by Jim Kerr

2006 Honda Civic Hybrid
2006 Honda Civic Hybrid. Photos: Honda. Click image to enlarge

One of the new technologies presented to journalists this Fall at the Automobile Journalists Association of Canada (AJAC) annual Car and Truck of the Year test session was Honda’s new Civic Hybrid. The Civic Hybrid first entered the market as a 2003 model. Utilizing a four-cylinder gasoline engine and an electric Integrated Motor Assist (IMA), the Civic was a fine combination of economy and functionality. For 2006, Honda has used the introduction of a new Civic design to refine every aspect of the Hybrid technology to offer even better performance and economy than before. All this comes at a lower price too!

New features in this hybrid include the ability for the Civic to operate on electric motor propulsion only. To accomplish this, the VTEC engine design is used to deactivate all four cylinders by keeping the valves closed under some programmed conditions such as gentle acceleration from a stop or slow speed cruise up to 56 km/h. The electric motor, which is integrated into the engine flywheel assembly now powers the vehicle. The crankshaft on the gas engine still turns and the pistons still go up and down, but because all the valves are deactivated by the VTEC operation, no cylinders are firing and they place very little drag on the electric motor. I did try to drive the Hybrid so it would operate on electric only, but wasn’t able to verify its operation because I wasn’t able to duplicate the programmed operating conditions.

2006 Honda Civic Hybrid
2006 Civic Hybrid IMA Modes of operation. Click image to enlarge

The ability to deactivate all the cylinders provides another benefit. During deceleration, the deactivated engine allows all deceleration forces to go into the IMA, which now becomes a generator to recharge the battery pack. In previous designs, the gasoline engine provided some braking forces during deceleration, but now all forces are utilized by the IMA for improved efficiency. During a typical city drive cycle, the battery will remain nearly fully charged because of the frequent deceleration cycles of the vehicle. If the battery does become low on charge during highway cruising, the vehicle can be propelled by the gasoline engine and the IMA can be used as a generator at the same time to charge the battery.

2006 Honda Civic Hybrid
Click image to enlarge

The Civic Hybrid also has an “idle-stop” feature that temporarily turns off the engine to save fuel and minimize emissions when the vehicle comes to a stop. A green auto-stop light on the instrument display
flashes to notify the driver when the idle-stop feature is activated. As soon as the driver releases the brake pedal, the IMA becomes a starter motor to start the engine smoothly, quietly and immediately.

While accelerating and in most cruising conditions, the gasoline engine provides power and the IMA adds power as needed. A new flat wire design electric motor produces +80% torque and +50% power compared to last year’s model. Together, the IMA motor and gasoline engine produce 110 hp @ 6000 rpm, an increase of 17 hp over the previous generation.

Every aspect of the Hybrid technology was worked on. For example, the smaller 203 mm thick battery module is mounted behind the rear seat and has a 25% improvement in power output. The air conditioning compressor can now be operated by electric power, a belt driven by the engine, or both at the same time. Electric operation of the AC compressor keeps the car cool even when the engine idle-stop feature is activated.

2006 Honda Civic Hybrid
Click image to enlarge

Internally the gas engine has 8% less frictional losses compared to an ’05 Civic Hybrid. A grinding process is now used instead of honing for cylinder finish, reducing friction and retaining oil better. Overall, the Civic powertrain efficiency is up 10%, improving fuel economy from 4.9 L/100 km City last year to 4.7 L/100 km now. Highway economy is improved by 0.3 litre/100 km.

The Civic Hybrid is much more than just a hybrid powertrain. An electro-hydraulic brake booster provides power brakes during electric motor operation only. The Civic windshield angle has been reduced to improve aerodynamics. Lowering the windshield angle also required a complete redesign of the body structure and passenger compartment to maintain passenger compartment room. Overall, the Civic has 5% less
aerodynamic drag,

A lower price, lower emissions, more power and better fuel economy. None of the Civic Hybrid improvements have been individually huge, but when taken all together, the improved technologies provide a significant benefit for Hybrid drivers.

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