In the petrol engine models, the new Honda Civic is a brilliant car – frugal on fuel, roomy inside, good in ride and handling. So what’s it like when you add a fourth generation Honda hybrid battery electric system?

Well, the answer is not unambiguously positive.

Yes, the hybrid Civic gets excellent fuel economy – clearly better than the more expensive diesel competitors that we’ve driven like the Peugeot 307 HDi – and at AUD$31,990, is substantially cheaper than the base model Toyota Prius over which it has more equipment, especially in the number of airbags.

But in the driving – especially in city conditions – it is well behind the Prius and the calibration of some aspects of the electric system had us quite puzzled.

The main problem is intrinsic to the Honda system. Unlike the Prius, which mounts its electric motors in what can be termed the gearbox, Honda’s Integrated Motor Assist places the electric motor on the end of the engine’s crankshaft. Simply put, the electric motor cannot propel the car forward without the petrol engine also turning. In this latest Honda approach, the engine’s valve openings can be configured to effectively decompress the engine, thus enabling the electrics to power the car in certain narrowly defined conditions without having to push against engine compression. But in the vast majority of cases, if the car is moving forward, the petrol engine is running.

That might not sound like a big deal but step out of a Prius, where - like the Honda - the engine stops when you stop, and the Civic’s petrol engine seems to be drinking fuel on dozens of occasions when the car should be drifting forward on electric power alone. The best example is in a slow moving traffic jam. In these conditions, the Prius petrol engine will stay off for hundreds of metres at a time. In the hybrid Civic, each time you lift the brake pedal (even if it’s just to roll down a slight incline), the engine restarts. The constant engine on, engine off, engine on, engine off is irritating and can at times feel quite jerky. In this respect the system is light-years behind the Prius, and it could be argued, even inferior to the original IMA system in the manual transmission 2001 Insight which at least allowed you to roll forward with the engine off.

The calibration of the electric assist is also a little odd. Even when the high voltage battery is full (battery level is shown on a dash gauge), the degree of electric assist that occurs at small throttle openings is subdued. So as an example, if you’ve driven down a long hill and the battery has been topped-up through regenerative braking, you’d then expect to see better fuel economy as the system actively use up that stored energy. But the Civic has none of that: it’s frustrating to see the instantaneous fuel consumption gauge at the maximum of 12 litres/100km during acceleration – and the electric assist gauge showing that little or no electric power is being drawn from the full battery to help the car along. The system is also calibrated to keep the high voltage battery level quite high - so there’s not a lot of room left for power storage from regenerative braking.

We’re sure Honda engineers must have very good reasons for these calibration decisions, but they’re not clear to us.

But what is clear is the way they’ve calibrated the continuously variable transmission (CVT). Generally it keeps engine revs low – below 3000 rpm. This means that as you drive around the city normally, the Civic Hybrid is very quiet and refined. Apart from tyre noise on some surfaces, in these conditions the car has NVH (noise vibration harshness) of a car many classes more expensive. And it must be pointed out, this scenario represents the majority of driving.

But floor the throttle and the tacho leaps to 3000 rpm, the CVT then allowing revs to slowly rise to the redline. Trouble is, the engine has by now become loud and harsh, with tinny resonances making themselves felt as the tacho needle moves slowly around the dial. The contrast from absolute smoothness and quietness to an unbecoming shriek is quite amazing. At high revs the 1.3 litre four cylinder engine simply doesn’t feel like a Honda.

Although in the Prius revs also rise with load, the result is far more refined.

So what’s the fuel economy like? We recorded 5.5 litres/100km over a variety of driving conditions, although they were biased a bit towards the highway. That’s a little worse than the Prius, but still excellent economy in anyone’s language. As a direct comparison, it’s 24 per cent better than we recorded in similar conditions in the current 1.8 litre VTi Civic, and much better than the previous model Civic Hybrid in which we achieved 6.3 litres/100km.

The available performance depends a fair bit on how much noise you want: when driven at full throttle, it’s quite adequate (although never grunting-fast-off-the-line like the Prius) and when driven gently, it can paradoxically feel more torquey. The combined power and torque figures of the electric motor and petrol engine are 85kW and 170Nm respectively.

Getting away from the driveline, how’s the rest of the car? Well, it’s excellent. Inside the cabin you’ll find a welcoming and roomy space. Unlike some much more expensive European cars we’ve recently sampled, the Civic shows thoughtful, well executed design. The door pockets – all four of them – are large; there are compartments everywhere in the dash and centre console; and the seats – newly designed for this model – are wide, comfortable and supportive. However, if you’re a driver of just the right (wrong) size, your left knee will annoyingly touch the handbrake lever rather than the smooth side of the console.

The steering wheel is height- and reach-adjustable and the driver’s seat is height adjustable. The instruments are arranged in two binnacles, one above the other. The lower contains a centrally-mounted analog tacho and electronic bargraphs for electric assist/regeneration and high voltage battery level. This space also houses the warning lights. Directly above, the second binnacle mounts a large digital speedo and electronic bargraphs for fuel and coolant temperature (the latter switchable to instantaneous fuel consumption). These displays are easy to read (even through sunglasses) and the speedo is especially effective, being only a tiny eye movement away from the road. All the controls are clear and work with a quality feel.

The equipment level is excellent – six airbags, dual trip fuel consumption readout, cruise control, ABS - and the 6-stack MP3 CD sound system is very good in this class. Electronic stability control – while offered in other markets - is not available.

Step into the back through the wide-opening rear doors and there’s plenty of knee and foot-room, although for the very tall, headroom is limited. The boot is large but the boot opening is only class average and the rear seat does not fold. The boot also doesn’t have an external unlocking handle and there’s no boot unlocking button on the key remote.

The Hybrid has some aerodynamic tweaks over the other Civics, reducing the drag coefficient of the body from 0.31 to 0.27. These changes include flush alloy wheels, a bootlid spoiler and additional engine and underfloor covers. While Honda doesn’t say so, the ride height also looks a little lower than other Civic models.

So what to make of this car?

In some conditions the Civic Hybrid is quite brilliant. A longish daily freeway or highway commute would see it in almost its ideal environment – refined, comfortable, capacious, adequately quick and extremely frugal on fuel. But in other conditions the Civic Hybrid is disappointing. A daily dose of slow moving city traffic mixed with the need for assertive lane changing would find the Civic Hybrid driver frustrated at the noise and the engine on/off cycling. Fuel economy in these conditions would also considerably worsen.

From the perspectives of cost, fuel economy, interior space and features, the Civic hybrid is an excellent car. But Honda’s hybrid system needs more sorting – there’s nothing wrong with the petrol/electric philosophy but its execution requires refinement.