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Honda Civic Hybrid 2009: Engine mechanism

14 May 2010 - 04:05 pm

When people comes to have two or three choices at the same par to buy new car, most of them are first look at engine power followed by price and lastly "It is worth to buy this car?". Comparing Honda Civic Hybrid against Civic 2.0L is probably not fair unless you only thinking about fuel efficiency, then HCH is the winner.

Most probably is comparing against Civic 1.8L which consume less fuel than 2.0L and more cheaper than HCH. But if you still consider of having HCH with price of same to Civic 2.0L but only get 1.3L engine, then keep continue to read this.

The concept

In engine development today, one factor that contribute to fuel saving is the engine capacity. Normal concept, large capacity engine produce more power but consume more fuel. The main idea to lower fuel consuming is by making an engine with small capacity which is 1.3 L engine in HCH.

But small capacity engine produce small power. So the idea concept start to develop here. There is no different between Civic 2.0, 1.8 and Hybrid in car's body size and this will burden the engine to carry such a large weight.

Here the technology was injected. By producing or supplied another source power to help current engine will make it enable to be drive on as normal car. Integrated Motor Assist or IMA is attach with gasoline engine. When both sources were combine together it produce the almost same horse power with 1.8L.


Above is just a simple concept. But there are much features that implement in HCH engines and you should know. In making an engine to be more efficient handling fuel consumption, HCH engine is using i-DSI based structure engine development.

i-DSI based engine structure

i-DSI (intelligent Dual & Sequential Ignition System) is a technology of engine designation build up in 4 cylinders with specification of two valves for each cylinders (total 8 valves), two spark plugs for each (total 8 spark plugs) and have dual ignition activity to archieve complete burning of air-fuel mixed.

Although mixed fuel-air is completely burn during ignition phase, there probably can cause engine knocking when drive in high speed mode. So, we need another mechanism that can handle this such problem matter.

i-VTEC shifting mode cam profile

The most advance technology is inject once again. i-VTEC (Variable Valve Timing and Lift Electronic Control with Intelligent) is attach to HCH engine to make it have multi-mode engine profile.

The normal VTEC engine currently have 2 cam profiles which are "low mode" and "high mode". New i-VTEC engine have 3 cam profiles which are low, mid and high mode. But in HCH, 3 cam profiles stand for low, high and idle mode. In low mode, the ignition phase is contributing from two spark plugs. While in "high mode" only one spark plug is ignite to avoid knocking situation.

Another profiles is idle mode. During deceleration until car stop, in normal car the engine still running. Although it consume a little fuel but there is zero (0) mileage which lower your MPG. HCH have ability to shut down the engine during car stopped and re-activate when it need. To make it possible another technology must be attach.

VCM is coming..

VCM (Variable Cylinder Management) is currently being use in Honda Accord 3.6L. To archieve a very high fuel efficiency, VCM will handle all close and open valves depend on the situation. During acceleration, VCM keep all 8 valves open, activated all 4 cylinders. When the car start to decelerate, VCM closed 6 valves and make it only one cylinder to be activate.

Another three cylinders are in vacuum mode, prevent from losing power through burning fuel, heat loss and friction. During this time also, the kinetic energy (which is supposed to be convert to heat loss and friction) is captured by IMA.

All the kinetic energy then will convert into electrical energy and being handled by Intelligent Power Unit to be stored in NiMH battery. In simple word, it is charging the battery. When the car nearly or closely going stop, VCM will close those 2 valves balance, stop all ignition activity and shut down the engine. Now is idle mode.


By combining all of these features i-DSI, i-VTEC and VCM, Honda called it as 1.3L 3-stage i-VTEC engine integrated with IMA technology. In summary, HCH engine technology have built up with a lots of advance technology while 1.8L engine comprising i-VTEC technology only.

engine mechanism