Hybrid Honda Civic Introduced

In the over 100 years that the automobile has been around, the infrastructure of fossil fuel (petrol and diesel) stations has become so extensive that fuel supplies for the internal combustion (IC) engine can be obtained in virtually any place on earth. Thus, motorists remain ‘loyal’ to the IC engine even though it has been identified as one of the culprits of atmospheric pollution.

The alternatives – electric motors, fuel cells, even solar power – are round the corner and will certainly become commonplace within a few decades. However, issues of refuelling and recharging worry motorists because the resupply infrastructure is just not in place. Even in Malaysia, taxi drivers who use gas-fuelled (NGV) engines find refuelling a hassle; if it’s not the limited stations in the Klang Valley, then it’s the problems with inadequate pressure in the tanks.

The manufacturers understand such concerns and some, like Honda and Toyota, have come up with interim solutions in the form of hybrid powerplants which use an electric motor and a small petrol engine. Though not pollution free, these powerplants consume fuel at a much lower rate and also generate far less pollution.

Honda has made much progress in the hybrid powerplant field since the introduction of the Insight. The heart of the Insight is the Integrated Motor Assist (IMA) system – a combination of a super-efficient and super-light 1-litre Honda VTEC lean-burn petrol engine with an ultra-thin 10 kW electric motor – which gives an incredible fuel-sipping performance of 48 kms/litre (135 mpg) at a constant 60 km/h. This remains the best fuel economy achievement in the world for a production vehicle.

Although it seemed like the IMA system was mainly a demonstration of its advanced technology, Honda stressed that the technology would be used for other models and even motorcycles before long. In fact, Honda president H. Yoshino mentioned this point when he was in Malaysia a year ago to sign the joint-venture agreement with DRB-Hicom to form DRB-Oriental-Honda (DOH).

The Civic Hybrid
Now Honda has made good on the promise with an improved IMA system which powers a Civic sedan which will go on sale later this year. The new IMA System has Honda’s state-of-the-art lean-burn combustion technology with dual and sequential ignition, along with a newly-developed cylinder idling system that adapts the VTEC system to significantly increase the amount of electrical energy recovered during deceleration. These new features contribute to improved fuel economy.

Other technological advances provide increases in both motor assist system performance and Power Control Unit (PCU) efficiency. Combined with the Honda Multimatic S automatic CVT, this new system is claimed to achieve a combination of excellent drivability and superior fuel economy. Using the Japanese 10-15 test cycle as a basis, Honda says the Civic Hybrid can get over 29 kms/litre (82 mpg), putting it at the top of its class for 5-passenger, mass-produced petrol-engined vehicles. It also runs cleanly enough to be recognized by the Japanese Ministry of Transport as an Ultra Low-Emissions Vehicle (ULEV).

The New IMA System
The new IMA System, like the original used in the Insight, employs a petrol engine as its main power source that is assisted by an electric motor as the need arises. However, it offers improved efficiency over the previous IMA System on which its design is based. During acceleration and other times of heavy engine load, the motor assist system contributes considerable torque, resulting in both lower fuel consumption and powerful acceleration. At cruising speeds when engine load is lower, the motor assist system shuts down.

During deceleration, the motor converts the dissipated energy into electricity (regenerative braking). The newly-developed cylinder idling system reduces engine resistance during deceleration (formerly a problem with regenerative braking) greatly improving the vehicle’s electrical regenerative efficiency.

When stopping, at traffic lights, the engine shuts off automatically. It then restarts immediately when the driver steps on the accelerator pedal. This auto idle stop system contributes to both greater fuel efficiency and also lower emissions.

New 1.3-litre Lean Burn Engine
The new engine features the basic i-DSI configuration of two spark plugs per cylinder. This allows the fuel-air mixture to be made even leaner, for improved fuel economy. The rocker arms that open and close the intake and exhaust valves are configured for dual operation in either valve-lift mode or idle mode. Normally, they are engaged via a synchronizing piston. During deceleration, the synchro piston is housed inside the idle-mode rocker arm, disengaging the lift-mode rocker arm so that the valve remains at rest, effectively sealing off the cylinder. Three of the four cylinders can be shut down, achieving 50% less engine resistance during deceleration than the present IMA System.

New Motor Assist System
The motor assist system is composed of an ultra-thin DC brushless motor, a nickel metal hydride battery, and a Power Control Unit (PCU). The new system employs a higher-output motor, a more efficient battery, and a lighter, more compact PCU that results in greater packaging freedom.

Improvements to the internal magnetic coils of the ultra-thin DC brushless motor, which boasts the world’s highest output density and practical efficiency, achieve 30% greater assisting and regenerative torque than the previous model – without increasing the size. A sintering diffusion bonding process is used to firmly fuse different metals together, allowing the most appropriate materials to be used in construction of the rotor to meet the different demand criteria for its inner section, which transmits torque, and its outer section, which is in contact with the magnetic coils. Strengthening the section that transmits the torque and increasing the magnetic-flux density results in higher torque output.

The efficiency of the battery modules has been increased, resulting in reduced energy losses. The battery, storage box and peripheral equipment have been made more compact, for an approximate 30% reduction in volume.

The lighter, more compact, more efficient PCU and battery have been integrated into a single Intelligent Power Unit (IPU) that can be stored behind the rear seat of a passenger sedan. Integrating the IPU allows the two cooling circuits previously used to be combined into one. Total volume of the PCU and battery has been reduced by 50%.