get over 200 miles on the trip the consumption figure hardly changes whether you are driving carefully or driving pretty briskly. That is why it is good advice to reset one of the trips every time you fill up ( personally i reset the 'A' trip and leave the B alone), then you can see quickly what effect different driving styles and conditions (temperature etc) have on the MPG.  The truth is that most petrol cars only do about 25mpg until they reach operating temperature (Diesels are a bit better).

[guest3880]

Having had the hybrid car out for a .longish run last sunday, we have now discovered that it did in fact average between 55 and 60 mpg.The reason she bought the hybrid was her choice as she feels she is doing her bit for the environment,and also the cvt transmission.

[John Ratsey]

I've just exercised my Hybrid with an 11 day trip from southern England, around various parts of Scotland and home again. Perhaps 25% motorway and the balance mainly on A and B roads. 2155 miles and 162.47 litres = 60.3 mpg (the car's computer claimed 63.7 mpg - optimistic as always). I was hoping for better: A similar trip in August 2011 gave 65.8 mpg. On this occasion we had an extra passenger for about half the trip. I was beginning to think that the car (and/or battery) isn't operating as efficiently as when almost new although I have to wonder if the culprit is the wind which was noticeable and predominantly northerly. Heading up the M6 / M74 into the wind resulted in 55.3 mpg while the trip home worked out at 64.1 mpg.  As I have previously hypothesised, a round trip with wind increases the fuel consumption since the aerodynamic drag is proportional to V squared.

Has anyone else got any updates on their Hybrid Jazz fuel consumption?

John

[culzean]

could be temperature as it makes a big difference to mpg when it is cold (last August was probably at least 10 degree warmer than the cold May  we had this year).

[Ozzie]

I have just done 32 miles with the fuel range showing zero !

Then filled the tank with 33 litres   

[John Ratsey]

And the miles remaining shown by the computer is no better. it seems to do a decent job of the forecast until the tank is half empty but then swaps to another algorithm so it forecasts 0 miles remaining when the gauge shows empty. I think the handbook somewhere does state that empty = 7 litres remaining but it's annoyingly conservative given the good mpg but perhaps they assume that the driver will be stuck for several hours in a traffic crawl just when they plan to refill.

[guest3761]

My summer fuel consumption on regular petrol (shell) is pretty steady at 57mpg on the display.  Tank to tank 55mpg is more accurate.  Mainly 3 mile journeys in the country, with an occasional (once or twice a month) 40 mile journey.   A little hilly, (Hampshire downs). Nearly 10mpg  better than my previous regular Jazz for the same use - so about 15-20% improvement, which is at the top end of expectations, I think.