Daisuke Horiuchi is Chief Engineer for Civic WTCC Development at Honda R & D who has been responsible for the 1.6 L engine with turbo charger and direct injection system even before Honda’s official entry to the WTCC series in 2012, and still is in charge of the WTCC Project as its Development Leader.
The Civic WTCC chassis are designed, built and operated by JAS Motorsport, the Italian race team that has been Honda’s racing partner in Europe since 1998.
Having already participated in 10 races of 5 rounds in this season, it seems to be a good time to review how the development of cars and race performances have progressed so far, and to let our fans be informed of the essence of WTCC as well as some fierce contests fought behind the scene.
The engine for WTCC
“I would like to briefly talk about the engine for the World Touring Car Championship.
The power unit for the WTCC must comply with the FIA Super 2000 regulations. More precisely, the engine in the touring car arena, known as Global Race Engine (GRE), features a turbocharger and a direct injection system with a displacement of 1.6 liters.
Looking at the technical regulations, the power unit must have an in-line four-cylinder configuration. The direct injection system pressure is specified to be 200 bars or less. The engine revolution must not exceed 8,500rpm. The controlled turbocharger, sanctioned by the FIA, is supplied by Garrett. The boost pressure is specified to be 2.5 bars or less. The number of the turbo chargers allowable within a season per vehicle is limited to six. In addition to the minimum weight for the engine, which is set at 82kg or more, the rule book specifies the details such as the dimensions and weights of the pistons and connecting rods.
Only one engine is permitted to be used in a season per vehicle. When the unit replacement is called for due to technical issues and/or damage by the crash, the participant may be penalized.
Listening to what I have mentioned above, you may have an impression that no engine development is possible during the season. It is not permitted to modify the basic engine configuration. No fundamental changes/modifications to the powerplant are possible. Having said that, there are still rooms for adjustment and improvements. We are able to adjust and fine-tune the control strategies of the turbochargers, anti-lag system (ALS) and fuel injection system. Also, the intake system upstream of the air restrictor as well as the exhaust system downstream of the turbocharger can be modified and customized. In such areas, we are constantly and continuously seeking for the excellence.
Now, let's turn the focus to the ALS which comply with the FIA Super2000 regulation. In general, turbocharged engines suffered from the turbo lag, which corresponds to the time required to resume the sufficient supercharging effect. The turbocharger's revolution goes down when lifting off and needs a short period of time to regain the high-speed revving for power boosting. The ALS minimizes the turbo lag and ensures a quick engine response to the accelerator pedal. The ALS valve opens in the lifting-off condition to direct the fresh air into the exhaust pipes where additional combustion occurs when the air meets the unburned fuel from the combustion chamber. The pressure caused by the combustion makes the turbine wheel spinning at speeds. Even during the lifting-off situation, the turbocharger maintains the boost pressure. We have to pay attention, however, to precisely regulate the amount of the unburned fuel and the fresh air to prevent the exhaust pipes and turbochargers from being overheated.
According to the technical regulations, we have to install the air restrictor with a diameter of 33mm to the intake manifold. Additionally, the maximum revolution allowed must be set at 8,500rpm. Since the amount of the fresh air, or oxidant, is limited by the restrictor, the WTCC engine generates the maximum power exceeding 300ps at around 6,000rpm. It is thus extremely important to optimize the combustion efficiency at the peak power speed. The traditional way of boosting power by increasing the engine speed doesn't make sense any longer.
Also of great importance is driveability in the extremely crowded competitive field unique to the WTCC. The engine should respond quickly to the driver's input and generate the right amount of power/torque. In order to ensure the characteristics, we finely and precisely adjust the engine management strategy including ignition timing for each racetrack.
As I said before, the engine's basic structure and configurations are not changeable after being homologated. The engineers in charge of the power unit development compete with one another by fine-tuning the intake/exhaust systems and controlling logics to find rooms for further improvement.”